JP5312309B2 - Optical multiplexer / demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical multiplexer/demultiplexer which can easily perform alignment of common ports and thereby reducing manufacturing cost. <P>SOLUTION: The optical multiplexer/demultiplexer 1A which multiplexes a plurality of optical signals having a wavelength different from each other into an optical signal with the wavelengths multiplexed and which demultiplexes the wavelength multiplexed optical signal into optical signals with respective wavelengths. The optical multiplexer/demultiplexer includes: a common port 11 for incidence and emission of a wavelength multiplexed optical signal; a plurality of channel ports 12-15 for incidence and emission of optical signals of respective wavelengths; and a multiple reflection part 20A which multiply reflexes the optical signals made incident from the common port 11 or the plurality of channel ports 12-15. The multiple reflection part 20A has a notch 311 by which optical signals having other than target wavelengths are reflected and made to exit from the common port 11, when the wavelength multiplexed optical signals containing optical signals of wavelengths other than target multiplexing or demultiplexing are made incident from the common port 11 at a prescribed design angle. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical multiplexer / demultiplexer that is used for optical communication and multiplexes or demultiplexes a plurality of optical signals having different wavelengths.

  In recent years, in the field of optical communications, optical transmission systems have been increased in speed and capacity, and as a core technology, wavelength division multiplexing (WDM) system that performs optical multiplex transmission with a single optical fiber has become widespread. Yes. In a WDM optical transmission system, a plurality of optical signals having different wavelengths are combined with a wavelength-multiplexed optical signal and output to a single optical transmission line, and a plurality of light signals having different wavelengths are combined. An optical multiplexer / demultiplexer is used that demultiplexes an optical signal that has been wavelength-multiplexed and entered from one optical transmission line into an optical signal for each wavelength. Here, in order to construct a large-capacity network to which the WDM optical transmission system is applied at low cost, it is required to reduce the cost of the optical multiplexer / demultiplexer.

In a conventional optical multiplexer / demultiplexer, all input / output ports (common ports, channel ports) are provided with a first virtual plane in which a plurality of wavelength selection elements are arranged in an array, and a plurality of light reflecting / condensing elements (reflection) (Elements) are arranged so as to be orthogonal to the second virtual plane arranged in an array (see, for example, Patent Document 1).
This makes it possible to easily align the input / output port with respect to the optical multiplexer / demultiplexer as compared with the case where the input / output port is arranged obliquely with respect to the first and second virtual planes. The manufacturing cost of the vessel can be reduced.

JP 2005-17683 A

However, the prior art has the following problems.
In the conventional optical multiplexer / demultiplexer, all input / output ports are connected to the first and second ports in order to reduce the loss caused by the incident light from the common port through which the wavelength multiplexed optical signal enters and exits from the design optical path. It is necessary to arrange so as to be orthogonal to the second virtual plane with high accuracy. For example, assuming that the distance between the first virtual plane and the second virtual plane is 5 mm, the optical signal that has been reflected six times when the common port is shifted by 0.1 ° deviates by about 60 μm from the design position. It will be. Therefore, in this example, in order to reduce the loss due to the deviation of the optical path, a highly accurate alignment of 0.1 ° or less is necessary, and there is a problem that the manufacturing cost cannot be reduced sufficiently.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical multiplexer / demultiplexer that can easily execute alignment of a common port and can reduce manufacturing costs. And

  An optical multiplexer / demultiplexer according to the present invention multiplexes a plurality of optical signals having different wavelengths into a wavelength-multiplexed optical signal and demultiplexes the wavelength-multiplexed optical signal into an optical signal for each wavelength. An optical multiplexer / demultiplexer, a common port for receiving and outputting wavelength-multiplexed optical signals, a plurality of channel ports for inputting and outputting optical signals for each wavelength, and light incident from the common port or the plurality of channel ports A multiple reflection unit that multi-reflects the signal, and the multiple reflection unit receives a wavelength-multiplexed optical signal including an optical signal having a wavelength not to be multiplexed or demultiplexed from a common port at a predetermined design angle. And a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port.

According to the optical multiplexer / demultiplexer according to the present invention, the multiple reflection unit allows the wavelength-multiplexed optical signal including the optical signal having a wavelength not to be multiplexed or demultiplexed at a predetermined design angle from the common port. It has a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port when it is incident. Thereby, the common port can be set to the designed angle by adjusting the angle of the common port so that the power of the optical signal emitted from the common port becomes the maximum value.
Therefore, it is possible to obtain an optical multiplexer / demultiplexer that can easily perform alignment of the common port and can reduce the manufacturing cost.

It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the relationship between the coupling efficiency of the incident light and the emitted light in the common port of the optical multiplexer / demultiplexer which concerns on Embodiment 1 of this invention, and the shift | offset | difference from the design angle of the incident angle of incident light. It is explanatory drawing which shows the relationship between the shift | offset | difference from the design angle of the incident angle of the incident light in the common port of the optical multiplexer / demultiplexer which concerns on Embodiment 1 of this invention, and optical power distribution and phase distribution. It is another block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 1 of this invention. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the relationship between the coupling efficiency of the incident light and the emitted light in the common port of the optical multiplexer / demultiplexer which concerns on Embodiment 2 of this invention, and the shift | offset | difference from the design angle of the incident angle of incident light. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 3 of this invention. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 4 of this invention. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 5 of this invention. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 6 of this invention. It is a block diagram which shows the optical multiplexer / demultiplexer which concerns on Embodiment 7 of this invention.

