JP3500176B2 - Optical prism and optical device thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical prism and an optical device including the optical prism applicable to a wide range of optical fields such as optical communication equipment and optical measuring devices.

[0002]

2. Description of the Related Art In optical devices used for optical communication equipment and the like, optical transmission technology equipped with an optical amplification system in a long-distance optical communication network has been rapidly developed, and large-capacity signal transmission can be instantly performed all over the world. It is about to be distributed. Almost all the technical difficulties in the early stages have been solved on a laboratory scale, but in consideration of actual mass production, multiplexing of pump light sources, demultiplexers, and polarization-independent optical isolators placed between optical fibers are considered. In the case of mounting an optical passive component such as, the finish degree and shape intersection of each component are directly reflected in the assembly accuracy and the ease of assembly.

Therefore, it is a necessary condition that those optical parts are structured to be easily assembled with high precision. For example, when a device having a certain function is inserted between optical fibers and optical coupling is achieved through a lens, the light beam propagation direction is defined as the z axis and the orthogonal direction is defined as the x axis and the y axis. However, the adjustment of the propagating ray coupling axis (hereinafter referred to as axis alignment) is not limited to these z, x, y3 directions, but the meridian direction centered on the z axis is the θ axis, and the direction orthogonal to the meridian is the φ axis. It is also necessary to adjust the angle.

That is, ideally, the axis alignment should be spatially adjusted in five directions, but in the field of a communication switch or the like in which related systems must be condensed in a limited space, an optical isolator, etc. The thickness allotted to the passive optical components is limited to about 8 mm or less than 8 mm, and it is impossible to expect a space where individual components can be freely adjusted and aligned. Therefore, it is required to reduce the degree of freedom of components in advance.

On the other hand, in the optical amplification system and the like, cost reduction of the signal beam transmission / reception system should be carried out as a matter of course, but the present situation is, for example, as shown in FIG. The structure shown in Fig. 262) has been attempted, and since each component constitutes an independent serial optical path, the number of components in the entire system increases, and the facility must be economically expensive. Absent. For example, in FIG. 12, an in-line type non-polarization optical isolator 3A, an optical multiplexer 4A, an optical pumping pump light source 5A, which is inserted between the optical coupling fibers of the signal input port 1A and the output port 2A,
6A, a wavelength selection filter 7A, a non-polarizing beam splitter 8A for extracting monitor light, etc. are arranged independently or in a state where they are bonded with an adhesive, and of course the optical characteristics such as optical coupling efficiency and optical absorption loss However, there remain problems in manufacturing complexity, reduction in the number of parts, and the like.

On the other hand, there are already a large number of optical components for deflecting the light beam direction at right angles as referred to in the present invention, and they are used according to their respective applications. For example, FIG. 13 shows an example of the penta prism. The incident light can be deflected by 90 degrees as in the present invention, but when used as a wavelength multiplexer / demultiplexer as proposed by the present invention, the parallelism of the transmitted light with respect to the incident light is also a very important structural advantage. However, as is easily recognized from the figure, there is a problem that the parallelism of transmitted light cannot be maintained.

There is also a structure in which a dielectric multilayer film is formed in the middle of a triangular prism as a multiplexer / demultiplexer and the triangular prisms of the same shape are bonded together. In that case, the light beam is incident at 45 degrees, and the incident light polarization vector s There is a large difference in the transmission wavelength characteristic (dispersion characteristic) between the wave and the p-wave, and when used in an optical amplification system, the bonding surface is considered to be a factor that impairs long-term reliability. Therefore, as an optical multiplexer / demultiplexer, there is also a structure in which a multiplexer / demultiplexer film is formed on one surface of a parallel plate as shown in FIG. 14, and the parallelism of the transmitted light with respect to the incident light is maintained, but in this case it is shown in the drawing. As described above, the angle variation of the flat plate with respect to the incident light ray causes a large variation in the outgoing light ray direction, and there arises a disadvantage that it becomes difficult to align the combined or demultiplexed light ray directions, and thus it is used for the application intended to be achieved by the present invention. There is a problem that you cannot do it.

The present invention has been made in order to solve the above problems, and provides an optical prism which can easily combine and demultiplex light and an optical device which is easy to assemble using the optical prism. With the goal.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is such that a portion of a prismatic body having a rectangular cross section or a square cross-section on the side of two ridges located obliquely is a prismatic side surface as a prism surface. On the other hand, it is formed on prism surfaces that are inclined surfaces that are parallel to each other and form 45 degrees, and the cross-sectional shape is hexagonal.

In this optical prism, the first incident light incident from the one prism surface and the second incident light incident from the other prism surface deviated from the first prism surface by 90 degrees and the first incident light It is preferable that the ellipticity of the polarized light orthogonal to each of the second outgoing lights is 100 to 90%.

According to a second aspect of the present invention, in this optical prism, the first incident light incident from one prism surface and the other incident prism surface shifted by 90 degrees with respect to the first prism surface. The ellipticity of the polarization of the outgoing light combined by the second incident light may be 100 to 90%.

Further, in this optical prism, a reflecting mirror may be provided on a pair of parallel prism surfaces among the prism surfaces.

