JP2022142502A - Optical transmission device - Google Patents

Abstract

To provide an optical transmission device capable of receiving light while suppressing fluctuations in the angle of incidence and performing more stable communication.SOLUTION: In an optical transmission device for performing optical communication between a light projecting portion including an emitting means for emitting communication light and a light projecting optical system, and a light receiving portion including light receiving optical system and light receiving means for receiving the communication light, the light receiving optical system includes first correcting means that corrects variations in the incident angle of the communication light with respect to the light receiving means by moving an imaging element, and second correction means that corrects the variation of the incident angle by moving an optical element.SELECTED DRAWING: Figure 2

Description

The present invention relates to an optical transmission device that is arranged at a distance and performs information transmission, and an adjustment method for the optical transmission device.

The optical transmission device includes a light projecting section for transmitting communication light and a light receiving section for receiving communication light. In order to perform stable communication, it is necessary to correct the eccentricity of the communication light beam caused by disturbance.

Therefore, especially in an optical transmission device, correcting the eccentricity of a communication light beam is a problem. Patent Documents 1 and 2 disclose zoom lenses that correct image blur caused by vibration of the zoom lens using a plurality of image stabilization mechanisms.

JP 2017-161567 A JP-A-07-027978

However, when the prior art of Patent Document 1 and Patent Document 2 is adopted for an optical transmission device, there are the following problems.
Because the optical transmission equipment is installed in a high place or in an external environment, the wind and shaking of the ground cause a gentle and large shaking of about 1 Hz, and a passing car causes a fine shaking of about 30 Hz. Occur.
Therefore, the optical transmission device is always affected by some kind of vibration or the like, and there is a problem that the incident angle changes when the light from the light projecting section is incident on the light receiving section.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical transmission apparatus which solves the above problems, receives communication light while suppressing variations in the incident angle of the communication light, and enables more stable communication.

An optical transmission apparatus according to the present invention for achieving the above object comprises a light projecting section including emitting means for emitting communication light and a light projecting optical system, a light receiving optical system, and light receiving means for receiving the communication light. wherein the light receiving optical system corrects variations in the angle of incidence of the communication light with respect to the light receiving means by moving an imaging element. The apparatus is characterized by comprising correcting means and second correcting means for correcting the variation of the incident angle by moving an optical element.

With the above configuration, it is possible to provide an optical transmission device capable of receiving communication light while suppressing fluctuations in the incident angle of the communication light and performing more stable communication.

1 is an overall configuration diagram of an optical transmission device according to an embodiment; FIG. 3A and 3B are a detailed configuration diagram of a light-projecting unit and a detailed configuration diagram of a light-receiving unit of the optical transmission device according to the embodiment; FIG. (a) lens cross-sectional view, (b) main part schematic diagram of the first light beam angle correcting means, and (c) main part schematic diagram of the second light beam angle correcting means of the light receiving portion of the optical unit of the first embodiment. be. 3 shows (a) time change of angular deflection of light beam, and (b) time change of eccentricity of an optical element for correcting angular deflection of light beam in Example 1. FIG. (a) lens sectional view of the light receiving part of the optical unit used in Example 1, (b) main part schematic diagram of the first beam angle correcting means, (c) main part schematic diagram of the second beam angle correcting means is. 3 shows (a) time change of angular deflection of light beam, and (b) time change of eccentricity of an optical element for correcting angular deflection of light beam in Example 2. FIG.

[Example 1]
Embodiment 1 of the present invention will be described below. In the explanatory diagrams, the scale may differ from the actual scale for the sake of clarity.

FIG. 1 is a schematic diagram of the configuration of an optical transmission device showing an embodiment of the present invention. Although the description is for one-way communication, the same is true for reverse-direction communication.

In an optical transmission device, when optical communication is performed between a light-projecting part that transmits communication light and a light-receiving part that receives communication light, the light emitted from the light-projecting part is detected by a light-receiving element of the light-receiving part. For this purpose, it is necessary to correct the ray angle (angle of incidence on the light receiving element).

