JP2001147452A - Optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the capacity of an optical element and to reduce the size thereof. SOLUTION: This optical element is provided with return waveguides 28 and respective second input/output ports P2 are equally distributed and disposed by one piece each in second regions R2 and third regions R3 across first regions R1 including first input/output ports P1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device,
The present invention relates to an optical element having a folded structure.

[0002]

2. Description of the Related Art Conventionally, there are optical devices (optical switches, optical multiplexer / demultiplexers, optical branching couplers, etc.) in the field of optical communication. In order to make this optical element compact, a folded optical element has been proposed. A folded optical element refers to an optical signal that is input and reflected by a reflective structure (for example, a reflecting mirror) provided on an end face of the optical element, so that the optical signal is reciprocated one to several times inside the optical element. After that, the optical device has a structure to output to the outside. A configuration example of this folded optical element is described in Document 1 (IEICE Technical Report PS98-3).
8, October 1998, pp. 61-65) and Reference 2 (Ph
otonic Switching, March 1987,
ThD4-1 to ThD4-3).

[0003] An optical element disclosed in Document 1 (hereinafter referred to as a "first conventional optical element") is a multiplexing / demultiplexing element utilizing surface acoustic waves. The first conventional optical device can confine a surface acoustic wave in a thin film provided on a waveguide in the first conventional optical device.
The wavelength division multiplexed optical signal propagating through the waveguide can be demultiplexed in a specific direction for each wavelength. Thereafter, the first conventional optical device separately reciprocates each single wavelength optical signal several times in the first conventional optical device and outputs the signal to the outside. As a result, for example, effects such as a reduction in crosstalk are obtained.

On the other hand, an optical element disclosed in Document 2 (hereinafter referred to as a “second conventional optical element”) is a completely non-blocking type q × q having optical switch elements arranged in a pyramid shape. An optical switch (q is a natural number). The second conventional optical element has q input ports, q output ports, and 2q dummy ports on the end face on the top side of the pyramid. In addition, a reflection structure is provided on the end face on the bottom side of the pyramid. For example, when an optical signal is input to the input port from the outside, the optical signal propagates through the group of optical switch elements, and is reflected by the reflective structure.
Again, the light propagates through the group of optical switch elements, and thereafter is output from the output port to the outside. During this time, by switching one of the optical switch elements, an optical signal can be output from a desired output port.

[0005]

However, usually,
The first conventional optical element can be used as a two-wavelength wavelength filter (a wavelength filter for demultiplexing a wavelength division multiplexed signal composed of two wavelengths), and the first conventional optical element is increased in capacity (for example, Is not possible because of its structure.

On the other hand, in the second conventional optical element, it is possible to increase the capacity by increasing the number of optical switch elements, but the number of dummy ports irrelevant to the input / output of optical signals also increases accordingly. Would. As a result, there is a problem that the second conventional optical element becomes large. Furthermore,
Since the total number of intersections between the waveguides included in the second conventional optical element is large, there is also a problem that the propagation loss of the optical signal increases.

Therefore, it is possible to increase the capacity,
There has been a demand for an optical element that can be miniaturized. Also, there has been a demand for an optical device having a structure capable of reducing the total number of intersections between waveguides included in the optical device.

[0008]

In order to achieve this object, an optical device according to the present invention has a first end face and a second end face facing each other. Also, 2n (n is a natural number) provided on the first end face and having a relationship of mutually inputting an optical signal to the optical element from the outside or outputting the optical signal from the optical element to the outside. ) First input / output ports and 2n second input / output ports. In addition, a reflection portion provided on the second end surface is provided.
An optical signal which is provided between the first end face and the second end face and which is input from the outside to the input / output port is reflected toward the direction of the first end face by the reflection surface of the reflection portion, and thereafter, , And a propagation path unit for outputting from a predetermined input / output port to the outside.

At this time, the second input / output ports are provided separately in a second area and a third area sandwiching the first area including the first input / output port.

Preferably, the number of first input / output ports is 2n (n is a natural number), the number of second input / output ports is 2n, and the second input / output port is It is preferable that n regions are equally distributed and provided in the second region and the third region, respectively.

According to such a configuration, each of the second input / output ports is provided equally distributed between the second area and the third area sandwiching the first area including the first input / output port. Therefore, by devising and patterning the waveguides included in the optical element, the total number of intersections between the waveguides can be reduced as compared with the conventional configuration (described later).
Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

Alternatively, there is provided a plurality of port block areas each including a first input / output port and a second input / output port. In each port block area, the second input / output port is provided separately in a second area and a third area sandwiching the first area including the first input / output port.

Preferably, the number of the first input / output ports is 2n (n is a natural number), and the number of the second input / output ports is 2n. The number of input / output ports is equal, the number of second input / output ports included in each port block area is equal, and in the same port block area, the second input / output ports are the second area and the third area. It is good to be equally distributed.

[0014] Even with such a configuration, in each port block area, each second input / output port is provided with the second area and the third area sandwiching the first area including the first input / output port. Since they are provided equally distributed in the region, the total number of intersections between the waveguides can be reduced as compared with the conventional configuration by devising and patterning the waveguides included in the optical element (described later). . Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

In practicing these inventions, the propagation path section preferably includes 2m (m is a natural number) intermediate ports, m folded waveguides, and a propagation path connection section. However, each intermediate port has a first end face and a second end face.
It is assumed that it is provided in a region between the end faces. Each of the folded waveguides has one end and the other end connected to each of the intermediate ports.
Connected in a one-to-one relationship, and in a plane including the above-described incident light signal on the reflecting surface and the reflected light signal from the reflecting surface, are symmetrical with respect to a line perpendicular to the reflecting surface, It has a structure folded back from the second end face toward the first end face. In addition, the propagation path connection unit connects the two intermediate ports connected by the same folded waveguide to each other.
It has a function of connecting to the first input / output port and the second input / output port.

With this configuration, unlike the configuration of the second conventional optical element, a dummy port irrelevant to the input / output of an optical signal is not required. Therefore, the size of the optical element can be reduced. In addition, by increasing the number of intermediate ports and folded waveguides and expanding the connection function in the propagation path connection portion, it is possible to increase the capacity of the optical element.

In carrying out the above invention, preferably,
Each of the folded waveguides connected to the intermediate port, which can be connected only to the second input / output port in the second region, passes through the reflecting surface from the intermediate port to the first waveguide.
To the intermediate port that can be connected only to the input / output port of the third region, and that can be connected only to the second input / output port in the third area. The connected folded waveguides each preferably cross each other once from the intermediate port to the intermediate port that can be connected only to the first input / output port via the reflection surface. . Each folded waveguide may be arranged substantially line-symmetrically with respect to the center line of the group of folded waveguides in a plane including the folded waveguide.

With this configuration, the total number of intersections between the folded waveguides can be effectively reduced as compared with the conventional configuration (second conventional optical device). Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

In carrying out the above invention, preferably,
The propagation path connection unit preferably has one of an optical switching function, an optical multiplexing / demultiplexing function and an optical branching / coupling function.

With such a configuration, the optical element becomes an optical switch, an optical multiplexer / demultiplexer, or an optical splitter / coupler.