According to a sixth aspect of the present invention, the two-ridge-line-side portions located diagonally to the prismatic body having a rectangular or square cross section have a prism surface of 45 to the prismatic side surface.
It is formed on the prism surface which is a slope that is parallel to each other at a certain degree,
With respect to the first and second prism surfaces that are parallel to each other, the incident angle is within 0 to 10 degrees from the third and fourth prism surfaces that are parallel to each other and are adjacent to the second and first prism surfaces, respectively. The angle of the optical prism is made such that the first light ray is made incident and the reflection angles of the first and second prism surfaces at the wavelength of the first light ray are in the range of the critical angle + (0 to 0.2 degree). Adjust the total reflection to adjust the total reflection first.
Light rays are reflected by the other parallel fifth and sixth prism surfaces within a reflection angle of 0 to 10 degrees, and the sixth and fifth prism surfaces are opposed to the fifth and sixth prism surfaces. When emitting those first rays more, those first rays
Light ray is incident on the fifth and sixth prism surfaces and is superposed on the second light ray emitted from the sixth and fifth prism surfaces on the optical axis connecting the fifth and sixth prism surfaces. An optical device including an optical prism having a hexagonal cross section may be used.

According to a seventh aspect of the present invention, the two ridge-side portions located diagonally to the prismatic body having a rectangular or square cross section form mutually parallel slopes forming 45 degrees with respect to the prismatic side surface as the prism surface. The first and second prism surfaces parallel to each other, which are formed on the prism surface of
The first light ray is made incident from the fourth prism surface within an incident angle of 0 to 10 degrees, and the reflection angles of the first and second prism surfaces at the wavelength of the first light ray are the critical angle +
The angle of the optical prism is adjusted so as to be in the range of (0 to 0.2 degrees), and total reflection is performed, and the first reflected total rays are further parallel to each other on the fifth and sixth prism surfaces. The reflection angle is within 0 to 10 degrees, and the first light rays are emitted from the sixth and fifth prism surfaces facing the fifth and sixth prism surfaces, while the sixth and fifth prisms are emitted. The remaining first light ray reflected on the surface is totally reflected on the first and second side surfaces, and then the third light ray.
The optical device is provided with an optical prism having a hexagonal cross section that is emitted from the fourth prism surface.

According to an eighth aspect of the present invention, a section of one side of the prism having a rectangular or square cross section on the ridgeline side is formed as a prism surface which is an inclined surface forming an angle of 45 degrees with respect to the side surface of the prism as a prism surface. A pentagonal shape, and the polarization of the outgoing light combined by one incident light incident from the one prism surface and two incident light incident from the other prism surface which is shifted by 90 degrees with respect to the one prism surface. The ellipticity of was set to 100 to 90%.

According to a ninth aspect of the present invention, one ridge line side portion of a prismatic body having a rectangular or square cross section is formed into a prism surface which is an inclined surface forming an angle of 45 degrees with respect to the prismatic side surface as a prism surface. The cross-sectional shape is a pentagon, and the incident light incident from the first prism surface is reflected by the second prism surface of the optical prism and the first outgoing light emitted from the third prism surface and the third prism surface. Furthermore, the ellipticity of the polarization of each of the second outgoing lights that are reflected and emitted from the fourth prism surface is 100 to 90%.

In the invention of claim 8, a ray of light is made incident on the inclined prism surface from another prism surface not adjacent to this prism surface within an incident angle of 0 to 10 degrees,
The angle of the optical prism is adjusted so that the reflection angle of the prism surface serving as the inclined surface at the wavelength of this light ray is in the range of the critical angle + (0 to 0.2 degree), and the total reflection is performed. An optical prism in which a part of the light is emitted from another prism surface, while the remaining light rays that are further reflected within the reflection angle of 0 to 10 degrees on the other prism surface are emitted from the prism surface facing the other prism surface. It may be an optical device provided with.

According to a tenth aspect of the present invention, the one ridge line side portion of the prismatic body having a rectangular or square cross section is formed into a prism surface which is an inclined surface forming an angle of 45 degrees with respect to the prismatic side surface as a prism surface. The cross-sectional shape is a pentagon, and one of the incident light that is incident from the one prism surface and the emitted light that is combined by the two incident light that is incident from the other prism surface that is deviated by 90 degrees from the one prism surface are combined. The ellipticity of polarized light is 100 to 90%, and a light ray is incident on a prism surface that is an inclined surface within an angle of incidence of 0 to 10 degrees from another prism surface that is not adjacent to this prism surface. The angle of the optical prism is adjusted so that the reflection angle of the prism surface, which is an inclined surface, is within the range of the critical angle + (0 to 0.2 degree), and the light is totally reflected and the reflected light beam is further reflected on another prism surface. When the reflected light is reflected within a reflection angle of 0 to 10 degrees and the reflected light ray is further emitted from the prism surface facing the other prism surface, the emitted light ray is incident from the prism surface facing the output surface. An optical device may be provided with an optical prism having a pentagonal cross-section that is superposed on the optical axis connecting the opposite prism surfaces with the light beam emitted from the emission surface.

The eleventh aspect of the present invention is configured such that the optical prism according to the first, fourth, and fifth aspects is housed in a rectangular parallelepiped container and is optically coupled through a lens with the wall surface of the rectangular parallelepiped container as a reference .
In addition, the rectangular parallelepiped container has an optical isolator that does not depend on polarization.
The first lens-equipped connector that houses the data and is placed on the rectangular parallelepiped wall surface.
Introduces ray 1 of wavelength λ ₁ from the nectar and attaches the first lens
The light is emitted to the second connector with a lens that faces the connector.
With a second lens facing the first connector with a lens
The light is emitted to the connector, and the first connector with a lens and the second connector
Third lens connector that directly illuminates the lens connector
Or wave from either one of the 4th connector with lens.
Introduce a ray 2 of long λ ₂ (λ ₂ <λ ₁ ) and
Reflection mirror and wavelength selection filter formed on the prism surface
By the action of the first connector with a lens or the second
The light beam 1 from the connector with a lens is multiplexed and
From the connector with lens or the fourth connector with lens
A monitor for detecting the light intensity of the light beam 1 is obtained.
It was

[0020]

[0021]

According to the optical prism described in claim 1, the other four
By forming the prism surface so that the prism surface has an inclination angle of 45 degrees with respect to the surface, a separation mechanism for returning the light intensity level is formed, so that it is possible to monitor the light intensity at the same time. Further, even if the arrangement angle of the prism changes, the light rays change only in parallel or at right angles, so that combining of the light becomes extremely easy with a simple configuration.

