JPS597364B2 - Optical non-reciprocal circuit - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in optical non-reciprocal circuits.

Conventionally, an optical non-reciprocal circuit having the configuration described below with reference to FIG. 1 has been proposed.

That is, by receiving a predetermined magnetic field in the thickness direction, the magneto-optic effect plate 1 has an angle of approximately 45 degrees between the polarization direction of the incident light and the polarization direction of the output light. It also has polarizing prisms 3 and 4 arranged to face opposing surfaces 2a and 2b of the magneto-optic effect plate 1, respectively.

Therefore, now, the thickness direction of the magneto-optic effect plate 1 is the Z-axis direction, and the plane perpendicular to the Z-axis direction is the X-Y plane.
When the directions extending orthogonally to each other on a plane are respectively the X-axis direction and the Y-axis direction, and the planes orthogonal to the X-axis direction and the Y-axis direction are respectively the Y-Z plane and the X-Z plane, polarized light The surface 5 of the prism 3 parallel to the X-Z plane is connected to the first port P.
1, when linearly polarized light L1 in the X-axis direction is incident as incident light from the first port P1, based on this, on the X-Y plane with respect to the X-Z plane of the polarizing prism 4. A surface 6 parallel to the surface rotated by approximately 45 mm is set as a second port P2, and from the second port P2, linearly polarized light L1' in a direction inclined by 45 degrees with respect to the Y-axis direction is transmitted. ,
It is configured so that it can be obtained as emitted light.

Furthermore, when the linearly polarized light L2 in the 45th inclined direction with respect to the Y-axis direction is made incident as incident light from the second port P2, based on this, the X-Y
The surface 7 parallel to the plane is the third port P3, and the third port P3 is the third port P3.
The configuration is such that linearly polarized light L2' in the Y-axis direction can be obtained as output light from port P3.

Furthermore, linearly polarized light L in the Y-axis direction is transmitted from the third port P3.
3 as incident light, based on this,
The plane parallel to the X-Y plane of the polarizing prism 4 is set as the fourth port P4, and from the fourth port P4, linearly polarized light L3' in a direction inclined at 45 with respect to the Y-axis direction is emitted. It is configured so that it can be obtained as follows.

Furthermore, if the linearly polarized light L4 in the 45th inclination direction with respect to the Y-axis direction is incident as incident light from the fourth port P4, based on this, from the first port , the linearly polarized light L4/ in the X-axis direction is obtained as the emitted light.

The above is the configuration of the conventionally proposed optical non-reciprocal circuit.

By the way, the optical non-reciprocal circuit having such a configuration has a function as an optical circulator itself, but optical waveguides such as optical fibers are connected to the first port P1 and the second port P2, respectively. In addition, by optically coupling a light emitting section to the fourth port P4, the light obtained by being emitted from the optical waveguide coupled to the first port P1 is transmitted to the second port P4. It can be made incident on the optical waveguide coupled to port P2 and transmitted thereto,
In addition, an optical non-reciprocal method in which the light obtained by being emitted from the light emitting section coupled to the fourth port P4 is made incident on the optical waveguide coupled to the first port P1 and transmitted thereto. function can be obtained.

However, in the case of the above-mentioned conventional optical non-reciprocal circuit, the output light is obtained at the first port P1 based on the incident light on the fourth port P4 when the incident light is in the Y-axis direction. 45 has a linearly polarized light component in the direction in which it is tilted, but based on the incident light to the first port P1, the output light is obtained at the second port P2 when the incident light is This is limited to cases where the light has a linearly polarized component in the X-axis direction.

Therefore, if the incident light to the first port P1 has a linearly polarized component in the X-axis direction and a linearly polarized component in the direction orthogonal to this, the output light obtained from the second port P2 will be , is obtained with a large loss to the incident light.