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical transmission device capable of correcting the light beam angle of the optical transmission device with a simple configuration and method.

The communication light transmitted from the optical transmission device 1000 on the transmission side is received by the optical transmission device 2000 on the reception side at a distance, and communication is performed. An optical transmission device 1000 on the transmission side has a configuration in which a light projecting unit 100 for emitting communication light is mounted on an angle adjustment base 101, and the orientation of the light projecting unit 100 can be adjusted along two axes.

The optical transmission device 2000 on the receiving side has a configuration in which a light receiving unit 200 for receiving communication light is mounted on an angle adjustment table (angle adjusting unit) 201, and the orientation of the light receiving unit 200 can be adjusted along two axes.

In order to align the optical axes of the light projecting optical system 120 (not shown in FIG. 1) of the light projecting unit 100 and the light receiving optical system 220 (not shown in FIG. 1) of the light receiving unit 200 at the time of installation. Then, the angle is adjusted by the angle adjustment table 101 and the angle adjustment table 201. FIG. This ensures communication.

However, if the optical transmission devices 1000 and 2000 continue to be used as they are, atmospheric fluctuations, vibrations of members (not shown) holding the angle adjustment base 101 and the light receiving optical system 220, environmental temperature fluctuations, etc. , the optical path of the communication light fluctuates, and the communication becomes unstable. Therefore, the transmission light detection section of the light projecting section 100 and the reception light detection section of the light receiving section 200 detect variations in the communication light and correct the optical path of the communication light to stabilize communication.

Details of the configuration will be described below with reference to FIGS.
2A is a detailed configuration diagram of the light projecting section 100, and FIG. 2B is a detailed configuration diagram of the light receiving section 200. FIG.
The light projecting unit 100 has a communication light emitting unit (ejecting means) 110 , a light projecting optical system 120 , and a transmission light control unit 140 . A communication light emitting unit (ejecting means) 110 emits communication light, and the communication light passes through a projection optical system 120 and is transmitted.

In Example 1, the communication light emitting section 110 is an optical fiber, and emits communication light with a wavelength of 1540 nm to 1560 nm incident from the other end (not shown). It also serves as a communication light receiving section (light receiving means), and receives communication light at the other end (not shown). Thus, the optical transmission device 1000 on the transmission side and the optical transmission device 2000 on the reception side have substantially the same structure, and if the direction of the communication light in the optical fiber is reversed, the relationship between transmission and reception is reversed. . Thereby, two-way communication is established.

The projection optical system 120 is composed of 13 lenses (imaging elements), which will be described later, and includes a first ray angle correction means (first correction means) 121 and a second ray angle correction means (second correction means) 122 and light beam separation means (dividing optical element) 131 . The light beam angle correction means 121 and 122 have an image blur correction mechanism (double-lined frame in the drawing), and shift (movement) in a direction perpendicular to the optical axis to correct the direction of the communication light (incidence to the light receiving element). angle) can be fine-tuned. The light beam angle correcting means 121 and 122 include a lens (imaging element), a lens holding portion for holding the lens, and a driving means (such as a motor) for driving the lens holding portion in a direction perpendicular to the optical axis. be.
The projection optical system 120 has an aperture stop, and is configured such that a second light beam angle correction means 122 is arranged between the aperture stop and the communication light output section 110 .

The light beam separating means 131 partially returns the light amount of the communication light transmitted from the optical transmission device 2000 .
A position detection sensor (detection means) 132 arranged in the optical path of the reflected light receives the light (reflected light) reflected by the light beam separation means 131 and detects the arrival position. The light (transmitted light) that has passed through the light beam separating means 131 is guided to the communication light emitting section 110 . Here, the reflected light is guided to the position detection sensor 132 and the transmitted light is guided to the communication light emitting section 110, but the present invention is not limited to this, and the position detection sensor 132 The transmitted light may be guided to and the reflected light may be guided to the communication light emitting section 110 .