According to the optical prism of the second aspect, the ellipticity of the polarization of the emitted light combined by the first incident light and the second incident light is set to 100 to 90%, thereby combining the lights. Can be done more effectively.

According to the optical prism of claim 3, 1
When the ellipticity of each of the first outgoing light and the second outgoing light, which are incident from the prism surface of the first and exit from the prism surfaces that are deviated from each other by 90 degrees, are set to 100 to 90%, the demultiplexing of the light is performed. Is done more effectively.

According to the optical prism of the fourth aspect, the light incident on these reflecting mirrors is totally reflected by the reflecting mirrors provided on the pair of parallel prism surfaces. The waves can be done more effectively.

According to the fifth aspect of the invention, only the selected light is made incident by the wavelength selection filters provided on the four prism surfaces other than the pair of parallel prism surfaces.

According to the invention of claim 6, the incident angle is 0.
Since the prism surface that reflects the light rays that are incident within 10 degrees is adjusted to achieve total reflection within the range of the critical angle + (0 to 0.2 degrees), reflection mirrors are provided on those reflection surfaces. Even if it does not exist, the incident light beam can be totally reflected to effectively combine the light beam with other incident light beams.

According to the invention of claim 7, the incident angle is 0.
Since the prism surface that reflects the light rays that are incident within 10 degrees is adjusted to achieve total reflection within the range of the critical angle + (0 to 0.2 degrees), reflection mirrors are provided on those reflection surfaces. Even if it does not exist, the incident light beam can be totally reflected to effectively split the light beam.

According to the invention described in claim 8, even in the pentagonal optical prism, the polarization of the outgoing light combined by the first incident light and the second incident light which are incident from the prism surfaces which are mutually shifted by 90 degrees. By setting the ellipticity of 100 to 90%, optical coupling can be performed more effectively.

According to the ninth aspect of the present invention, the ellipticity of each of the first outgoing light and the second outgoing light that are incident from one prism surface and are emitted from the prism surfaces that are mutually offset by 90 degrees. Is 100 to 90%, the demultiplexing of light is more effectively performed.

[0030]

According to the tenth aspect of the present invention, even in the pentagonal optical prism, the angle of the optical prism is adjusted so that the reflection angle of the prism surface which is an inclined surface falls within the range of the critical angle + (0 to 0.2 degree). When the incident light is adjusted to be totally reflected, and the totally reflected light is reflected again on another prism surface to be emitted, the incident angle of the incident light and the reflection angle of the total reflection are set to 0 to 10 degrees. , The output light ray is superposed on the optical axis that connects the opposing prism surface with the light ray that is incident from the prism surface that opposes the output surface and that is output from the output surface, so that the light combining is more effective. Can be done

According to the eleventh aspect of the present invention, by using the optical prism for the first, fourth, and fifth aspects, it is possible to effectively combine and demultiplex light, and to use the optical isolator and the light.
The light with different wavelengths is placed in the optical device that houses the prism.
Introduced, the action of the reflection mirror and wavelength selection filter
Then, it is combined with the light rays incident from other prism surfaces,
For detecting the light intensity of the light beam incident from the other prism surface
To get a monitor for.

[0033]

[0034]

【Example】

<First Embodiment> FIG. 1 is an overall perspective view of a hexagonal optical prism according to an embodiment of the present invention, and FIG. 2 shows optical paths of transmitted and reflected light when light rays are incident from the side surface of the optical prism. It is a top view.

The optical prism 1 is transparent (including translucent) made of glass or the like having a rectangular or square cross section.
The diagonal two-sided ridge lines 11 and 12 of the rectangular prism 10 are
By forming side faces 16 and 17 as prism faces parallel to each other, which are θ (= 45 °) with respect to the side faces 1a and 1b as prism faces of the prismatic body 10, the cross-section is hexagonal. Has been.

Side surfaces 1a to 1 as six prism surfaces
In this optical prism 1 having d, 16 and 17, for example, when the signal light A is incident from the side surface 1c, the side surface 1d
Is emitted with a displacement of δ1 from the optical path,
The emitted light only moves parallel to the incident light A, and no angular blur occurs.

Here, an antireflection film for signal light is formed outside the side surfaces 1c and 1d, and an antireflection film for combined light (pump light) is formed outside the side surfaces 1a and 1b, and inward reflection mirrors are formed on the side surfaces 16 and 17, respectively. Form. Then, by introducing the combined light (pump light) from the side surface 1b into the backward pumping type multiplexing module having the optical amplification section on the side surface 1c and reflecting it by the inward reflecting mirror of the side surface 17, Since both the pump light and the pump light are forward excitation modules that are emitted from the side surface 1d and there is no relative positional deviation, the degree of freedom in design is increased and adjustment is possible.

Moreover, side surfaces which are not parallel to each other, for example, 1
The transmitted light entering the optical prism 1 from c and the light rays entering the optical prism 1 from the side surfaces 1a and 1b are orthogonal to each other, while the side surfaces parallel to each other, for example, 1c,
Since the incident light beam entering from one side of 1d and the outgoing light beam emerging from the other side are parallel, the superiority in optical coupling is preserved.