Therefore, if the above-described conventional optical non-reciprocal circuit is used as described above to obtain the above-mentioned optical non-reciprocal function, the first
The light obtained by being transmitted to the optical waveguide coupled to port P1 of
In the case of multimode light, the light that enters the optical waveguide coupled to the second port P2 and is transmitted to the first
This has the drawback that the light obtained by being emitted toward the first port P1 from the optical waveguide coupled to the port P1 of the first port P1 is obtained with a large loss.

Therefore, the present invention, without having the above-mentioned drawbacks,
The purpose is to propose a novel optical non-reciprocal circuit that can obtain the above-mentioned optical non-reciprocal function, which will become clear from the detailed description of the embodiments of the optical non-reciprocal circuit according to the present invention with reference to the drawings below. Will.

FIG. 2 shows a first embodiment of the optical non-reciprocal circuit according to the present invention. The optical non-reciprocal circuit according to the present invention shown in FIG.
optical system A1, and a second optical system disposed opposite to each other across it.
and third optical systems A2 and A3.

The first optical system A1 includes first and second birefringent crystal plates B1 and B2, which are arranged facing each other with a predetermined interval.

Further, the first optical system A1 includes birefringent crystal plates B1 and B2.
A skewer optical effect plate D that is placed between the two and receives a predetermined magnetic field in the thickness direction, so that the angle between the polarization direction of the incident light and the polarization direction of the output light is approximately 45 degrees. has.

Furthermore, the first optical system A1 includes birefringent crystal plates B1 and B.
2, for example, between the birefringent crystal plate B2 and the magneto-optic effect plate D, the angle between the polarization direction of the incident light and the polarization direction of the output light is Approximately 4
It has an optically active or anisotropic crystal plate E obtained in five directions.

Furthermore, the first optical system A1 includes a converging lens F disposed to face the surface of the birefringent crystal plate B1 opposite to the birefringent crystal plate B2 side.

The first optical system A1 includes the above-mentioned birefringent crystal plates B1 and B.
2, magneto-optic effect plate D, and optically active or anisotropic crystal plate E
and a converging lens F.

Further, the second optical system A2 has one free end surface kl as the first optical system.
A first optical waveguide K1 made of, for example, an optical fiber is opposed to the surface b1 of the birefringent crystal plate B1 of the optical system A1 on the side opposite to the birefringent crystal plate B2 side through a lens F. has been done.

Furthermore, the third optical system A3 connects one free end surface K2 to the birefringent crystal plate B1 of the birefringent crystal plate B2 of the first optical system A1.
A second optical waveguide K2 made of, for example, an optical fiber is provided on the surface B2 on the opposite side.

Similarly, the third optical system A3 has one free end surface K3 on the surface B2 of the birefringent crystal plate B2 of the first optical system A1.
It has a third optical waveguide K3 made of, for example, an optical fiber, facing each other, and a light source S disposed opposite to the other free end surface K3'. , has a light emitting part G that emits the light from the light source S to the first optical system A1 example.

The third optical system includes the above-mentioned second optical waveguide K2 and a third optical waveguide K2.
It is composed of an optical waveguide K3 and a light source S.

Therefore, now, the birefringent crystal plate B1 of the first optical system A1
The thickness direction is the Z-axis direction, and the plane perpendicular to the Z-axis direction is the X-axis direction.
- The directions extending orthogonally on the Y plane and X-Y plane are respectively the X-axis direction and the Y-axis direction, and the planes orthogonal to the When the Z plane is used, the birefringent crystal plate B in the first optical system A1
1 and B2, a magneto-optic effect plate D, and an optically active or anisotropic crystal plate E are arranged with their plate surfaces in a plane parallel to the X-Y plane.

Further, the lens F in the first optical system A1 is arranged with its optical axis in the Z-axis direction.

Furthermore, the optical waveguide K1 of the second optical system A2 is arranged as follows. That is, one end surface k1 of the optical waveguide "0K1 is connected to the first optical system A with its optical axis on a first plane parallel to the Y-Z plane and in the Z-axis direction.
so as to face the surface bl of the birefringent crystal plate B1 of No. 1 opposite to the birefringent crystal plate B2 side via the lens F,
It is arranged. Furthermore, the optical waveguide K of the third optical system A3
2 and the optical waveguide K3 of the light emitting section G are arranged as follows.