The direction of the communication light transmitted from the optical transmission device 2000 can be calculated from the imaging position detected by the position detection sensor 132 .

The transmission light control unit 140 is connected to the position detection sensor 132 and calculates the direction of the light beam from the detected imaging position. Further, based on the calculation result, the transmission light control section 140 controls the first ray angle correction means 121 and the second ray angle correction means 122 of the projection optical system 120 .

The light projecting section 100 has a holding member 151 and a holding member 152 . The communication light emitting section 110 , the position detection sensor 132 and the transmission light control section 140 are held by a holding member 151 . The projection optical system 120 and the beam separating means 131 are held by a holding member 152 . The control signal from the transmission light control unit 140 is transmitted to and received from the light projecting optical system 120 by a mechanism (electrical contact, optical coupling, etc.) configured between the holding member 151 and the holding member 152 and capable of transmitting and receiving signals. It is transmitted to the first ray angle correction means 121 and the second ray angle correction means 122 inside.

FIG. 2B is a detailed configuration diagram of the light receiving section 200 on the receiving side.
The light receiving unit 200 includes a light receiving optical system 220 for receiving and condensing communication light, a communication light receiving unit 210 for receiving the communication light collected by the light receiving optical system 220, and a position detector for detecting the position of the arriving communication light. It consists of a sensor 232 , a received light control section 240 that controls communication light, and holding members 251 and 252 .

The light receiving optical system 220 is composed of 13 lenses (imaging elements), which will be described later, and has a first ray angle correction means 221, a second ray angle correction means 222, and a ray separation means 231. ing. The light beam angle correction means 221 and 222 have an image blur correction mechanism (double-lined frame in the drawing), and by shifting (moving) in a direction perpendicular to the optical axis, the direction of communication light can be finely adjusted. can.
The light-receiving optical system 220 has an aperture stop, and is configured such that a second beam angle correction means 222 is arranged between the aperture stop and the communication light receiving section 210 .

The communication light receiving section 210 is an optical fiber as described above, and receives communication light at the other end (not shown). The spot diameter of the communication light condensed by the light receiving optical system 220 is 11 μm for the core diameter of the optical fiber of the communication light receiving unit 210 of 50 μm. there is The communication light receiving section 210 is arranged on the optical axis of the light receiving optical system 220 .

The light beam splitter 231 partially folds back the light quantity of the communication light transmitted from the optical transmission device 1000 .
A position detection sensor (detection means) 232 arranged in the optical path of the reflected light receives the light reflected by the light beam separation means 231 and detects the arrival position. The light (transmitted light) that has passed through the light beam separating means 231 is guided to the communication light receiving section 210 . Although the reflected light is guided to the position detection sensor 232 and the transmitted light is guided to the communication light receiving section 210, the present invention is not limited to this. , and the reflected light may be guided to the communication light receiving section 210 .

The direction of the communication light transmitted from the optical transmission device 1000 can be calculated from the imaging position detected by the position detection sensor 232 .

The received light control unit 240 is connected to the position detection sensor 232 and calculates the direction of the light beam from the detected imaging position. Based on the calculation result, the received light control section 240 controls the first ray angle correction means 221 and the second ray angle correction means 222 of the light receiving optical system 220 .

The light receiving section 200 has a holding member 251 and a holding member 252 . The communication light receiver 210 , the position detection sensor 232 and the received light controller 240 are held by a holding member 251 . The light receiving optical system 220 and the beam separating means 231 are held by a holding member 252 . A control signal from the received light control unit 240 is transmitted to and received from the light receiving optical system 220 by a mechanism (electrical contact, optical coupling, etc.) configured between the holding member 251 and the holding member 252 and capable of transmitting and receiving signals. is transmitted to the first ray angle correction means 221 and the second ray angle correction means 222 of .