In FIG. 2, the signal light is incident on the side surface 1c at an angle of θi, and when the pump light is introduced to the side surface 1b at an angle of θpi from the direction orthogonal to the signal light, this optical demultiplexing is performed. From the geometrical shape of the prism 1, it can be easily estimated that (Equation 1) θi = θpi and (Equation 2) θi = θ ₀ .

The light rays incident from the side surface 1c are
The light is refracted at an angle of α with respect to, and the reflection angle at the side surface 1d is also α.

Here, assuming that the refractive index in air is n 0 and the refractive index of glass is n, from Snell's law (Formula 3) α = sin ⁻¹ (n 0 / n · sin θi) 45 ° inclined surface , (4) β = 45 ° -α due to its geometrical structure, and the angle γ with the side surface 1a when emitted from the side surface 1a.
And the angle φ with the side surface 1a after emission is (Equation 5) γ = 180 °-{45 ° + 90 ° + β} = 45 ° -β (Equation 6) φ = sin ^-1 (n / n 0 · sinγ) From these relationships, (Equation 7) φ = θi, that is, if the squareness of the prism is accurately formed, there is no error and a right-angled or parallel light beam is emitted.
This relationship does not change even if the prism installation angle with respect to the ray direction changes.

The side surface 1d is a bare glass surface without an antireflection film, and the side surface 1c has a long wavelength transmission filter (LP).
If F) is formed on the side surface 1a similarly, the side surface 1b is an antireflection film for pump light, and the inward reflection mirrors are formed on the side surfaces 16 and 17, about 4% of the signal light and the excitation light are generated on the side surface 1d. Although it reaches the side surface 1a, since the side surface 1a is an LPF, only the signal light is transmitted, and the signal light intensity can be returned by monitoring the output light level. Moreover, as described in FIG. 2, the optical prism 1 is incident from one side surface.
All the light rays that are incident from one side surface and the side surface that is 90 degrees apart are orthogonal to each other, and the incident light ray that enters from one side surface and the exit light ray that exits from the other side surface are the optical path displacement δ1 minutes. However, they are parallel to each other.

Here, the demultiplexing and combining of the light performed by the optical prism 1 of this embodiment will be described. First, the demultiplexing means the first and second side surfaces 16 and 1 which are parallel to each other.
7, the third and fourth side faces 1a, 1b parallel to each other and adjacent to the second and first side faces 17, 16 respectively.
From the first and second side surfaces 16 and 17, and the reflected first light ray is reflected by the fifth and fifth parallel rays. The angle of reflection is 6 to 10 degrees on the side surfaces 1c and 1d of the six side surfaces of the sixth and fifth side surfaces 1d and 1c facing the fifth and sixth side surfaces 1c and 1d. While partially emitting the remaining first light ray reflected by the sixth and fifth side surfaces 1d and 1c, the first and second side surfaces 16,
17 and then the third and fourth side faces 1a, 1b
It means to emit from.

Next, with respect to the first and second side surfaces 16 and 17 which are parallel to each other with the multiplexing, the second and first side surfaces 17 and 17,
16. The first light ray is made incident from the parallel third and fourth side surfaces 1a, 1b adjacent to 16, respectively, and the incident first light ray is reflected by the first and second side surfaces 16, 17,
These reflected first light rays are reflected on the other parallel fifth and sixth side surfaces 1c and 1d within a reflection angle of 0 to 10 degrees, and the first light rays are reflected on the fifth and sixth side surfaces 1c and 1d. Sixth and fifth side faces 1d facing the six side faces 1c, 1d,
When it is emitted from 1c, the first ray is changed to the second ray that is incident from the fifth and sixth side faces 1c and 1d and is emitted from the sixth and fifth side faces 1d and 1c. It means that they are superposed on the optical axis connecting the prism surfaces of 6.

Here, in consideration of the ellipticity of the reflectance due to the polarization plane when glass is used, in what state it is preferable to use the optical prism 1, and in what state it is applied to an optical device. Consider what to do.

Here, a graph (FIGS. 4 and 5) of the relationship between the incident angle and the reflectance is drawn based on the calculation formula of the Fresnel reflectance of the light ray incident on the glass plate from the air, and based on these graphs. Then, draw a graph (FIG. 6) showing the ellipticity of the reflectance by the plane of polarization.

First, as a premise, the wavelength of incident light is 150
At 0 nm, borosilicate crown (BK-
When 7) is used, the refractive index n becomes 1.5. Then, assuming that the refractive index in air is 1, the reflectance of the plane of polarization parallel to the plane of incidence is Rp, and the reflectance of the plane of polarization perpendicular to the plane of incidence is Rs.
And

Further, the incident angle (incident angle from the air to the glass plate) θin = in (deg), in = 0 to 90 degrees, and the incident angle θin expressed in radian (rad.) Is α1. , (Equation 8) α ₁ = π · i / 180 (rad.). Then, let the exit angle (the exit angle into the glass plate) be β
Let i be (Equation 9) βi = asin (n1 · sinα ₁ / n2), and (Equation 10) Rpi = (sin (α ₁ −β ₁ ) / sin (α ₁ + β ₁ )) ² · 100 ( %) (Equation 11) Rsi = (tan (α ₁ -β ₁ ) / tan (α ₁ + β ₁ )) ² · 100 (%).

From these equations, the incident angle; the value of θin (0 to
90 degrees), the reflectances Rp and Rs are calculated, and the incident angle θi
FIG. 4 is a graph in which n is the horizontal axis and reflectances Rpi and Rsi are the vertical axes. In FIG. 5, θin = 0 to 1
5 shows an enlarged graph of FIG. 4 at 5 degrees.

