Prism and optical device

Abstract

The prism has, for example, an incident surface, a reflective surface, and an exit surface, the incident surface, the reflective surface, and the exit surface extending in directions that intersect the first direction and that are different from each other, the prism changes the direction of travel of light substantially along an imaginary plane that is orthogonal to the first direction, and the refractive index of the prism is n (where n > 1), and when viewed in the first direction, the refractive index of the prism is greater than n (where n > 1). The angle difference between the incident surface and the exit surface is 90 DEG, the light incident on the incident surface advances in the second direction, the incident surface extends in the second direction as the light approaches the exit surface from the incident position of the light, and the angle difference between an imaginary orthogonal plane with respect to the second direction and the incident surface is [theta] (where [theta] > 0 DEG]). When the angle difference between the emission surface and the reflection surface is set to be x [deg], the following formula (1) is satisfied: 45 < x < 45 + 2 [theta] / n (1).

Description

Technical Field

[0001] The invention relates to a prism and an optical device. Background Art

[0002] Conventionally, there is known an optical device including a cubic beam splitter that splits incident light into a straight direction parallel to the traveling direction of the incident light and an orthogonal direction orthogonal to the straight direction (for example, Patent Document 1).

[0003] This cubic beam splitter is usually made by joining two right-angle prisms. In this case, the two right-angle prisms have the same shape of a triangular prism with an isosceles right triangle cross section. Then, the faces of the two right-angle prisms that are the hypotenuse in the cross section are joined to each other, thereby making a cubic beam splitter.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-021775 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Patent Document 1 discloses a cubic beam splitter whose incident surface is orthogonal to the incident light. In this case, reflected light at the incident surface returns along the transmission path of the incident light, which may cause problems such as light interference or damage to optical components.

[0009] As a countermeasure, if the incident surface is tilted with respect to a direction perpendicular to the incident light, the reflected light at the incident surface can be deviated from the transmission path of the incident light, thereby avoiding the above-mentioned inconvenience.

[0010] However, in this case, light is output from the cubic beam splitter in the above-mentioned straight direction and in an inclined direction inclined to the orthogonal direction relative to the straight direction. As described in Patent Document 1, an optical component that receives light output in an orthogonal direction from a cubic beam splitter whose incident surface is orthogonal to the incident light is arranged in an orthogonal direction orthogonal to the straight direction relative to the cubic beam splitter, so there is no positional offset in the straight direction. In contrast, in the case where light is output in an inclined direction from a cubic beam splitter whose incident surface is inclined relative to the orthogonal direction orthogonal to the incident light, the optical component that receives the light is arranged in an inclined direction relative to the cubic beam splitter instead of in an orthogonal direction, so there is an offset in the straight direction. Therefore, an optical device including the cubic beam splitter and the optical component is likely to be large in the straight direction.

[0011] Therefore, one of the objects of the present invention is to obtain a prism and an optical device that can be configured to be more compact and that are novel and improved, for example.

[0012] Solutions to Solve Problems

[0013] The prism of the present invention, for example, comprises: an incident surface, which is a plane extending along a first direction and for light to be incident; a reflecting surface, which is a plane extending along the first direction and for reflecting at least a portion of the light incident on the incident surface; and an emitting surface, which is a plane extending along the first direction and for emitting the light reflected on the reflecting surface, wherein the incident surface, the reflecting surface and the emitting surface extend in directions intersecting the first direction and different from each other, respectively, and the prism changes the traveling direction of the light substantially along an imaginary plane orthogonal to the first direction, and the refractive index of the prism is n (where n>1), when observed along the first direction, the angle difference between the incident surface and the exit surface is 90 [deg], the light incident on the incident surface advances along the second direction, the incident surface extends toward the second direction as it approaches the exit surface from the incident position of the light, and when the angle difference between the imaginary orthogonal plane relative to the second direction and the incident surface is set to θ (where θ>0 [deg]), and the angle difference between the exit surface and the reflection surface is set to x [deg], the following formula (1) is satisfied:

[0014] 45<x<45+2θ / n……(1).

[0015] In the prism, the following formula (1-1) may also be satisfied:

[0016] x=45+θ / n……(1-1).

[0017] The prism of the present invention, for example, comprises: an incident surface, which is a plane extending along a first direction and for light to be incident; a reflection surface, which is a plane extending along the first direction and for reflecting at least a portion of the light incident on the incident surface; and an exit surface, which is a plane extending along the first direction and for emitting the light reflected on the reflection surface, wherein the incident surface, the reflection surface and the exit surface extend in directions intersecting the first direction and different from each other, respectively, and the prism changes the traveling direction of the light substantially along an imaginary plane orthogonal to the first direction, and the refractive index of the prism is n (where n is the refractive index of the prism). , n>1), when observed along the first direction, the angle difference between the incident surface and the exit surface is 90 [deg], the light incident on the incident surface advances along the second direction, the incident surface extends in a manner opposite to the second direction as it approaches the exit surface from the incident position of the light, and when the angle difference between the imaginary orthogonal plane relative to the second direction and the incident surface is set to θ (where θ>0 [deg]), and the angle difference between the exit surface and the reflection surface is set to y [deg], the following formula (2) is satisfied:

[0018] 45-2θ / n<y<45……(2).

[0019] In the prism, the following formula (2-1) may also be satisfied:

[0020] y=45-θ / n……(2-1).

[0021] In the prism, the reflecting surface may transmit a part of the light from the incident surface.

[0022] The prism may include a filter that transmits light having a predetermined wavelength among the light transmitted through the reflecting surface.

[0023] The optical device of the present invention includes the prism, an optical component through which the light emitted from the emission surface is input or passes, and a base to which the prism and the optical component are fixed.

[0024] The optical device may include, as the prism, a first prism and a second prism into which light output from the first prism is input.

[0025] Effects of the Invention

[0026] According to the present invention, it is possible to obtain a novel and improved prism and optical device that can be configured to be more compact, for example. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an illustrative and schematic top view of the prism according to the first embodiment.

[0028] Figure 2 It is a top view of a conventional prism as a reference example.

[0029] Figure 3 It is an illustrative and schematic plan view of an optical device including the prism according to the first embodiment.

[0030] Figure 4 It is a top view of an optical device including a conventional prism as a reference example.

[0031] Figure 5 It is an illustrative and schematic top view of a prism according to the second embodiment.

[0032] Figure 6 It is an illustrative and schematic plan view of an optical device including a prism according to the second embodiment.

[0033] Figure 7 It is equipped with existing Figure 2 Top view of the optical setup with different prisms.

[0034] Figure 8 It is an illustrative and schematic top view of the optical device according to the third embodiment.

[0035] Fig. 9 It is an illustrative and schematic top view of an optical device according to a fourth embodiment.

[0036] Fig.10 It is an illustrative and schematic top view of the optical device of the fifth embodiment.

[0037] Fig.11 It is an illustrative and schematic top view of the optical device of the sixth embodiment.

[0038] Fig.12 It is an illustrative and schematic top view of a prism according to the seventh embodiment.

[0039] Fig.13 It is an illustrative and schematic top view of the optical device of the eighth embodiment.