FIG. 3A is a detailed diagram of the light projecting optical system 120 and the light receiving optical system 220 used in this embodiment, FIG. is a schematic diagram of a main part of a second light beam angle correcting means;
In Example 1, the light projecting optical system 120 and the light receiving optical system 220 are composed of 13 lenses (imaging elements).

Here, optical detailed values of the light receiving optical system 220 are shown below. As mentioned above, due to the symmetry, the optical details of the projection optics 120 are also similar. In numerical examples, for surface number i which is the order of surfaces (optical surfaces) from the object side, ri is the radius of curvature of the i-th surface from the object side, and d is the i-th surface from the object side. It shows the interval (on the optical axis) between the (i+1)th surface and the (i+1)th surface. Also, ndi and νdi represent the refractive index and Abbe number of the medium (optical member) between the i-th surface and the (i+1)-th surface.

[Numeric data 1]
unit mm

Surface data Surface number rd nd vd Effective diameter
1 ∞ 1.5
2 235.559 3.86 1.94225 19 75.13
3 97.884 10.83 1.497 81.5 73.92
4 200.465 5.91 74.06
5 174.932 10.85 2.05751 35.8 75.49
6 -348.78 81.31 74.94
7 -101.495 7.09 1.47567 75.9 36.6
8 42.948 68.9 34.24
9 63.809 8.12 1.91316 33.5 42.42
10 996.275 42.58 41.19
11 41.274 2.99 1.91659 25.9 21
12 40.29 3.67 19.61
13 (aperture) ∞ 2.31 18.42
14 -187.791 1.07 1.51195 78.3 17.4
15 67.995 1 1.51846 51.6 16.89
16 33.517 8.86 16.46
17 571.16 1 1.5207 51.6 15.09
18 95.698 11.79 14.93
19 14.687 8.6 1.89191 28.8 13.5
20 -11.154 5.09 1.92232 20.9 10.59
21 7.734 45 6.93
22 9.871 1.5 1.74789 27.8 4.69
23 4.696 3 1.54941 65.4 4.4
24 -21.178 7.21 4.24
Image plane ∞

Various data focal length 317.82
F number 4.23
Lens length 344.03

Entrance pupil position 831.21
Exit pupil position 22.19
Front principal point position 7893.98
Rear principal point position 310.61

Single lens data lens Starting surface Focal length
1 1 -194.84
2 3 380.49
3 5 116.34
4 7 -64.14
5 9 77.87
6 11 4752
7 14 -99.91
8 15 -133.29
9 17 -228.75
10 19 8.83
11 20 -4.73
12 22 -14.36
13 23 7.51

Characteristic configurations of the present invention will be described below.
The first light beam angle correcting means 221 has an angle correcting mechanism 301 and an imaging element 302 with the position A as the center of the movable range. The imaging element 302 is held by the angle correction mechanism 301 by spring means (not shown) that is any one of mechanical, electrical, and magnetic means.

The second light beam angle correction means 222 has an angle correction mechanism 303 and an imaging element 304 with the position A as the center of the movable range. The imaging element 304 is held by the angle correction mechanism 303 by spring means (not shown) that is any one of mechanical, electrical, and magnetic means.

The imaging elements 302 and 304 are driven and controlled by a driving means (not shown) so as to change their positions based on the information of the transmission light control section 140 and the reception light control section 240 with the position A as the center of the movable range. Position A is a predetermined position with respect to the optical system, for example, the position of the optical axis.

4A and 4B show time variation of the angle of incidence of the communication light on the light receiving unit 200 in the first embodiment, and FIG. 4B shows the first and second beam angle correction means. is the amount of eccentricity from the center position of the movable range of the imaging element.

As shown in FIG. 4A, the generated vibration 401 has a plurality of frequency components of low frequency and high frequency.
In the present embodiment, as a reference, a composite vibration of 1 Hz vibration and 20 Hz vibration will be described as an example.

