Light receiving position identifying device and optical communication device

Abstract

To easily achieve optical alignment between an optical system and a light receiving unit in an optical communication device.SOLUTION: A light receiving position identifying device (10) controls the rotation of a wedge prism (13) in an optical system of an optical communication device (100) to deflect, using a rotation control unit, convergent light toward a core portion (106), and identifies the position of the core portion (106) using a position identifying unit based on a rotation angle of the wedge prism (13) when the core portion (106) receives the convergent light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light receiving position specifying device and an optical communication device. [Background technology]

[0002] In optical communications, it is preferable to reduce the number of intermediate transmission devices up to the destination of the signal light in terms of increasing efficiency. To achieve this, higher accuracy is required for the transmission and reception of the signal light. From this perspective, an optical communications device is known that adjusts the angle of a mirror arranged on the optical path of the branched signal light so as to reduce the difference between the traveling direction of the signal light and a reference direction (for example, see Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Mitsuji Matsumoto, "Challenges and Future Prospects of Optical Wireless Communication", [online], March 17, 2016, [Retrieved April 6, 2022], Internet<https: / / www.ieice.org / ~wbs / pdf / taikai_matsumoto.pdf> Summary of the Invention [Problem to be solved by the invention]

[0004] Misalignment of the optical axes between optical elements in optical communication devices (hereinafter also referred to as "center misalignment"), for example, center misalignment of the laser axis, depends heavily on the accumulated errors of major components. In particular, it is difficult and often time-consuming to align the optical axis of the optical system through which the signal light passes with the light-receiving unit that transmits and receives the signal light to and from the optical system, for example, the core part (diameter: about 9 μm) of an SMF (single mode fiber). This is because it is difficult to find the position of the center of the laser axis.

[0005] In addition, when optical communication devices deteriorate over time, the laser axis may become misaligned. This requires periodic maintenance. However, in many cases, optical communication devices are not installed in an environment where maintenance can be easily performed. This means that optical communication devices are required to not require frequent maintenance.

[0006] An object of one aspect of the present invention is to easily realize optical alignment between an optical system and a light receiving unit in an optical communication device. [Means for solving the problem]

[0007] In order to solve the above problems, a light receiving position identification device according to one embodiment of the present invention includes an optical system for adjusting the beam diameter of a signal light, and a light receiving unit for receiving convergent light of the signal light by the optical system in an optical communication device, the light receiving unit including: a rotation control unit for controlling the rotation of a wedge prism incorporated in the optical system to deflect the convergent light; and a position identification unit for identifying the position of the light receiving unit based on the rotation angle of the wedge prism when the light receiving unit receives the convergent light.

[0008] In order to solve the above problem, an optical communication device according to one aspect of the present invention can be equipped with the above-described light receiving position specifying device. Effect of the Invention

[0009] According to one aspect of the present invention, optical alignment between an optical system and a light receiving unit in an optical communication device can be easily achieved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a schematic configuration of a light receiving position identifying device and an optical communication device according to a first embodiment of the present invention. [Diagram 2] 1 is a diagram showing a functional configuration of a light receiving position identifying device according to a first embodiment of the present invention. [Diagram 3]FIG. 2 is a first diagram for explaining a configuration for rotating a wedge prism in the first embodiment of the present invention. [Figure 4] FIG. 4 is a second diagram for explaining the configuration for rotating the wedge prism in the first embodiment of the present invention. [Diagram 5] FIG. 2 is a first diagram for explaining a rotation direction of a wedge prism in the first embodiment of the present invention. [Figure 6] FIG. 4 is a second diagram for explaining the rotation direction of the wedge prism in the first embodiment of the present invention. [Figure 7] FIG. 4 is a first diagram for explaining a method for determining a rotation angle of a wedge prism in the first embodiment of the present invention. [Figure 8] FIG. 11 is a second diagram for explaining how to find the rotation angle of the wedge prism in the first embodiment of the present invention. [Figure 9] FIG. 2 is a first diagram for explaining deflection of a signal light by a wedge prism in the first embodiment of the present invention. [Figure 10] FIG. 4 is a second diagram for explaining deflection of a signal light by a wedge prism in the first embodiment of the present invention. [Figure 11] FIG. 11 is a third diagram for explaining deflection of a signal light by a wedge prism in the first embodiment of the present invention. [Figure 12] 5 is a flowchart showing a flow of an example of control for determining the position of the light receiving unit according to the first embodiment of the present invention. [Figure 13] 5A and 5B are diagrams for explaining detection of the position of a light receiving section by scanning with a signal light in the first embodiment of the present invention. [Figure 14] 3A to 3C are diagrams illustrating a first mode of optical alignment of a light receiving section in the first embodiment of the present invention. [Figure 15] 4A to 4C are diagrams illustrating a second mode of optical alignment of the light receiving section in the first embodiment of the present invention. [Figure 16] FIG. 11 is a first diagram for explaining an example of deflection of a signal light by a wedge prism in another embodiment of the present invention. [Figure 17]FIG. 11 is a second diagram for explaining an example of deflection of a signal light by a wedge prism in another embodiment of the present invention. [Figure 18] 13A and 13B are first diagrams for explaining another example of deflection of signal light by a wedge prism in another embodiment of the present invention. [Figure 19] FIG. 11 is a second diagram for explaining another example of deflection of a signal light by a wedge prism in another embodiment of the present invention. [Figure 20] FIG. 11 is a third diagram for explaining another example of deflection of a signal light by a wedge prism in another embodiment of the present invention. [Figure 21] FIG. 11 is a first diagram for explaining a configuration for rotating a wedge prism in another embodiment of the present invention. [Figure 22] FIG. 11 is a second diagram for explaining a configuration for rotating a wedge prism in another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment 1] An embodiment of the present invention will be described in detail below. Fig. 1 is a diagram showing a schematic configuration of a light receiving position specifying device and an optical communication device according to this embodiment. As shown in Fig. 1, an optical communication device 100 has an optical system that adjusts the beam diameter of a signal light, and a light receiving unit that receives the convergent light of the signal light by the optical system. The optical system is composed of lenses 101, 102, 104 and a mirror 103. The light receiving unit is composed of a single mode fiber 105, a light receiving device 107, and a communication control unit 108.

