JP4128547B2 - Optical branching element and optical transceiver for bidirectional optical communication - Google Patents

Description

  The present invention relates to an optical branch element used for bidirectional optical communication in which light is transmitted and received through a single optical fiber, and an optical transceiver configured using the optical branch element.

FIG. 15 shows an example of a conventional configuration of an optical branching element used for this type of application, together with an optical fiber, a light emitting element, and a light receiving element. In this example, the optical branching element 10 has a transparent block shape, and the block The base 11 constituting the cross-sectional shape is a pentagon.
The second surface 11b and the third surface 11c, which are adjacent to the first surface 11a of the base 11, respectively, are perpendicular to the first surface 11a and face each other, and the remaining fourth pentagonal surface 11d and the 5th surface 11e are made into the surface dented inward, and shall be V-shaped.
Transmitting light condensing lenses 12 and 13 are integrally formed on the first surface 11a and the second surface 11b, respectively, and receiving light condensing lenses 14 and 15 are formed on the first surface 11a and the third surface 11b. Each is formed integrally with the surface 11c. The two lenses 12 and 14 located on the first surface 11a are both partially cut out, and the cut-out portions are adjacently coupled.

The optical fiber 21 is disposed so that its end surface is close to and opposed to the lenses 12 and 14 located on the surface 11a. The light emitting element 22 is disposed opposite to the lens 13 located on the surface 11b, and the light receiving element 23 is disposed opposite to the lens 15 located on the surface 11c. The light receiving element 22 and the light emitting element 23 are arranged to face each other in parallel.
In this example, the light receiving element 22 and the light emitting element 23 are both mounted on a lead frame and sealed with resin by a transparent resin. In FIG. 15, 24 indicates a lead frame, and 25 indicates a sealing resin. Show. The light emitting element 22 is, for example, a light emitting diode (LED) or a laser diode (LD), and the light receiving element 23 is, for example, a photodiode (PD).

In FIG. 15, reference numeral 31 denotes a transmission path, and reference numeral 32 denotes a reception path. Transmission light emitted from the light emitting element 22 is collected by the lens 13, enters the substrate 11, is reflected by the surface 11d, and faces the surface 11a. The light is condensed by the lens 12 and coupled to the end face of the optical fiber 21. On the other hand, the received light emitted from the end face of the optical fiber 21 is condensed by the lens 14 and enters the substrate 11, is reflected by the surface 11 e, faces the surface 11 c, is collected by the lens 15, and is collected by the light receiving element 23. Combined.
As described above, in this example, the optical branching element 10 is disposed to face the three members of the light emitting element 22, the light receiving element 23, and the end face of the optical fiber 21, and light is transmitted and received through the optical branching element 10. Note that the configuration in which the light emitting element 22 and the light receiving element 23 are opposed to the optical branching element 10 as in this example is electrically isolated because the light emitting element 22 and the light receiving element 23 are separated from each other. It is easy to reduce the size of the optical transceiver (see, for example, Patent Document 1).
JP 2003-337264 A

By the way, in bidirectional optical communication in which light is transmitted and received using a single optical fiber in this way, there is a path that is shared between transmission and reception, so that transmitted light is mixed (interference) in the receiving system of the local station and received light. Crosstalk incident on the element occurs. This stroke is a serious problem in terms of performance, and reducing crosstalk is an important issue.
FIG. 16 illustrates a configuration of a pair of communication systems configured using the optical branching element 10 illustrated in FIG. 15 and various optical paths. Here, transmission light transmitted from the transmission system 1 of the port 1 is transmitted. Various optical paths are shown by way of example in which the signal is received by the receiving system 2 of the port 2. The transmission system refers to a configuration including a light emitting element, a deflection system (reflection surface, refraction surface, etc.), a lens, and the like. A reception system includes a light receiving element, deflection system (reflection surface, refraction surface, etc.), a lens, and the like. Say the composition. Moreover, an opening surface means the surface which opposes an optical fiber in an optical transmitter / receiver (optical branching element). In FIG. 15, dotted line frames 26 and 27 indicate a transmission system and a reception system. Hereinafter, each route will be described with reference to FIG.