In practicing the present invention, preferably
(2n) ² = m is preferable. However, the propagation path connection unit includes 2n 1 × 2n-type first sub-optical switches, and 2
Assume that n 1 × 2n second sub-optical switches are provided. Each first sub-optical switch has one end connected to the 2n first input / output ports in a one-to-one relationship, and the other end connected to m (= (2n) ² ) intermediate ports. And are connected in a one-to-one relationship. Each of the second sub-optical switches has one end connected to the 2n second input / output ports in a one-to-one relationship, and the other end not connected to the first sub-optical switch. m (= (2
n) ² ) intermediate ports are connected in a one-to-one relationship. In addition, 2n intermediate ports connected to the same first sub-optical switch and 2n intermediate ports connected to different second sub-optical switches are connected in a one-to-one relationship with each folded waveguide. They are connected in a relationship.

With this configuration, a 2n × 2n completely non-blocking optical switch can be formed. The complete non-blocking type optical switch is an optical switch that can always connect any free first input / output port and any free second input / output port regardless of other connection states.

In carrying out the above-mentioned invention, preferably,
The reflector preferably has a function of performing mode conversion between the TE mode and the TM mode in the optical signal reflected by the reflector. For example, the reflecting section may be constituted by a quarter-wave plate and a reflecting mirror.

With this configuration, the optical element can be replaced by T
A polarization-independent optical element that does not depend on the E mode and the TM mode can be obtained.

In practicing the present invention, it is preferable that another waveguide crossing a waveguide (hereinafter referred to as "outgoing waveguide") through which an optical signal input to the input / output port propagates until reaching the reflecting surface. The total number of waveguides is equal to the total number of other waveguides that intersect with the waveguides (hereinafter referred to as “return waveguides”) that propagated from the time when the optical signal was reflected by the reflection surface to the time when the optical signals reached the input / output ports. If not, it is preferable to provide a dummy waveguide that intersects with the outward waveguide or the backward waveguide so that the total number of them is equal to each other.

With this configuration, the propagation loss of an optical signal between any input / output ports can be made substantially uniform.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the size, shape and arrangement of each component are only schematically shown to the extent that the present invention can be understood, and therefore, the present invention is not limited to the illustrated example. .

[First Embodiment] First, FIGS. 1 and 2
With reference to FIG. 1, an optical switch (hereinafter, referred to as a “first optical switch 1”) which is an example of an optical
0 ". ) Will be described.

FIG. 1 is a configuration diagram for explaining an example of the configuration of the first optical switch, and is shown in a perspective view. or,
FIG. 2 is a plan view in which a waveguide is projected on a main surface of a clad layer constituting a part of the first optical switch.

The first optical switch 10 includes a waveguide 12 for transmitting an optical signal, a substrate 14 and a cladding layer 16 for confining the optical signal in the waveguide 12, and a waveguide for transmitting the optical signal (“propagation path”). The variable electrode 18 and the ground electrode 20 for controlling the refractive index, and the reflecting portion 22 for reflecting the optical signal in the direction of incidence on the first optical switch 10 (this configuration example). Then, it is referred to as a “reflecting mirror”.)
Equipped. In practice, the waveguide 12 is interposed between the substrate 14 and the cladding layer 16, but in FIG. 1, in order to emphasize the shape of the waveguide 12, the boundary of the waveguide 12 is indicated by a solid line, and The boundary line of the cladding layer 16 is indicated by a dotted line.

Next, the manufacturing process of the first optical switch 10 will be described.

In this configuration example, as the above-mentioned substrate 14,
A rectangular parallelepiped substrate having an electro-optic effect is used. Examples of the material of the substrate 14 include an organic material, a ferroelectric, glass, InP, and LiNbO3. On a main surface 14A of the substrate 14, a core layer (for example, non-doped InGaAsP (when the substrate 14 is composed of InP)) is formed by chemical vapor deposition (CVD).
Method) or by epitaxial growth. Next, the waveguide 12 is formed by, for example, photolithography.
Is formed on the main surface of the core layer, and then the core layer is processed by dry etching using the pattern. As a result, a core for the waveguide 12 is formed. Next, for example, the core (waveguide 1)
2) On the main surface 14A, a cladding layer 16 (in this configuration example, the same material as the substrate 14) is formed by chemical vapor deposition (CVD) or epitaxial growth until the same height from the main surface 14A is reached. Thus, the film is formed to have a uniform film thickness. Next, the variable electrode 18 is attached on the main surface 16A of the cladding layer 16. Next, the main surface 1 of the substrate 14
The ground electrode 20 is attached to the main surface 14B facing 4A. Next, the reflecting portion 22 is attached to one end face (second end face S2) of the first optical switch 10. Thereby, the first optical switch 10 is completed.

Next, the characteristic configuration of the first optical switch 10 will be described.

In this configuration example, the first optical switch 10 is
This is a 2n × 2n optical switch. That is, the first optical switch 10 has a plurality of (in this configuration example, 2n) optical signals that are mutually input / output to / from the first optical switch 10.
(N is a natural number) first input / output ports P1, and
A plurality (2n in this configuration example) of second input / output ports P2 is provided. In this configuration example, n = 1. Therefore, the first optical switch 10 includes P1A and P1B as the first input / output port P1, and P2A and P2B as the second input / output port P2.

Each of the first input / output ports P1 has a central region (hereinafter, referred to as a "first region R1") of the first end surface S1 opposed to the second end surface S2 provided with the reflection portion 22. It is provided within. More specifically, the first input / output ports P1A and P1B are respectively connected to the first end face S1.
And a third end surface S3 and a fourth end surface S4, which are perpendicular to the second end surface S2.

On the other hand, the second input / output ports P2 are provided on the first end face S1 at equal intervals of n each to the second area R2 and the third area R3 sandwiching the first area R1. ing. However, the second region R2 and the third region R3 are regions closer to the third end surface S3 and the fourth end surface S4, respectively. In this configuration example, the second input / output ports P2A and P2B are respectively connected to the second region R2 and the third region R2.
It is provided in region R3.

The first optical switch 10 has a first input / output port P1 between the first end face S1 and the second end face S2.
The optical signal input from the second input / output port P2 is reflected by the reflection surface 22A of the reflection section 22 in the direction of the first end face S1, and then the predetermined second input / output port P2
(If the optical signal is input from the second input / output port P2, the transmission path unit 24 for outputting the optical signal to the outside from the first input / output port P1) is provided. That is, the propagation path unit 24 has a control function for determining the propagation path of the optical signal in the first optical switch 10.

Therefore, regarding the configuration of the propagation path section 24,
This will be described in more detail.

The propagation path section 24 includes 2m (m is a natural number) intermediate ports P3, a propagation path connection section 26, and m folded waveguides 28. In this configuration example, m =
(2n) ² (as described later, this condition is a necessary condition for making the first optical switch 10 a 2n × 2n completely non-blocking optical switch). In this embodiment, as described above, since n = 1, m = 4. Therefore, the propagation path unit 24 includes eight intermediate ports P3
A to P3H and four folded waveguides 28A to 28
D (constituting a part of the waveguide 12).

The intermediate ports P3A to P3H are respectively
In the vicinity of the center between the first end face S1 and the second end face S2, it is assumed that the third end face S3 and the fourth end face S4 are sequentially and linearly arranged. However, the intermediate port P3
It should be understood that A to P3H are not actually present physically, but are merely provided virtually for the sake of convenience in order to facilitate understanding of the internal configuration of the propagation path unit 24.

Each of the folded waveguides 28A to 28D has one end and the other end connected to each of the intermediate ports P3A to P3H in a one-to-one relationship.
In a plane including the light signal incident on the second surface 2A and the reflected light signal from the reflection surface 22A, the second end surface S2 moves from the second end surface S2 toward the first end surface S1 in line symmetry with respect to the perpendicular to the reflection surface 22A. It has a folded structure. Thus, the optical signal is
After being reflected by the reflecting surface 22A, the folded waveguide 2
Along 8, it can be folded back and propagated successfully. Therefore, the radiation loss due to the reflection of the optical signal can be minimized.