The first light beam angle correction means 221 corrects low frequency vibration of 1 Hz, and the second light beam angle correction means 222 corrects high frequency vibration of 20 Hz.
Further, in this embodiment, the imaging element (driven part) 302 has the sensitivity that the ray angle is tilted by -0.5 degrees when the eccentricity is 1 mm, and the ray angle of the imaging element (driven part) 304 is 1 mm eccentrically inclined. It has a sensitivity of tilting 0.05 degrees. That is, the first ray angle correcting means 221 and the second ray angle correcting means 222 differ from each other in the amount of change in the ray angle with respect to the driving amount of the imaging element, which is the driven portion.

Therefore, the position of the imaging element 302 changes with time as shown by the correction amount 402 in FIG. 4B, and the position of the imaging element 304 changes with time as shown by the correction amount 403 in FIG. 4B. do.

When correcting the vibration 401, an angular shake of vibration with a maximum shake of 1.1 degrees occurs. By applying vibration of 20 Hz with an amplitude of 2 mm shift to the element 304, the angular deflection of the incident light beam on the communication light receiving unit 210 can be brought close to zero.
With the above configuration, the effects of the present invention can be obtained.

Up to this point, the optical transmission device 2000 on the receiving side has been mainly discussed for the sake of explanation. The present invention can be applied in the same way. In particular, it should be noted that both devices have a transmitted light detector and a received light detector, although only one side is shown.

[Example 2]
Embodiment 2 of the present invention will be described below with reference to the drawings. In the explanatory diagrams, the scale may differ from the actual scale for the sake of clarity.

Since only the optical system differs from the first embodiment, the optical system of the second embodiment will be described.

Details of the configuration will be described below with reference to FIGS.
FIG. 5(a) is a detailed diagram of the light projecting optical system 120 and the light receiving optical system 220 used in Example 2, (b) is a schematic diagram of the main part of the first light beam angle correction means 521, and (c ) is a schematic view of the essential part of the second light beam angle correction means 522. FIG.
In Example 2, the light projecting optical system 120 and the light receiving optical system 220 are composed of 13 lenses (imaging elements).

Here, optical detailed values of the light receiving optical system 220 are shown below. As mentioned above, due to the symmetry, the optical details of the projection optics 120 are also similar. In numerical examples, for surface number i which is the order of surfaces (optical surfaces) from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th surface from the object side, and It shows the interval (on the optical axis) of the (i+1)th surface. Also, ndi and νdi represent the refractive index and Abbe number of the medium (optical member) between the i-th surface and the (i+1)-th surface.

[Numeric data 2]
unit mm

Surface data Surface number rd nd vd Effective diameter
1 ∞ 1.5
2 130.507 5.8 1.92441 18.9 75.17
3 99.353 14.57 1.497 81.5 73.19
4 -3709.486 5.23 72.08
5 887.572 4 1.62534 60 70.65
6 1047.757 170.37 69.97
7 -90.241 7 1.51532 66.7 29.34
8 70.972 8.43 28.88
9 79.201 5.96 1.91132 35.3 30.03
10 -2622.11 39.2 29.55
11 42.702 4.25 1.91119 35.3 21
12 49.339 3.36 19.64
13 (aperture) ∞ 2.66 18.93
14 -92.317 1 1.51789 52.2 18.28
15 26.158 3.69 1.91115 35.3 17.89
16 55.424 1.18 17.21
17 66.848 1 1.49733 80.3 17.01
18 62.21 1.72 16.8
19 14.858 8.55 1.90098 36.1 16.17
20 -18.895 6 1.91805 27.9 12.82
21 6.604 45 7.39
22 12.495 1.5 1.67167 32.1 4.28
23 4.653 3 1.51878 67.7 4.1
24 -12.921 6.82 4.05
Image plane ∞

Various data focal length 317.99
F number 4.23
Lens length 351.8

Entrance pupil position 1035.87
Exit pupil position 23.69
Front principal point position 7350.85
Rear principal point position -311.16