[0040] Fig.14 It is an illustrative and schematic top view of an optical device according to a ninth embodiment. DETAILED DESCRIPTION

[0041] Hereinafter, an exemplary embodiment of the present invention is disclosed. The structure of the embodiment shown below, and the function and effect that can be achieved by the structure are examples. The present invention can also be implemented by a structure other than the structure disclosed in the following embodiment. In addition, according to the present invention, at least one of the various effects (including derived effects) obtained by the structure can be obtained.

[0042] The multiple embodiments shown below have the same structure. Therefore, according to the structure of each embodiment, the same action and effect obtained based on the same structure can be obtained. In addition, the same reference numerals are sometimes used to mark these same structures below, and repeated descriptions are omitted.

[0043] Each figure is a schematic drawing, and the dimensions in the figure may be different from the dimensions of the actual object. In each figure, the X direction is indicated by an arrow X, the Y direction is indicated by an arrow Y, and the Z direction is indicated by an arrow Z. The X direction, the Y direction, and the Z direction intersect and are orthogonal to each other. In addition, in each figure, the light path is indicated by a dotted line.

[0044] In addition, in this specification, serial numbers are given for the purpose of distinguishing directions, components, etc., and do not limit priority, order, number, etc.

[0045] [First embodiment]

[0046] Figure 1 This is a plan view of the prism 100A ( 100 ) of the first embodiment viewed in the direction opposite to the Z direction. The prism 100 is made of, for example, a quartz glass material. The refractive index n of the prism 100 is greater than 1.

[0047] The prism 100 has an incident surface 101, an exit surface 102, and a reflection surface 103. Light incident into the prism 100 from an incident position Pi of the incident surface 101 is reflected at a reflection position Pr of the reflection surface 103, and is emitted from an exit position Po of the exit surface 102 to the outside of the prism 100. In the prism 100, the direction of travel of the incident light Li incident into the incident surface 101 is the X direction, and the direction of travel of the exit light Lo emitted from the exit surface 102 is the Y direction.

[0048] The incident surface 101, the exit surface 102, and the reflection surface 103 are all planes extending along the Z direction. In addition, the incident surface 101, the exit surface 102, and the reflection surface 103 extend in directions that intersect the Z direction and are different from each other. The incident surface 101 and the exit surface 102 are orthogonal to each other. Figure 1 In a plan view, the incident surface 101, the emitting surface 102, and the reflecting surface 103 form a right triangle. That is, the prism 100 has a triangular prism shape extending in the Z direction.

[0049] However, in this embodiment, when viewed from above, the length of the side corresponding to the incident surface 101 and the length of the side corresponding to the exit surface 102 are different from each other. That is, although the shape of the cross section of the prism 100 that is orthogonal to the Z direction is a right triangle, it is not an isosceles right triangle. Therefore, when viewed from above, the angle c between the incident surface 101 and the exit surface 102 is 90°, and the angle x between the exit surface 102 and the reflecting surface 103 and the angle y between the incident surface 101 and the reflecting surface 103 are both greater than 0° and less than 90°, and are different from each other. In this embodiment, the angle x is greater than the angle y. The Z direction is an example of a first direction.

[0050] The incident surface 101 is inclined at an angle θ relative to an imaginary orthogonal plane Pv that is orthogonal to the traveling direction (X direction) of the incident light Li incident on the incident surface 101. In the present embodiment, the incident surface 101 extends in a manner toward the X direction as it approaches the exit surface 102 from the incident position Pi of the incident light Li. Therefore, the reflected light of the incident light Li at the incident surface 101 does not move in the opposite direction of the X direction, that is, it moves in a direction deviating from the transmission path of the incident light Li toward the Y direction. Thus, it is possible to avoid the undesirable phenomenon caused by the reflected light at the incident surface 101 returning to the transmission path of the incident light Li. The X direction is an example of the second direction. In this case, the angle of incidence is θ.

[0051] The incident angle θ and the refraction angle at the incident position Pi are angles of the light traveling direction relative to the perpendicular line Vi of the incident surface 101 at the incident position Pi. According to Snell's law, when sinθ≒θ is assumed for the incident angle θ, the refraction angle at the incident position Pi is θ / n.

[0052] The light travels from the incident position Pi along the path shown by the dotted line and reaches the reflecting surface 103. The incident angle and the reflection angle at the reflecting position Pr are the angles of the traveling direction of the light relative to the perpendicular Vr of the reflecting surface 103 at the reflecting position Pr. At the reflecting position Pr, the incident angle is the same as the reflection angle.

[0053] The light travels along the path indicated by the dotted line from the reflection position Pr and reaches the exit surface 102. The incident angle at the exit position Po and the exit angle θo as the refraction angle are the angles of the traveling direction of the light relative to the perpendicular Vo of the exit surface 102 at the exit position Po. According to Snell's law, when the exit angle θo is set to sinθ≒θ, the incident angle at the exit position Po is θo / n.

[0054] exist Figure 1 In the case of , geometrically, the following equation holds true for the incident angle θo / n[deg] at the emission position Po.

[0055] 2x-θ / n=θo / n+90……(10)

[0056] When θo=θ, the incident light Li is orthogonal to the outgoing light Lo. Therefore, if θo=θ is set and equation (10) is solved for x, the following equation is obtained:

[0057] x=45+θ / n……(1-1)

[0058] That is, when the angle x [deg] between the emission surface 102 and the reflection surface 103 is 45+θ / n, the incident light Li and the emission light Lo are orthogonal.

[0059] Figure 2 1 is a top view of a so-called right-angle prism 100R1 of a conventional reference example, which is an isosceles right triangle when viewed from above, as viewed in the opposite direction of the Z direction. Figure 2 As shown in FIG. 1 , when the incident surface 101 is inclined at an angle θ relative to the imaginary orthogonal plane Pv that is orthogonal to the traveling direction (X direction) of the incident light Li incident on the incident surface 101 and extends in the X direction as it approaches the exit surface 102 from the incident position Pi, the exit angle at the exit position Po is θ. In addition, the angle between the vertical line Vo at the exit position Po and the imaginary line Vy extending in the Y direction at the exit position Po is also θ. Therefore, the angle between the traveling direction of the exit light Lo and the Y direction is 2θ.

[0060] Figure 3 1 is a plan view of a portion of an optical device 1A ( 1 ) including a prism 100A ( 100 ) according to the first embodiment, an optical component 200 , and a base 1 d . Figure 4 Yes Figure 2 1 is a top view of a part of an optical device including a prism 100R1 and an optical component 200 as a reference example. The optical component 200 is for the outgoing light Lo to enter or pass through. In addition, the base 1d supports the prism 100 and the optical component 200. In other words, the prism 100 and the optical component 200 are fixed to the base 1d.

[0061] like Figure 3 As shown, in the optical device 1A (1) of the first embodiment, the outgoing light Lo travels from the prism 100 in the Y direction orthogonal to the X direction which is the traveling direction of the incident light Li. Therefore, the prism 100 and the optical component 200 are arranged in the Y direction.