In this configuration example, specifically, one end and the other end of the folded waveguide 28A are respectively connected to the intermediate port P
3A and P3C. One end and the other end of the folded waveguide 28B are respectively connected to the intermediate port P3B.
And P3E. Also, the folded waveguide 28
One end and the other end of C are connected to intermediate ports P3D and P3G, respectively. One end and the other end of the folded waveguide 28D are respectively connected to intermediate ports P3F and P3F.
H is connected.

The propagation path connecting section 26 connects two intermediate ports connected by the same folded waveguide 28 (for example, intermediate ports P3A and P3C connected by the folded waveguide 28A) to the first, respectively. It has a function of connecting to the input / output port P1 and the second input / output port P2. As a result, the first input / output port P1 and the second
Predetermined switching between the input / output ports P2.

Therefore, the configuration of the propagation path connection unit 26 will be described in more detail.

In this configuration example, the propagation path connecting unit 26
2n 1 × 2n-type first sub optical switches 30 and 2
It includes n 1 × 2n second sub-optical switches 32.

Each first sub optical switch 30 has one end thereof
It is connected to 2n first input / output ports P1 in a one-to-one relationship, and the other end is connected to m (= (2n) ² ) intermediate ports P3 in a one-to-one relationship. .

On the other hand, one end of each second sub-optical switch 32 is connected to the 2n second input / output ports P2 in a one-to-one relationship, and the other end is connected to the first sub-optical switch 3.
It is connected to m (= (2n) ² ) intermediate ports P3 that are not connected to 0 in a one-to-one relationship.

Thus, the same first sub-optical switch 30
And the 2n intermediate ports P3 connected to the second sub-optical switches 32 different from each other are connected one-to-one by the folded waveguides 28.
Connected in a relationship.

With this configuration, the first optical switch 1
0 is a 2n × 2n completely non-blocking optical switch. This is because the first optical switch 10 is functionally the same as a 2n × 2n matrix switch (completely non-blocking type optical switch).

The first sub-switch 30 and the second sub-switch 32 are Y branch optical switches (known). Y
The branch optical switch forms a part of the Y branch waveguide,
An optical switch in which electrodes are arranged from the tapered waveguide to at least one of two branch waveguides (also referred to as “branch waveguides”). By applying a voltage to this electrode, the refractive index of the core of the branch waveguide portion is changed, thereby outputting an optical signal to one of the branch waveguides. The above-mentioned variable electrode 18 corresponds to this electrode. In this example, since n = 1, there are a total of eight branch waveguides. Therefore, a rectangular variable electrode 18 is provided one by one on the main surface 16A of the cladding layer 16 immediately above these eight branch waveguides. Then, the ground electrode 20 (that is, the variable electrode 18)
As described above, the electrode having a constant potential is provided on the main surface 14B facing the main surface 14A of the substrate 14.
Instead of the Y-branch optical switch, another optical switch element (for example, “Mach-Zehnder type optical switch (known)” or the like) may be used.

In this embodiment (n = 1), the propagation path connecting section 26 is composed of two 1 × 2 first sub-optical switches 30.
A and 30B and two 1 × 2 type second sub optical switches 3
2A and 32B.

Specifically, the propagation path connecting portion 26 is provided near the center of the main surface 14A of the substrate 14 near the center of the first Y branch waveguide 3A.
4A and 34B and a second Y-branch waveguide 36A sandwiching the first Y-branch waveguides 34A and 34B.
And 36B. From the third end surface S3 to the fourth end surface S4
The second Y-branch waveguide 36A and the first Y-branch waveguide 34
A, first Y-branch waveguide 34B and second Y-branch waveguide 36
B are arranged in order. Each of the Y-branch waveguides has one non-branch waveguide (also referred to as “main waveguide”) in the direction of the first end surface S1 and two branch waveguides (also referred to as “main waveguide”) in the direction of the second end surface S2. Also referred to as a "branch waveguide.") In this configuration example, the waveguide 12 is configured by the first Y-branch waveguide 34, the second Y-branch waveguide 36, and the folded waveguide 28 described above.

One end of the first Y-branch waveguide 34A is
The other end is connected to the intermediate ports P3C and P3D while being connected to the first input / output port P1A. The first Y-branch waveguide 34A and the variable electrode 18 disposed immediately above the first Y-branch waveguide 34A provide a first
A sub optical switch 30A is configured.

Similarly, the first Y branch waveguide 34B has one end connected to the first input / output port P1B and the other end connected to the intermediate ports P3E and P3F. The first Y branch waveguide 34B and the first
The first sub-optical switch 30B is configured by the variable electrode 18 disposed immediately above the Y branch waveguide 34B.

Similarly, the second Y-branch waveguide 36A has one end connected to the second input / output port P2A and the other end connected to the intermediate ports P3A and P3B. The second Y branch waveguide 36A and the second
The second sub-optical switch 32A is configured by the variable electrode 18 disposed immediately above the Y-branch waveguide 36A.

Similarly, the second Y branch waveguide 36B has one end connected to the second input / output port P2B and the other end connected to the intermediate ports P3G and P3H. The second Y branch waveguide 36B and the second
The variable electrode 18 disposed immediately above the Y-branch waveguide 36B constitutes a second sub-optical switch 32B.

Each Y-branch waveguide is connected smoothly to the intermediate port P3 corresponding to the Y-branch waveguide (ie, having a continuously differentiable curve shape). I do. This is to reduce the propagation loss.

Next, an example of an optical signal propagation path in the first optical switch 10 will be described.

For example, when an optical signal is input from the first input / output port P1A, the optical signal is converted from the first sub optical switch 30A → the intermediate port P3C → the folded waveguide 28A →
Route from intermediate port P3A to second input / output port P2A,
Or, the first sub optical switch 30A → the intermediate port P3D
The signal is output via the path of the folded waveguide 28C → the intermediate port P3G → the second input / output port P2B.

By the way, according to the configuration of the first optical switch 10, the following conditions (A) to (C) are satisfied.
Each folded waveguide 28 is arranged.

Condition (A): Each folded waveguide 28 is located at the center line CL of the group of folded waveguides 28 on the plane including the folded waveguide 28 (provided that the third end face S3 and the fourth end face S4 Are parallel to each other). For example, folded waveguide 2
8B is arranged substantially line-symmetrically with the folded waveguide 28C with respect to the center line CL. In addition, the folded waveguide 28A is arranged such that the folded waveguide 28D
Are arranged substantially line-symmetrically.

Condition (B): The folded waveguide 28 connected to the intermediate port P3, which can be connected only to the second input / output port P2 in the second region R2,
Each crosses once from the intermediate port P3 to the intermediate port P3 that can be connected only to the first input / output port P1 via the reflection surface 22A. For example, in this case, the folded waveguide 28
A and 28B are intermediate ports P which can be connected only to the second input / output port P2A in the second region R2.
3A and P3B, and cross each other only once.

Condition (C): Similarly, the folded waveguide 28 connected to the intermediate port P3, which can be connected only to the second input / output port P2 in the third region R3,
Each crosses once from the intermediate port P3 to the intermediate port P3 that can be connected only to the first input / output port P1 via the reflection surface 22A. For example, in this case, the folded waveguide 28
C and 28D are intermediate ports P that can be connected only to the second input / output port P2B in the third region R3.
It is connected to 3G and P3H and crosses each other only once.