Single lens data lens Starting surface Focal length
1 1 -532.95
2 3 199.37
3 5 9490.41
4 7 -78.24
5 9 88.29
6 11 280.55
7 14 -40.62
8 15 53.69
9 17 -1988.78
10 19 10.93
11 20 -5.07
12 22 -12.51
13 23 7.2

Characteristic configurations of the present invention will be described below.
The first light beam angle correcting means 521 has an angle correcting mechanism 501 with the position A as the center of the movable range and an imaging element 502, and is a spring means by any one of mechanical, electrical, and magnetic means. (not shown) holds the imaging element 502 in the angle correction mechanism 501 .

The second ray angle correcting means 522 has an angle correcting mechanism 503 with the position A as the center of the movable range, an angle correcting mechanism 504 with the position B as the center of the movable range, and an imaging element 505 . The angle correction mechanism 504 is held by the angle correction mechanism 503 by spring means (not shown) that is any one of mechanical, electrical, and magnetic means. The imaging element 505 is held in the angle correction mechanism 504 by spring means (not shown) that is any one of mechanical, electrical, and magnetic means.

The image forming element 502 and the angle correction mechanism 504 are driven by driving means (not shown) so as to change their positions based on the information of the transmission light control section 140 and the reception light control section 240 with the position A as the center of their respective movable ranges. Drive controlled.

The imaging element 505 is driven and controlled by a driving means (not shown) so as to change the position based on the information of the transmission light control section 140 and the reception light control section 240 with the position B as the center of the movable range.

Position A is a predetermined position with respect to the optical system, for example, the position of the optical axis. Position B is a predetermined position with respect to the angle correction mechanism 503 .

6A and 6B show angular fluctuations in the angle of incidence of communication light on the light-receiving unit 200 in Example 2. FIG. This is the amount of eccentricity from the central position of the respective movable ranges of the imaging elements 502 and 505 by the first and second light beam angle correcting means for the purpose.

As shown in FIG. 6A, the generated vibration 601 has a plurality of frequency components of low frequency and high frequency.

In the present embodiment, as a reference, a composite vibration of 2 Hz vibration and 20 Hz vibration will be described as an example.

The first light beam angle correcting means 521 and the second light beam angle correcting means 522 are driven by the imaging element 502 and the angle correcting mechanism 504, respectively, in order to correct the low-frequency vibration of 2 Hz. do. The second light beam angle correcting means 522 drives the imaging element 505 as a driven part with respect to the angle correcting mechanism 504 in order to correct the high frequency vibration of 20 Hz.

Further, in this embodiment, the imaging element 502 has a sensitivity of −0.006° for a 1 mm eccentricity, and the imaging element 505 has a 1 mm eccentricity for a 0.006° inclination of the ray angle.

For example, when correcting the vibration 601, there is an angular shake of 0.0066 degrees at maximum. An angle change of 0.006 degrees can be compensated. The amount of change in the incident angle due to the shift of the angle correction mechanism 504 with respect to the angle correction mechanism 503 assumes that the position of the imaging element 505 held in the angle correction mechanism 504 with respect to the angle correction mechanism 504 does not change. is the amount Furthermore, by shifting the imaging element 505 by 0.1 mm with respect to the angle correction mechanism 504, the maximum amount of light beam deflection at the communication light receiving unit 210 can be brought close to zero.

As shown in FIG. 6B, the image forming element 502 is oscillated with respect to the position A by the correction amount 602, the angle correction mechanism 504 is oscillated with respect to the position A by the correction amount 603, and the imaging element 505 is oscillated with respect to position B like the correction amount 604 . By vibrating the imaging element 502, the angle correction mechanism 504, and the imaging element 505 in this way, the vibration 401 of the ray angle of the incident light in FIG. can be received while suppressing

By doing so, the amount of eccentricity of the first light beam angle correction means 521 can be reduced, and image deterioration can be reduced.