From these graphs (FIGS. 4 and 5), the ellipticity ratio of the reflectance due to the polarization plane is obtained and shown in the graph with the incident angle θj as the abscissa and the ellipticity ratio Rsi / Rpi as the ordinate.
become that way.

From the graph of FIG. 6, the incident angle is 0 to 1
The ellipticity ((Rsi / Rpi) × 100%) is 100 to 90% at 0 degree.

On the other hand, a relational graph (FIGS. 7 and 8) between the incident angle and the reflectance is drawn based on the calculation formula of the Fresnel reflectance of the light beam entering the air from the glass plate, and the deflection is performed based on these graphs. Draw and see graphs (FIGS. 9 and 10) showing the ellipticity of the reflectance by the surface.

First, as the premise, the wavelength of the reflected light is 1
At 500 nm, borosilicate crown (B
When K-7) is used, its refractive index n1 = 1.5.
Then, the refractive index in the air is n1, the reflectance Rp of the polarization plane parallel to the incident plane, and the reflectance Rp of the polarization plane perpendicular to the incidence plane are R
Let s.

When the incident angle (incident angle from the glass plate into the air) θim = im (deg) and im = 0 to 90 degrees, and the value represented by the incident angle θim radian (rad.) Is α1, (Equation 12) α ₁ = π · i / 180 (rad.). When the emission angle (emission angle in air) is βi, (Equation 13) βi = asin (n1 · sinα ₁ / n2), and (Equation 14) Rpi = (sin (α ₁ -β ₁ ) / sin ( α ₁ + β ₁ )) ² · 100 (%) (Equation 15) Rsi = (tan (α ₁ −β ₁ ) / tan (α ₁ + β ₁ )) ² · 100 (%).

From these equations, the value of the incident angle θim (0-9
The reflectances Rp and Rs are calculated according to (0 degree), and the incident angle θim
Is plotted on the horizontal axis and the reflectances Rp and Rs are plotted on the vertical axis. FIG. 8 shows an enlarged graph of FIG. 7 at θi = 0 to 15 degrees.

From these graphs (FIGS. 7 and 8), the ellipticity of the reflectance due to the plane of polarization is obtained and expressed in a graph with the incident angle θj as the horizontal axis, as shown in FIG. A graph obtained by enlarging a part (θj = 41.5 to 42 degrees) of FIG. 9 is shown in FIG. 10.

Here, since n1> n2, the incident angle θj
Is greater than the critical angle, both P and S waves are totally reflected.

The critical angle θc is (Equation 16) θc = asin (n2 ・ n1) / π ・ 180 It becomes 41.81 from the formula.

From the graph of FIG. 10, the critical angle 41.
Total reflection is possible in the range of 81 degrees to 42.01 degrees without polarization dependency.

In view of the above, when using the optical prism 1 of the first embodiment or applying it to an optical device, it can be said that it is desirable to use it as follows.

For example, the incident light incident from the side surface 1b (1a) is reflected by the side surface 17 and emitted from the side surface 1c (1d), and further reflected by the side surface 1c (1d). If the ellipticity of the polarization of each of the second outgoing lights emitted from 1d (1c) is set to 100 to 90%, the demultiplexing of the light can be more effectively performed.

First and second optical prisms 1 parallel to each other
The second and the first side surface 1 with respect to the side surfaces 16 and 17 of
The first and second side surfaces 16 at the wavelength of the first light ray with an incident angle of 0 to 10 degrees from the parallel third and fourth side surfaces 1a and 1b adjacent to 7 and 16, respectively.
The angle at which the reflection angle of 17 is polarization independent (critical angle θc + (0 to
The angle of the optical prism 1 is adjusted so as to be 0.2 degrees)), and the total reflection of the first light rays is performed by the other fifth and sixth side surfaces 1c and 1d parallel to each other. When the first light ray is emitted, it is necessary to superimpose the second light ray emitted from the sixth and fifth side surfaces 1d and 1c on the optical axis connecting the fifth and sixth side surfaces 1c and 1d. In this case, the light can be combined more effectively without forming the reflection mirror on the first and second side surfaces.

For the first and second side faces 1c and 1d of the optical prism 1 which are parallel to each other, these second and first side faces are formed.
From the parallel third and fourth side faces 1a, 1b adjacent to the side faces 1d, 1c, respectively, into the first light beam within an incident angle of 0 to 10 degrees, and the first light beam at the wavelength of the first light beam is incident. 1, the angle of the optical prism 1 is adjusted so that the reflection angles of the second side surfaces 16 and 17 are polarization independent angles (critical angle θc + (0 to 0.2 degrees)), and total reflection is performed.
A part of the totally reflected first light ray has a reflection angle of 0 on the other parallel fifth and sixth side surfaces 1c and 1d.
The light is reflected within 10 degrees, and the fifth and sixth side surfaces 1
While the first light rays are emitted from the sixth and fifth side faces 1d, 1c facing the c, 1d, the sixth and fifth side faces 1
d and 1c, the remaining first light rays are totally reflected by the first and second side surfaces, and then the third and fourth side surfaces 1
If the light is emitted from c and 1d, the light can be effectively demultiplexed.

<Second Embodiment> FIG. 3 shows a plan view of a third embodiment of an optical prism having a pentagonal cross section.

In this optical prism 100, a portion of one side of one ridgeline 111 of a transparent prismatic body 110 made of glass or the like having a rectangular or square cross section forms an angle of 45 degrees with respect to a prismatic prism side surface 120c. By forming it on the side surface 121 as a prism surface which is an inclined surface, the cross-sectional shape is formed into a pentagon.