[0062] In contrast, Figure 4 In this case, the outgoing light Lo travels from the prism 100R1 in a direction tilted 2θ toward the X direction relative to the Y direction. Therefore, the prism 100R1 and the optical component 200 are arranged not in the Y direction but in the traveling direction of the outgoing light Lo, that is, in a direction tilted 2θ toward the X direction relative to the Y direction.

[0063] Compare Figure 3 and Figure 4 It can be seen that the layout of this embodiment ( Figure 3 ) has a length La in the X direction of the occupied area of ​​the prism 100 and the optical component 200 than that of the layout of the reference example ( Figure 4 ) has a shorter length Lr1 in the X direction of the area occupied by the prism 100R1 and the optical components. That is, according to this embodiment, the length of the optical device 1A (1) in the X direction can be further shortened compared to the reference example, thereby making the optical device 1A (1) smaller.

[0064] Based on the above considerations, it can be understood that if the incident surface 101 is inclined at an angle θ with respect to an imaginary orthogonal plane Pv that is orthogonal to the traveling direction (X direction) of the incident light Li incident on the incident surface 101 and extends in the X direction as it approaches the exit surface 102 from the incident position Pi, then when the angle x [deg] between the exit surface 102 and the reflection surface 103 is greater than 45°, Figure 2 Compared with the existing structure, the length La of the area occupied by the prism 100 and the optical component 200 in the X direction can be shortened.

[0065] In addition, Figure 2 In the existing structure, the emission angle θo is θ, and the emission light Lo is offset by 2θ in the X direction relative to the imaginary line Vy. Figure 2 As shown in FIG. 1 , when the displacement of the emitted light Lo2 from the imaginary line Vy to the opposite direction of the X direction is less than 2θ, it can also be said that Figure 2 Compared with the existing structure, the length La of the area occupied by the prism 100 and the optical component 200 in the X direction can be shortened. When the offset of the emitted light Lo2 from the imaginary line Vy in the opposite direction of the X direction is 2θ, the emission angle θo is -3θ, so in formula (10), θo=-3θ is substituted to obtain the following formula:

[0066] 2x-θ / n=-3θ / n+90……(11)

[0067] Then it becomes the following formula:

[0068] x=45+2θ / n……(12)

[0069] Therefore, when the following equation is satisfied:

[0070] 45<x<45+2θ / n……(1)

[0071] In the case of Figure 2Compared with the conventional structure of the right angle prism, the length La of the occupied area of ​​the prism 100 and the optical component 200 in the X direction can be shortened. It should be noted that in a prism having a mirror image relationship with the prism 100A of the first embodiment, the formula (1) and the formula (1-1) also hold.

[0072] [Second embodiment]

[0073] Figure 5 This is a top view of the prism 100B (100) of the second embodiment observed in the opposite direction of the Z direction. In the top view, the angle c between the incident surface 101 and the exit surface 102 is 90°, and the angle y between the exit surface 102 and the reflection surface 103 and the angle x between the incident surface 101 and the reflection surface 103 are both greater than 0° and less than 90°, and are different from each other. In this embodiment, the angle x is also greater than the angle y.

[0074] Compare Figure 5 and Figure 1 It can be seen that the prism 100B of this embodiment has a mirror image relationship with the prism 100A of the first embodiment, and the light travels in the opposite direction to the first embodiment. In the second embodiment, it can be said that the incident surface 101 is inclined at an angle θ relative to the imaginary orthogonal plane Pv that is orthogonal to the traveling direction (X direction) of the incident light Li incident on the incident surface 101, and extends in the opposite direction of the X direction as it approaches the exit surface 102 from the incident position Pi.

[0075] In the present embodiment, geometrically, the following equation (20) holds true regarding the incident angle θo / n [deg] at the emission position Po.

[0076] 2y+θ / n=90-θo / n……(20)

[0077] When θo=θ, the incident light Li is orthogonal to the outgoing light Lo. Therefore, if θo=θ is set and equation (20) is solved for y, the following equation is obtained:

[0078] y=45-θ / n……(2-1)

[0079] That is, when the angle x[deg] between the emission surface 102 and the reflection surface 103 is 45-θ / n, the incident light Li and the emission light Lo are orthogonal.

[0080] Figure 6 1 is a plan view of a portion of an optical device 1B ( 1 ) including a prism 100B ( 100 ) according to the second embodiment, an optical component 200 , and a base 1 d . Figure 7 1 is a plan view of a portion of an optical device including a prism 100R2 and an optical component 200 as a reference example.

[0081] like Figure 6 As shown, in the optical device 1B (1) of the second embodiment, the outgoing light Lo travels from the prism 100 in the Y direction orthogonal to the X direction which is the traveling direction of the incident light Li. Therefore, the prism 100 and the optical component 200 are arranged in the Y direction.

[0082] In contrast, Figure 7 In this case, the outgoing light Lo travels from the prism 100R2 in a direction tilted 2θ in the opposite direction to the X direction relative to the Y direction. Therefore, the prism 100R2 and the optical component 200 are not arranged in the Y direction, but in the traveling direction of the outgoing light Lo, that is, in a direction tilted 2θ in the opposite direction to the X direction relative to the Y direction.

[0083] Compare Figure 6 and Figure 7 It can be seen that the layout of this embodiment ( Figure 6 ) has a length Lb in the X direction of the occupied area of ​​the prism 100 and the optical component 200 greater than that of the layout of the reference example ( Figure 7 ) is shorter in length Lr2 in the X direction of the occupied area of ​​the prism 100R2 and the optical components. That is, according to this embodiment, the length of the optical device 1B (1) in the X direction can be further shortened compared to the reference example, thereby making the optical device 1B (1) smaller. That is, the second embodiment can also obtain the same effect as the first embodiment.

[0084] In the existing prism which is an isosceles right triangle when viewed from above, y=45[deg]. At this time, the outgoing light Lo is as follows: Figure 7 As shown in FIG. 1 , the emitted light Lo is offset by 2θ in the opposite direction of the X direction relative to the imaginary line Vy extending in the Y direction. On the other hand, when the emitted light Lo is offset by 2θ in the X direction relative to the imaginary line Vy, the emission angle θo is 3θ. Therefore, in the formula (20), θo=3θ is substituted to obtain the following formula:

[0085] 2y+θ / n=90-3θ / n……(21)

[0086] Then it becomes the following formula:

[0087] y=45-2θ / n……(22)

[0088] Therefore, when the following equation is satisfied:

[0089] 45-2θ / n<y<45……(2)

[0090] In the case of Figure 2Compared with the conventional structure of the right angle prism, the length Lb of the occupied area of ​​the prism 100 and the optical component 200 in the X direction can be shortened. It should be noted that in the prism having a mirror image relationship with the prism 100B of the second embodiment, the formula (2) and the formula (2-1) also hold.

[0091] [Third embodiment]

[0092] Figure 8 FIG. 1 is a top view of an optical device 1C (1) according to the third embodiment. Figure 8 As shown, in this embodiment, the optical device 1C (1) includes a plurality of cubic prisms 100A1. The cubic prisms 100A1 are each produced by bonding together the oblique surfaces of the prism 100A (100) of the first embodiment in a plan view.