  Hereinafter, preferred embodiments of an optical multiplexer / demultiplexer according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a block diagram showing an optical multiplexer / demultiplexer 1A according to Embodiment 1 of the present invention.
In FIG. 1, an optical multiplexer / demultiplexer 1A includes an input / output port 11 (hereinafter referred to as “common port 11”) through which a wavelength-multiplexed optical signal enters and exits and an input / output port through which a single wavelength optical signal enters and exits. Output ports 12 to 15 (hereinafter referred to as “channel ports 12 to 15”) and a multiple reflection unit 20A that multi-reflects optical signals from the common port 11 or the channel ports 12 to 15 are provided.

  The common port 11 includes an optical fiber 111 and a lens 112. The channel ports 12 to 15 are configured by optical fibers 121 to 151 and lenses 122 to 152, respectively. Further, the common port 11 and the channel ports 12 to 15 are arranged so as to sandwich the multiple reflection portion 20A.

The multiple reflection unit 20A transmits only an optical signal in a desired wavelength band, reflects a light signal having a wavelength other than that, and reflects the incident optical signal with high efficiency. The reflection element 25 and the prism block 31 that fixes the wavelength selection elements 21 to 24 and the reflection element 25 so as to face each other are provided. Specifically, the wavelength selection elements 21 to 24 transmit only optical signals having wavelengths λ _{1 to} λ ₄ , respectively.

  Here, a cutout 311 having an angle orthogonal to the optical path of the optical signal is formed on one side of the prism block 31 on the common port 11 side. The notch 311 is a wavelength not included when a wavelength-multiplexed optical signal including an optical signal having a wavelength that is not subject to multiplexing or demultiplexing is incident from the common port 11 at a predetermined design angle. An optical signal having a vertical reflection is emitted from the common port 11 by vertical reflection.

Next, the demultiplexing operation of the optical multiplexer / demultiplexer 1A according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 conceptually shows an optical path of an optical signal propagated through the multiple reflection section 20A when the optical multiplexer / demultiplexer 1A is used as an optical demultiplexer.
First, a wavelength-multiplexed optical signal including a plurality of optical signals having _five different wavelengths λ _{1 to} λ ₅ is incident on the prism block 31 from the common port 11.

The optical signal incident on the prism block 31 is transmitted through the optical signal having the wavelength λ _{1 by} the wavelength selection element 21, and the wavelength-multiplexed optical signal including the optical signals having the remaining wavelengths λ _{2 to} λ ₅ is reflected. .
Subsequently, the wavelength multiplexed optical signal including the optical signals having the wavelengths λ _{2 to} λ ₅ is reflected by the reflecting element 25 toward the wavelength selecting element 22, and the optical signal having the wavelength λ ₂ is transmitted by the wavelength selecting element 22. Then, the wavelength-multiplexed optical signal including the remaining optical signals having the wavelengths λ _{3 to} λ ₅ is reflected.
By repeating the above operation, among the wavelength multiplexed optical signals incident from the common port 11, the optical signals having wavelengths λ _{1 to} λ ₄ are emitted from the channel ports 12 to 15, respectively.

At this time, the optical signal having the wavelength λ ₅ is vertically reflected by the notch 311 formed in the prism block 31, is again reflected between the wavelength selection elements 21 to 24 and the reflection element 25, and returned to the common port 11. It is.
Here, if the wavelength multiplexed optical signal comprising a plurality of optical signals having wavelengths lambda ₁ to [lambda] ₅ are incident at an angle as designed from common port 11 to the prism block 31, the wavelength lambda ₅ of the optical signal Is vertically reflected by the notch 311 and is emitted from the common port 11 along the same optical path as that at the time of incidence.

On the other hand, when a plurality of wavelength-multiplexed optical signal includes an optical signal having a wavelength lambda ₁ to [lambda] ₅ are incident at an angle different from that of the design from the common port 11 to the prism block 31, the wavelength lambda ₅ of the optical signal Is not vertically reflected by the notch 311 and is emitted from the common port 11 along an optical path different from that at the time of incidence. Note that when the outgoing optical path is deviated from the incident optical path, the power of the optical signal emitted from the common port 11 decreases.

  Therefore, the power of the optical signal emitted from the common port 11 is observed, and the angle between the common port 11 and the prism block 31 is adjusted so that the power of the optical signal becomes the maximum value. The prism block 31 can be set at an angle as designed.

  Next, a method of adjusting the angle between the common port 11 and the prism block 31 while observing the optical signal vertically reflected by the notch 311 in the optical multiplexer / demultiplexer 1A will be described in detail. The relationship between the coupling efficiency between the incident light at the common port 11 of the optical multiplexer / demultiplexer 1A and the outgoing light that is vertically reflected by the notch 311 and returned to the common port 11, and the deviation from the design angle of the incident angle of the incident light. As shown in FIG.

  FIG. 2 shows that a prism block 31 of 5 mm in length made of synthetic quartz (ES grade) with a refractive index of 1.448 has a wavelength of 1.3 μm which becomes a beam waist with a radius of 0.3 mm at the incident position of the prism block 31. The coupling efficiency when a Gaussian beam is incident is shown. The angle of the notch 311 is 3 °.