If the configuration is such that the conditions (A) to (C) are simultaneously satisfied, the total number of intersections between the folded waveguides 28 can be reduced as compared with the conventional configuration (the second conventional optical device). Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

Also, unlike the configuration of the second conventional optical device,
The need for a dummy port irrelevant to the input / output of optical signals is eliminated.
Therefore, the size of the optical element can be reduced.

The intermediate port P3 and the folded waveguide 2
By increasing the number of 8 and expanding the connection function in the propagation path connection unit 26, it is possible to increase the capacity of the first optical switch 10 (for example, a 32 × 32 optical switch).

[Second Embodiment] Referring to FIG. 3, an optical switch (hereinafter, referred to as a "second optical switch 50") which is an example of an optical device according to a second embodiment of the present invention will be described. The characteristic configuration will be described.

FIG. 3 is a configuration diagram for explaining an example of the configuration of the second optical switch, and is shown in a perspective view.

Conventionally, in an optical element, a substrate (cladding) and a waveguide are often formed based on an anisotropic medium (also referred to as a birefringent medium) such as LiNbO ₃ . However, when an optical signal propagates through a waveguide in an anisotropic medium, the optical signal is polarized into a TE mode and a TM mode. As a result, since various characteristics (propagation speed and the like) of the optical signals in the TE mode and the TM mode are different from each other, there is a problem that a time lag occurs when receiving the optical signals in the TE mode and the TM mode. Then, the second optical switch 50 sets the reflection unit 22 so that the TE signal of the optical signal reflected by the reflection unit 22
It has a function of performing mode conversion between the mode and the TM mode. As a result, the effects of the TE mode and the TM mode can be offset. This is different from the first optical switch 10.

In this embodiment, the reflection part 22 is a quarter
It is composed of a wave plate 22B and a reflecting mirror 22C. The quarter-wave plate 22 is provided on the second end face S2 of the second optical switch 50.
B, and a reflecting mirror 22C may be attached to the quarter-wave plate 22B. Quarter wave plate 22B
Has a function of performing mode conversion between the TE mode and the TM mode.

As a result, the optical signal which has been in the TE mode from the time when it is input to one input / output port to the time when it reaches the reflection unit 22 is kept at T
The mode becomes the M mode. Conversely, an optical signal in TM mode from being input to one of the input / output ports to reaching the reflection section 22 has a TE signal from the reflection section to the other input / output port.
Mode. Therefore, while the optical signal travels from one input / output port to the other input / output port, the state in the TE mode and the state in the TM mode are canceled. Therefore, the second optical switch 50 can be a polarization independent optical switch.

[Third Embodiment] In addition to FIG.
, An optical switch (hereinafter referred to as a “third optical switch 6”) which is an example of an optical element according to the third embodiment of the present invention.
0 ". ) Will be described.

FIG. 4 is a configuration diagram for explaining an example of the configuration of the third optical switch, and is shown in a perspective view.

According to the configuration of the second optical switch 50, for example, the optical signal input to the input / output port intersects with the waveguide (hereinafter referred to as "outgoing waveguide") which propagates until reaching the reflection surface. The total number of other waveguides intersecting with the waveguides (hereinafter, referred to as “return waveguides”) that propagated from the time when the optical signal was reflected by the reflection surface to the time when the optical signal reached the input / output port is crossed. Not equal to the total number of

For example, an optical signal is transmitted from the first input / output port P1A to the first sub optical switch 30A → intermediate port P3C →
In the case of following the path of the folded waveguide 28A (the forward waveguide to this point) → the reflecting surface → the folded waveguide 28A → the intermediate port P3A → the second input / output port P2A (the backward waveguide), the forward waveguide is Other waveguides (in this case,
While it intersects the folded waveguide 28B) once, the return waveguide does not intersect with the other waveguides. Therefore, the total number of crossings (= 1 time) in the outward waveguide is not equal to the total number of crossings (= 0 times) in the return waveguide.

By the way, the propagation loss of the optical signal in the TE mode at the time of passing through the waveguide intersection is different from the propagation loss of the optical signal in the TM mode. As a result, there is a problem that the propagation loss of the optical signal varies greatly depending on the waveguide through which the optical signal has propagated.

Therefore, by providing the dummy waveguide 38 which intersects the outward waveguide or the backward waveguide, the total number of them is made equal to each other. For example, in this embodiment, since the dummy waveguides 38A and 38B that intersect with the folded waveguides 28A and 28D are provided, the number of intersections is uniformly two. Therefore, the third optical switch 60
Can make the propagation loss in the optical signal between any input / output ports substantially uniform.

Fourth Embodiment Referring to FIG. 5, an optical switch (hereinafter, referred to as a "fourth optical switch 70") which is an example of an optical device according to a fourth embodiment of the present invention will be described. The characteristic configuration will be described.

FIG. 5 is a configuration diagram for explaining an example of the configuration of the fourth optical switch, and is a plan view in which a waveguide is projected onto the main surface of a cladding layer constituting a part of the fourth optical switch. Is shown.

The fourth optical switch 70 is a 4 × 4 completely non-blocking type optical switch. This is the first optical switch 10
(2 × 2 completely non-blocking optical switch).
The configuration of the optical switch 70 is the same as that of the first embodiment.
This corresponds to the case where n = 2 and m = 8. ).

Therefore, in the fourth optical switch 70, the wiring and connection relationship of the waveguide and the like will be mainly described.

The fourth optical switch 70 is provided in the first region R1.
Four first input / output ports P1A to P1D are provided from the third end face S3 to the fourth end face S4. Also, the second region R
2 is provided with two second input / output ports P2A and P2B from the third end face S3 to the fourth end face S4. In the third region R3, two second input / output ports P2C and P2D are provided from the third end face S3 to the fourth end face S4.

The propagation path section 24 (not numbered in FIG. 5; the same applies to FIGS. 6 to 8 hereinafter) is connected to the propagation path connecting section 26 (numbered in FIG. 5;
6 to 8), 32 intermediate ports P3
-1 to P3-32 and 16 folded waveguides 28
A to 28P.

The intermediate ports P3-1 to P3-32 are located near the center between the first end face S1 and the second end face S2, respectively, from the third end face S3 to the fourth end face S4, and are virtually formed for convenience. It is assumed that they are sequentially arranged in a straight line.

The folded waveguides 28A to 28P are:
The conditions (A) to (C) described in the first embodiment are simultaneously satisfied. Specifically, the folded waveguide 28
One end and the other end of A are connected to intermediate ports P3-1 and P3-9, respectively. Also, the folded waveguide 28
One end and the other end of B are connected to intermediate ports P3-2 and P3-10, respectively. Also, folded waveguide 2
8C is connected to the intermediate port P3-3, respectively.
And P3-11. One end and the other end of the folded waveguide 28D are respectively connected to the intermediate port P3-
4 and P3-12. One end and the other end of the folded waveguide 28E are respectively connected to the intermediate port P3.
-5 and P3-17. One end and the other end of the folded waveguide 28F are respectively connected to the intermediate port P
3-6 and P3-18. One end and the other end of the folded waveguide 28G are connected to the intermediate ports P3-7 and P3-19, respectively. One end and the other end of the folded waveguide 28H are connected to the intermediate ports P3-8 and P3-20, respectively. One end and the other end of the folded waveguide 28I are connected to the intermediate ports P3-13 and P3-25, respectively. or,
One end and the other end of the folded waveguide 28J are connected to intermediate ports P3-14 and P3-26, respectively.
One end and the other end of the folded waveguide 28K are connected to the intermediate ports P3-15 and P3-27, respectively. One end and the other end of the folded waveguide 28L are connected to the intermediate ports P3-16 and P3-28, respectively. One end and the other end of the folded waveguide 28M are connected to the intermediate ports P3-21 and P3-29, respectively. One end and the other end of the folded waveguide 28N are connected to intermediate ports P3-22 and P3-3, respectively.
0 is connected. One end and the other end of the folded waveguide 28O are connected to intermediate ports P3-23 and P3, respectively.
-31. One end and the other end of the folded waveguide 28P are connected to the intermediate ports P3-24 and P3-32, respectively.