[0093] In this case, the cubic prism 100A1 can achieve the same functions and effects as the prism 100A (100) of the first embodiment. That is, the incident light Li and the outgoing light Lo to each cubic prism 100A1 are orthogonal to each other. Figure 8 The incident light Li incident on the upper side of the cubic prism 100A1 and the incident light Li from the Figure 8 The outgoing light Lo emitted from the lower side of the cubic prism 100A1 is antiparallel to each other, that is, parallel and in opposite directions. According to such a structure, the optical device 1C (1) can be made smaller in the X direction and the Y direction. In this example, the front stage ( Figure 8 The cubic prism 100A1 on the upper side of the prism is an example of a first prism. Figure 8 The cubic prism 100A1 (on the lower side) is an example of a second prism.

[0094] [Fourth embodiment]

[0095] Fig. 9 FIG. 1 is a top view of an optical device 1D ( 1 ) according to a fourth embodiment. Fig. 9 As shown, in this embodiment, the optical device 1D (1) includes a plurality of cubic prisms 100B1. The cubic prisms 100B1 are each produced by bonding together the oblique surfaces of the prism 100B (100) of the second embodiment in a plan view.

[0096] In this case, the cubic prism 100B1 can obtain the same function and effect as the prism 100B (100) of the second embodiment. That is, the incident light Li and the outgoing light Lo to each cubic prism 100B1 are orthogonal to each other. Fig. 9 The incident light Li incident on the upper side of the cubic prism 100B1 and the incident light Li from the Fig. 9The outgoing light Lo emitted from the lower side of the cubic prism 100B1 is antiparallel to each other. According to such a structure, the optical device 1D (1) can be made smaller in the X direction and the Y direction. In this example, the front stage ( Fig. 9 The cubic prism 100B1 of the upper side) is an example of a first prism, and the subsequent stage ( Fig. 9 The cubic prism 100B1 (on the lower side) is an example of a second prism.

[0097] [Fifth Embodiment]

[0098] Fig.10 FIG. 1 is a top view of an optical device 1E (1) according to the fifth embodiment. Fig.10 As shown, in this embodiment, the optical device 1E( 1 ) includes a cubic prism 100A1 similar to that of the third embodiment and a cubic prism 100B1 similar to that of the fourth embodiment.

[0099] In this case, the cubic prisms 100A1 and 100B1 can respectively obtain the same functions and effects as the prism 100A (100) of the first embodiment and the prism 100B (100) of the second embodiment. That is, the incident light Li and the outgoing light Lo for the cubic prism 100A1 are orthogonal to each other, and the incident light Li and the outgoing light Lo for the cubic prism 100B1 are orthogonal to each other. Fig.10 The incident light Li incident on the upper side of the cubic prism 100A1 and the incident light Li from the Fig.10 The outgoing light Lo emitted from the lower side of the cubic prism 100B1 is antiparallel to each other. According to such a structure, the optical device 1E (1) can be made smaller in the X direction and the Y direction. In this example, the front stage ( Fig.10 The cubic prism 100A1 on the upper side of the prism is an example of a first prism. Fig.10 The cubic prism 100B1 (on the lower side) is an example of a second prism.

[0100] [Sixth embodiment]

[0101] Fig.11 FIG. 1 is a top view of an optical device 1F (1) according to the sixth embodiment. Fig.11 As shown, in this embodiment, the optical device 1F( 1 ) includes a cubic prism 100A1 similar to that of the third embodiment and a cubic prism 100B1 similar to that of the fourth embodiment.

[0102] in addition, Fig.11The cubic prism 100A1 located in the middle stage functions as a beam splitter. That is, the reflection surface 103 reflects a part of the light reaching the reflection surface 103 and transmits a part. Therefore, the cubic prism 100A1 outputs an outgoing light Lo that is transmitted through the reflection surface 103 and emitted in the X direction from the outgoing surface 104 on the side opposite to the incident surface 101, and an outgoing light Lo that is reflected from the reflection surface 103 and emitted in the Y direction from the outgoing surface 102 adjacent to the incident surface 101.

[0103] In this case, the cubic prisms 100A1 and 100B1 can also achieve the same functions and effects as the prism 100A (100) of the first embodiment and the prism 100B (100) of the second embodiment. That is, the incident light Li and the outgoing light Lo for the cubic prism 100A1 are orthogonal to each other, and the incident light Li and the outgoing light Lo for the cubic prism 100B1 are orthogonal to each other. Fig.11 The incident light Li incident on the intermediate cubic prism 100A1 and the incident light Li from Fig.10 The outgoing light Lo1 (Lo) emitted from the lower side of the cubic prism 100A1 is antiparallel to each other. Fig.10 The incident light Li incident on the intermediate cubic prism 100A1 and the incident light Li from Fig.10 The outgoing light Lo2 (Lo) emitted from the upper side of the cubic prism 100B1 is antiparallel to each other. Therefore, the outgoing light Lo1 and the outgoing light Lo2 are parallel to each other. According to such a structure, the optical device 1F (1) can be made smaller in the X direction and the Y direction. In this example, the front stage ( Fig.11 The cubic prism 100A1 in the middle of the prism is an example of a first prism, and the other cubic prisms 100A1 and 100B1 are examples of a second prism. It should be noted that the combination of the plurality of cubic prisms 100A1 and 100B1 is not limited to Figures 8 to 11 In addition, Figures 8 to 11 In the example, the prism 100A (see Figure 1 ) and prism 100B (refer to Figure 5 ).

[0104] [Seventh embodiment]

[0105] Fig.12 is a top view of a cubic prism 100A1-1 (100A1) according to the seventh embodiment. Fig.11 The cubic prism 100A1 in the middle is similarly produced by bonding the oblique surfaces of the prism 100A ( 100 ) of the first embodiment together in a plan view.

[0106] However, in this embodiment, the wavelength filter 105 is provided on the reflection surface 103. Therefore, when the wavelength filter 105 reflects, for example, light of wavelengths λ1 and λ2 and transmits light of wavelengths λ3 and λ4, the output light Lo emitted from the output surface 104 on the side opposite to the incident surface 101 includes light of wavelengths λ3 and λ4, and the output light Lo emitted from the output surface 102 adjacent to the incident surface 101 includes light of wavelengths λ1 and λ2.

[0107] In this case, the incident light Li is also parallel to the outgoing light Lo emitted from the outgoing surface 104 and is orthogonal to the outgoing light Lo emitted from the outgoing surface 102. Therefore, an optical device including the cubic prism 100A1-1 (100A1) of this embodiment can be further miniaturized.

[0108] [Eighth Embodiment]

[0109] Fig.13 This is a top view showing the internal structure of an optical device 1G (1) according to an eighth embodiment, and is a view obtained by viewing from above with the upper cover 1e removed. The optical device 1G includes a housing 1g having a signal light output port 1a, a signal light input port 1b, a side wall portion 1c, a base portion 1d, an upper cover 1e, and a terminal portion 1f.

[0110] like Fig.13 As shown, the terminal portion 1f protrudes inside and outside the optical device 1G. The terminal portion 1f is made of an insulating material, and a wiring pattern made of a conductor is formed on its surface and inside. The wiring pattern of the terminal portion 1f is electrically connected to a controller that is provided outside the optical device 1G and controls the operation of the optical device 1G. The controller is configured to include an IC (Integrated Circuit), for example.