[0012] Lenses 101, 102, and 104 are a group of optical lenses that guide signal light to single mode fiber 105. Lens 101 focuses the signal light, which is collimated light, toward lens 102, which outputs the signal light as collimated light with a smaller beam diameter toward mirror 103. Mirror 103 forms an optical path for the signal light (collimated light) between lenses 102 and 104, and has a mechanism for canceling noise of the signal light, such as atmospheric fluctuation or vibration caused by the installation location. Lens 104 outputs the signal light as converging light with a gradually decreasing beam diameter toward the light receiving section.

[0013] The single mode fiber 105 has one end disposed facing the lens 104, and the other end connected to the light receiving device 107. A core portion 106 is exposed at one end of the single mode fiber 105, and the core portion 106 is usually disposed at a position where the convergent light is received from the lens 104. The core portion 106 corresponds to a light receiving portion that receives the convergent light. The light receiving device 107 is a device that detects light and converts it into an electrical signal, and is, for example, a complementary metal oxide semiconductor (CMOS) sensor. The communication control unit 108 is configured to be able to receive a detection value of the signal light in the light receiving device 107, and may be, for example, a central processing unit (CPU).

[0014] The light receiving position identifying device 10 has a CPU 11, a first wedge prism group 12A, a second wedge prism group 12B, a first voice coil motor 15, and a second voice coil motor 18. Both the light receiving position identifying device 10 and the communication control unit 108 are configured to be capable of transmitting and receiving data via external communication.

[0015] The CPU 11 is a control device for controlling the rotation of a wedge prism for aligning the optical system and the light receiving unit in the light receiving position specifying device 10.

[0016] The first wedge prism group 12A has a pair of wedge prisms, a first wedge prism 13 and a second wedge prism 14, and a first voice coil motor 15 for rotating each of the first wedge prism 13 and the second wedge prism 14. The second wedge prism group 12B has a pair of wedge prisms, a third wedge prism 16 and a fourth wedge prism 17, and a second voice coil motor 18 for rotating each of the third wedge prism 16 and the fourth wedge prism 17.

[0017] The optical communication device 100 is configured so that the first wedge prism group 12A and the second wedge prism group 12B can be detachably arranged between the mirror 103 and the lens 104 in the optical path of the collimated light in the optical system of the optical communication device 100, for example, via an adapter. The light receiving position specifying device 10 is incorporated into the optical communication device 100 by mounting the first wedge prism group 12A and the second wedge prism group 12B to the adapter. In this way, the optical communication device 100 is an optical communication device that does not originally include a wedge prism group in its optical system, and is configured so that the light receiving position specifying device 10 including the first and second wedge prism groups 12A and 12B that can be incorporated into the above-mentioned optical system can be mounted thereon.

[0018] Fig. 2 is a diagram showing a functional configuration of the light receiving position identifying device 10 of this embodiment. As shown in Fig. 2, the CPU 11 includes a rotation control unit 111 and a position identifying unit 112. The rotation control unit 111 controls the rotation of the wedge prisms 13, 14, 16, and 17 of the first and second wedge prism groups 12A and 12B to deflect the convergent light traveling from the lens 104 toward the core unit 106. The position identifying unit 112 identifies the position of the core unit 106 based on the rotation angles of the wedge prisms 13, 14, 16, and 17 when the core unit 106, which is a light receiving unit, receives the convergent light. Identification of the light receiving position by the CPU 11 will be described later.