The propagation path connecting section 26 has four 1 × 4
First auxiliary optical switches 30A to 30D (not numbered in FIG. 5; the same applies to FIGS. 6 to 8);
And four 1 × 4 type second sub optical switches 32A to 32
D (No number is added in FIG. 5; the same applies to FIGS. 6 to 8 hereinafter). Each of the first sub-optical switches 30 and each of the second sub-optical switches 32 are formed by cascade-connecting 1 × 2 switch elements in two stages. Thereby, the propagation path connecting unit 26 is in the first stage (the first stage).
It is the end surface S1 side. ) To 8 optical switch elements,
The second stage (on the side of the intermediate port P3) includes 16 optical switch elements. In FIG. 5, each optical switch element is conceptually represented by a hatched rectangle.
As in the “first embodiment”, any optical switch such as a Y-branch optical switch or a Mach-Zehnder optical switch may be used.

Here, the optical switch elements in the first stage are defined as first optical switch elements 72A to 72H in order from the third end face S3 to the fourth end face S4. Each optical switch element in the second stage is defined as second optical switch elements 74A to 74P in order from the third end face S3 to the fourth end face S4.

At this time, the first sub optical switch 30A is connected to the first input / output port P1A → the first optical switch element 7
2C → second optical switch element 74E and 74G → intermediate port P3-9, 11 (second optical switch element 7
4E) and P3-13, 15 (connected to the second optical switch element 74G) in this order.

Similarly, the first sub optical switch 30B is connected to the first sub optical switch 30B.
Input / output port P1B → first optical switch element 72
D → second optical switch element 74F and 74H → intermediate port P3-10, 12 (second optical switch element 7
4F) and P3-14, 16 (connected to the second optical switch element 74H) in this order.

Similarly, the first sub optical switch 30C is connected to the first sub optical switch 30C.
Input / output port P1C → first optical switch element 72
E → second optical switch element 74I and 74K → intermediate port P3-17, 19 (second optical switch element 7
4I) and P3-21, 23 (connected to the second optical switch element 74K) in this order.

Similarly, the first sub optical switch 30D is connected to the first sub optical switch 30D.
Input / output port P1D → first optical switch element 72
F → second optical switch element 74J and 74L → intermediate port P3-18, 20 (second optical switch element 7
4J) and P3-22, 24 (connected to the second optical switch element 74L) in this order.

Similarly, the second sub optical switch 32A is connected to the second sub optical switch 32A.
Input / output port P2A → first optical switch element 72
A → second optical switch element 74A and 74C → intermediate port P3-1,2 (second optical switch element 74A
) And P3-5, 6 (connected to the second optical switch element 74C) in this order.

Similarly, the second sub optical switch 32B is connected to the second sub optical switch 32B.
Input / output port P2B → first optical switch element 72
B → second optical switch element 74B and 74D → intermediate port P3-3,4 (second optical switch element 74B
) And P3-7, 8 (connected to the second optical switch element 74D) in this order.

Similarly, the second sub optical switch 32C is connected to the second sub optical switch 32C.
Input / output port P2C → first optical switch element 72
G → second optical switch element 74M and 74O → intermediate port P3-25, 26 (second optical switch element 7
4M) and P3-29, 30 (connected to the second optical switch element 74O) in this order.

Similarly, the second sub optical switch 32D is connected to the second sub optical switch 32D.
Input / output port P2D → first optical switch element 72
H → second optical switch element 74N and 74P → intermediate port P3-27, 28 (second optical switch element 7
4N) and P3-31, 32 (connected to the second optical switch element 74P) in this order.

With this configuration, the conditions (A) to (A)
Since (C) is simultaneously satisfied, the folded waveguide 28
The total number of intersections between the two is determined by the conventional configuration (second conventional optical device).
Can be effectively reduced as compared to. Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

[Fifth Embodiment] Referring to FIG. 6, an optical switch (hereinafter, referred to as a "fifth optical switch 80") which is an example of an optical device according to a fifth embodiment of the present invention will be described. The characteristic configuration will be described.

FIG. 6 is a configuration diagram for explaining an example of the configuration of the fifth optical switch, and is a plan view in which a waveguide is projected onto the main surface of a cladding layer constituting a part of the fifth optical switch. Is shown.

The fifth optical switch 80 is a 4 × 4 completely non-blocking type optical switch. However, the wiring and connection relationship of the waveguide and the like are different from the configuration of the fourth optical switch 70.

[0100] First, the wiring pattern of the folded waveguide 28 will be described.

The folded waveguides 28A to 28P are referred to as “first
Of Embodiments "are simultaneously satisfied. Specifically, one end and the other end of the folded waveguide 28A are connected to intermediate ports P3-1 and P3, respectively.
-9. One end and the other end of the folded waveguide 28B are connected to intermediate ports P3-2 and P3, respectively.
-11. One end and the other end of the folded waveguide 28C are connected to intermediate ports P3-3 and P3, respectively.
3-13. Also, the folded waveguide 28D
Are connected to intermediate ports P3-4 and P3-15, respectively. Also, the folded waveguide 28
One end and the other end of E are connected to intermediate ports P3-5 and P3-17, respectively. Also, folded waveguide 2
8F is connected to the intermediate port P3-6, respectively.
And P3-19. One end and the other end of the folded waveguide 28G are respectively connected to the intermediate port P3-
7 and P3-21. One end and the other end of the folded waveguide 28H are respectively connected to the intermediate port P3.
-8 and P3-23. One end and the other end of the folded waveguide 28I are respectively connected to the intermediate port P
3-10 and P3-25. One end and the other end of the folded waveguide 28J are connected to the intermediate ports P3-12 and P3-26, respectively. One end and the other end of the folded waveguide 28K are connected to the intermediate ports P3-14 and P3-27, respectively.
One end and the other end of the folded waveguide 28L are connected to the intermediate ports P3-16 and P3-28, respectively. One end and the other end of the folded waveguide 28M are connected to the intermediate ports P3-18 and P3-29, respectively. One end and the other end of the folded waveguide 28N are connected to the intermediate ports P3-20 and P3-30, respectively. One end and the other end of the folded waveguide 280 are connected to intermediate ports P3-22 and P3-3, respectively.
1 is connected. One end and the other end of the folded waveguide 28P are connected to intermediate ports P3-24 and P3, respectively.
-32.

Next, the wiring patterns of the first sub optical switches 30A to 30D and the second sub optical switches 32A to 32D will be described.

The first sub optical switch 30A is composed of the first input / output port P1A, the first optical switch element 72C, and the second
Optical switch elements 74E and 74G → Intermediate port P
3-9, 10 (connected to the second optical switch element 74E) and P3-13, 14 (connected to the second optical switch element 74G) in this order.

Similarly, the first sub optical switch 30B is connected to the first sub optical switch 30B.
Input / output port P1B → first optical switch element 72
D → second optical switch element 74F and 74H → intermediate port P3-11, 12 (second optical switch element 7
4F) and P3-15, 16 (connected to the second optical switch element 74H) in this order.