That is, the end faces K2 and K of those waveguides K2 and K3
3 are arranged at a predetermined distance from each other on a second plane that allows their optical axes to be the same as the first plane parallel to the Y-Z plane common to them. Because of the relationship, the first
The birefringent crystal plates B2 of the optical system A1 are arranged in parallel so as to face each other on the surface B2 of the birefringent crystal plate B2 on the opposite side to the birefringent crystal plate B1 side. Furthermore, as will become clear later, lens F is
The light from the free end surface k1 of the optical waveguide K1 of the second optical system A2 is converged onto the free end surface K2 of the optical waveguide K2 of the third optical system A3. Light emitting part G
The light from the free end surface K3 of the optical waveguide K3 constituting the
It is configured to converge onto the free end surface k1 of the optical waveguide K1 of the second optical system A2.

Furthermore, the birefringent crystal plates B1 and B2 of the first optical system A1 are arranged with their optical axes on a third plane parallel to the Y-Z plane common to them. .

The above is the configuration of the first embodiment of the optical non-reciprocal circuit according to the present invention.

The optical non-reciprocal circuit according to the present invention having such a configuration can provide the following effects.

Now, the point on the optical axis of the lens F constituting the first optical system A1 on the side opposite to the birefringent crystal plate B1 side of the lens F is defined as a point M1, and the optical rotation of the birefringent crystal plate B2 A point on the opposite side to the anisotropic crystal plate E side is defined as a point M2.

Also, between the lens F and the birefringent crystal plate B1; between the birefringent crystal plate B1 and the magneto-optic effect plate D; between the magneto-optic effect plate D and the optically active or anisotropic crystal plate E; between the optically active or anisotropic crystal plate E
and the birefringent crystal plate B2; and the spatial regions on the side opposite to the optically active or anisotropic crystal plate E side of the birefringent crystal plate B2 are defined as Z1; Z2; Z3; Z4; and Z5, respectively.

Then, at point M1, as shown in FIG. Two linearly polarized lights S that exist on the optical axis
Assume that a light source from which lO and S2O (not shown) are obtained is arranged.

In such a case, as shown in FIG. 3, in the spatial region Z1,
Linearly polarized lights Sll and S2l, whose centers lie on the same point as indicated by 011 and 021, respectively, are based on the linearly polarized lights S10 and S2O, respectively, and have the same polarization directions as those of the linearly polarized lights S10 and S20, respectively. In addition, the spatial area Z2
Because of the presence of the birefringent crystal plate B1, the linearly polarized lights Sl whose centers are spaced apart from each other in the Y-axis direction along the Y-Z plane, as shown by 012 and 022, respectively,
1 and S2l, linearly polarized lights Sl2 and S22 having the same polarization directions as those, respectively, are obtained.

In this case, the reason why the centers 012 and 022 are spaced apart from each other in the Y-axis direction along the Y-Z plane is because the linearly polarized light S2l is
Since it is linearly polarized light in the Y-axis direction along the Y-Z plane, the center 021 of the linearly polarized light S2l is in the Y-axis direction along the Y-Z plane.
This is because it moves in the axial direction. Furthermore, in the spatial region Z3, due to the presence of the magneto-optic effect plate D, the centers of the linearly polarized lights Sl2 and S22 are spaced apart from each other in the Y-axis direction, as shown by 013 and 023, respectively. ,
Linearly polarized light S whose polarization direction is rotated clockwise, as seen in the figure, by approximately 45 degrees with respect to those polarization directions.
l3 and S23 are obtained.