[0019] Fig. 3 is a first diagram for explaining the configuration for rotating the wedge prism in this embodiment, and Fig. 4 is a second diagram for explaining the configuration for rotating the wedge prism in this embodiment. Here, the first wedge prism 13 in the first wedge prism group 12A will be explained as an example, but the second wedge prism 14 is configured in the same way. Also in the second wedge prism group 12B, the third and fourth wedge prisms 16 and 17 are configured to be rotatable in a similar manner.

[0020] The first wedge prism 13 is disposed on a movable frame 130 that is rotatably supported on a fixed frame 120 .

[0021] The fixed frame 120 is a member having a circular ring shape in a plan view, and has a circular window 121 in the center. Two sets of coils 123 and 124 are arranged on the surface of the fixed frame 120. The coils 123 and 124 are arranged side by side in the circumferential direction of the fixed frame 120, and both coils are connected in series to a power source 125 outside the fixed frame 120. Of the two coils in the set, the coil 123 on the anode side forms an N-pole magnetic field, and the coil 124 on the cathode side forms an S-pole magnetic field. In addition, a Hall element 126 is arranged between the coils 123 and 124 on the opposite side of the power source 125 in a plan view.

[0022] The movable frame 130 is a member that has a circular shape in a plan view, has a circular window in the center, and the first wedge prism 13 is fitted into the window. Two magnets are arranged on the surface of the movable frame 130 at positions corresponding to the set of coils 123, 124 of the fixed frame 120. The magnets extend in the circumferential direction of the movable frame 130, with the central portion being an N pole 132 and both ends being S poles 131, 133. In addition, the movable frame 130 has three grooves 134 that extend in the circumferential direction on the surface facing the fixed frame 120. The grooves 134 are formed at positions that sandwich the respective magnets in the circumferential direction. A ball 135 is movably accommodated in the grooves 134. The balls 135 come into contact with the surface of the fixed frame 120 when the movable frame 130 is placed on the fixed frame 120, and move the movable frame 130 smoothly with low resistance relative to the fixed frame 120 during rotational motion in the circumferential direction of the movable frame 130. Furthermore, a magnet 136 is disposed between two of the three grooves 134 in a plan view and on the opposite side to the remaining groove 134. That is, the magnet 136 is disposed at a position corresponding to the Hall element 126 of the fixed frame 120.

[0023] Fig. 5 is a first diagram for explaining the rotation direction of the wedge prism in this embodiment, and Fig. 6 is a second diagram for explaining the rotation direction of the wedge prism in this embodiment. As described above, the coils 123 and 124 of the fixed frame 120 and the magnet of the movable frame 130 are arranged in opposing positions. When a magnetic field of an N pole is formed in the coil 123 by energization from the power source 125 and a magnetic field of an S pole is formed in the coil 124, the movable frame 130 rotates counterclockwise with respect to the fixed frame 120 as shown by the arrow in Fig. 5. Conversely, when a magnetic field of an S pole is formed in the coil 123 by energization from the power source 125 and a magnetic field of an N pole is formed in the coil 124, the movable frame 130 rotates clockwise with respect to the fixed frame 120 as shown by the arrow in Fig. 6.

[0024] Fig. 7 is a first diagram for explaining how to obtain the rotation angle of the wedge prism in this embodiment, and Fig. 8 is a second diagram for explaining how to obtain the rotation angle of the wedge prism in this embodiment.

[0025] As described above, the Hall element 126 moves relatively along the circumferential direction on the magnetic circuit formed by the magnet 136 in synchronization with the rotation of the first wedge prism 13 (movable frame 130). Meanwhile, the rotation angle of the first wedge prism 13 has a relationship that can be approximated by a linear expression with the voltage value (magnetic flux density) detected by the Hall element 126 in a specific range, as shown in Fig. 8. Therefore, by setting the magnetic distribution in the magnetic circuit uniformly so that the output voltage of the Hall element 126 maintains linearity, the rotation angle of the first wedge prism 13 can be calculated by an inverse trigonometric function calculation using the relative movement distance of the Hall element 126 with respect to the magnet 136 and the distance from the center to the Hall element 126.

[0026] That is, as shown in FIG. 7, if the distance from the center of rotation (the center of the first wedge prism 13) to the Hall element 126 is R, and the distance between positions P1 and P2 in the rotation direction (the relative movement distance of the Hall element 126) is A, then the rotation angle θ is expressed by the following equation. θ=arcsin(A / R)

[0027] The deflection angle γ of the signal light can be easily calculated mathematically from the rotation angle θ of the wedge prism. Therefore, if the distance between the wedge prism and the light receiving surface of the core portion 106 is known, the position of the light receiving surface can be calculated by trigonometric functions.