A route [1] indicated by a solid line is a normal route of the transmission light transmitted from the transmission system 1.
A path [2] indicated by a two-dot chain line is a path in which transmission light is mixed into the transmission system 2 and causes loss, far-end crosstalk, and noise mixing in the transmission signal of the transmission system 2.
The locations marked with numerals <1> to <7> and filled with broken arrows are mixed in the receiving system 1 of the own station out of the transmitted light transmitted from the transmitting system 1, and the S of the received signal of the receiving system 1 <1> to <7> are each <1>: each surface of the transmission system 2 (light emitting element surface, lead frame, lens surface, etc.) <2>: Reflection on each surface of the receiving system 2 (light receiving element surface, lead frame, lens surface, etc.) <3>: Reflection on the opening surface of the port 2 <4>: Far end of the optical fiber (partner (port 2)) <5>: Reflection at the near end of the optical fiber (fiber end face on the local station (port 1) side) <6>: Reflection at the opening of the port 1 <7>: Representation of contamination from the gap Yes. Note that the entire crosstalk (<1> to <4> and other stray light) generated on the port 2 side is called the far-end crosstalk of the port 1, and the crosstalk generated on the port 1 side (<5> to <7>). And other stray light) is called near-end crosstalk of port 1, and crosstalk (indicated by arrow [3]) in which transmitted light is mixed into the receiving system 1 of the local station is near-end crosstalk and far-end crosstalk. It becomes the sum of talk.

The present invention aims to reduce <1>, <5>, and <6> in the various optical paths shown in FIG. 16, and this point will be described in further detail below.
FIG. 17 shows the basic shape (base 11) of the optical branching element 10 shown in FIG. 15. The side faces 11a to 11c facing the optical fiber, the light emitting element, and the light receiving element are as shown in FIG. In general, condensing lenses 12 to 15 are added to the lens, but illustration of these lenses is omitted in the following explanatory diagrams. Although illustration of the lens is omitted, as surfaces provided with the lens, in the following, the surfaces 11a to 11c are referred to as an opening surface, a light emitting element facing surface, and a light receiving element facing surface, and the surfaces 11d and 11e are referred to as transmitting side reflecting surfaces, This is referred to as a receiving side reflection surface. The optical axis direction of the optical fiber is the Z axis, perpendicular to the Z axis, the direction in which the light emitting element facing surface 11b and the light receiving element facing surface 11c are opposed is the X axis, and the direction perpendicular to the X axis and the Z axis is the Y axis. It is defined as

  FIG. 18 schematically shows the positional relationship among the optical fiber 21, the transmission system 26, the reception system 27, the aperture surface 11a, the transmission-side reflection surface 11d, and the reception-side reflection surface 11e in the above-described conventional example. , 42 indicate main directions of the transmission path and the reception path, respectively, and an arrow 52 indicates the main direction of the transmission light reflection path in the vicinity of the opening surface 11a. The transmission light reflection in the vicinity of the opening surface 11a includes reflection on the end surface of the optical fiber 21 and reflection on the opening surface 11a. In FIG. 18, the main directions of the reflection path generated on the end surface of the optical fiber 21 are representative of them. As shown. The point Q indicates the light emission center of the light emitting element 22, and the point R indicates the intersection of the transmission path main direction 32 parallel to the X axis and the transmission side reflection surface 11d. Point P indicates an incident point on the end face of the optical fiber 21 in the transmission path main direction 32.