Furthermore, in the spatial region Z4, due to the presence of the optically active or anisotropic crystal plate E, the centers are 014 and 024, respectively.
As shown, linearly polarized light S separated from each other in the Y-axis direction
Linearly polarized lights Sl4 and S24 are obtained whose polarization directions are rotated clockwise, as seen in the figure, by approximately 45 degrees with respect to their polarization directions based on I3 and S23, respectively.

Also, in the spatial region Z5, due to the presence of the birefringent crystal plate B2, the centers are as indicated by 015 and 025, respectively.
Linearly polarized lights Sl4 and S, respectively, existing on the same point
24, linearly polarized lights Sl5 and S25 having the same polarization directions as those of the above are obtained.

In this case, the centers 015 and 025 are on the same point because the linearly polarized light Sl4 is linearly polarized light in the Y-axis direction along the Y-Z plane.
This is because it moves in the Y-axis direction along the Y-Z plane.
Therefore, on the XY plane including point M2, linearly polarized light SlO
Linearly polarized light Sl whose polarization direction is the Y-axis direction based on
6 (not shown) and linearly polarized light S26 (not shown), which is based on linearly polarized light S2O and whose polarization direction is the X-axis direction, are obtained by making their centers on the same point.

Conversely, at point M2, as seen in spatial region Z5, as shown in FIG. 4, linearly polarized light Sl5' in the Y-axis direction and linearly polarized light S25' in the 0
Two linearly polarized lights Sl such that 25' are on the same point
6' and S26' (not shown) are provided.

In such a case, as shown in FIG. 4, in the spatial region Z5,
As the centers are indicated by 015' and 025/, respectively,
Linearly polarized lights Sl6' and S2, respectively, existing on the same point
6', linearly polarized lights S15/ and S25' having the same polarization direction as those of the linearly polarized lights S15/ and S25' are obtained.

Furthermore, in the spatial region Z4, due to the presence of the birefringent crystal plate B2, the centers are spaced apart from each other in the Y-axis direction along the Y-Z plane, as shown by 014' and 024', respectively. , based on the linearly polarized lights Sl5/ and S25', respectively, and the linearly polarized lights Sl having the same polarization direction as those polarization directions, respectively.
4' and S24' are obtained.

In this case, the reason why the centers 014' and 024' are spaced apart from each other in the Y-axis direction along the Y-Z plane is because the linearly polarized light Sl5
This is because since ' is linearly polarized light in the Y-axis direction along the Y-Z plane, the center 015' of the linearly polarized light Sl5' moves in the Y-axis direction along the Y-Z plane. Furthermore, in the spatial region Z3, due to the presence of the optically active or anisotropic crystal plate E,
As the centers are indicated by 013/ and 023', respectively,
Each linear direction Sl4 is spaced apart from each other in the Y-axis direction.
' and S24', linearly polarized lights S13' and S23' are obtained which are rotated counterclockwise by approximately 45 degrees with respect to their polarization directions, respectively, as seen in the figure.

Furthermore, in the spatial region Z2, due to the presence of the magneto-optic effect plate D, the linearly polarized lights Sl35 and S23, whose centers are spaced from each other in the Y-axis direction, as indicated by 012' and 022', respectively, ′, linearly polarized lights Sl2′ and S22′ are obtained which are rotated clockwise, as seen in the figure, by approximately 45 degrees, respectively, relative to their polarization directions.

In addition, in the spatial region Z1, due to the presence of the birefringent crystal plate B1, the centers are aligned along the Y-Z plane, as shown by 011' and 021', respectively, and the linearly polarized light Sl
Based on the linearly polarized lights Sl2' and S22', which are separated by a distance that is larger than the distance between the centers 012/ and 02γ of S2' and S22', respectively, in the same direction as their polarization directions, Linearly polarized lights Sll' and S2l' are obtained. In this case, the centers 011' and 021' are Y
The reason why the linearly polarized light Sl2' is spaced apart in the Y-axis direction along the -Z plane is because the linearly polarized light Sl2' is linearly polarized light in the Y-axis direction along the Y-Z plane, so the center 0121 of the linearly polarized light Sl2/ is
This is because it moves in the Y-axis direction along the -Z plane. Therefore, on the XY plane including point M1, linearly polarized light Sl6'
Linearly polarized light S1 whose polarization direction is the Y-axis direction based on
"(not shown) and linearly polarized light S2O' (based on linearly polarized light S26', whose polarization direction is in the X-axis direction) are separated by a large distance from their centers in the Y-axis direction. You can get it in a relationship.