[0111] The optical device 1G contains the following components: a chip 2 with an auxiliary base, a lens 3, a wavelength locker 4 as a wavelength detector, a photodiode (PD) array 5, a lens 6, an optical isolator 7, a beam splitter 8, a mirror 9, a lens 10, a modulator 11, a modulator driver 12, a terminator 13, lenses 14 and 15, a beam splitter 16, a polarization beam combiner 17, monitor PDs 18 and 19, a beam splitter 20, and a monitor PD 21. In addition, the optical device 1G contains the following components: a lens 30, a coherent mixer 31, a mirror 32, a lens 33, a monitor PD 34, a balanced PD array 35, and a transimpedance amplifier (TIA) 36.

[0112] In the optical device 1G, these components are installed inside the housing 1g, and the upper cover 1e is installed to seal it airtightly. In addition, these components, except for the modulator driver 12 and TIA36, are installed on the base or temperature adjustment element arranged inside the housing 1g. The modulator driver 12 and TIA36 are installed on the terminal part 1f.

[0113] The optical device 1G is configured as an optical transceiver that outputs output signal light from a signal light output port 1a as a light output section and receives input signal light from a signal light input port 1b as a light input section. The configuration and function of each component will be described below.

[0114] [Light emitter]

[0115] First, the structure and function of a component that functions as a light transmitter will be described.

[0116] The chip 2 with auxiliary base includes a laser element 2a and an auxiliary base 2b on which the laser element 2a is mounted. The laser element 2a is, for example, a wavelength-variable laser element. The auxiliary base 2b is made of a material with high thermal conductivity, so that the heat generated by the laser element 2a is efficiently dissipated to the base on which the auxiliary base 2b is mounted.

[0117] The laser element 2a is supplied with power through a wiring pattern formed on the terminal portion 1f, and outputs a continuous wave (CW) linearly polarized laser light L1 from a front end surface located at the front side in the longitudinal direction to the front side in the longitudinal direction. In addition, the laser element 2a outputs a wavelength-locking laser light L2 from a rear end surface to the rear side in the longitudinal direction.

[0118] The lens 3 focuses the laser light L2 and inputs it to the wavelength locker 4. The wavelength locker 4 is a well-known structure including a planar lightwave circuit (PLC), for example. The wavelength locker 4 branches the laser light L2 into three, outputs one of them to the PD array 5, and outputs the other two to the PD array 5 after passing through two filters whose transmission characteristics periodically change with respect to the wavelength and have wavelength resolution characteristics. The two filters include, for example, a ring resonator and an etalon filter, and have different transmission wavelength characteristics.

[0119] The PD array 5 is composed of three PDs arranged in an array. The three PDs of the PD array 5 each receive three lasers output by the wavelength locker 4 and output a current signal corresponding to the intensity of the received light. Each current signal is sent to the controller through a wiring pattern formed in the terminal portion 1f, and is used for detecting and controlling the wavelength of the laser L1.

[0120] The laser element 2a and the wavelength locker 4 are arranged along the long side direction. In addition, the laser element 2a and the wavelength locker 4 are arranged so that the output position of the laser light L2 input to the wavelength locker 4 of the laser element 2a and the input position of the laser light L2 of the wavelength locker 4 are roughly aligned in the width direction, thereby constituting the laser unit LA.

[0121] On the other hand, lens 6 collimates laser light L1 and outputs it to optical isolator 7. Optical isolator 7 allows laser light L1 to pass through beam splitter 8 and blocks the passage of light from beam splitter 8. Thus, optical isolator 7 blocks reflected light and the like from being input to laser element 2a.

[0122] The beam splitter 8 splits the laser light L1 that has passed through the optical isolator 7 into laser light L11 and laser light L12. The laser light L11 travels to the right in the width direction, and the laser light L12 travels to the left in the width direction. The laser light L12 will be described in detail later.

[0123] The reflector 9 reflects the laser light L11 and changes its traveling direction to the rear side in the longitudinal direction. The lens 10 condenses the laser light L11 and inputs it to the modulator 11 .

[0124] The modulator 11 is roughly rectangular in shape and is configured so that its long side direction is roughly consistent with the long side direction of the housing 1g. The modulator 11 modulates the laser L11 to generate modulated light. The modulator 11 is, for example, an MZ (Mach-Zehnder) type phase modulator made of InP (indium phosphide) as a constituent material, and is a well-known structure driven by a modulator driver 12 and functions as an IQ modulator. Such a phase modulator is, for example, the same as the modulator disclosed in International Publication No. 2016 / 021163. The modulator driver 12 is, for example, configured to include an IC, and its operation is controlled by a controller. The modulator 11 and the modulator driver 12 are arranged in series and roughly parallel to the long side direction of the housing 1g to form a modulation unit M. In addition, the terminator 13 electrically terminates the modulator 11 to which a high-frequency modulation signal is applied by the modulator driver 12.

[0125] The modulator 11 outputs modulated lights L31 and L32 that have been subjected to IQ modulation, respectively, wherein the modulated lights L31 and L32 are linearly polarized lights whose polarization planes are orthogonal to each other. Here, the modulator 11 has a folding structure in which the traveling direction of the input light is folded back internally. As a result, for the modulator 11, the input position of the laser L11 and the output position of the modulated lights L31 and L32 are arranged on the same side, which is the side of the modulator 11 located on the front side in the long-side direction in this embodiment. In addition, the side of the modulator 11 located on the front side in the long-side direction is roughly parallel to the side wall portion 1c on the front side in the long-side direction of the housing 1g.

[0126] The lens 14 collimates the modulated light L31 and outputs it to the beam splitter 16. The beam splitter 16 reflects most of the modulated light L31 toward the polarization beam combiner 17, and transmits a part of it and outputs it to the monitor PD18. The lens 15 collimates the modulated light L32 and outputs it to the polarization beam combiner 17. The polarization beam combiner 17 performs polarization synthesis on the modulated lights L31 and L32 to generate an output signal light L4 containing the modulated lights L31 and L32. It should be noted that the polarization beam combiner 17 outputs a part of the modulated light L32 to the monitor PD19.

[0127] Monitor PD18 receives a portion of modulated light L31 input from beam splitter 16, and outputs a current signal corresponding to the intensity of the received light. The current signal is sent to the controller through the wiring pattern formed at terminal 1f, and is used to monitor the intensity of modulated light L31. Monitor PD19 receives a portion of modulated light L32 input from polarization beam combiner 17, and outputs a current signal corresponding to the intensity of the received light. The current signal is sent to the controller through the wiring pattern formed at terminal 1f, and is used to monitor the intensity of modulated light L32.

[0128] The beam splitter 20 transmits most of the output signal light L4, and reflects a part of it to output it to the monitor PD21. The monitor PD21 receives a part of the output signal light L4 input from the beam splitter 20, and outputs a current signal corresponding to the intensity of the received light. The current signal is sent to the controller through the wiring pattern formed on the terminal part 1f, and is used to monitor the intensity of the output signal light L4.