  On the other hand, FIG. 19A shows the path of the received light 40 emitted from the end face of the optical fiber 21, and FIG. 19B shows the path of the transmitted light 30 emitted from the light emitting element and the transmitted light 30. The path of the reflected light (transmitted light reflected light) 50 in the vicinity of the opening surface 11a is shown. In FIG. 19, 28 indicates a light emitting surface position of the light emitting element 22, and 29 indicates a light receiving surface position of the light receiving element 23. Transmission light reflection in the vicinity of the opening surface 11a includes reflection at the end surface of the optical fiber 21 and reflection at the opening surface 11a. In FIG. 19, the main reflection path generated at the end surface of the optical fiber 21 is the same as in FIG. Directions are shown on behalf of them. In addition, in FIG. 19, it has shown typically using ideal collimated light, but when using a light emitting diode (LED) with a large light emission area, a large-diameter optical fiber with a large NA, etc., it is not sufficiently collimated and illustrated. In many cases, off-axis rays are widely distributed around the principal ray. Therefore, in the figure, some off-axis rays actually enter even if the crosstalk does not enter the light receiving surface.

  In the conventional optical branching element 10, as shown in FIG. 18, the transmission-side reflection surface 11d and the reception-side reflection surface 11e are both rotated by a plane parallel to the opening surface 11a (XY plane) only around the Y axis. In view of efficiency, the optical fiber 21 and the light receiving / emitting centers of the light receiving / emitting elements 23 and 22 are conventionally arranged on substantially the same XZ plane from the viewpoint of efficiency. As a result, the transmission light reflection path main direction 52 in the vicinity of the aperture surface 11a is close to the reception path main direction 42, so that the transmission light reflection light 50 is mixed into the reception path and crosstalk (<5>, <6 in FIG. 16). >) Was very likely.

  In order to prevent the transmitted light reflected light 50 in the vicinity of the aperture surface 11a from causing crosstalk, the transmitted light reflected light 50 in the vicinity of the aperture surface 11a must be sufficiently separated from the reception path. For this reason, for example, as shown in FIG. 20, it is possible to change the inclination angle around the Y-axis of the transmission-side reflecting surface 11d or to shift the light emitting surface position 28 in the Z-axis direction. As shown in FIG. 20 (2), there is an increased risk that the transmitted light reflected light 50 in the vicinity of 11a is mixed directly into the light receiving element without passing through the receiving-side reflective surface 11e. It has been difficult to reduce crosstalk due to the light 50.

In addition, each side surface (11a to 11e) of the optical branching element 10 is a vertical surface (here, a surface perpendicular to the XZ plane). In this case, the principal ray direction of the transmitted light reflected light 50 in the vicinity of the aperture surface 11a. Is present on the same XZ plane as the XZ plane on which the receiving / emitting centers of the optical fiber 21 and the receiving / emitting elements 23 and 22 are located even when high-order reflection is reached, stray light is likely to be mixed into the receiving element. It was.
Further, the direction of the maximum intensity portion (the central portion of the light beam) of the transmission light beam emitted from the light emitting element 22 is generally the element front direction, and therefore the front direction of the light emitting element 22 is determined from the transmission efficiency in the main direction 32 of the transmission path. In this arrangement, the received light 40 reflected by the light emitting element 22 is recombined with the optical fiber 21 and becomes crosstalk (<1> in FIG. 16) on the other side.

As a countermeasure against <1> crosstalk in FIG. 16, Patent Document 1 describes a configuration in which the transmission path main direction 32 is shifted from the front direction of the light emitting element 22, but such a method sacrifices efficiency. It was supposed to be.
The present invention has been made in view of such a situation. Crosstalk due to transmission light reflection in the vicinity of the aperture surface being mixed into the reception path is greatly reduced without impairing efficiency, and the transmission path is also improved. It is an object of the present invention to provide an optical branching element for bidirectional optical communication, and an optical transceiver using the same, which can greatly reduce the reflection of invading received light again from being coupled to an optical fiber.