Follow.

According to the first embodiment C of the optical nonreciprocal circuit according to the present invention described above in FIG. 2, the optical waveguide K1 of the second optical system 7A2 faces the birefringent crystal plate B1 of the first optical system A1. The position of the free end surface k1 in the Y-axis direction and the birefringent crystal plate B of the first optical system A1 of the optical waveguides K2 and K3 of the third optical system A3.
If the mutual positions and intervals in the Y-axis direction O of the end surfaces K2 and K3 facing each other are appropriately selected in advance,
As shown in FIG. 5, the optical waveguide K1 of the second optical system A2
, light having two linearly polarized components whose polarization directions are orthogonal to each other is made incident as incident light L1, and the light L1 is transmitted to the R5 optical waveguide K1 from the end face kl. To be emitted, the light passes through the first optical system A1 between its birefringent crystal plates B1 and B2 as two linearly polarized components whose polarization directions are orthogonal to each other, as shown by solid lines and dotted lines, respectively. 4 in the Y-axis direction
0 The light passes through two light paths that are separated from each other. Light having two linearly polarized components whose polarization directions are orthogonal to each other is obtained from the optical waveguide K2 of the third optical system A3 as the output light L1/.

Further, as shown in FIG. 6, light whose polarization directions each have two linearly polarized components is obtained as incident light L3 from the light source S of the light emitting part G of the third optical system A3. Light L
3 enters the optical waveguide K3 from its end face K3', is transmitted thereto, and is then emitted from its end face K3, so that the light passes through the first optical system A1 through its birefringent crystal plate. After the position B2, two linearly polarized light components with mutually orthogonal polarization directions are formed, and the optical paths are separated from each other in the Y-axis direction as shown by solid lines and dotted lines, respectively, as two lights. Pass in a manner that passes.

Then, only one of these two lights enters the optical waveguide K1 of the second optical system A2 from its end face k1,
Then, it is transmitted to the optical waveguide K1, and then obtained as output light L3/ from the optical waveguide K1.

Therefore, according to the first embodiment of the optical asymmetric circuit according to the present invention described above in FIG. 2, the light obtained by being broadly transmitted to the optical waveguide K1 of the second optical system A2 and then emitted is incident on the optical waveguide K2 of the third optical system A3 and transmitted thereto, and the light obtained by being emitted from the light output section G of the third optical system A3 is transmitted to the optical waveguide K2 of the second optical system A2. A non-reciprocal optical function is obtained in which the light is made incident on the optical waveguide K1 and transmitted therethrough.

In this case, even if the light transmitted to and emitted from the optical waveguide K1 of the second optical system A2 is multimode light, it is not input to the optical waveguide K2 of the third optical system A3. It has the characteristic that the light obtained by this is not obtained with a large loss compared to the light obtained by being transmitted to the optical waveguide K1 of the second optical system A2 and emitted from there. .

Next, a second embodiment of the optical non-reciprocal circuit according to the present invention will be described.

The second embodiment of the optical non-reciprocal circuit according to the present invention has the structure of the first embodiment of the optical non-reciprocal circuit according to the present invention described above in FIG. The anisotropic or anisotropic crystal plate E is replaced with a birefringent crystal plate B3,
Accordingly, the birefringent crystal plate B1 changes its optical axis to the second
As in the case shown in the figure, the birefringent crystal plates B2 and B are arranged on the third plane parallel to the Y-Z plane.
3, their optical axes are located on the fourth and fifth planes, which form an angle of approximately 45B with the third plane and an angle of approximately 90B with each other, It has the same configuration as the case of FIG. 2, except that

The above is the configuration of the second embodiment of the optical nonreciprocal circuit according to the present invention.