  From FIG. 2, when the incident light is incident at the designed angle, the coupling efficiency between the incident light and the outgoing light is −0.07 dB. On the other hand, when the incident light is incident with a deviation of 0.1 ° from the design angle, the coupling efficiency between the incident light and the outgoing light is −14.9 dB, and the incident light is 0.2 ° from the design angle. When the light is incident with a deviation, the coupling efficiency between the incident light and the outgoing light is −59.3 dB. That is, as the angular deviation increases, the coupling efficiency to the common port 11 rapidly decreases.

  For this reason, the exit light coupled to the common port 11 is observed, and the angle between the common port 11 and the prism block 31 is adjusted so that the coupling efficiency between the incident light and the exit light becomes the maximum value. Can be aligned to the designed angle.

Here, the principle that the coupling efficiency between the incident light and the outgoing light decreases as the incident angle of the incident light deviates from the design angle will be described.
First, the coupling efficiency | C | ² of two different beams is expressed by the following equation (1).

In Equation (1), E ₁ (x, y) and E ₂ (x, y) indicate the electric field distribution of each beam, and φ ₁ (x, y) and φ ₂ (x, y) indicate the respective beams. The phase distribution of is shown.
From the equation (1), it can be seen that the coupling efficiency increases when the phase distributions match in a region where the electric field distributions match and the electric field strength is large.

FIG. 3 shows the relationship between the deviation of the incident angle of incident light at the common port 11 of the optical multiplexer / demultiplexer 1A from the design angle, the optical power distribution (the square of the electric field distribution) and the phase distribution.
FIG. 3 shows the optical power distribution and phase distribution of the emitted light when the incident light and the deviation of the incident angle of the incident light from the design angle are 0.0 °, 0.1 °, and 0.2 °. Yes.
As can be seen from FIG. 3, the optical power distribution and the phase distribution change as the angular deviation increases, and the coupling efficiency to the common port 11 decreases. The reason why the phase distribution changes due to the tilt of the beam is that the cross section in which the calculation of equation (1) is calculated and the optical axis of the beam are not orthogonal.

As described above, according to the first embodiment, the multiple reflection unit allows the wavelength-multiplexed optical signal including the optical signal having a wavelength not to be multiplexed or demultiplexed to be a predetermined design angle from the common port. And a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port. The reflection mechanism is a notch having an angle that is formed on one side of the prism block and vertically reflects an optical signal having an untargeted wavelength. Thereby, the common port can be set to the designed angle by adjusting the angle of the common port so that the power of the optical signal emitted from the common port becomes the maximum value.
Therefore, it is possible to obtain an optical multiplexer / demultiplexer that can easily perform alignment of the common port and can reduce the manufacturing cost.

In the first embodiment, the case where four channel ports 12 to 15 and four wavelength selection elements 21 to 24 are arranged has been described. However, the present invention is not limited to this. The number may be three or five or more.
In the first embodiment, the case where the prism block 31 is synthetic quartz (ES grade) has been described. However, the present invention is not limited to this, and the prism block may be other synthetic quartz, artificial quartz, Si, GaAs, or InP. It may be a semiconductor such as.
In the first embodiment, the reflection element 25 is provided in the notch 311 in order to improve the reflectance. However, the present invention is not limited to this, and wavelength selection such as a band cut filter, a low-pass filter, or a high-pass filter is possible. An element may be provided.
In these cases, the same effect as in the first embodiment can be obtained.

In the first embodiment, the numerical values of the optical multiplexer / demultiplexer 1A and the shapes of the prism block 31 and the notch 311 are not limited to those described above.
In the first embodiment, the wavelength selection elements 21 to 24 may be a dielectric multilayer film such as a band pass filter, a low pass filter or a high pass filter, or may be an etalon filter or the like.
In the first embodiment, the optical fibers 121 to 151 and the lenses 122 to 152 constituting the channel ports 12 to 15 may be laser diodes (LDs) and lenses, respectively, or photodiodes. (PD: Photo Diode) and a lens may be sufficient, or only LD or only PD may be sufficient.
In these cases, the same effect as in the first embodiment can be obtained.

In the first embodiment, as shown in FIG. 4, gonio mechanisms 101 and 102 may be provided on the common port 11, the channel ports 12 to 15, and the package 100 that fixes the prism block 31, respectively.
In this case, the angle between the common port 11 and the prism block 31 can be easily fixed at a desired angle.
This can be similarly applied to the following embodiments.

Embodiment 2. FIG.
5 is a block diagram showing an optical multiplexer / demultiplexer 1B according to Embodiment 2 of the present invention.
In FIG. 5, the optical multiplexer / demultiplexer 1B includes a multiple reflection unit 20B instead of the multiple reflection unit 20A shown in FIG.

  The multiple reflection unit 20B transmits only an optical signal in a desired wavelength band, reflects a light signal having a wavelength other than that, and reflects the incident optical signal with high efficiency. The reflection element 25 and the prism block 41 that fixes the wavelength selection elements 21 to 24 and the reflection element 25 so as to face each other are provided.

  Here, a cutout 411 having an angle orthogonal to the optical path of the optical signal is formed on one side of the prism block 41 on the common port 11 side. In addition, a curved condensing unit 412 that condenses the beam of the optical signal diffused by the prism block 41 is provided at a portion of the prism block 41 where the optical signal is reflected by the reflecting element 25. Other configurations are the same as those in FIG.