  According to the present invention, an optical branching element used for bidirectional optical communication that transmits and receives via a single optical fiber is adjacent to an opening surface that faces the end surface of the optical fiber and substantially perpendicular to the opening surface. And a light-emitting element facing surface that faces the light-emitting element, and a light-receiving element facing surface that is adjacent to the light-receiving element and is adjacent to the opening surface on the side facing the light-emitting element facing surface. A transmission side reflection surface that reflects transmission light incident from the surface toward the aperture surface, and a reception side reflection surface that reflects reception light incident from the aperture surface toward the light receiving element facing surface; When the Z axis is the Z axis, the X axis is the direction in which the light emitting element facing surface and the light receiving element facing surface are opposed, and the direction perpendicular to the X axis and the Z axis is the Y axis, The transmission side reflective surface is rotated about the Y axis in a plane parallel to the aperture surface. The receiving-side reflecting surface is a surface that is inclined by rotating a plane parallel to the aperture surface in the opposite direction to the transmitting-side reflecting surface about the Y-axis. It is said.

  Furthermore, according to this invention, the optical transceiver includes the optical branch element, a light emitting element whose optical axis direction is the X axis direction and disposed opposite to the light emitting element facing surface, and the optical axis direction is the X axis direction. And a light receiving element disposed opposite to the light receiving element facing surface.

According to the optical branching element of the present invention, the main direction of the transmission light reflection path and the main direction of the reception path in the vicinity of the aperture surface can be greatly separated, so that the crossing due to the transmission light reflection in the vicinity of the aperture surface entering the reception path. Talk can be greatly reduced.
In addition, since the received light that has entered the transmission path is not guided to the vicinity of the light emitting element and can be released in other directions, for example, the crosstalk (far end) due to the received light reflected on the light emitting element surface being coupled to the optical fiber again. Crosstalk) can also be greatly reduced.
Since the received light is not guided to the vicinity of the light emitting element in this way, the front direction of the light emitting element can be arranged as the main direction of the transmission path, and thus efficiency is not impaired.

  In addition, as a countermeasure against crosstalk, new components such as a light shielding plate and a polarizing plate are not used, and therefore, the number of components does not increase and can be configured at low cost.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of an optical branching element according to the present invention. In this example, the optical branching element 10-1 includes an opening surface 11a facing the end face of the optical fiber, and its opening surface 11a. A light emitting element facing surface 11b that is adjacent to form a right angle and is opposed to the light emitting element, and a light receiving element facing that is adjacent to the opening surface 11a at a right angle on the side facing the light emitting element facing surface 11b and is opposed to the light receiving element. The surface 11c, the transmission-side reflection surface 11d-1 that reflects the transmission light incident from the light emitting element facing surface 11b toward the opening surface 11a, and the reception light that enters from the opening surface 11a toward the light receiving element facing surface 11c. And a receiving-side reflecting surface 11e-1 that reflects the light.

Although the optical branching element 10-1 has a transparent block shape and is not shown in the drawing, the transmission light condensing lenses 12 and 13 are arranged on the aperture surface 11a as in the conventional optical branching element 10 shown in FIG. In addition, the lens 14 and 15 for condensing received light are provided on the opening surface 11a and the light receiving element facing surface 11c.
The X, Y, and Z3 axes shown in FIG. 1 are defined in the same manner as the X, Y, and Z3 axes in FIG. 17, that is, the optical axis direction of the optical fiber is orthogonal to the Z and Z axes, and the light emitting element facing surface 11b. The direction in which the light receiving element facing surface 11c faces is the X axis, and the direction orthogonal to the X axis and the Z axis is the Y axis.

  In this example, the transmission-side reflecting surface 11d-1 is a surface that is inclined by rotating a plane parallel to the opening surface 11a (XY plane) around the Y axis and further rotating around the X axis. On the other hand, the receiving-side reflecting surface 11e-1 is inclined such that a plane (XY plane) parallel to the opening surface 11a is rotated around the Y axis in the direction opposite to the transmitting-side reflecting surface 11d-1, and further on the transmitting side around the X axis. The surface is rotated and inclined in the same direction as the reflecting surface 11d-1. Note that the transmission-side reflection surface 11d-1 and the reception-side reflection surface 11e-1 have one side that is adjacent to each other across the one side (valley line) and has a V-shaped cross section.