[0129] The signal light output port 1 a receives input of the output signal light L4 transmitted through the beam splitter 20 , and outputs it to the outside of the housing 1 g .

[0130] [Optical receiver]

[0131] Next, the structure and function of a component that functions as an optical receiver will be described.

[0132] The signal light input port 1b receives input signal light L5 from the outside and outputs it to the lens 30. The input signal light L5 travels from the front side to the rear side in the longitudinal direction in the housing 1g. The lens 30 condenses the input signal light L5 and inputs it to the coherent mixer 31.

[0133] On the other hand, the mirror 32 reflects the laser light L12 branched by the beam splitter 8 and changes its traveling direction from the left side in the width direction to the rear side in the longitudinal direction. The laser light L12 is condensed by the lens 33 and input to the coherent mixer 31 as local light.

[0134] The coherent mixer 31 is roughly rectangular in shape and is configured so that its long side direction is roughly consistent with the long side direction of the housing 1g. In the coherent mixer 31, the input position of the input signal light L5 and the input position of the laser L12 are configured on the same side, which is the side of the coherent mixer 31 located at the front side in the long side direction in this embodiment. In addition, for the coherent mixer 31, the side for inputting the input signal light L5 is roughly parallel to the side wall portion 1c on the front side in the long side direction of the housing 1g, and is roughly parallel to the side of the modulator 11 where the input position of the laser L11 and the output position of the modulated light L31, L32 are configured.

[0135] The coherent mixer 31 causes the input laser light L12 as local light and the input signal light L5 to interfere and process, generates a processed signal light, and outputs it to the balanced PD array 35. The processed signal light is four kinds of light, namely, an Ix signal light corresponding to the I component of the X polarization, a Qx signal light corresponding to the Q component of the X polarization, an Iy signal light corresponding to the I component of the Y polarization, and a Qy signal light corresponding to the Q component of the Y polarization. The coherent mixer 31 is, for example, a well-known coherent mixer composed of a PLC. It should be noted that the coherent mixer 31 is configured to branch a part of the input signal light L5 and output it to the monitor PD34. The monitor PD34 receives a part of the input signal light L5 and outputs a current signal corresponding to the intensity of the received light. The current signal is sent to the controller through the wiring pattern formed on the terminal portion 1f, and is used to monitor the intensity of the input signal light L5.

[0136] The balanced PD array 35 as a photoelectric element has four balanced PDs, which receive four processed signal lights respectively and convert them into current signals and output them to TIA36. TIA36 has four TIAs, and its operation is controlled by the controller. The TIAs of TIA36 convert the current signals input from each of the four balanced PDs into voltage signals and output them. The output voltage signal is sent to the controller or a higher-level control device through the wiring pattern formed on the terminal part 1f, and is used for demodulation of the input signal light L5.

[0137] The coherent mixer 31 , the balanced PD array 35 , and the TIA 36 are arranged in series substantially parallel to the long side direction of the housing 1 g , thereby constituting the optical processing unit OP.

[0138] In the optical device 1G, the laser element 2a and the wavelength locker 4 are arranged between the width center line CL1 of the coherent mixer 31 and the width center line CL2 of the modulator 11 in the width direction of the housing 1g. It should be noted that the so-called arrangement between the width center line CL1 and the width center line CL2 also includes the state of being arranged between the extension lines extending each center line to the outside in the long side direction of the coherent mixer 31 or the modulator 11. In addition, the modulator 11 has a folding structure in which the traveling direction of the input light is folded back inside. In addition, the optical device 1G is configured in such a way that the optical axes of the input signal light L5 and the laser light L2, which are two lights, intersect.

[0139] In addition, the laser element 2a and the wavelength locker 4 are arranged in series and approximately parallel to the long side direction of the housing 1g, and are arranged in such a manner that the output position of the laser light L3 input to the wavelength locker 4 of the laser element 2a and the input position of the laser light L2 of the wavelength locker 4 are approximately consistent in the width direction of the housing 1g. In addition, the laser assembly LA, the modulation unit M, and the optical processing unit OP are arranged in parallel in the width direction of the housing 1g. In addition, for the modulator 11, the input position of the laser light L11 and the output position of the modulated light L31 and L32 are arranged on the same side. In addition, this side is approximately parallel to the side of the coherent mixer 31 for inputting the input signal light L5. The two side surfaces are also approximately parallel to the side wall portion 1c on the front side of the long side direction of the housing 1g.

[0140] In the optical device 1G thus constructed, among all the components of the laser element 2a, the wavelength locker 4, the modulator 11, and the coherent mixer 31, components that are longer in the long side direction than in the width direction can be used. In addition, by arranging them in parallel, the dimension in the width direction of the housing 1g, that is, the width W, can be set to 15 mm or less. In addition, for the optical device 1G, the length from the rear end of the housing in the long side direction to the optical reference plane abutting the end face of the optical fiber for inputting and outputting optical signals can be set to 35 mm or less and the height can be set to 6.5 mm or less. As a preferred example, the width is about 14 mm, the length is about 31.5 mm, and the height is about 4 mm. Thus, an optical transceiver that complies with the QSFP-DD standard, which is the next generation standard of MSA, can be realized.

[0141] It should be noted that, as in the optical transceiver of Patent Document 1, when the components are housed in different housings, even if they are housed in one housing to form an optical transceiver, it is difficult to set the width to less than 15 mm. For example, in the CFP2-ACO standard, the width of the uITLA (Micro Integrated Tunable Laser Assembly) as a light source mounted on the optical transceiver is about 20 mm, the width of the HBPMQ (High Bandwidth Integrated Polarization Multiplexed Quadrature Modulators) as a modulator is about 12.5 mm, and the width of the uICR (Micro Intradyne Coherent Receivers) as a receiver is about 12.5 mm. Even if they are housed in one housing to form an optical transceiver, it is difficult to set the width to less than 15 mm.

[0142] like Fig.13 As shown, in this embodiment, the reflector 9 is configured as a cubic prism 100B1, the beam splitter 16 is configured as a cubic prism 100A1, the polarization beam combiner 17 is configured as a cubic prism 100B1, and the reflector 32 is configured as a cubic prism 100A1. Therefore, according to this embodiment, as in the above-mentioned embodiment, it is possible to obtain an effect that the optical device 1G can be configured in a smaller size. It should be noted that this application example is an example, and the reflector 9 or the beam splitter 16, the polarization beam combiner 17, and the reflector 32 can also be configured as other prisms 100A, 100B or cubic prisms 100A1, 100B1.

[0143] [Ninth embodiment]

[0144] Fig.14 1 is a plan view showing the internal structure of an optical device 1H ( 1 ) according to the ninth embodiment. The optical device 1H has a structure similar to that of the optical device 1G according to the eighth embodiment.