In this optical prism 100, as in the case of the first embodiment, the light incident from the side surface 120a of one side 1
When the ellipticity of the emitted light combined with the incident light of 2 and the incident light of 2 incident from the other side surface 120d which is deviated by 90 degrees with respect to the side surface 120a of 100 to 90% is used, The multiplexing and demultiplexing of can be performed more effectively.

For example, incident light incident from the side surface 120d is reflected by the side surface 121 and emitted from the side surface 120b, and second emitted light is further reflected by the side surface 120b and emitted from the side surface 120a. If the ellipticity of each polarization of the emitted light is 100 to 90%, the light can be more effectively demultiplexed.

Further, in the optical prism 100, the side surface 121 as a prism surface which is an inclined surface as in the first embodiment is different from the side surface 121 which is not adjacent to the side surface 121.
A light ray is made incident from 21 within an angle of incidence of 0 to 10 degrees, and the angle of the optical prism 100 is set so that the reflection angle of the side surface 121 which is the inclined surface at the wavelength of this light ray becomes a critical angle (0 to +0.2 degree). It is adjusted to be totally reflected, and a part of the totally reflected light is emitted from the other side surface 120b, while the remaining light rays further reflected within the reflection angle of 0 to 10 degrees on the other side surface 121b. When the light is emitted from another side surface 120a facing the other side surface 120b, the demultiplexing function is more effectively achieved.

Also, in the optical prism 100, as in the first embodiment, the angle of incidence is within 0 to 10 degrees with respect to the side surface 121 as a prism surface which is an inclined surface from another side surface 120d not adjacent to this prism surface. Inject a ray,
The angle of the optical prism 100 is adjusted so that the reflection angle of the side surface 121 which is the inclined surface at the wavelength of this light ray becomes a critical angle (0 to 0.2 degree), and the totally reflected light ray is separated. The side surface 120b of the other side surface 120b which is reflected within a reflection angle of 0 to 10 degrees and faces the other side surface 120b.
When the reflected light beam is further emitted from 20a,
If this emitted light ray is superposed on the optical axis that joins the facing side surface 120a with the light ray that is incident from the side surface 120b facing the output surface and is emitted from the output surface, the light combining will be more effective. Can make waves.

<Third Embodiment> When the optical prism of the first embodiment is used in the optical device 20 as shown in FIG. 11, the effect is remarkably exhibited. The optical isolator 21 that does not depend on the polarization plane direction is arranged horizontally in the container 30 in the shape of a rectangular parallelepiped, and the optical prism 1 of the present invention is arranged in front of it. In this case, since the horizontal plane of the container 30 causes a light beam shift, the container floor surface 32 must have a strict right angle, and the adjacent rectangular parallelepiped wall surfaces must ensure 90 degrees. Of course, if it is finished within ± 5 minutes as a processing intersection,
It does not cause much optical coupling loss.

Next, installation of the hexagonal prism is simple, and a deviation of about ± 5 minutes causes no problem in principle. This is because when considering the signal light, the displacement of the hexagonal prism at the exit point only induces the parallel movement of the light beam. Therefore, when the signal light entering from the connector P1 with the coupling lens is coupled with the connector P2 with the coupling lens, the position of the coupling lens is changed. This is due to the fact that the optimum position can be easily found because the object moves in a plane (a rectangular parallelepiped wall surface).

The excitation light input from the connector P3 with the coupling lens can monitor the signal light intensity from the port P4 with the coupling lens without waste by only operating the rectangular parallelepiped wall surface to find the optimum position in a plane. In any optical coupling, the orthogonality and parallelism described in the first embodiment are preserved regardless of the installation orientation of the hexagonal prism,
An optical coupling with a high efficiency can be realized by a very simple coupling process.

[0073] Also, emitted from the first coupling lens with connector P1 to place the parallelepiped wall introducing light 1 of the wavelength lambda _1, the second coupling lens with connector P2 opposite to the first coupling lens with connector P1 And a second connector P2 with a coupling lens facing the first connector P1 with a coupling lens.
To the first connector P1 with the coupling lens and the second
Ray 2 of wavelength λ ₂ (λ ₂ <λ ₁ ) from either the third connector P3 with a coupling lens or the fourth connector P4 with a coupling lens that directly irradiates the connector P2 with the coupling lens.
And is combined with the light beam 1 from the connector P1 with the first coupling lens or the connector P2 with the second coupling lens by the action of the reflection mirror and the wavelength selection filter formed on the prism surface of the optical prism 1, and Since a monitor for detecting the light intensity of the light ray 1 can be obtained from the third connector P3 with a coupling lens or the fourth connector P4 with a coupling lens, when light rays having different wavelengths are introduced into this optical device. By the action of the reflection mirror and the wavelength selection filter, a monitor for detecting the light intensity of the light beam incident from the other prism surface after being combined with the light beam incident from the other prism surface can be obtained.

[0074]

According to the optical prism of the first aspect,
By forming a hexagonal shape in which a prism surface is formed with an inclination angle of 45 degrees with respect to the other four surfaces, a separation mechanism for returning the light intensity level is formed, so that the light intensity can be monitored at the same time. Moreover, even if the arrangement angle of the prism changes, the light rays change only in parallel or at right angles, so that the light can be combined very easily.

According to the optical prism of the second aspect, the ellipticity of the polarization of the outgoing light combined by the first incident light and the second incident light which are incident from the prism surfaces which are deviated from each other by 90 degrees is 100. By setting the ratio to 90%, the light can be more effectively combined.

According to the optical prism of claim 3, 1
When the ellipticity of each of the first outgoing light and the second outgoing light, which are incident from the prism surface of the first and exit from the prism surfaces that are deviated from each other by 90 degrees, are set to 100 to 90%, the demultiplexing of the light is performed. Is done more effectively.