According to the optical non-reciprocal circuit according to the present invention having such a configuration, detailed explanation will be omitted, but in the same way as described above with reference to FIG. As shown, the linearly polarized light Sll in the X-axis direction and the linearly polarized light S21 in the Y-axis direction are two linearly polarized lights S such that their centers 011 and 012 are both on the optical axis of the lens F.
If a light source that can obtain lO and S2O (not shown) is arranged, as shown in FIG.
Linearly polarized lights Sll and S2l similar to those described above in FIG. 3 are obtained, and also in spatial regions Z2;
l3 and S24 are obtained.

However, in the spatial region Z4, due to the presence of the birefringent crystal plate B3, the centers are aligned along the above-mentioned fourth plane, as indicated by 014 and 024, respectively, and the polarization direction of the linearly polarized light S23 (this Based on the linearly polarized lights Sl3 and S23, respectively, which are spaced apart in the Y'-axis direction, linearly polarized lights Sl4 and S24 having the same polarization directions as those are obtained.

In this case, the centers 014 and 024 are spaced apart from each other in the Y'-axis direction along the fourth plane because of the birefringent crystal plate B.
The optical axis of No. 3 is located on a fourth plane forming an angle of approximately 45 axes with respect to the third plane on which the optical axis of birefringent crystal plate B1 lies, but , linearly polarized light Sl
3 is linearly polarized light in the Y'-axis direction along the fourth plane, the center 013 of the linearly polarized light Sl3 moves in the Y'-axis direction along the fourth plane. moreover,
In the spatial region Z5, due to the presence of the birefringent crystal plate B2, the centers are located on the same point, as indicated by 015 and 025, respectively, with their polarization directions based on the linearly polarized lights Sl4 and S24, respectively. Linearly polarized lights Sl5 and S25 having the same polarization direction are obtained.

In this case, the centers 015 and 025 are the same point because the optical axis of the birefringent crystal plate B2 is located on the fifth plane mentioned above, in accordance with the birefringent crystal plate B3. Then, the linearly polarized light S24 becomes the linearly polarized light S2 along the fifth plane.
This is because the center 024 of the linearly polarized light S24 moves along the fifth plane l in the Y'' axis direction. Therefore, as in the case of the optical nonreciprocal circuit according to the present invention described above in FIG. Linearly polarized lights Sl6 and S26 (not shown) which are inclined by 45° with respect to the axial direction and have a 90° angle with respect to each other,
It is obtained by placing their centers on the same point.

Conversely, as shown in FIG. 8, the linearly polarized lights Sl5 and S2 described above in FIG.
5, the linearly polarized lights Sl5' and S25 are inclined by approximately 45 degrees with respect to the Y-axis direction and make an angle of approximately 90 degrees with each other.
2 is provided with a light source that can obtain linearly polarized lights Sl6' and S26' (not shown) such that their centers 015' and 025' lie on the same point, then the spatial region Z5
As shown in FIG. 8, the centers are located on the same point, as shown by 015' and 025', respectively, and are based on the linearly polarized lights Sl6' and S26', respectively, in the same direction as their polarization direction. Linearly polarized lights Sl5' and S25' (in the above-mentioned Y/axis direction and Y7 axis direction, respectively) are obtained.

Also, in the spatial region Z4, due to the presence of the birefringent crystal plate B2, the centers are 014 ' and 024', along the fifth plane, based on the linearly polarized lights Sl5' and S25', which are spaced apart from each other in the Y7 axis direction, and having the same polarization direction as those, respectively. Linearly polarized light Sl4'
and S24' are obtained.

Furthermore, in the spatial region Z3, due to the presence of the birefringent crystal plate B3, the center is
013' and 024', respectively, along the Y-Z plane and spaced apart from each other by l in the Y-axis direction. Linearly polarized lights Sl3' and S23/ having the same polarization direction are obtained.