[0028] That is, when the deflection angle uniquely determined from the rotation angle θ is γ and the distance from the wedge prism to the light receiving surface is C, the amount of movement D is expressed by the following formula. Movement amount D=tanγ×C

[0029] In this embodiment, each wedge prism group is set to deflect signal light in one direction. A method of deflecting signal light in this embodiment will be described. Fig. 9 is a first diagram for explaining the deflection of signal light by the wedge prisms in this embodiment, and Fig. 10 is a second diagram for explaining the deflection of signal light by the wedge prisms in this embodiment. Fig. 11 is a third diagram for explaining the deflection of signal light by the wedge prisms in this embodiment.

[0030] The first wedge prism 13 and the second wedge prism 14 of the first wedge prism group 12A are set and controlled to rotate in opposite directions at the same rotation angle to deflect the signal light in the pitch direction (vertical direction) as shown in Fig. 9. The third wedge prism 16 and the fourth wedge prism 17 of the second wedge prism group 12B are set and controlled to rotate in opposite directions at the same rotation angle to deflect the signal light in the yaw direction (horizontal direction) as shown in Fig. 10.

[0031] By setting each wedge prism in this manner and controlling its rotational motion, it is possible to deflect the signal light to any position on a plane perpendicular to the optical axis of the wedge prism, as shown in Figure 11 (see JP 2016-164548 A).

[0032] Next, the control for identifying the light receiving surface in this embodiment will be described. FIG. 12 is a flowchart showing an example of the flow of the control for determining the position of the light receiving unit in this embodiment. For example, assume that the reception state of the optical communication in the optical communication device 100 is poor, and it becomes necessary to search for the position of the light receiving unit in the optical communication device 100. In this case, a signal light for starting the search is transmitted to the optical communication device 100 from the optical communication device 100 or another device capable of communicating with it. The communication of the signal light does not have to be optical communication. In addition, the signal light may be the same as the signal light of normal optical communication, or may be light having optical characteristics different from those of the signal light and suitable for searching the core portion 106.

[0033] In step S1, the CPU 11 receives the signal light.

[0034] In step S2, the CPU 11 detects the reception signal (detection signal) of the signal light from the light receiving device 107.

[0035] When the CPU 11 receives the reception signal in step S2, in step S3, the CPU 11 calculates the position of the core unit 106 from information on the rotation angle of the wedge prism at the time of reception. More specifically, the communication control unit 108 acquires information on the signal light detected by the light receiving device 107 and outputs it to the CPU 11. The CPU 11 acquires a signal of signal light detection acquired from the communication control unit 108. The position identification unit 112 acquires information on the rotation angle of the wedge prism at the time of reception from the rotation control unit 111, and calculates the position of the core unit 106 by referring to the signal light detection signal and the acquired information on the rotation angle. Then, the CPU 11 transmits the calculated position information of the core unit 106 to the outside as necessary.

[0036] If the CPU 11 does not receive the reception signal in step S2, in step S4, the rotation control unit 111 rotates one or more of the first to fourth wedge prisms 13, 14, 16, and 17 by a specific amount. Then, the CPU 11 detects whether the light receiving device 107 in step 2 has a searching signal light.

[0037] In step S4, the CPU 11 appropriately selects a search pattern according to the environment, and identifies the position of the core 106 of the single mode fiber 105. For example, the rotation control unit 111 selects a specified search pattern from among previously prepared search patterns, and sets it as a command value in feedback control. The position identification unit 112 calculates the rotation position of the wedge prism based on the output value from the Hall element described above. The rotation control unit 111 acquires the rotation position calculated by the position identification unit 112, compares it with the command value, and calculates the deviation. Then, the rotation control unit 111 controls the rotational movement of the wedge prism so as to eliminate the deviation. For example, the rotation control unit 111 applies a voltage having a voltage value that realizes the calculated rotation angle from the power supply 125 to the coils 123 and 124, and calculates the actual rotation angle of the wedge prism based on the detection signal of the Hall element. In this way, the rotational movement of the wedge prism is matched to the above-mentioned search pattern.

[0038] The search pattern will be described. FIG. 13 is a diagram for explaining detection of the position of the light receiving unit by scanning the signal light in this embodiment. The search pattern has a shape that meanders in one direction in the pitch direction between both ends in the yaw direction, as shown in FIG. 13, for example. The rotation control unit 111 deflects the convergent light so that the convergent light scans a plane perpendicular to the optical axis of the optical system along a specific pattern as shown in FIG. 13. By deflecting the signal light so that the position Ps of the signal light moves along the pattern, when the core portion 106 is located on the pattern on the plane perpendicular to the optical axis of the wedge prism, the signal light reaches the position of the core portion 106. At this time, the signal light that has reached the core portion 106 is detected by the light receiving device 107, and as a result, the position of the core portion 106 is identified.