Similarly, the first sub optical switch 30C is connected to the first sub optical switch 30C.
Input / output port P1C → first optical switch element 72
E → second optical switch element 74I and 74K → intermediate port P3-17, 18 (second optical switch element 7
4I) and P3-21, 22 (connected to the second optical switch element 74K) in this order.

Similarly, the first sub optical switch 30D is connected to the first sub optical switch 30D.
Input / output port P1D → first optical switch element 72
F → second optical switch element 74J and 74L → intermediate port P3-19, 20 (second optical switch element 7
4J) and P3-23, 24 (connected to the second optical switch element 74L) in this order.

Similarly, the second sub optical switch 32A is connected to the second sub optical switch 32A.
Input / output port P2A → first optical switch element 72
A → second optical switch element 74A and 74C → intermediate port P3-1,2 (second optical switch element 74A
) And P3-5, 6 (connected to the second optical switch element 74C) in this order.

Similarly, the second sub optical switch 32B is connected to the second sub optical switch 32B.
Input / output port P2B → first optical switch element 72
B → second optical switch element 74B and 74D → intermediate port P3-3,4 (second optical switch element 74B
) And P3-7, 8 (connected to the second optical switch element 74D) in this order.

Similarly, the second sub optical switch 32C is connected to the second sub optical switch 32C.
Input / output port P2C → first optical switch element 72
G → second optical switch element 74M and 74O → intermediate port P3-25, 26 (second optical switch element 7
4M) and P3-29, 30 (connected to the second optical switch element 74O) in this order.

Similarly, the second sub optical switch 32D is connected to the second sub optical switch 32D.
Input / output port P2D → first optical switch element 72
H → second optical switch element 74N and 74P → intermediate port P3-27, 28 (second optical switch element 7
4N) and P3-31, 32 (connected to the second optical switch element 74P) in this order.

Even if the wiring is patterned in this manner, the conditions (A) to (C) are simultaneously satisfied, so that the total number of intersections between the folded waveguides 28 is smaller than that of the conventional configuration (second conventional optical device). In comparison, it can be reduced effectively.
Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

[Sixth Embodiment] Referring to FIG. 7, an optical switch (hereinafter, referred to as a "sixth optical switch 90") which is an example of an optical device according to a sixth embodiment of the present invention will be described. The characteristic configuration will be described.

FIG. 7 is a configuration diagram for explaining an example of the configuration of the sixth optical switch, and is a plan view in which a waveguide is projected onto the main surface of a cladding layer constituting a part of the sixth optical switch. Is shown.

The sixth optical switch 90 is a 4 × 4 completely non-blocking type optical switch. However, the wiring and connection relationship of the waveguide and the like are different from the configurations of the fourth optical switch 70 and the fifth optical switch 80.

Therefore, first, the wiring pattern of the folded waveguide 28 will be described.

The folded waveguides 28A to 28P are provided in the “first
Of Embodiments "are simultaneously satisfied.

Specifically, one end and the other end of the folded waveguide 28A are connected to the intermediate ports P3-1 and P3-, respectively.
5 is connected. One end and the other end of the folded waveguide 28B are connected to intermediate ports P3-2 and P3-, respectively.
6 is connected. One end and the other end of the folded waveguide 28C are connected to the intermediate ports P3-3 and P3-, respectively.
7 is connected. One end and the other end of the folded waveguide 28D are connected to intermediate ports P3-4 and P3-
8 is connected. One end and the other end of the folded waveguide 28E are connected to the intermediate ports P3-9 and P3-
13 is connected. One end and the other end of the folded waveguide 28F are connected to the intermediate ports P3-10 and P3, respectively.
3-14. Also, a folded waveguide 28G
Are connected to intermediate ports P3-11 and P3-15, respectively. Also, folded waveguide 2
8H is connected to the intermediate port P3-1
2 and P3-16. One end and the other end of the folded waveguide 28I are respectively connected to the intermediate port P3.
-17 and P3-21. One end and the other end of the folded waveguide 28J are connected to the intermediate ports P3-18 and P3-22, respectively. One end and the other end of the folded waveguide 28K are connected to the intermediate ports P3-19 and P3-23, respectively. or,
One end and the other end of the folded waveguide 28L are connected to intermediate ports P3-20 and P3-24, respectively.
One end and the other end of the folded waveguide 28M are connected to the intermediate ports P3-25 and P3-29, respectively. One end and the other end of the folded waveguide 28N are connected to the intermediate ports P3-26 and P3-30, respectively. One end and the other end of the folded waveguide 280 are connected to intermediate ports P3-27 and P3-31, respectively. One end and the other end of the folded waveguide 28P are connected to intermediate ports P3-28 and P3-3, respectively.
2 is connected.

Next, the wiring patterns of the first sub optical switches 30A to 30D and the second sub optical switches 32A to 32D will be described.

The first sub optical switch 30A is composed of a first input / output port P1A, a first optical switch element 72C, and a second
Optical switch elements 74C and 74I → Intermediate port P
3-5 and 7 (connected to the second optical switch element 74C) and P3-17 and P3 (connected to the second optical switch element 74I) in this order by waveguides.

Similarly, the first sub optical switch 30B is connected to the first sub optical switch 30B.
Input / output port P1B → first optical switch element 72
D → second optical switch element 74D and 74J → intermediate port P3-6,8 (second optical switch element 74D
) And P3-18 and P3-20 (connected to the second optical switch element 74J) in this order.

Similarly, the first sub optical switch 30C is connected to the first sub optical switch 30C.
Input / output port P1C → first optical switch element 72
E → second optical switch element 74G and 74M → intermediate port P3-13, 15 (second optical switch element 7
4G) and P3-25, 27 (connected to the second optical switch element 74M) in this order.

Similarly, the first sub optical switch 30D is connected to the first sub optical switch 30D.
Input / output port P1D → first optical switch element 72
F → second optical switch element 74H and 74N → intermediate port P3-14, 16 (second optical switch element 7
4H) and P3-26, 28 (connected to the second optical switch element 74N) in this order.

Similarly, the second sub optical switch 32A is connected to the second sub optical switch 32A.
Input / output port P2A → first optical switch element 72
A → second optical switch element 74A and 74E → intermediate port P3-1,2 (second optical switch element 74A
) And P3-9, 10 (connected to the second optical switch element 74E) in this order.

Similarly, the second sub optical switch 32B is connected to the second sub optical switch 32B.
Input / output port P2B → first optical switch element 72
B → second optical switch element 74B and 74F → intermediate port P3-3,4 (second optical switch element 74B
) And P3-11 and P3-11 (connected to the second optical switch element 74F) in this order.

Similarly, the second sub optical switch 32C is connected to the second sub optical switch 32C.
Input / output port P2C → first optical switch element 72
G → second optical switch element 74K and 74O → intermediate port P3-21, 22 (second optical switch element 7
4K) and P3-29, 30 (connected to the second optical switch element 74O) in this order.

Similarly, the second sub optical switch 32D is connected to the second sub optical switch 32D.
Input / output port P2D → first optical switch element 72
H → second optical switch elements 74L and 74P → intermediate ports P3-23, 24 (second optical switch element 7
4L) and P3-31, 32 (connected to the second optical switch element 74P) in this order.

Even if the wiring is patterned in this manner, the conditions (A) to (C) are simultaneously satisfied. In comparison, it can be reduced effectively.
Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

"Seventh Embodiment" Referring to FIG. 8, an optical switch (hereinafter, referred to as a "seventh optical switch 100") which is an example of an optical device according to a seventh embodiment of the present invention will be described.
Will be described.