Furthermore, in the spatial region Z2, due to the presence of the magneto-optic effect plate D, the center is
As shown by 012' and 022', respectively, 1C.
Based on the linearly polarized lights Sl3' and 23', respectively, spaced apart in the Y-axis direction, it? Linearly polarized lights S12' and S22' (with polarization directions in the X-axis direction and Y-axis direction, respectively) are obtained, which are rotated clockwise in the figure by approximately 45 degrees with respect to the polarization direction.

In addition, in the spatial region Z1, due to the presence of the birefringent crystal plate B1, the center is 011', contrary to the linearly polarized lights Sl2 and S22 obtained from the linearly polarized lights Sll and S22 in FIG. and 021', which are separated from each other in the Y-axis direction by a distance that is larger than the distance between the centers 0122 and 022/ of the linearly polarized lights Sl22 and S22', respectively. Linearly polarized lights Sll' and S2l' in the same direction are obtained. Therefore, as in the case of the optical non-reciprocal circuit according to the invention described above in FIG.
On the X-Y plane containing 1, the linearly polarized lights Sl6' and S26
Based on ', linearly polarized light S1' and S2O' (not shown), whose polarization directions are in the X-axis direction and the Y-axis direction, are obtained with their centers separated largely in the Y-axis direction. .

Therefore, the second embodiment of the optical non-reciprocal circuit according to the present invention described above has the same optical non-reciprocal function as the first embodiment of the optical non-reciprocal circuit according to the present invention described above. is obtained.

Note that the above description has only shown a few embodiments of the present invention, and detailed explanations are omitted, as shown in FIG. 9, for example, where the same reference numerals are given to parts corresponding to those in FIG. 2. However, in the configuration shown in FIG. 2, the optical waveguide K3 is omitted from the light output section G of the third optical system A3, so that the light from the light source S is directly input to the first optical system A1. It is also possible to have a configuration in which the

In this case, the light source S may be configured using a light emitting diode or a semiconductor laser as shown in the figure. For example, as shown in FIG. 10, in which parts corresponding to those in FIG. , correspondingly, any one or more of the birefringent crystal plates B1 and B2, the magneto-optic effect plate D1, and the optical rotation or anisotropic crystal plate E, for example, as shown in the figure (this, the birefringent crystal plate B1 It is also possible to make the plate surface into a curved surface f, thereby giving the birefringent crystal plate B1 the same function as the lens F.

Furthermore, as shown in FIG. 11, in which parts corresponding to those in FIG. X-
The magneto-optic effect plate D is placed on a plane that is inclined with respect to a plane parallel to the Y plane, and reflective films h and i are attached to opposing surfaces of the magneto-optic effect plate D. According to
Even if the magneto-optic effect plate D in this case is made of a material with a small so-called Faraday rotation angle, it may be configured so that it exhibits the same effect as the magneto-optic effect plate D in the case of FIG. Alternatively, it is also possible to have a configuration in which the positions of the magneto-optic effect plate D and the optically active or anisotropic crystal plate E are exchanged.

Of course, the above-described modifications and changes can also be made to the second embodiment of the optical non-reciprocal circuit according to the present invention described above.

Furthermore, in the configuration described above in FIG.
It is possible to have a configuration in which another lens corresponding to the lens F is provided, or in the case of such a configuration, the lens F may be omitted from purchase, and of course, the lens F in the case of this configuration may be purchased by using a plurality of lenses. It can also be composed of lenses.