[0039] In this way, CPU 11 identifies the position of core unit 106 based on the search pattern according to the environment. CPU 11 performs the above calculations until the search pattern ends or until a search end signal is received. After the calculations are completed, CPU 11 transmits a part or all of the calculation results related to identifying the position of core unit 106 to the outside as the search results of the light receiving unit.

[0040] Next, the position of the core 106 is optically adjusted to resolve the poor reception of the optical adjustment device. Fig. 14 is a diagram showing a first mode of optical alignment of the core 106 in this embodiment, and Fig. 15 is a diagram showing a second mode of optical alignment of the core 106 in this embodiment. As shown in Fig. 14, the above-mentioned position identification process reveals that the optical axis OAc in the core 106 of the single mode fiber 105 is shifted from the optical axis OAs in the optical system of the optical communication device 100.

[0041] The first aspect is an aspect in which the deflection characteristics of the light beam caused by the rotation of the wedge prism are utilized to correct the misalignment that has occurred. That is, the rotation angle of the wedge prism when the position of the core portion 106 is identified is set as a reference value. As a result, the misalignment between the optical system and the core portion 106 is eliminated. The first aspect can be implemented by leaving the light reception position identifying device 10 built in without removing it from the optical communication device 100, and is advantageous, for example, when it is difficult to recover the light reception position identifying device 10.

[0042] In the second mode, the amount of movement to the misaligned position is calculated from the amount of rotation of the wedge prism group, and the single mode fiber 105 is moved accordingly. That is, the position of the single mode fiber 105 is adjusted so that the core 106 is on the optical axis OAs of the optical system. As a result, the optical axis OAc of the core 106, which was initially misaligned with the optical axis OAs of the optical system, overlaps with the optical axis OAs of the optical system, thereby eliminating the misalignment between the optical system and the core 106. The second mode is advantageous when precise alignment of the single mode fiber 105 is possible (for example, alignment at the time of product shipment, etc.).

[0043] In this way, the light receiving position identifying device 10 can be permanently incorporated into the optical system of the optical communication device 100. Alternatively, the light receiving position identifying device 10 has a mechanism that allows it to be detached from the optical communication device 100, so that it can be incorporated into the optical communication device 100 only when it is to be used.

[0044] Furthermore, it is possible to select whether or not to separate the light receiving position identifying device 10 from the optical communication device 100 as an adjustment jig during adjustment after assembly of the optical communication device 100 or during maintenance work after installation of the optical communication device 100. For example, when the light receiving position identifying device 10 cannot be easily detached due to the location where the optical communication device 100 is used, it is possible to incorporate the light receiving position identifying device 10 in the optical communication device 100 in advance so that it can be used as needed. In contrast, for example, during adjustment during the manufacturing process of the optical communication device 100, if the light receiving position identifying device 10 is removed after aligning the position of the light receiving unit, it is possible to suppress the impact on the size or weight of the optical communication device 100.

[0045] [Major effects] In the optical communication device 100, in order to realize inexpensive and high-speed communication, it is sometimes required to guide the signal light to the core 106 of the single mode fiber 105 after receiving the signal light in the optical system. However, as described above, the size of the core 106 is about 9 μm in diameter, and adjustment to align the optical axis of the optical system thereto usually requires time and precision. In this embodiment, the light receiving position specifying device 10 includes the rotation control unit 111 and the position specifying unit 112 described above. Then, in accordance with communication from the outside, it has a function of rotating the wedge prism as an internal process and calculating the amount of rotation. Therefore, if the light receiving position specifying device 10 is an optical communication device 100 that can be attached to the optical system of the signal light, it is possible to easily eliminate the optical alignment of the core 106 or the optical position deviation. This embodiment is also applicable to an optical communication device that does not include a wedge prism group in the optical system.

[0046] In this embodiment, the rotation drive source for the wedge prism is a voice coil motor. A voice coil motor generally has the following driving characteristics, and is suitable for searching for the core 106 by deflecting the signal light. -Thrust ripple caused by current commutation is small, enabling smooth control. -Excellent operational response and high frequency operation. -Precise load control is possible because the thrust is proportional to the current.

[0047] In this embodiment, the fixed frame 120 and the movable frame 130 are joined together to form a voice coil motor with the coil and the magnet facing each other. A ball 135 is accommodated in a groove 134 in the movable frame 130, which has an arc-shaped shape when viewed in a plane. In this embodiment, this configuration maintains the distance between the fixed frame 120 and the movable frame 130, defines the rotation range of the movable frame 130, and realizes smooth rotational motion. In addition, since the coils 123 and 124 of the fixed frame 120 are connected in series, no time difference occurs in the energization of the coils arranged on the fixed frame 120. Furthermore, a coil configuration is adopted in which a bipolar magnetic field is formed by energizing the coils. Thus, in this embodiment, the voice coil motor has a structure that is particularly suitable for transmitting torque in the rotation direction of the wedge prism.