[0145] The optical device 1H contains the following components: a chip 2 with an auxiliary base, a lens 3, a wavelength locker 4, a PD array 5, a lens 6, an optical isolator 7, a beam splitter 8, a lens 10, a modulator 11, a modulator driver 12, a terminator 13, lenses 14 and 15, a beam splitter 16, a polarization beam combiner 17, monitor PDs 18 and 19, a beam splitter 20, and a monitor PD 21. In addition, the optical device 1H contains the following components: a lens 30, a coherent mixer 31A, a lens 33, a monitor PD 34, a balanced PD array 35, a transimpedance amplifier (TIA) 36, a monitor PD 40, and a beam splitter 41.

[0146] It should be noted that, regarding the components of the optical device 1H, if compared with the components of the optical device 1G, the reflector 32 is not accommodated, and the configuration of the lens 30, lens 33, and monitor PD34 is changed, the coherent mixer 31 is replaced by the coherent mixer 31A, and the monitor PD40 and beam splitter 41 are added.

[0147] In the optical device 1H, these components are installed inside a housing 1g, and an upper cover 1e is attached to perform airtight sealing.

[0148] The optical device 1H is configured as an optical transceiver that outputs output signal light from a signal light output port 1a and receives input signal light from a signal light input port 1b. The structure and function of each component will be described below.

[0149] [Light emitter]

[0150] First, the structure and function of a component that functions as an optical transmitter will be described. It should be noted that the description of components having the same structure and function as the optical device 1G is appropriately omitted.

[0151] The laser element 2a outputs the laser light L1 to the rear side of the long side direction of the housing 1g. In addition, the laser element 2a outputs the laser light L2 for intensity monitoring to the front side of the long side direction of the housing 1g. The monitor PD40 receives the laser light L2 and outputs a current signal corresponding to the intensity of the received light. The current signal is sent to the controller through the wiring pattern formed in the terminal portion 1f and is used for intensity monitoring of the laser element 2a.

[0152] The lens 6 collimates the laser light L1 and outputs it to the beam splitter 41. The beam splitter 41 transmits most of the laser light L1 toward the optical isolator 7, and reflects a part of it and outputs it to the beam splitter 8 as the laser light L13.

[0153] The beam splitter 8 splits the laser beam L13 into laser beams L14 and L15. The laser beam L14 will be described in detail later.

[0154] The lens 3 focuses the laser light L15 and inputs it to the wavelength locker 4. The wavelength locker 4 branches the laser light L15 into three, outputs one of them to the PD array 5, and outputs the other two to the PD array 5 after passing through two filters respectively.

[0155] The three PDs of the PD array 5 receive the three laser beams outputted by the wavelength locker 4, respectively, and output a current signal corresponding to the intensity of the received light. Each current signal is sent to the controller for detecting and controlling the wavelength of the laser beam L1.

[0156] The laser element 2a and the wavelength locker 4 are arranged in parallel along the width direction. In addition, the laser element 2a and the wavelength locker 4 are arranged in such a manner that the output position of the laser L15 input to the wavelength locker 4 of the laser element 2a, that is, the output position of the laser L1 and the input position of the laser L15 of the wavelength locker 4 are different from each other in the width direction, thereby constituting the laser assembly LAA.

[0157] The optical isolator 7 transmits the laser light L1 and inputs the laser light L1 to the lens 10 . The lens 10 condenses the laser light L11 and inputs the laser light L11 to the modulator 11 .

[0158] The modulator 11 is arranged so that its long side direction is roughly consistent with the long side direction of the housing 1g. The modulator 11 is driven by a modulator driver 12 and functions as an IQ modulator. The modulator driver 12 is controlled by a controller. The modulator 11 and the modulator driver 12 are arranged in series in the long side direction of the housing 1g to form a modulation unit M. The terminator 13 electrically terminates the modulator 11.

[0159] The modulator 11 outputs modulated lights L31 and L32 that have been subjected to IQ modulation. The modulator 11 has a folded structure. As a result, for the modulator 11, the input position of the laser light L1 and the output position of the modulated lights L31 and L32 are arranged on the same side surface located at the front side in the long-side direction. The side surface located at the front side in the long-side direction of the modulator 11 is substantially parallel to the side wall portion 1c located at the front side in the long-side direction of the housing 1g.

[0160] The structures and functions of the lens 14 , the beam splitter 16 , the lens 15 , the polarization beam combiner 17 , the monitor PDs 18 , 19 , and the beam splitter 20 are the same as those of the corresponding components of the optical device 1G, and thus description thereof will be omitted.

[0161] The signal light output port 1 a receives input of the output signal light L4 transmitted through the beam splitter 20 , and outputs the signal light to the outside of the housing 1 g .

[0162] [Optical receiver]

[0163] Next, the structure and function of a component that functions as an optical receiver will be described.

[0164] The signal light input port 1 b receives input of the input signal light L5 from the outside, and outputs the input signal light to the lens 30 . The lens 30 condenses the input signal light L5 and inputs the condensed signal light to the coherent mixer 31 .

[0165] On the other hand, the laser light L14 branched by the beam splitter 8 is condensed by the lens 33 and input to the coherent mixer 31A as local light.

[0166] The coherent mixer 31A is roughly rectangular in shape and is configured so that its long side direction is roughly consistent with the long side direction of the housing 1g. In the coherent mixer 31A, the input position of the input signal light L5 and the input position of the laser L14 are configured on the same side of the coherent mixer 31A located on the front side in the long side direction. For the coherent mixer 31A, the side for inputting the input signal light L5 is roughly parallel to the side wall portion 1c on the front side in the long side direction of the housing 1g, and is roughly parallel to the side of the modulator 11 where the input position of the laser L1 and the output position of the modulated light L31, L32 are configured.

[0167] Similar to the coherent mixer 31, the coherent mixer 31A generates four processed signal lights and outputs them to the balanced PD array 35. The coherent mixer 31A is configured to branch a part of the input signal light L5 and output it to the monitor PD 34. The monitor PD 34 is used to monitor the intensity of the input signal light L5.

[0168] The structure and function of the balanced PD array 35 and the TIA 36 are the same as those of the corresponding components of the optical device 1G, and thus description thereof is omitted.

[0169] The coherent mixer 31A, the balanced PD array 35 , and the TIA 36 are arranged in series substantially parallel to the long side direction of the housing 1 g , thereby constituting the optical processing unit OPA.

[0170] In the optical device 1H, the laser element 2a is arranged in the housing 1g so as to output the laser light L1 in the direction opposite to the side (front side in the long-side direction) where the signal light output port 1a is provided (the direction of the rear side in the long-side direction). In addition, the laser element 2a and the wavelength locker 4 are arranged between the width direction center line CL1 of the coherent mixer 31A and the width direction center line CL2 of the modulator 11 in the width direction of the housing 1g. In addition, the modulator 11 has a folding structure in which the traveling direction of the input light is folded back inside.

[0171] In addition, the laser element 2a and the wavelength locker 4 are arranged so that the output position of the laser L15 (laser L1) input to the wavelength locker 4 of the laser element 2a and the input position of the laser L15 of the wavelength locker 4 are different from each other in the width direction. In addition, the modulation unit M and the optical processing unit OPA are arranged in parallel in the width direction of the housing 1g. In addition, for the modulator 11, the input position of the laser L11 and the output position of the modulated light L31 and L32 are arranged on the same side. In addition, this side is roughly parallel to the side of the coherent mixer 31A for inputting the input signal light L5. The two side surfaces are also roughly parallel to the side wall portion 1c on the front side of the longitudinal direction of the housing 1g.