The condensing part 412 has a lens effect. For this reason, for example, even when a Gaussian beam having a small beam waist diameter and easily diffusing is incident, the optical signal is propagated over a long distance while the beam is condensed and the beam diameter is kept constant. be able to.
The relationship between the coupling efficiency between the incident light at the common port 11 of the optical multiplexer / demultiplexer 1B and the outgoing light reflected by the notch 411 and returned to the common port 11 and the deviation of the incident angle of the incident light from the design angle is shown. It is shown in FIG.

6 shows a prism block 41 having a refractive index of 1.448 and made of synthetic quartz (ES grade) having a length of 1.3 μm and a beam waist having a radius of 0.1 mm at the incident position of the prism block 41. The coupling efficiency when a Gaussian beam is incident is shown. The angle of the notch 411 is 3 °.
As shown in FIG. 6, compared with the first embodiment having a beam waist diameter of 0.3 mm, the coupling is equivalent to that of the first embodiment although the beam waist diameter is 1/3. It turns out that efficiency is obtained.

As described above, according to the second embodiment, a curved-surface condensing unit that condenses the beam of the optical signal diffused by the prism block is provided at the portion of the prism block where the optical signal is reflected by the reflecting element. Is provided.
Therefore, the same effect as in the first embodiment can be obtained, and an optical signal can be propagated over a long distance even when a beam having a small beam waist diameter and easily diffused is incident.

In the second embodiment, the case where three light collecting portions 412 are provided is shown, but the number of light collecting portions is not limited to this.
In the second embodiment, the beam waist diameter of the incident Gaussian beam is not limited to 0.1 mm, and may be larger or smaller than this.
In these cases, the same effect as in the second embodiment can be obtained.

Embodiment 3 FIG.
FIG. 7 is a block diagram showing an optical multiplexer / demultiplexer 1C according to Embodiment 3 of the present invention.
In FIG. 7, an optical multiplexer / demultiplexer 1C includes a multiple reflection unit 20C instead of the multiple reflection unit 20A shown in FIG.

  The multiple reflection unit 20C transmits only an optical signal in a desired wavelength band, reflects a light signal having a wavelength other than that, and reflects the incident optical signal with high efficiency. The reflection element 25, the prism block 51 that fixes the wavelength selection elements 21 to 24 and the reflection element 25 so as to face each other, and a block 52 that is fixed to one side of the prism block 51 are provided. Other configurations are the same as those in FIG.

  The block 52 has an inclined surface having an angle orthogonal to the optical path of the optical signal. The block 52 is provided with a reflective element 25 in order to improve the reflectance on the inclined surface. Further, the block 52 is configured so that a wavelength-multiplexed optical signal including an optical signal having a wavelength that is not subject to multiplexing or demultiplexing is incident on the common port 11 at a predetermined design angle. An optical signal having a wavelength is reflected vertically from the inclined surface and emitted from the common port 11.

As described above, according to the third embodiment, the reflection mechanism is a block that is fixed to one side of the prism block and has an inclined surface having an angle that vertically reflects an optical signal having an untargeted wavelength. That is, in the first embodiment, a notch is formed on one side of the prism block. However, in the third embodiment, an inclined surface is formed on a block smaller than the prism block and is fixed to the prism block.
Therefore, the same effect as in the first embodiment can be obtained, and the material cost can be reduced as compared with that in the first embodiment.
In the third embodiment, similarly to the second embodiment, a curved condensing unit that condenses the beam of the optical signal diffused by the prism block may be provided.

Embodiment 4 FIG.
In the optical multiplexers / demultiplexers 1A to 1C shown in the first to third embodiments, the Gaussian beam propagating in the free space such as the prism block has to be diffused in principle, and the channel ports increase and propagate. When the distance becomes long, there is a problem that the spread of the beam changes for each channel port.
In the fourth embodiment, an optical multiplexer / demultiplexer that can solve such problems will be described.

FIG. 8 is a block diagram showing an optical multiplexer / demultiplexer 1D according to Embodiment 4 of the present invention.
In FIG. 8, an optical multiplexer / demultiplexer 1D includes a multiple reflection unit 20D instead of the multiple reflection unit 20A shown in FIG.

  The multiple reflection unit 20D transmits only an optical signal in a desired wavelength band and reflects optical signals having other wavelengths, and reflects the incident optical signal with high efficiency. The reflection element 25 and the substrate 61 that fixes the wavelength selection elements 21 to 24 and the reflection element 25 so as to face each other are provided.

Here, an optical waveguide 611 and a reflection mechanism 612 are formed on the substrate 61. Other configurations are the same as those in FIG.
The optical waveguide 611 guides an optical signal in a specific direction by confining an optical signal in a minute region. The reflection mechanism 612 also excludes a wavelength multiplexed optical signal including an optical signal having a wavelength that is not subject to multiplexing or demultiplexing from the common port 11 at a predetermined design angle. An optical signal having a wavelength of 1 is vertically reflected on the inclined surface and emitted from the common port 11.

As described above, according to the fourth embodiment, the multiple reflection section has the substrate on which the optical waveguide that guides the optical signal in a specific direction is formed. The reflection mechanism is formed on the substrate and vertically reflects an optical signal having a wavelength outside the target.
Therefore, the same effect as in the first embodiment can be obtained, and even if the propagation distance of the optical signal is different for each channel port by propagating the beam through the optical waveguide, all are the same. An optical signal can be incident with an optical waveform.
Further, since the optical waveguide and the reflection mechanism can be integrally formed on the substrate 61, the manufacturing cost can be reduced.