[0048] In this embodiment, the rotation control unit 111 deflects the convergent light of the signal light so that the convergent light scans a plane perpendicular to the optical axis of the optical system along a specific pattern, which is suitable for searching and identifying the position of the core portion 106 appropriately in a wide range according to the pattern.

[0049] In this embodiment, the light receiving portion that receives the convergent light of the optical system is the core portion 106 of the single mode fiber 105. As described above, the core portion 106 is very small, and optical alignment is difficult. In this embodiment, the core portion 106 can be precisely searched for by the wedge prism, and optical alignment to a small area such as the core portion 106 is more effective.

[0050] Other embodiments Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0051] In the first embodiment, the light receiving position specifying device 10 is attached to an optical communication device that does not have a wedge prism group, but the present invention is also applicable to an optical communication device that originally has a wedge prism group. That is, the optical communication device may be an optical communication device that includes a communication control wedge prism group in its optical system. In this case, the rotation control unit controls the rotation of the wedge prisms of the communication control wedge prism group as the wedge prism group for communication control. This embodiment is advantageous in that it enables the search and alignment of the position of the core part described above even when it is difficult to later incorporate a light receiving position specifying device into the optical communication device.

[0052] In addition, the present invention is not limited to two pairs of four wedge prisms. It is known that a wedge prism can deflect light passing through it by rotating it. In this way, various deflections are possible depending on the combination of wedge prisms, and these deflection modes can also be applied to the present invention.

[0053] For example, if the detection target is large, the number of wedge prisms may be one. Using only one wedge prism is preferable from the viewpoint of simplifying the device, such as downsizing the light receiving position specifying device and reducing the load of the wedge prism rotation control. Also, if the detection target is small, such as the aforementioned core portion 106, it is preferable to use a combination of multiple wedge prisms. Increasing the number of wedge prisms is preferable from the viewpoint of improving search capabilities, such as realizing a wide range of search, realizing a locally precise search, and simultaneously realizing these contradictory searches.

[0054] FIG. 16 is a first diagram for explaining an example of deflection of signal light by a wedge prism in another embodiment of the present invention, and FIG. 17 is a second diagram for explaining an example of deflection of signal light by a wedge prism in another embodiment of the present invention. As shown in FIG. 16, two wedge prisms 161 and 162 are arranged so that the surfaces perpendicular to the optical axis face each other and the surfaces oblique to the optical axis face each other outward, and are rotated. As a result, as shown in FIG. 17, it is possible to deflect the signal light so as to scan it in a spiral shape on a plane perpendicular to the optical axis (see https: / / www.thorlabs.co.jp / newgrouppage9.cfm?objectgroup_id=147). Therefore, in the present invention, such a single wedge prism group can be applied to a light receiving position specifying device, and such a form is advantageous for configuring a light receiving position specifying device in a smaller size.

[0055] In addition, in the present invention, a wedge prism group may be further added, and the wedge prism groups that deflect the signal light in the same direction may each exhibit different functions. Fig. 18 is a first diagram for explaining another example of the deflection of the signal light by the wedge prism in another embodiment of the present invention, and Fig. 19 is a second diagram for explaining another example of the deflection of the signal light by the wedge prism in another embodiment of the present invention. Fig. 20 is a third diagram for explaining another example of the deflection of the signal light by the wedge prism in another embodiment of the present invention.

[0056] Using two wedge prism groups each consisting of two wedge prisms (four wedge prisms) as in the first embodiment described above is suitable for calculating the position of the light receiving part on the surface. Furthermore, by adding an additional wedge prism group, it is possible to further increase the accuracy in identifying the position of the light receiving part.

[0057] That is, as shown in Fig. 18, two wedge prism groups, a first wedge prism group 180A and a second wedge prism group 180B, are used to deflect the signal light in the pitch direction, and as shown in Fig. 19, two wedge prism groups, a third wedge prism group 190A and a fourth wedge prism group 190B, are used to deflect the signal light in the yaw direction.

[0058] The first wedge prism group 180A is composed of two wedge prisms 181 and 182. The rotation of the wedge prisms 181 and 182 is controlled more roughly, and the signal light is deflected roughly in the pitch direction. The second wedge prism group 180B is composed of two wedge prisms 183 and 184. The rotation of the wedge prisms 183 and 184 is controlled more precisely, and the signal light is deflected precisely in the pitch direction. The third wedge prism group 190A is composed of two wedge prisms 191 and 192. The rotation of the wedge prisms 191 and 192 is controlled more roughly, and the signal light is deflected roughly in the yaw direction. The fourth wedge prism group 190B is composed of two wedge prisms 193 and 194. The wedge prisms 193, 194 have their rotation more precisely controlled, and deflect the signal light precisely in the yaw direction.