FIG. 2 shows the optical fiber 21, the transmission system 26, the reception system 27, the opening surface 11a, and the transmission-side reflection surface 11d-1 in a state where the optical branching element 10-1 is disposed opposite to the optical fiber and the light receiving / emitting element. FIG. 3 schematically shows the positional relationship of the reception reflecting surface 11e-1 as in FIG. 18, and FIG. 3 shows the path of the received light 40 emitted from the end face of the optical fiber 21 and the transmission emitted from the light emitting element. The path of the light 30 and the path of the reflected light (transmitted light reflected light) 50 in the vicinity of the opening surface 11a of the transmitted light 30 are shown in the same manner as in FIG.
In this example, both the transmission-side reflection surface 11d-1 and the reception-side reflection surface 11e-1 are rotated and inclined not only about the Y axis but also about the X axis. , 22 are not arranged on the same XZ plane as in the conventional example, but are shifted in the Y direction. That is, the light emission center Q of the light emitting element 22 is arranged on a plane S that is perpendicular to the transmission-side reflecting surface 11d-1 and parallel to the X axis and intersects the end face of the optical fiber 21, and the front direction of the light emitting element 22 is the X direction. It is said.

The path of the transmission light 30 emitted from the light emitting element 22 arranged as described above is as shown in FIG. 3B and is coupled to the optical fiber 21. On the other hand, the path of the received light 40 emitted from the optical fiber 21 is as shown in FIG. 3 (1), and the light receiving center of the light receiving element 23 is disposed on this received path principal ray.
The path of the transmitted light reflected light 50 in the vicinity of the aperture surface 11a is as shown in FIG. 3B, and the gap between the light receiving surface position 29 and the gap g _{1Y in the} Y direction and the gap g _{1Z in the} Z direction are as follows. This is a significant increase over the conventional example. As shown in FIG. 3A, the gap g _{2Y in} the Y direction between the path of the received light 40 entering the transmission system and the light emitting surface position 28 is also greatly increased compared to the conventional example.

  As described above, according to this example, the transmission-side reflection path main direction 52 in the vicinity of the opening surface 11a is the Y-direction component by rotating the transmission-side reflection surface 11d-1 around the X axis to be inclined. Thus, the transmission light reflection path main direction 52 and the reception path main direction 42 can be largely separated. Even if the transmission light reflection path main direction 52 is greatly separated from the reception path main direction 42 as described above, the transmission light reflection path main direction 52 is not reflected on the reception side reflection surface as in the conventional study example shown in FIG. It does not go in the direction of direct incidence to the light receiving element without passing through 11e.

In addition, the higher-order reflection of the transmission light reflected light 50 does not stay on the same plane due to the presence of the transmission-side reflection surface 11d-1 and the reception-side reflection surface 11e-1 inclined about the X axis. Crosstalk (<5> and <6> in FIG. 16) due to the transmission light reflection in the vicinity of the aperture surface 11a from entering the reception path can be greatly reduced.
Furthermore, since the received light 40 that has entered the transmission system is not guided to the vicinity of the light emitting surface as shown in FIG. 3A, that is, can escape to other directions, the front direction of the light emitting element is set as the main direction 32 of the transmission path. Even if it is arranged, crosstalk (<1> in FIG. 16) due to re-coupling of the received light 40 reflected by the light emitting element 22 to the optical fiber 21 can be greatly reduced.

In the above-described embodiment, the optical branching element 10-1 has a transmission-side reflection surface 11d-1 and a reception-side reflection surface 11e-1 that are both inclined about the X axis. Only the reflective surface may be a surface inclined by rotating around the X axis.
FIG. 4 shows a second embodiment of the optical branching element having such a configuration. In this example, the transmission-side reflecting surface 11d-2 of the optical branching element 10-2 is a plane parallel to the opening surface 11a. (XY plane) is a surface that is rotated and tilted about the Y axis, and is further rotated and tilted about the X axis. On the other hand, the reception-side reflecting surface 11e-2 is a plane parallel to the opening surface 11a. The (XY plane) is a surface inclined only in the direction opposite to the transmission-side reflecting surface 11d-2 around the Y axis.