In the fourth embodiment, the wavelength selection elements 21 to 24, the reflection element 25, or the reflection mechanism 612 may be a dielectric multilayer film such as a filter, or may be a grating formed on the substrate 61 or the like. A structure having a periodic refractive index distribution may be used.
In the fourth embodiment, the optical waveguide 611 may be a fine wire waveguide, a rib waveguide, or a buried waveguide.
In the fourth embodiment, the substrate 61 may be a semiconductor such as Si, GaAs, or InP, or may be a dielectric such as niobium lithium oxide.

Embodiment 5 FIG.
FIG. 9 is a block diagram showing an optical multiplexer / demultiplexer 1E according to Embodiment 5 of the present invention.
In FIG. 9, an optical multiplexer / demultiplexer 1E includes a multiple reflection unit 20E instead of the multiple reflection unit 20A shown in FIG.

  The multiple reflection portion 20E includes a rib-type optical waveguide 711, a grating (diffraction grating) 712, a slab 713 having the grating 712 as a side wall, rib-type optical waveguides 714 to 718, and a vertical end surface formed on a Si (silicon) substrate 71. 719. Other configurations are the same as those in FIG.

The rib-type optical waveguide 711 guides an optical signal in a specific direction by confining an optical signal in a minute region. The grating 712 has a function of reflecting the optical signal at different angles depending on the wavelength and condensing the optical signal beam, and has a so-called Rawland circular structure. The rib-type optical waveguides 714 to 718 are designed so that each of the optical signals collected at different positions for each wavelength by the grating 712 can be coupled with high efficiency. Specifically, the rib-type optical waveguides 714 to 718 are designed to couple with optical signals having wavelengths λ _{1 to} λ ₅ , respectively.

  The vertical end face 719 receives a wavelength-multiplexed optical signal including an optical signal having a wavelength not to be multiplexed or demultiplexed from the common port 11 at a predetermined design angle, and is propagated through the rib-type optical waveguide 718. In this case, an optical signal having a wavelength outside the target is vertically reflected and emitted from the common port 11.

  Subsequently, a demultiplexing operation of the optical multiplexer / demultiplexer 1E according to the fifth embodiment of the present invention will be described with reference to FIG. FIG. 9 conceptually shows the optical path of the optical signal multiplexed / demultiplexed by the grating 712.

First, a wavelength-multiplexed optical signal including a plurality of optical signals having _five different wavelengths λ _{1 to} λ ₅ is incident on the slab 713 from the common port 11 via the rib optical waveguide 711.
The optical signal incident on the slab 713 is propagated while diffusing in the slab 713, reflected and condensed at different angles for each wavelength by the grating 712, and respectively incident on the rib-type optical waveguides 714 to 718.

Thereby, among the wavelength-multiplexed optical signals incident from the common port 11, optical signals having wavelengths λ _{1 to} λ ₄ are emitted from the channel ports 12 to 15, respectively.
At this time, the optical signal having the wavelength λ ₅ is vertically reflected by the vertical end surface 719 formed at the tip of the rib-type optical waveguide 718, propagated again through the slab 713, the grating 712, and the rib-type optical waveguide 711, Returned to

Here, when a wavelength-multiplexed optical signal including a plurality of optical signals having wavelengths λ _{1 to} λ ₅ is incident on the rib-type optical waveguide 711 from the common port 11 at the designed position and angle, the common port The coupling from 11 to the rib-type optical waveguide 711 is maximized. At this time, the power of the optical signal having the wavelength λ ₅ that is vertically reflected by the vertical end face 719 and is emitted from the common port 11 is maximized.

Therefore, the power of the optical signal having the wavelength λ ₅ emitted from the common port 11 is observed, and the position and angle of the common port 11 and the Si substrate 71 are adjusted so that the power of the optical signal becomes the maximum value. Thus, the common port 11 and the rib-type optical waveguide 711 can be set to an angle as designed.

As described above, according to the fifth embodiment, the multiple reflection unit allows the wavelength-multiplexed optical signal including the optical signal having a wavelength not to be multiplexed or demultiplexed to be a predetermined design angle from the common port. And a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port. The reflection mechanism is formed on a substrate provided with an optical waveguide and a diffraction grating, and vertically reflects an optical signal having a wavelength outside the target. Thereby, the common port can be set to the designed angle by adjusting the position and angle of the common port so that the power of the optical signal emitted from the common port becomes the maximum value.
Therefore, it is possible to obtain an optical multiplexer / demultiplexer that can easily perform alignment of the common port and can reduce the manufacturing cost.

In the fifth embodiment, the case where four channel ports 12 to 15 are arranged has been described. However, the present invention is not limited to this, and the number of channel ports may be two or three, or five or more. It may be.
In the fifth embodiment, the case where the substrate 71 is Si has been described. However, the present invention is not limited to this, and the substrate may be a semiconductor such as Ge, GaAs, or InP, or may be niobium lithium oxide or the like. It may be a dielectric.
In the fifth embodiment, the rib type optical waveguides 711 and 714 to 718 have been described as examples. However, the optical waveguide is not limited to the rib type, and is a thin wire type, a buried type, or a photonic crystal guide. It may be like a waveguide.
In these cases, the same effect as in the fifth embodiment can be obtained.