[0059] As a result, as shown in Fig. 20, the four wedge prism groups 180A, 180B, 190A and 190B make it possible to deflect the signal light roughly by coarse control and finely by precise control in any direction in a plane perpendicular to the optical axis of the wedge prisms. Therefore, the embodiment shown in Fig. 20 is advantageous from the viewpoint of searching the position of the light receiving unit in a wide range and precisely.

[0060] In the present invention, the rotary drive source of the wedge prism does not have to be a voice coil motor. For example, when it is difficult to supply sufficient power to the light receiving position specifying device, it is also possible to rotate the wedge prism manually. FIG. 21 is a first diagram for explaining a configuration for rotating a wedge prism in another embodiment of the present invention, and FIG. 22 is a second diagram for explaining a configuration for rotating a wedge prism in another embodiment of the present invention. As shown in FIG. 21, the optical communication device 200 has substantially the same configuration as the optical communication device 100 described above, except that it has a light receiving position specifying device 220 instead of the light receiving position specifying device 10. The light receiving position specifying device 220 has a first wedge prism group 212A and a second wedge prism group 212B, and is configured to manually rotate the wedge prism in each wedge prism group.

[0061] 22, the first wedge prism 13 has teeth 221 along a portion of its outer periphery. A gear 222 that is rotatably attached meshes with the teeth 221, and a knob 223 for rotating the gear 222 is attached to the gear 222. The other wedge prisms in the light receiving position specifying device 220 other than the first wedge prism 13 have a similar configuration.

[0062] In the optical communication device 200, for example, an operator rotates the wedge prism using the knob 223. When the communication control unit 108 receives a detection signal of the signal light from the light receiving device 107, it notifies the operator of the reception by a visual stimulus (such as light) or an auditory stimulus (such as sound) so that the operator can recognize it. The operator records the rotation position at that time and causes another computer connected via external communication to calculate the position of the core unit 106 at that time. By fixing the wedge prism at that rotation position, it may be possible to set it as a new reference position after the optical axis readjustment, or to move the position of the core unit 106 to the position of the optical axis of the optical system. In this way, in the light receiving position identification device 220, even if there is no supply power, it is possible to rotate the wedge prism group by performing manual adjustment using a rotating gear, and to deflect the signal light to identify the position of the core unit 106.

[0063] In the above-described first embodiment, communication is performed with the outside, and the position of the core 106 is identified by confirming reception of the signal light by the optical communication device. Most optical communication devices have a processing device analyze the acquired data.

[0064] In the present invention, the state of the reception error at that time may be used as a trigger to identify the position of the light receiving unit. Therefore, the position of the light receiving unit can be identified without relying on external communication. For example, if the light receiving device 107 has an LED for checking whether the communication state is good or bad, for example, a light emitting unit that emits green when the communication state is good and red when the communication state is poor, the position of the light receiving unit can be identified by having an operator rotate the wedge prism while checking the light emitting unit with the naked eye.

[0065] In addition, in the present invention, an optical communication device including a wedge prism group for communication control in the optical system of the signal light may be further equipped with a light receiving position identification device having a wedge prism group for identifying the light receiving position, and the position of the light receiving unit may be identified by the wedge prism group of the light receiving position identification device without using the wedge prism group for communication control.

[0066] 〔summary〕 As is clear from the above description, a first aspect of the present invention is a light-receiving position identifying device (10) including an optical system for adjusting the beam diameter of a signal light, and a light-receiving unit (core unit 106) for receiving convergent light of the signal light by the optical system, a rotation control unit (111) for controlling the rotation of wedge prisms (13, 14, 16, 17) incorporated in the optical system of the optical communication device (100) to deflect the convergent light, and a position identifying unit (112) for identifying the position of the light-receiving unit based on the rotation angle of the wedge prism when the light-receiving unit receives the convergent light. According to the first aspect, optical alignment between the optical system and the light-receiving unit in the optical communication device can be easily achieved.

[0067] In the second aspect of the present invention, the light receiving position specifying device in the first aspect has a plurality of wedge prisms, and the rotation control section controls the rotation of the wedge prisms as a group (wedge prism group 12A, 12B) of a specific number (two pieces). The second aspect is even more effective from the viewpoint of specifying the position of the light receiving section widely or precisely.