According to the optical prism of the fourth aspect, since the light incident on these reflecting mirrors is totally reflected by the reflecting mirrors provided on the pair of parallel prism surfaces, the light is combined with the split light. The waves can be done more effectively.

According to the fifth aspect of the invention, only the selected light is made incident by the wavelength selection filters provided on the four prism surfaces other than the pair of parallel prism surfaces.

According to the invention of claim 6, the incident angle is 0.
Since the prism surface that reflects the light rays that are incident within 10 degrees is adjusted to be within the range of the critical angle + (0 to 0.2 degrees), even if a reflection mirror is not provided on those reflection surfaces, It is possible to totally reflect the incident light and effectively combine the light with other incident light.

According to the invention of claim 7, the incident angle is 0.
Since the prism surface that reflects the light rays that are incident within 10 degrees is adjusted to be within the range of the critical angle + (0 to 0.2 degrees), even if a reflection mirror is not provided on those reflection surfaces, The incident light beam can be totally reflected to effectively split the light beam.

According to the eighth aspect of the present invention, also in the pentagonal optical prism, the ellipticity of orthogonal polarization of the outgoing light combined by the first incident light and the second incident light is 100.
By combining 90%, the light can be combined more effectively.

According to the invention described in claim 9, the ellipticity of each of the first outgoing light and the second outgoing light which are incident from one prism surface and are emitted from the prism surfaces which are shifted from each other by 90 degrees. Is 100 to 90%, the demultiplexing of light is more effectively performed.

[0083]

According to the tenth aspect of the present invention, even in the pentagonal optical prism, the angle of the optical prism is set so that the reflection angle of the prism surface, which is an inclined surface, falls within the range of the critical angle + (0 to 0.2 degree). When the incident light is adjusted to be totally reflected, and the totally reflected light is reflected again on another prism surface to be emitted, the incident angle of the incident light and the reflection angle of the total reflection are set to 0 to 10 degrees. , The output light ray is superposed on the optical axis that connects the opposing prism surface with the light ray that is incident from the prism surface that opposes the output surface and that is output from the output surface, so that the light combining is more effective. Can be done

According to the eleventh aspect of the present invention, by using the optical prism for the first, fourth, and fifth aspects, it is possible to effectively combine and demultiplex light, and to use the optical isolator and the optical
The light with different wavelengths is placed in the optical device that houses the prism.
Introduced, the action of the reflection mirror and wavelength selection filter
Then, it is combined with the light rays incident from other prism surfaces,
For detecting the light intensity of the light beam incident from the other prism surface
To get a monitor for.

[0086]

[Brief description of drawings]

FIG. 1 is a perspective view of a hexagonal optical prism according to an embodiment of the present invention.

FIG. 2 is a plan view showing the optical paths of transmitted and reflected light when a light ray is incident on the optical prism.

FIG. 3 is a plan view showing optical paths of transmitted and reflected light when a light ray is incident on a pentagonal optical prism.

FIG. 4 is a graph showing the relationship between the incident angle and the reflectance when a light ray is incident on a glass plate from the air.

5 is an enlarged view of FIG.

6 is a graph showing the ellipticity of the reflectance by the polarization plane obtained based on the graph of FIG.

FIG. 7 is a graph showing the relationship between the incident angle and the reflectance when an optical axis is emitted from a glass plate into the air.

FIG. 8 is an enlarged view of FIG.

9 is a graph showing the ellipticity of the reflectance by the polarization plane obtained based on the graph of FIG.

FIG. 10 Enlarged view

FIG. 11 is a schematic configuration diagram of an optical coupling device using a hexagonal prism optical prism.

FIG. 12 is a schematic diagram of a conventional optical amplification system.

FIG. 13 is a plan view of a conventional pentaprism.

FIG. 14 is a side view of a parallel plate type multiplexer / demultiplexer.

[Explanation of symbols]

1 Hexagonal optical prism 1a Side surface (prism surface) 1b Side surface (prism surface) 1c Side surface (prism surface) 1d Side (prism surface) 10 prismatic body 11 ridge 12 ridges 16 Sides (prism surface) 17 Sides (prism surface) θ0 Exit angle (incident angle) θi incident angle (incident angle) θPi incident angle 20 Optical device 30 containers 31 Container floor 32 container side P1, P2, P3, P4 connectors 100 pentagonal optical prism 110 prism 111 ridge 120a side surface (prism surface) 120b Side surface (prism surface) 120c side surface (prism surface) 120d side surface (prism surface) 121 Side surface (prism surface)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Heiichi Sato 3-8-22 Nitta, Adachi-ku, Tokyo Namiki Precision Gem Co., Ltd. (72) Nobuo Imaizumi 3-8-22 Nitta, Adachi-ku, Tokyo No. Namiki Seimitsu Gem Co., Ltd. (56) Bibliographical Report 2-35332 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 5/04 G02B 27/10 G02B 6 / 28 G02B 27/28

Claims (11)