In the fifth embodiment, the shape of the substrate 71 is not limited to that described above.
In the fifth embodiment, the vertical end surface 719 may be a reflective film, a band-pass filter, a low-pass filter, or a high-pass filter in order to increase the reflectance, or may be a reflection formed on the rib-type optical waveguide 718. It may be a grating.
In the fifth embodiment, the optical fibers 121 to 151 and the lenses 122 to 152 constituting the channel ports 12 to 15 may be laser diodes (LD) and lenses, respectively, or photodiodes (PD). And a lens, or only LD or only PD.
In the fifth embodiment, the common port 11 and the channel ports 12 to 15 may be formed outside the substrate 71, directly fixed on the substrate 71, or integrally formed with the substrate 71. May be.
In these cases, the same effect as in the fifth embodiment can be obtained.

Embodiment 6 FIG.
FIG. 10 is a block diagram showing an optical multiplexer / demultiplexer 1F according to Embodiment 6 of the present invention.
In FIG. 10, the optical multiplexer / demultiplexer 1F includes a multiple reflection unit 20F instead of the multiple reflection unit 20A shown in FIG.

  The multiple reflection portion 20F includes a rib-type optical waveguide 811, an arrayed-wavelength grating (AWG) 812, rib-type optical waveguides 815 to 819, and vertical end surfaces formed on a Si (silicon) substrate 81. 820. The AWG 812 includes a slab waveguide 813 and a plurality of waveguides 814 having different lengths. Other configurations are the same as those in FIG.

The rib optical waveguide 811 guides an optical signal in a specific direction by confining an optical signal in a minute region. The AWG 812 collects the optical signal at a specific position that differs depending on the wavelength. The rib-type optical waveguides 815 to 819 are designed so that each of the optical signals collected at different positions for each wavelength by the AWG 812 can be coupled with high efficiency. Specifically, the rib-type optical waveguides 815 to 819 are designed to couple with optical signals having wavelengths λ _{1 to} λ ₅ , respectively.

  The vertical end face 820 receives a wavelength-multiplexed optical signal including an optical signal having a wavelength not to be multiplexed or demultiplexed from the common port 11 at a predetermined design angle, and propagates through the rib optical waveguide 819. In this case, an optical signal having a wavelength outside the target is vertically reflected and emitted from the common port 11.

  Subsequently, a demultiplexing operation of the optical multiplexer / demultiplexer 1F according to the sixth embodiment of the present invention will be described with reference to FIG.

First, a wavelength-multiplexed optical signal including a plurality of optical signals having _five different wavelengths λ _{1 to} λ ₅ is incident on the AWG 812 from the common port 11 via the rib optical waveguide 811.
The optical signals incident on the AWG 812 are condensed at different positions for each wavelength and are incident on the rib-type optical waveguides 815 to 819, respectively.

Thereby, among the wavelength-multiplexed optical signals incident from the common port 11, optical signals having wavelengths λ _{1 to} λ ₄ are emitted from the channel ports 12 to 15, respectively.
At this time, the optical signal having the wavelength λ ₅ is vertically reflected by the vertical end face 820 formed at the tip of the rib optical waveguide 819, propagated again through the AWG 812 and the rib optical waveguide 811, and returned to the common port 11.

Here, when a wavelength-multiplexed optical signal including a plurality of optical signals having wavelengths λ _{1 to} λ ₅ is incident on the rib-shaped optical waveguide 811 from the common port 11 at a designed position and angle, the common port The coupling from 11 to the rib-type optical waveguide 811 is maximized. At this time, the power of the optical signal having the wavelength λ ₅ that is vertically reflected by the vertical end face 820 and emitted from the common port 11 is maximized.

Therefore, the power of the optical signal having the wavelength λ ₅ emitted from the common port 11 is observed, and the position and angle of the common port 11 and the Si substrate 81 are adjusted so that the power of the optical signal becomes the maximum value. Thus, the common port 11 and the rib-type optical waveguide 811 can be set at an angle as designed.

As described above, according to the sixth embodiment, the multiple reflection unit is configured such that a wavelength-multiplexed optical signal including an optical signal having a wavelength that is not subject to multiplexing or demultiplexing is a predetermined design angle from the common port. And a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port. The reflection mechanism is formed on a substrate provided with an optical waveguide and a diffraction grating, and vertically reflects an optical signal having a wavelength outside the target.
Therefore, the same effect as in the fifth embodiment can be obtained.

In the sixth embodiment, the case where four channel ports 12 to 15 are arranged has been described. However, the present invention is not limited to this, and the number of channel ports may be two or three, or five or more. It may be.
In the sixth embodiment, the case where the substrate 81 is Si has been described. However, the present invention is not limited to this, and the substrate may be a semiconductor such as Ge, GaAs, or InP, or may be niobium lithium oxide or the like. It may be a dielectric.
In the sixth embodiment, the rib-type optical waveguides 811 and 815 to 819 have been described as examples. However, the optical waveguide is not limited to the rib type, but is a thin wire type, a buried type, or a photonic crystal guide. It may be like a waveguide.
In these cases, the same effect as in the sixth embodiment can be obtained.