FIG. 8 is a configuration diagram for explaining an example of the configuration of the seventh optical switch, and is a plan view in which a waveguide is projected on the main surface of a cladding layer constituting a part of the seventh optical switch. Is shown.

The seventh optical switch 100 is a 4 × 4 completely non-blocking type optical switch. This seventh optical switch 100
The first end face S1 includes a plurality of port block areas. This point is different from the configuration example of each optical switch described above.

In this configuration example, the seventh optical switch 100
Has two first port block regions BL1 and two second port block regions BL2. The first port block region BL1 is on the third end surface S3 side. Further, the second port block region BL2 is on the fourth end surface S4 side.
The first port block region BL1 and the second port block region BL2 are adjacent to each other.

The first port block region BL1 and the second
The port block regions BL2 of the third end face S
From 3 toward the fourth end surface S4, a first region R1, and
A second region R2 and a third region R3 sandwiching the first region R1 are provided. Therefore, the first port block region BL
1, the third region R3 is adjacent to the second region R2 in the second port block region BL2. And
The first region R1 includes a first input / output port.
Further, the second region R2 includes a second input / output port P2.

The first input / output ports included in the first port block area BL1 (in this example, P1A and P1A
B) and the number of first input / output ports (P1C and P1C in this example) included in the second port block area BL2.
D) are equal to each other (the number is set to 2). Further, the second input / output ports (P2A and P2A in this example) included in the first port block area BL1
B) and the number of second input / output ports (P2C and P2C in this example) included in the second port block area BL2.
D) are equal to each other (the number is set to 2).

In the same port block area, the second input / output ports are equally distributed and provided in the second area R2 and the third area R3. In this configuration example, second input / output ports P2A and P2B are provided in the second region R2 and the third region R3 in the first port block region BL1, respectively. In addition, the second region R2 and the third region R2 in the second port block region BL2
A second input / output port P2C and a second input / output port P2D are provided in the region R3.

Next, the wiring pattern of the folded waveguide 28 will be described.

The folded waveguides 28A to 28P are provided in the “first
Of Embodiments "are simultaneously satisfied.

Specifically, one end and the other end of the folded waveguide 28A are connected to the intermediate ports P3-1 and P3-, respectively.
3 is connected. One end and the other end of the folded waveguide 28B are connected to intermediate ports P3-2 and P3-, respectively.
5 is connected. One end and the other end of the folded waveguide 28C are connected to intermediate ports P3-4 and P3-
7 is connected. One end and the other end of the folded waveguide 28D are connected to the intermediate ports P3-6 and P3-
8 is connected. One end and the other end of the folded waveguide 28E are connected to the intermediate ports P3-9 and P3-
11 is connected. One end and the other end of the folded waveguide 28F are connected to the intermediate ports P3-10 and P3, respectively.
3-13. Also, a folded waveguide 28G
Are connected to intermediate ports P3-12 and P3-15, respectively. Also, folded waveguide 2
8H is connected to the intermediate port P3-1
4 and P3-16. One end and the other end of the folded waveguide 28I are respectively connected to the intermediate port P3.
-17 and P3-19. One end and the other end of the folded waveguide 28J are connected to intermediate ports P3-18 and P3-21, respectively. One end and the other end of the folded waveguide 28K are connected to the intermediate ports P3-20 and P3-23, respectively. or,
One end and the other end of the folded waveguide 28L are connected to intermediate ports P3-22 and P3-24, respectively.
One end and the other end of the folded waveguide 28M are connected to intermediate ports P3-25 and P3-27, respectively. One end and the other end of the folded waveguide 28N are connected to the intermediate ports P3-26 and P3-29, respectively. One end and the other end of the folded waveguide 280 are connected to intermediate ports P3-28 and P3-31, respectively. One end and the other end of the folded waveguide 28P are connected to intermediate ports P3-30 and P3-3, respectively.
2 is connected.

Next, the wiring patterns of the first sub optical switches 30A to 30D and the second sub optical switches 32A to 32D will be described.

The first sub optical switch 30A is composed of a first input / output port P1A, a first optical switch element 72B, and a second
Optical switch elements 74B and 74J → intermediate port P
3-3, 4 (connected to the second optical switch element 74B, respectively) and P3-19, 20 (connected to the second optical switch element 74J, respectively) in this order are connected by waveguides.

Similarly, the first sub optical switch 30B is connected to the first sub optical switch 30B.
Input / output port P1B → first optical switch element 72
C → second optical switch element 74C and 74K → intermediate port P3-5, 6 (second optical switch element 74C
) And P3-21, 22 (connected to the second optical switch element 74K) in this order.

Similarly, the first sub optical switch 30C is connected to the first sub optical switch 30C.
Input / output port P1C → first optical switch element 72
F → second optical switch element 74F and 74N → intermediate port P3-11, 12 (second optical switch element 7
4F) and P3-27, 28 (connected to the second optical switch element 74N) in this order.

Similarly, the first sub optical switch 30D is connected to the first sub optical switch 30D.
Input / output port P1D → first optical switch element 72
G → second optical switch element 74G and 74O → intermediate port P3-13, 14 (second optical switch element 7
4G) and P3-29, 30 (connected to the second optical switch element 74O) in this order.

Similarly, the second sub optical switch 32A is connected to the second sub optical switch 32A.
Input / output port P2A → first optical switch element 72
A → second optical switch element 74A and 74E → intermediate port P3-1,2 (second optical switch element 74A
) And P3-9, 10 (connected to the second optical switch element 74E) in this order.

Similarly, the second sub optical switch 32B is connected to the second sub optical switch 32B.
Input / output port P2B → first optical switch element 72
D → second optical switch element 74D and 74H → intermediate port P3-7, 8 (second optical switch element 74D
) And P3-15, 16 (connected to the second optical switch element 74H) in this order.

Similarly, the second sub optical switch 32C is connected to the second sub optical switch 32C.
Input / output port P2C → first optical switch element 72
E → second optical switch element 74I and 74M → intermediate port P3-17, 18 (second optical switch element 7
4I) and P3-25, 26 (connected to the second optical switch element 74M) in this order.

Similarly, the second sub optical switch 32D is connected to the second sub optical switch 32D.
Input / output port P2D → first optical switch element 72
H → second optical switch elements 74L and 74P → intermediate ports P3-23, 24 (second optical switch element 7
4L) and P3-31, 32 (connected to the second optical switch element 74P) in this order.

Even if the wiring is patterned in this manner, the conditions (A) to (C) are simultaneously satisfied, so that the total number of intersections between the folded waveguides 28 is smaller than that of the conventional configuration (the second conventional optical device). In comparison, it can be reduced effectively.
Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

The present invention is not limited only to the above-described embodiment, and various changes can be made according to the design.

For example, in the above embodiment, the propagation path connecting portion 26 has the optical switching function by including the variable electrode 18, but instead of using the variable electrode 18 and the ground electrode 20, the optical path It may have a demultiplexing function. Thereby, the optical element can be an optical multiplexer / demultiplexer.

Alternatively, the propagation path connecting section 26 may have an optical branching / coupling function (for example, a 3 dB optical coupler). Thus, the optical element can be an optical branching coupler.

[0151]

As is apparent from the above description, according to the optical device of the present invention, a dummy port irrelevant to the input / output of an optical signal becomes unnecessary. Therefore, the size of the optical element can be reduced.

Also, by increasing the number of intermediate ports and folded waveguides and expanding the connection function at the propagation path connection portion, it is possible to increase the capacity of the optical element.