(57) [Claims] 1. A prism face having a rectangular or square cross section, which is diagonally positioned on the two ridge lines, is formed on prism faces which are slopes parallel to each other and forming 45 degrees with respect to the prism side faces as prism faces. , An optical prism having a hexagonal cross section. 2. The optical prism according to claim 1, wherein
The ellipticity of the polarization of the outgoing light combined by the first incident light incident from the first prism surface and the second incident light incident from the other prism surface that is shifted by 90 degrees with respect to the first prism surface is An optical prism characterized by being 100 to 90%. 3. The optical prism according to claim 1, wherein
Incident light incident from the first prism surface is reflected by the second prism surface of the optical prism and first emitted light emitted from the third prism surface and further reflected by the third prism surface, and the fourth prism An optical prism, wherein the ellipticity of the polarization of each of the second outgoing lights emitted from the surface is 100 to 90%. 4. The optical prism according to claim 1, wherein
An optical prism characterized in that a reflecting mirror is provided on a pair of parallel prism surfaces of the prism surfaces. 5. The optical prism according to claim 1, wherein a wavelength selection filter is provided on four prism surfaces other than a pair of parallel prism surfaces. 6. A prism surface having a rectangular or square cross-section, which is obliquely positioned on the side of two ridges, is formed on prism surfaces which are parallel to each other and form an angle of 45 degrees with respect to a prism side surface as a prism surface. , With respect to the mutually parallel first and second prism surfaces, the incident angle is within 0 to 10 degrees from the mutually parallel third and fourth prism surfaces adjacent to the second and first prism surfaces, respectively. At the wavelength of these first light rays so that the reflection angles of the first and second prism surfaces fall within the range of the critical angle + (0 to 0.2 degree). Adjust the angle to cause total reflection,
The totally reflected first light rays are reflected by the other parallel fifth and sixth prism surfaces within a reflection angle of 0 to 10 degrees, and the first and second prism surfaces are opposed to the fifth and sixth prism surfaces. 6, when the first light rays are emitted from the fifth prism surface, the first light rays are incident from the fifth and sixth prism surfaces and are emitted from the sixth and fifth prism surfaces. An optical device provided with an optical prism having a hexagonal cross section, which is superposed on the light beam of 2 on the optical axis connecting the fifth and sixth prism surfaces. 7. A prism face having a rectangular or square cross section, the two ridge-side portions of which are obliquely positioned, are formed on prism faces which are slopes parallel to each other and forming an angle of 45 degrees with respect to the prism side faces as prism faces. , With respect to the mutually parallel first and second prism surfaces, the incident angle is within 0 to 10 degrees from the mutually parallel third and fourth prism surfaces adjacent to the second and first prism surfaces, respectively. At the wavelength of these first light rays so that the reflection angles of the first and second prism surfaces fall within the range of the critical angle + (0 to 0.2 degree). Adjust the angle to cause total reflection,
The totally reflected first light rays are reflected by the other parallel fifth and sixth prism surfaces within a reflection angle of 0 to 10 degrees, and the first and second prism surfaces are opposed to the fifth and sixth prism surfaces. 6, while the first light rays are emitted from the fifth prism surface, the remaining first light rays reflected by the sixth and fifth prism surfaces are totally reflected by the first and second side surfaces. An optical device including an optical prism having a hexagonal cross-section for emitting light from the third and fourth prism surfaces. 8. A portion of one side of a prism having a rectangular or square cross section on one edge line is 4 with respect to a prism side surface as a prism surface.
By forming the prism surface as an inclined surface forming 5 degrees, the cross-sectional shape becomes a pentagon, and one incident light incident from the one prism surface and 90 degrees with respect to the one prism surface.
The ellipticity of the polarization of the emitted light combined by the two incident lights incident from the other prism surface with a deviation of 100 to 90%
Is an optical prism. 9. A prismatic body having a rectangular or square cross section, one edge side portion being 4 with respect to a prismatic prism side surface.
By being formed on the prism surface which is an inclined surface forming 5 degrees, the cross-sectional shape becomes a pentagon, and the incident light incident from the prism surface of 1 is reflected by the prism surface of 2 of the optical prism and is reflected from the prism surface of 3. The ellipticity of polarization of each of the first emitted light emitted and the second emitted light further reflected by the third prism surface and emitted from the fourth prism surface is 100 to 90%. Optical prism. 10. A prismatic surface having a rectangular or square cross section, one edge side portion of which is formed on a prism surface which is an inclined surface forming an angle of 45 degrees with respect to the prismatic prism side surface, thereby forming a pentagonal sectional shape. One incident light incident from the one prism surface and 9 to the one prism surface
The ellipticity of the orthogonal polarizations of the outgoing light combined by the two incident lights entering from the other prism surface deviated by 0 degree is 10
0 to 90%, a ray of light is incident on the prism surface that is the inclined surface at an incident angle of 0 to 10 degrees or less from another prism surface that is not adjacent to this prism surface. Adjust the angle of the optical prism so that the reflection angle of the prism surface becomes a critical angle,
When the totally reflected light ray is reflected on a further prism surface within a reflection angle of 0 to 10 degrees and the reflected light ray is further emitted from the prism surface facing the other prism surface, the emitted light ray Is an optical device having a pentagonal optical prism in cross section, which is superposed on a light beam incident from a prism surface facing the emission surface and emitted from the emission surface on an optical axis connecting the opposing prism surfaces. 11. An optical prism according to claim 1, 4, or 5.
Is stored in a rectangular parallelepiped container, and the wall surface of this rectangular parallelepiped container is used as a reference.
Lens optically coupled through said optical isolator that is not dependent on the polarization housed in a rectangular container, introducing a light beam 1 having a wavelength lambda ₁ from a first lens with connectors arranged in rectangular wall, with the first lens connector
From the third connector with a lens or the fourth connector with a lens, which is emitted to the second connector with a lens and which directly emits light to the first connector with a lens and the connector with a second lens. Ray 2 of ₂ (λ ₂ <λ ₁ )
Is introduced and combined with the light ray 1 from the connector with the first lens or the connector with the second lens by the action of the reflection mirror and the wavelength selection filter formed on the prism surface of the optical prism, and with the third lens. An optical device, wherein a monitor for detecting the light intensity of the light beam 1 is obtained from the connector or the fourth connector with a lens.