Various other modifications and changes may be made without departing from the spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a conventional optical non-reciprocal circuit. FIG. 2 is a schematic diagram showing a first embodiment of the optical non-reciprocal circuit according to the present invention. FIG. 3 and FIG. 4 are diagrams showing the aspect of linearly polarized light in a spatial region for explaining the same. 5 and 6 are line diagrams for explaining the operation of the first embodiment of the present invention shown in FIG. 2. 7 and 8 are diagrams similar to FIGS. 3 and 4, respectively, providing an explanation of a second embodiment of the optical non-reciprocal circuit according to the invention. FIG. 9, FIG. 10, and FIG. 11 are line diagrams showing other embodiments of the optical non-reciprocal circuit according to the present invention. Al, A2, A3...optical system,
Bl, B2... Birefringent crystal plate, D...
Magneto-optic effect plate, E... Optical rotation or anisotropic crystal plate, F... Convergence lens, K1 to K3...
...Optical waveguide, S... Light source.

Claims (1)

[Scope of Claims] 1. A first optical system, and second and third optical systems disposed opposite to each other with the first optical system in between, the first optical system being , the first ones arranged opposite to each other with a predetermined interval between them.
By receiving a predetermined magnetic field placed between the second birefringent crystal plate and the first and second birefringent crystal plates, the angle between the polarization direction of the incident light and that of the output light is changed. , approximately 45
The second optical system has a first optical waveguide with one free end facing the first optical system, and the third optical system has a magneto-optic effect plate obtained at The optical system includes a second optical waveguide having one free end face facing the first optical system, and a light emitting section facing the first optical system. In addition to the first and second birefringent crystal plates and the magneto-optic effect plate, the optical system transmits light from one free end surface of the first optical waveguide of the second optical system to the third optical waveguide.
The light from the light output section of the third optical system is converged onto one free end surface of the second optical waveguide of the optical system, and the light from the light output section of the third optical system is focused onto one free end surface of the first optical waveguide of the second optical system. A lens means for converging the light onto the free end surface, and a polarization direction of the incident light and an output light disposed between the first or second birefringent crystal plate and the magneto-optic effect plate and facing them. has an optically active or anisotropic crystal plate whose angle with that of the first and second birefringent crystal plates is approximately 45°; Therefore, the light obtained from the first optical waveguide of the second optical system through one free end surface thereof has a polarization direction of Irrespective of this, the light that is incident on the second optical waveguide of the third optical system from its one free end face and obtained from the light output section of the third optical system has a predetermined polarization direction. If you have,
An optical non-reciprocal circuit characterized in that the light is input to the first optical waveguide of the second optical system from one free end surface thereof. 2 Comprising a first optical system, and second and third optical systems arranged opposite to each other with the first optical system in between, the first optical system maintaining a predetermined interval. The first
and a second birefringent crystal plate, and by receiving a predetermined magnetic field arranged on the first and second birefringent crystal plates, the angle between the polarization direction of the incident light and that of the output light is Approximately 45°
The second optical system has a first optical waveguide with one free end facing the first optical system, and the third optical system has a magneto-optic effect plate obtained by The system includes a second optical waveguide having one free end facing the first optical system, and a light emitting section facing the first optical system, and the first optical system In addition to the first and second birefringent crystal plates and the magneto-optic effect plate, the system transmits light from one free end surface of the first optical waveguide of the second optical system to the third optical system. The light from the light emitting section of the third optical system is converged onto one free end surface of the second optical waveguide of the system, and the light from the light output section of the third optical system is directed onto one free end surface of the first optical waveguide of the second optical system. and a third birefringent crystal plate disposed between and facing the first or second birefringent crystal plate and the magneto-optic effect plate. The first birefringent crystal plate is arranged with its optical axis on the first plane, and the second and third birefringent crystal plates are
A configuration in which the optical axes thereof are arranged so as to form an angle of approximately 45° with the first plane and lie on second and third planes that form an angle of 90° with each other, respectively. Therefore, the light obtained from the first optical waveguide of the second optical system through one free end face of the first optical waveguide of the third optical system is independent of its polarization direction. When the light incident on the second optical waveguide from one free end surface and obtained from the light output section of the third optical system has a predetermined polarization direction,
An optical non-reciprocal circuit characterized in that the light is input to the first optical waveguide of the second optical system from one free end surface thereof.