In the sixth embodiment, the shape of the substrate 81 is not limited to that described above.
In the sixth embodiment, the vertical end surface 820 may be a reflective film, a band-pass filter, a low-pass filter, or a high-pass filter to increase the reflectance, or may be a reflection formed on the rib-type optical waveguide 819. It may be a grating.
In the sixth embodiment, the optical fibers 121 to 151 and the lenses 122 to 152 constituting the channel ports 12 to 15 may be laser diodes (LD) and lenses, respectively, or photodiodes (PD). And a lens, or only LD or only PD.
In the sixth embodiment, the common port 11 and the channel ports 12 to 15 may be formed outside the substrate 81, directly fixed on the substrate 81, or integrally formed with the substrate 81. May be.
In these cases, the same effect as in the sixth embodiment can be obtained.

Embodiment 7 FIG.
FIG. 11 is a block diagram showing an optical multiplexer / demultiplexer 1G according to Embodiment 7 of the present invention.
In FIG. 11, the optical multiplexer / demultiplexer 1G includes a multiple reflection unit 20G in place of the multiple reflection unit 20A shown in FIG.

The multiple reflection unit 20G is opposed to a plurality of wavelength selection elements 91 to 94 that transmit only an optical signal in a desired wavelength band and reflect an optical signal having other wavelengths, and a plurality of wavelength selection elements 91 to 94. And a reflecting element 95 that reflects the incident optical signal with high efficiency, and a synthetic quartz prism block 96 to which the reflecting element is attached. Specifically, the wavelength selection elements 91 to 94 transmit only optical signals having wavelengths λ _{1 to} λ ₄ , respectively. Other configurations are the same as those in FIG.

  The prism block 96 has an inclined surface having an angle perpendicular to the optical path of the optical signal. The reflective element is attached to the inclined surface of the prism block 96 to improve the reflectance on the inclined surface. Also, the prism block 96 excludes a wavelength-multiplexed optical signal including an optical signal having a wavelength that is not subject to multiplexing or demultiplexing from the common port 11 at a predetermined design angle. An optical signal having a wavelength of 1 is vertically reflected on the inclined surface and emitted from the common port 11.

Subsequently, a demultiplexing operation of the optical multiplexer / demultiplexer 1G according to the seventh embodiment of the present invention will be described with reference to FIG. FIG. 11 conceptually shows an optical path of an optical signal propagated through the multiple reflector 20G when the optical multiplexer / demultiplexer 1G is used as an optical demultiplexer.
First, a wavelength-multiplexed optical signal including a plurality of optical signals having _five different wavelengths λ _{1 to} λ ₅ is incident on the multiple reflection unit 20G from the common port 11.

Optical signal incident on multiple reflection portion 20G is transmitted optical signal of the wavelength lambda ₁ is the wavelength selecting element 91, a wavelength multiplexed optical signal containing optical signals of the remaining wavelengths lambda ₂ to [lambda] ₅ is reflected The
Subsequently, the wavelength multiplexed optical signal including the optical signals having the wavelengths λ _{2 to} λ ₅ is reflected by the reflecting element 95 toward the wavelength selecting element 92, and the optical signal having the wavelength λ ₂ is transmitted by the wavelength selecting element 92. Then, the wavelength-multiplexed optical signal including the remaining optical signals having the wavelengths λ _{3 to} λ ₅ is reflected.
By repeating the above operation, among the wavelength multiplexed optical signals incident from the common port 11, the optical signals having wavelengths λ _{1 to} λ ₄ are emitted from the channel ports 12 to 15, respectively.

At this time, the optical signal having the wavelength λ ₅ is vertically reflected by the prism block 96, is again subjected to multiple reflections between the wavelength selection elements 91 to 94 and the reflection element 95, and is returned to the common port 11.
Here, the optical signal wavelength-multiplexed comprises a plurality of optical signals having wavelengths lambda ₁ to [lambda] ₅ is, when incident at an angle as designed from common port 11 to the multiple reflection portion 20G, the wavelength lambda ₅ of light The signal is vertically reflected by the prism block 96 and is emitted from the common port 11 along the same optical path as that at the time of incidence.

On the other hand, the wavelength multiplexed optical signal comprising a plurality of optical signals having wavelengths lambda ₁ to [lambda] ₅ is, when incident at an angle different from that of the design from the common port 11 to the multiple reflection portion 20G, the wavelength lambda ₅ of light The signal is not vertically reflected by the prism block 96 but is emitted from the common port 11 along an optical path different from that at the time of incidence. Note that when the outgoing optical path is deviated from the incident optical path, the power of the optical signal emitted from the common port 11 decreases.

  Therefore, the power of the optical signal emitted from the common port 11 is observed, and the angle of the common port 11 and the multiple reflection unit 20G is adjusted so that the power of the optical signal becomes the maximum value, thereby the common port 11 And the multiple reflection portion 20G can be set at the designed angles.

As described above, according to the seventh embodiment, the multiple reflection unit is configured such that a wavelength-multiplexed optical signal including an optical signal having a wavelength that is not to be multiplexed or demultiplexed is a predetermined design angle from the common port. And a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits it from the common port. The reflection mechanism is a block having an inclined surface having an angle that vertically reflects an optical signal having a wavelength that is not the target. Thereby, the common port can be set to the designed angle by adjusting the angle of the common port so that the power of the optical signal emitted from the common port becomes the maximum value.
Therefore, it is possible to obtain an optical multiplexer / demultiplexer that can easily perform alignment of the common port and can reduce the manufacturing cost.