[0172] In the optical device 1H thus configured, it is not necessary to arrange the wavelength locker 4 and the laser element 2a on the same axis in the longitudinal direction. Therefore, although the same type of components (e.g., coherent mixer 31A relative to coherent mixer 31) are used that are larger in the width direction than those used in the optical device 1G, the width W of the housing 1g can be kept below 15 mm, and the length from the rear end of the housing in the longitudinal direction to the optical reference plane can be set to below 35 mm, and the height can be set to below 6.5 mm. As a result, an optical transceiver that complies with the QSFP-DD standard, which is the next-generation standard of MSA, can be realized.

[0173] like Fig.14 As shown, in this embodiment, the beam splitter 16 is configured as a cubic prism 100A1, the polarization beam combiner 17 is configured as a cubic prism 100B1, and the beam splitter 41 is configured as a cubic prism 100A1. Therefore, according to this embodiment, the effect of being able to make the optical device 1H more compact can be obtained in the same manner as in the above-mentioned embodiment. It should be noted that this application example is an example, and the beam splitter 16 or the polarization beam combiner 17, and the beam splitter 41 can also be configured as other prisms 100A, 100B or cubic prisms 100A1, 100B1.

[0174] The above is an example of the embodiment of the present invention, but the above embodiment is an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other ways, and can be omitted, replaced, combined, and changed in various ways without departing from the scope of the main purpose of the invention. In addition, the specifications such as various structures and shapes (structure, type, direction, model, size, length, width, thickness, height, number, configuration, position, material, etc.) can be appropriately changed for implementation.

[0175] Industrial Applicability

[0176] The present invention can be used in a prism and an optical device.

[0177] Description of Reference Numerals

[0178] 1, 1A~1H...Optical device

[0179] 1a...Signal light output port

[0180] 1b...Signal optical input port

[0181] 1c……Side wall

[0182] 1d...base

[0183] 1e...Upper cover

[0184] 1f……Terminal part

[0185] 1g……Casing

[0186] 2...Chip with auxiliary base

[0187] 2a...Laser Components

[0188] 2b... Auxiliary base

[0189] 3, 6, 10, 14, 15, 30, 33... Lenses

[0190] 4... Wavelength Locker

[0191] 5……PD array

[0192] 7...Optical isolator

[0193] 8, 16, 20, 41... beam splitter

[0194] 9,32...Reflector

[0195] 11...Modulator

[0196] 12...Modulator Driver

[0197] 13……Terminator

[0198] 17...Polarization beam combiner

[0199] 18, 19, 21, 34, 40... Monitor PD

[0200] 31, 31A... Coherent mixer

[0201] 35...Balanced PD Array

[0202] 36...Transimpedance amplifier (TIA)

[0203] 100A, 100B, 100... prism

[0204] 100A1, 100A1-1, 100B1... Cube prism

[0205] 100R1, 100R2... (reference example) prism

[0206] 101……Incident surface

[0207] 102...Ejection surface

[0208] 103...Reflective surface

[0209] 104...Exit surface

[0210] 105... Wavelength filter

[0211] 200...Optical components

[0212] c……angle

[0213] CL1, CL2... Center line in width direction

[0214] LA, LAA... Laser Components

[0215] La, Lb, Lr1, Lr2...length

[0216] Li... Incident light

[0217] Lo, Lo1, Lo2...Outgoing light

[0218] L1, L11, L12, L13, L14, L15, L2, L3...Laser

[0219] L31, L32... modulated light

[0220] L4... Output signal light

[0221] L5...Input signal light

[0222] M...Modulation Department

[0223] n……refractive index

[0224] OP, OPA... Optical Processing Department

[0225] Pi...Incident position

[0226] Po……Ejection position

[0227] Pr……Reflection position

[0228] Pv...Imaginary orthogonal surface

[0229] Vi, Vo, Vr...vertical lines

[0230] Vy...imaginary line

[0231] W...Width

[0232] x...angle

[0233] X...direction (second direction)

[0234] y...angle

[0235] Y...direction

[0236] Z...direction (first direction)

[0237] θ...angle (angle of incidence)

[0238] θo……angle (outgoing angle)

[0239] λ1~λ4...wavelength.

Claims

1. A prism having: An incident surface, which is a plane extending along a first direction and for light to be incident on; a reflective surface, which is a plane extending along the first direction and for reflecting at least a portion of the light incident on the incident surface; as well as an exit surface, which is a plane extending along the first direction and through which the light reflected by the reflection surface is emitted, The incident surface, the reflecting surface, and the emitting surface extend in directions that intersect the first direction and are different from each other. The prism changes the traveling direction of the light substantially along an imaginary plane orthogonal to the first direction, and the refractive index of the prism is n, wherein n>1, When viewed along the first direction, The angle difference between the incident surface and the exit surface is 90 [deg], The light incident on the incident surface travels along the second direction, The incident surface extends toward the second direction as it approaches the exit surface from the incident position of the light, and When the angle difference between the imaginary orthogonal plane with respect to the second direction and the incident plane is set to θ, and the angle difference between the exit plane and the reflection plane is set to x [deg], the following formula (1) is satisfied: 45<x<45+2θ / n……(1), Among them, θ>0[deg].

2. The prism according to claim 1, wherein: The prism satisfies the following formula (1-1): x=45+θ / n……(1-1).

3. A prism having: An incident surface, which is a plane extending along a first direction and for light to be incident on; a reflective surface, which is a plane extending along the first direction and for reflecting at least a portion of the light incident on the incident surface; as well as an exit surface, which is a plane extending along the first direction and through which the light reflected by the reflection surface is emitted, The incident surface, the reflecting surface, and the emitting surface extend in directions that intersect the first direction and are different from each other. The prism changes the traveling direction of the light substantially along an imaginary plane orthogonal to the first direction, and the refractive index of the prism is n, wherein n>1, When viewed along the first direction, The angle difference between the incident surface and the exit surface is 90 [deg], The light incident on the incident surface travels along the second direction, The incident surface extends in a direction opposite to the second direction as the light incident position approaches the exit surface, and When the angle difference between the imaginary orthogonal plane with respect to the second direction and the incident plane is set to θ, and the angle difference between the exit plane and the reflection plane is set to y [deg], the following formula (2) is satisfied: 45-2θ / n<y<45……(2), Among them, θ>0[deg].

4. The prism according to claim 3, wherein: The prism satisfies the following formula (2-1): y=45-θ / n……(2-1).

5. The prism according to any one of claims 1 to 4, wherein: The reflecting surface transmits a portion of the light from the incident surface.

6. The prism according to claim 5, wherein: The prism includes a filter that transmits light having a predetermined wavelength among the light transmitted through the reflection surface.

7. An optical device comprising: The prism according to claim 1 or 3; an optical component for the light emitted from the exit surface to be input or pass through; and A base is used to fix the prism and the optical component.

8. The optical device according to claim 7, wherein: The optical device includes a first prism and a second prism into which light output from the first prism is input as the prism.

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