5 and 6 are similar to FIGS. 2 and 3, the optical fiber 21, the transmission system 26, the reception system 27 and the aperture surface 11a, the transmission-side reflection surface 11d-2, and the reception-side reflection when the optical branching element 10-2 is used. The positional relationship of the surface 11e-2 and the paths of the received light 40, the transmitted light 30, and the transmitted light reflected light 50 are respectively shown. In this example, the gaps g _1Y and g _2Y are as shown in FIG. The transmission light reflection path main direction 52 and the reception path main direction 42 can be greatly separated, and the reception light 40 that has entered the transmission system can be prevented from being guided to the vicinity of the light emitting surface. The effect similar to the case where the optical branching element 10-1 shown in 1 is used can be obtained.

Next explained is a third embodiment of the optical branching element according to the invention. In the optical branching elements 10-1 and 10-2 described above, as shown in FIGS. 3 and 6, the positional relationship between the light emitting element 22 and the light receiving element 23 is different in the Y direction. However, the optical branch element 10-3 shown in FIG. 7 can solve such a problem. It has become.
In this example, the transmission-side reflecting surface 11d-3 is a surface that is inclined by rotating a plane parallel to the opening surface 11a (XY plane) around the Y axis, and further rotating around the X axis. On the other hand, the receiving-side reflecting surface 11e-3 is inclined such that a plane parallel to the opening surface 11a (XY plane) is rotated around the Y axis in the opposite direction to the transmitting-side reflecting surface 11d-3, and further on the transmitting side around the X axis. The surface is inclined by being rotated in the opposite direction to the reflecting surface 11d-3. That is, unlike the optical branching element 10-1 shown in FIG. 1, the transmission-side reflection surface 11d-3 and the reception-side reflection surface 11e-3 are alternately oriented around the X axis.

  8 and 9 show the positional relationship among the optical fiber 21, the transmission system 26, the reception system 27, the aperture surface 11a, the transmission-side reflection surface 11d-3, and the reception-side reflection surface 11e-3 when this optical branching element 10-3 is used. The paths of the received light 40, the transmitted light 30, and the transmitted light reflected light 50 are shown in the same manner as in FIGS. 2 and 3. In this example, the Y of the light emitting element 22 and the light receiving element 23 as shown in FIG. The height position in the direction can be aligned, so that positioning during mounting is facilitated, and inconvenience in mounting can be eliminated. Furthermore, the overall configuration, that is, the reduction in the height of the optical transceiver can be realized.

Also in this example, as shown in FIG. 9, the gaps g _1Y and g _2Y are increased, the transmission light reflection path main direction 52 and the reception path main direction 42 can be greatly separated, and the transmission system has been penetrated. The reception light 40 can be prevented from being guided to the vicinity of the light emitting surface, and thus the same effect as the optical branching element 10-1 shown in FIG. 1 can be obtained.
FIG. 10 shows a fourth embodiment of the optical branching element according to the present invention. In this example, the transmitting-side reflecting surface 11d-4 and the receiving-side reflecting surface 11e-4 are the optical branching elements shown in FIG. Similar to 10-3, the directions are staggered around the X-axis, and the upper half of the Y-direction of the transmitting-side reflecting surface 11d-4 is deleted, and the receiving-side reflecting surface 11e-4 is formed to extend to that portion. It has become.