[0068] A third aspect of the present invention is an optical communication device in which the optical communication device does not include a wedge prism in the optical system in the first or second aspect, and the light receiving position specifying device further includes a wedge prism that can be incorporated into the optical system. The second aspect is even more effective in terms of enabling alignment of the light receiving unit regardless of the configuration of the optical communication device (whether or not a wedge prism is included).

[0069] A fourth aspect of the present invention is an optical communication device according to the first or second aspect, in which the optical system includes a group of communication control wedge prisms, and the rotation control section controls the rotation of the communication control wedge prisms by using one of the communication control wedge prisms in the group of communication control wedge prisms as the above-mentioned wedge prism, or by using a specific number of the communication control wedge prisms as the group of wedge prisms. This fourth aspect is even more effective in terms of enabling optical alignment of the light receiving section regardless of the installation situation of the optical communication device.

[0070] A fifth aspect of the present invention is any one of the first to fourth aspects, in which the rotation drive source of the wedge prism is a voice coil motor (15, 18). The fifth aspect is even more effective from the viewpoint of precisely specifying the position of the light receiving part by deflecting the convergent light.

[0071] A sixth aspect of the present invention is any one of the first to fifth aspects, in which the rotation control unit deflects the convergent light so that the convergent light scans a plane perpendicular to the optical axis of the optical system along a specific pattern. This sixth aspect is even more effective in terms of searching for the light receiving unit in a wide range and identifying its position.

[0072] A seventh aspect of the present invention is an optical communication device to which the light receiving position specifying device according to any one of the first to sixth aspects can be attached. The seventh aspect, like the first aspect, can easily realize optical alignment between the optical system and the light receiving unit in the optical communication device.

[0073] An eighth aspect of the present invention is the seventh aspect, in which the light receiving portion is a core portion of a single mode fiber 105. The eighth aspect is even more effective from the viewpoint of realizing inexpensive and high-speed optical communication and from the viewpoint of easily eliminating misalignment of the light receiving portion.

[0074] According to the present invention, it is possible to realize inexpensive and high-speed optical communication using an optical communication device, and furthermore, it is possible to easily realize optical alignment of the light receiving part. Therefore, the present invention is expected to contribute to the achievement of, for example, Goal 9 "Build resilient infrastructure, promote inclusive and sustainable industrialization and innovation" of the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0075] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0076] 10, 220 Light receiving position identification device 11 CPU 12A, 180A, 212A First wedge prism group 12B, 180B, 212B Second wedge prism group 13 First wedge prism 14 Second wedge prism 15 First voice coil motor 16 Third Wedge Prism 17 Fourth Wedge Prism 18 Second voice coil motor 100, 200 Optical communication device 101, 102, 104 Lenses 103 Mirror 105 Single mode fiber 106 Core 107 Light receiving device 108 Communication control section 111 Rotation control section 112 Location identification part 120 Fixed Frame 121 Window 123, 124 Coil 125 Power supply 126 Hall element 130 Movable frame 131, 133 S pole 132 N pole 134 Groove 135 Ball 136 Magnet 161, 162, 181~184, 191~194 Wedge Prism 190A Third wedge prism group 190B Fourth wedge prism group 221 teeth 222 Gears 223 Knob

Claims

1. an optical communication device having an optical system for adjusting a beam diameter of a signal light and a light receiving unit for receiving a convergent light of the signal light by the optical system, the light receiving unit comprising: a rotation control unit for controlling a rotation of a wedge prism incorporated in the optical system to deflect the convergent light; a position identifying unit that identifies a position of the light receiving unit based on a rotation angle of the wedge prism when the light receiving unit receives the convergent light; A light receiving position specifying device comprising:

2. A plurality of the wedge prisms are provided, The light receiving position specifying device according to claim 1 , wherein the rotation control section controls the rotation of a specific number of the wedge prisms as one group.

3. the optical communication device is an optical communication device that does not include the wedge prism in the optical system, The light receiving position specifying device according to claim 1 , further comprising the wedge prism capable of being incorporated into the optical system.

4. the optical communication device includes a group of wedge prisms for communication control in the optical system, The light receiving position identification device according to claim 1, wherein the rotation control unit controls the rotation of the communication control wedge prism by using one of the communication control wedge prisms in the group of communication control wedge prisms as the wedge prism, or by using a specific number of the communication control wedge prisms as the group of wedge prisms.

5. 2. The light receiving position specifying device according to claim 1, wherein the rotation drive source for the wedge prism is a voice coil motor.

6. The light receiving position specifying device according to claim 1 , wherein the rotation control unit deflects the convergent light so that the convergent light scans a plane perpendicular to an optical axis of the optical system along a specific pattern.

7. An optical communication device to which the light receiving position specifying device according to any one of claims 1 to 6 can be attached.

8. The optical communication device according to claim 7 , wherein the light receiving portion is a core portion of a single mode fiber.

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