In the seventh embodiment, the case where four channel ports 12 to 15 and four wavelength selection elements 91 to 94 are arranged has been described. However, the present invention is not limited to this. The number may be three or five or more.
In the seventh embodiment, the prism block 96 is made of synthetic quartz. However, the present invention is not limited to this, and the prism block may be a metal block.
In the seventh embodiment, the reflecting element is provided on the inclined surface of the prism block 96 in order to improve the reflectance. However, the present invention is not limited to this, and a band cut filter, a low-pass filter, a high-pass filter, etc. A wavelength selection element may be provided.
In these cases, the same effect as in the seventh embodiment can be obtained.

In the seventh embodiment, the shape of the optical multiplexer / demultiplexer 1G and the shape of the prism block 96 are not limited to those described above.
In the seventh embodiment, the wavelength selection elements 91 to 94 may be a dielectric multilayer film such as a bandpass filter, a lowpass filter, or a highpass filter, or an etalon filter.
In the seventh embodiment, the optical fibers 121 to 151 and the lenses 122 to 152 constituting the channel ports 12 to 15 may be laser diodes (LD) and lenses, respectively, or photodiodes (PD). And a lens, or only LD or only PD.
In these cases, the same effect as in the seventh embodiment can be obtained.

  1A to 1G optical multiplexer / demultiplexer, 11 common port, 12 to 15 channel port, 20A to 20G multiple reflection section, 21 to 24, 91 to 94 wavelength selection element, 25, 95 reflection element, 31, 41, 51, 96 prism Block, 52 Block (reflection mechanism), 61, 71, 81 Substrate, 100 package, 101, 102 Gonior mechanism, 311, 411 Notch (reflection mechanism), 412 Condensing part, 611 Optical waveguide, 612 Reflection mechanism, 711, 714 to 718 Rib type optical waveguide, 712 grating, 719 vertical end face (reflection mechanism), 811, 815 to 819 Rib type optical waveguide, 812 AWG, 813 Slab waveguide, 814 waveguide, 820 Vertical end face (reflection mechanism).

Claims (8)

An optical multiplexer / demultiplexer that multiplexes a plurality of optical signals having different wavelengths into a wavelength-multiplexed optical signal and demultiplexes the wavelength-multiplexed optical signal into optical signals for each wavelength,
A common port through which the wavelength-multiplexed optical signal enters and exits;
A plurality of channel ports through which optical signals for each wavelength enter and exit;
A multiple reflection unit that multiple-reflects the optical signal incident from the common port or the plurality of channel ports, and
The multiple reflection unit, when the wavelength-multiplexed optical signal including an optical signal having a wavelength outside the target of the multiplexing or demultiplexing is incident at a predetermined design angle from the common port, An optical multiplexer / demultiplexer comprising a reflection mechanism that reflects an optical signal having a wavelength outside the target and emits the optical signal from the common port. The multiple reflection part is
A plurality of wavelength selection elements that transmit only an optical signal in a desired wavelength band and reflect an optical signal having other wavelengths;
A reflective element that reflects the incident optical signal;
A prism block that fixes the plurality of wavelength selection elements and the reflection element so as to face each other;
2. The optical multiplexer / demultiplexer according to claim 1, wherein the reflection mechanism is a cutout formed at one side of the prism block and having an angle at which an optical signal having a wavelength outside the target is vertically reflected. The multiple reflection part is
A plurality of wavelength selection elements that transmit only an optical signal in a desired wavelength band and reflect an optical signal having other wavelengths;
A reflective element that reflects the incident optical signal;
A prism block that fixes the plurality of wavelength selection elements and the reflection element so as to face each other;
2. The optical multiplexing / demultiplexing according to claim 1, wherein the reflection mechanism is a block having an inclined surface that is fixed to one side of the prism block and vertically reflects an optical signal having a wavelength outside the target. vessel.   The curved prism-shaped condensing part which condenses the beam of the optical signal diffused by the prism block is provided in the part of the prism block where the optical signal is reflected by the reflecting element. The optical multiplexer / demultiplexer according to claim 3. The multiple reflection part is
A plurality of wavelength selection elements that transmit only an optical signal in a desired wavelength band and reflect an optical signal having other wavelengths;
A reflective element that reflects the incident optical signal;
The plurality of wavelength selection elements and the reflection element are fixed so as to face each other, and a substrate on which an optical waveguide for guiding an optical signal in a specific direction is formed,
2. The optical multiplexer / demultiplexer according to claim 1, wherein the reflection mechanism is formed on the substrate and vertically reflects an optical signal having a wavelength outside the target. The multiple reflection unit includes a substrate on which an optical waveguide that guides an optical signal in a specific direction and a diffraction grating that collects the optical signal at different positions depending on the wavelength,
2. The optical multiplexer / demultiplexer according to claim 1, wherein the reflection mechanism is formed on the substrate and vertically reflects an optical signal having a wavelength outside the target. The multiple reflection part is
A plurality of wavelength selection elements that transmit only an optical signal in a desired wavelength band and reflect an optical signal having other wavelengths;
A reflective element that is provided opposite to the plurality of wavelength selection elements and reflects an incident optical signal;
2. The optical multiplexer / demultiplexer according to claim 1, wherein the reflection mechanism is a block having an inclined surface having an angle at which an optical signal having a wavelength outside the target is vertically reflected. 3.   The optical multiplexer / demultiplexer according to any one of claims 1 to 7, wherein a gonio mechanism is provided for each of the common port, the channel port, and a package for fixing the multiple reflection unit.

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