FIG. 11 shows each path of the received light 40, the transmitted light 30, and the transmitted light reflected light 50 when this optical branching element 10-4 is used. In this example as well, the light emission is similar to the optical branching element 10-3. The height positions of the element 22 and the light receiving element 23 in the Y direction can be aligned. In addition, a large gap g _1Y between the transmitted light reflected light 50 and the light receiving surface position 29 can be secured, and in this example, the received light 40 can be prevented from entering the transmission system.
By the way, in the optical branching element 10-3 shown in FIG. 7, for example, Z that connects the transmission-side reflection surface 11d-3 and the reception-side reflection surface 11e-3 in the portion surrounded by the two-dot chain line 16 in the drawing. There are acute concave portions between the connecting surface 17 parallel to the axis and the transmission side reflection surface 11d-3 and between the reception side reflection surface 11e-3, and the existence of such acute angle concave portions is an optical branching element. When producing 10-3 by resin molding, it was difficult to produce the mold. In addition, since the mold strength at that portion is weakened, the quality of the resin molded product may not be stable.

The optical branching element 10-5 shown in FIG. 12 is obtained by improving this point. In this example, the valley of the acute concave portion is cut off, that is, the connection surface 17, the transmission side reflection surface 11d-5, and the reception side. Narrow surfaces 18a and 18b parallel to the X-axis are provided between the side reflection surface 11e-5 and the side reflection surface 11e-5.
By providing such surfaces 18a and 18b, it becomes easy to manufacture the mold, and it is possible to reduce the cost and stabilize the quality of the mold.
On the other hand, the optical branching element 10-6 shown in FIG. 13 has a configuration in which the transmission-side reflection surface 11d-6 and the reception-side reflection surface 11e-6 are inclined by rotating in opposite directions around the X axis. In the Y direction, the receiving-side reflecting surface 11e-6 is positioned in the upper half and the transmitting-side reflecting surface 11d-6 is positioned in the lower half so that there is no such an acute-angle recess as in FIG. The direction of the boundary line dividing −6, 11e-6 is the X-axis direction, and such a configuration can also be adopted. In this example, the portion surrounded by the two-dot chain line 19 forms an obtuse angle.

  FIG. 14 shows an example of the configuration of a single-core optical connector 61 in which an optical transceiver comprising an optical branching element, a light emitting element 22 and a light receiving element 23 according to the present invention is incorporated. In this example, FIG. The optical branching element 10-1 shown in FIG. In FIG. 14, 62 indicates a sleeve into which the optical fiber plug is inserted.

The figure which shows one Example of the optical branching element by invention of Claim 2, A is a top view, B is a front view, C is a right view, D is a perspective view. The schematic diagram which shows the positional relationship of the optical branching element shown in FIG. 1, an optical fiber, a transmission system, and a receiving system, A is a top view, B is a side view. (1) is a diagram showing a path of received light in the optical branching element shown in FIG. 1, (2) is a diagram showing a path of transmitted light and reflected light in the optical branching element, A is a rear view, and B is Plan view. The figure which shows one Example of the optical branching element by invention of Claim 1, A is a top view, B is a front view, C is a right view, D is a perspective view. The schematic diagram which shows the positional relationship of the optical branching element shown in FIG. 4, an optical fiber, a transmission system, and a receiving system, A is a top view, B is a side view. (1) is a diagram showing a path of received light in the optical branch element shown in FIG. 4, (2) is a diagram showing paths of transmitted light and transmitted light reflected in the optical branch element, A is a rear view, B is Plan view. The figure which shows one Example of the optical branching element by invention of Claim 3, A is a top view, B is a front view, C is a right view, D is a perspective view. The schematic diagram which shows the positional relationship of the optical branching element shown in FIG. 7, an optical fiber, a transmission system, and a receiving system, A is a top view, B is a side view. (1) is a diagram showing a path of received light in the optical branching element shown in FIG. 7, (2) is a diagram showing paths of transmitted light and transmitted light reflected in the optical branching element, A is a rear view, and B is Plan view. The figure which shows the modification Example of the optical branching element by invention of Claim 3, A is a top view, B is a left view, C is a front view, D is a right view, E is a perspective view. (1) is a diagram showing a path of received light in the optical branching element shown in FIG. 10, (2) is a diagram showing paths of transmitted light and transmitted light reflected in the optical branching element, A is a rear view, and B is Plan view. The figure which shows one Example of the optical branching element by invention of Claim 5, A is a top view, B is a front view, C is a right view, D is a perspective view. The figure which shows the modification Example of the optical branching element by invention of Claim 3, A is a top view, B is a front view, C is a right view, D is a perspective view. The figure which shows the state in which the optical branching element shown in FIG. 1 was integrated in the optical connector. The figure which shows a mode that the transmission / reception of light is performed through the example of a conventional structure of an optical branch element, and the optical branch element. The figure for demonstrating a structure and various optical path | route of a pair of communication system of bidirectional | two-way optical communication. The figure which shows the basic shape of the optical branching element shown in FIG. 15, A is a top view, B is a front view, C is a right view, D is a perspective view. The schematic diagram which shows the positional relationship of the optical branching element shown in FIG. 17, an optical fiber, a transmission system, and a receiving system, A is a top view, B is a side view. (1) is a diagram showing a path of received light in the optical branching element shown in FIG. 17, (2) is a diagram showing paths of transmission light and reflected light in the optical branching element, A is a rear view, and B is Plan view. (1) is a plan view showing the path of the received light when the angle of the transmission side reflection surface and the position of the light emitting element are changed with respect to the optical branching element shown in FIG. 17, and (2) is the transmission light in that case and The top view which shows the path | route of transmission light reflected light.