Further, the total number of intersections between the folded waveguides can be reduced as compared with the conventional configuration (second conventional optical device). Therefore, the propagation loss of the optical signal can be reduced by the decrease in the number of intersections.

When the optical element is an optical switch,
And (first number of input / output ports) ^Two= Folded waveguide
Total non-blocking type optical switch.
Can be

In addition, by forming the reflecting portion with a quarter-wave plate and a reflecting mirror, the optical element can be a polarization-independent optical element.

Further, by providing a dummy waveguide that intersects the forward waveguide or the backward waveguide, the total number of intersections can be made equal to each other, so that the propagation loss in an optical signal between any input / output ports can be reduced. It can be substantially uniform.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of a configuration of a first optical switch.

FIG. 2 is a plan view illustrating an example of a configuration of a first optical switch.

FIG. 3 is a perspective view illustrating an example of a configuration of a second optical switch.

FIG. 4 is a perspective view illustrating an example of a configuration of a third optical switch.

FIG. 5 is a plan view illustrating an example of a configuration of a fourth optical switch.

FIG. 6 is a plan view illustrating an example of a configuration of a fifth optical switch.

FIG. 7 is a plan view illustrating an example of a configuration of a sixth optical switch.

FIG. 8 is a plan view illustrating an example of a configuration of a seventh optical switch.

[Explanation of symbols]

 10: First optical switch 12: Waveguide 14: Substrate 14A, 14B: Main surface 16: Cladding layer 16A: Main surface 18: Variable electrode 20: Earth electrode 22: Reflecting part 22A: Reflecting surface 22B: Quarter wavelength Plate 22C: Reflector 24: Propagation path section 26: Propagation path connection section 28A to 28P: Folded waveguide 30A, 30B: First sub optical switch 32A, 32B: Second sub optical switch 34A, 34B: First Y branch waveguide 36A, 36B: second Y branch waveguide 38A, 38B: dummy waveguide 50: second optical switch 60: third optical switch 70: fourth optical switch 72A to 72H: first optical switch element 74A to 74P: second optical Switch element 80: Fifth optical switch 90: Sixth optical switch 100: Seventh optical switch BL1: First port block area BL : Second port block area CL: center line P1A to P1D: first input / output port P2A to P2D: second input / output port P3A to P3H, P3-1 to P3-32: intermediate port R1 to R3: first First to third regions S1 to S4: first to fourth end surfaces

Claims (14)

[Claims] A first end face and a second end face facing each other, and provided on the first end face, respectively, to input an optical signal from outside to an optical element, or to transmit the optical signal to each other. A plurality of first input / output ports, a plurality of second input / output ports, and a reflection portion provided on the second end face, wherein the first end face and the plurality of first input / output ports have a relation of outputting the light to the outside from the optical element; And between the second end face,
Propagation for reflecting the optical signal input from outside to the input / output port toward the direction of the first end face on the reflection surface of the reflection section, and then outputting the signal to the outside from the predetermined input / output port In the optical device having a path section, the second input / output port is provided separately in a second area and a third area sandwiching the first area including the first input / output port. An optical element characterized in that: 2. A first end face and a second end face opposed to each other, and provided on the first end face, respectively, to input an optical signal to an optical element from the outside or to transmit the optical signal to each other. A plurality of first input / output ports, a plurality of second input / output ports, and a reflection portion provided on the second end face, wherein the first end face and the plurality of first input / output ports have a relation of outputting the light to the outside from the optical element; And between the second end face,
Propagation for reflecting the optical signal input from outside to the input / output port toward the direction of the first end face on the reflection surface of the reflection section, and then outputting the signal to the outside from the predetermined input / output port A plurality of port block areas each including the first input / output port and the second input / output port, wherein each of the port block areas includes the second input / output port and the second input / output port. Wherein the input / output ports are provided separately in a second area and a third area sandwiching the first area including the first input / output port. 3. The optical device according to claim 1, wherein the number of the first input / output ports is 2n (n is a natural number), and the number of the second input / output ports is 2n. A second input / output port is connected to the second area and the third area.
An optical element, wherein n elements are equally distributed in a region. 4. The optical device according to claim 2, wherein the number of the first input / output ports is 2n (n is a natural number), and the number of the second input / output ports is 2n. The number of the first input / output ports included in the port block area is equal, the number of the second input / output ports included in each port block area is equal, and in the same port block area, The optical element, wherein the second input / output port is provided equally distributed in the second area and the third area. 5. The optical element according to claim 3, wherein the propagation path portion includes 2m (m is a natural number) provided in a region between the first end face and the second end face. An intermediate port, one end and the other end of which are connected to each of the intermediate ports in a one-to-one relationship, and the optical signal incident on the reflective surface and the optical signal reflected from the reflective surface In the plane including the reflection waveguides, m folded waveguides having a structure folded back from the second end face toward the first end face in line symmetry with respect to a perpendicular to the reflection surface are connected by the same folded waveguide. An optical element, comprising: a propagation path connecting unit having a function of connecting the two intermediate ports to the first input / output port and the second input / output port, respectively. 6. The optical element according to claim 3, wherein the reflection section has a function of performing mode conversion between a TE mode and a TM mode in the optical signal reflected by the reflection section. An optical element characterized by the above. 7. The optical device according to claim 5, wherein each of the folded waveguides is substantially aligned with a center line of the group of the folded waveguides in a plane including the folded waveguide. An optical element characterized by being symmetrically arranged. 8. The optical device according to claim 5, wherein each of the folded waveguides connected to the intermediate port, which can be connected only to the second input / output port in the second region, The second port intersects once each from the intermediate port through the reflection surface to the intermediate port that can be connected only to the first input / output port, and the second port in the third region. The folded waveguides connected to the intermediate port, which can be connected only to the input / output port, are each connected only to the first input / output port via the reflection surface from the intermediate port. An optical element characterized by intersecting each other once to reach the intermediate port. 9. The optical device according to claim 5, wherein the propagation path connection unit has an optical switching function. 10. The optical device according to claim 5, wherein the propagation path connecting portion has an optical multiplexing / demultiplexing function. 11. The optical device according to claim 5, wherein the propagation path connecting portion has an optical branching / coupling function. 12. The optical element according to claim 6, wherein the reflecting section is constituted by a quarter-wave plate and a reflecting mirror. 13. The optical device according to claim 6, wherein the optical signal input to the input / output port propagates until reaching the reflection surface (hereinafter, “outgoing waveguide”).
Say The total number of other waveguides that intersect with the waveguides (hereinafter, referred to as “return waveguides”) propagated from when the optical signal was reflected by the reflection surface to when it reached the input / output port. If the total number of other waveguides is not equal to the total number of optical waveguides, a dummy waveguide intersecting the outward waveguide or the return waveguide is provided, and the total number is made equal to each other. . 14. The optical device according to claim 9, wherein, when (2n) ² = m, the propagation path connecting portion includes 2n 1 × 2n first sub-optical switches, and 2n Each of the first sub-optical switches has one end connected to the 2n first input / output ports in a one-to-one relationship. The other end is connected to the m (= (2n) ² ) intermediate ports in a one-to-one relationship, and each of the second sub-optical switches has one end having 2n second input ports. It is connected in a one-to-one relationship with an output port, and has a one-to-one relationship with m (= (2n) ² ) intermediate ports that are not connected at the other end to the first sub-optical switch. And 2n intermediate ports connected to the same first sub-optical switch. An optical element, wherein 2n intermediate ports connected to different second sub-optical switches are connected in a one-to-one relationship by the respective folded waveguides.