Claims (6)

An optical branching element used for bidirectional optical communication that transmits and receives via a single optical fiber,
An opening face facing the end face of the optical fiber;
A light emitting element facing surface that is adjacent to and substantially perpendicular to the opening surface and is opposed to the light emitting element;
A light receiving element facing surface which is adjacent to the light emitting element facing surface and is substantially perpendicular to the opening surface and facing the light receiving element;
A transmission-side reflection surface that reflects the transmission light incident from the light-emitting element facing surface toward the opening surface;
A reception-side reflection surface that reflects the reception light incident from the opening surface toward the light-receiving element facing surface;
The optical axis direction of the optical fiber is the Z-axis, the light-emitting element facing surface and the light-receiving element facing surface are opposed to the X-axis, and the direction perpendicular to the X-axis and the Z-axis is the Y-axis. The transmission-side reflecting surface is a plane that is inclined by rotating a plane parallel to the opening surface around the Y axis, and further rotated around the X axis.
An optical branch for bidirectional optical communication, wherein the reception-side reflection surface is a surface inclined in a direction parallel to the opening surface around the Y axis in the direction opposite to the transmission-side reflection surface. element. In the optical branching element for bidirectional optical communication according to claim 1,
An optical branching element for bidirectional optical communication, wherein the receiving-side reflecting surface is further rotated and tilted around the X axis in the same direction as the transmitting-side reflecting surface. In the optical branching element for bidirectional optical communication according to claim 1,
An optical branching element for bidirectional optical communication, wherein the receiving-side reflecting surface is further rotated and tilted about the X axis in the direction opposite to the transmitting-side reflecting surface. In the optical branching element for bidirectional optical communication according to claim 2,
An optical branching element for bidirectional optical communication, characterized in that one side of the transmitting-side reflecting surface and the receiving-side reflecting surface coincide with each other and are adjacent to each other across the one side. The optical branch element for bidirectional optical communication according to any one of claims 1 to 3,
The transmission side reflection surface and the reception side reflection surface are connected via a connection surface parallel to the Z-axis,
An optical branching element for bidirectional optical communication, wherein an acute-angle recess formed between the connection surface, the transmission-side reflection surface, and the reception-side reflection surface has a valley bottom. An optical branching element for bidirectional optical communication according to any one of claims 1 to 5,
A light emitting element having an optical axis direction as an X axis direction and disposed opposite to the light emitting element facing surface;
An optical transceiver comprising: a light receiving element disposed so as to face the light receiving element facing surface with an optical axis direction as an X axis direction.

Images