In the configuration of the second embodiment, even if the driving of only the second beam angle correction means 522 (the angle correction mechanism 504 and the imaging element 505) is controlled without driving the first beam angle correction means 521, the 6 oscillation 401 can compensate for the ray angle variation of the incident light. However, in this case, since the amplitude for compensating for the vibration of the low-frequency component by the angle correction mechanism 504 becomes large, optically, the image quality correction is more than when the first and second light beam angle correction means are driven. (image quality) tends to deteriorate. Therefore, it is more preferable to drive the first light beam angle correcting means and the second light beam angle correcting means as in the second embodiment to distribute the correction load.

With the above configuration, the effects of the present invention can be obtained.
In the present invention, the light emitting optical system and the light receiving optical system of the optical transmission device have the same optical axis. It doesn't matter if

Here, the "optical axis" discussed in the present invention means the central optical path of the communication light beam emitted from the emitting means and passing through the light projecting optical system, and the light receiving means passing through the light receiving optical system. It refers to the central optical path of the luminous flux of the communication light heading. Note that the definition is different from the optical axis of a general coaxial optical system.

In the second embodiment, in order to simplify the explanation, the form in which the emitting means exists on the optical axis of the coaxial light projecting optical system and the light receiving means exists on the optical axis of the coaxial light receiving optical system. explained as However, in cases such as when there are no emitting means and light receiving means on the optical axes of the light projecting optical system and the light receiving optical system, communication cannot be established even if the optical axes of a general coaxial optical system are aligned. Further, when the light projecting optical system and the light receiving optical system are decentered optical systems, it is difficult to clearly define the "optical axis". It should be appreciated that the definition of "optical axis" is different for the above reasons.

In the present invention, the communication light emitted from the optical fiber is received by the optical fiber, but the present invention is not limited to this. For example, the communication light emitted from the semiconductor laser may be received by the sensor.

In the description of the present invention, the image forming element is used as the second light beam angle correcting means. You can get the same effect by doing

In the present invention, the correction method has been described by taking the frequencies of the vibration of the angle of the light beam incident on the light receiving part as examples of 1 to 2 Hz and 20 Hz. , the high frequency band (second frequency band) is effective for vibrations with a center frequency of 100 Hz or less.

In particular, when the light beam angle is corrected using an imaging element, it is preferable that the low frequency band has a center frequency of 2 Hz or less and the high frequency band has a center frequency of 20 to 30 Hz. The center frequency of the high frequency band is ten or more times the center frequency of the low frequency band.
In the embodiments, for the sake of simplification of explanation, the correction of the variation in the incident angle of the communication light is limited to the variation in the incident angle within a predetermined cross section. not limited. The present invention can be applied to any variation in the angle of incidence of the communication light in any plane.

Here, in the second embodiment, part of the communication light emitted from the communication light emitting section 110 is utilized for detection, but the present invention is not limited to this. For example, a dedicated detection light may be used, for example, a light having a different wavelength from that of the communication light may be incident from the other end (not shown) of the optical fiber of the communication light emitting section 110 and used as the detection light.

100 light projection unit 110 communication light emission unit (emission means)
120 projection optical system 121, 122 first beam angle correction means (first correction means)
200 light receiving section 210 communication light receiving section (light receiving means)
220 light receiving optical system 221, 222 second light beam angle correcting means (second correcting means)
1000, 2000 Optical transmission equipment

Claims (12)

An optical transmission device for performing optical communication between a light projecting section including emitting means for emitting communication light and a light projecting optical system, and a light receiving section including a light receiving optical system and light receiving means for receiving the communication light. hand,
The light receiving optical system includes first correcting means for correcting fluctuations in the incident angle of the communication light with respect to the light receiving means by moving an imaging element, and correcting fluctuations in the incident angle by moving an optical element. and a second correcting means for adjusting the optical transmission. The first correcting means corrects vibrations in a first frequency band of the variation of the incident angle, and the second correcting means corrects a second frequency different from the first frequency band of the variation of the incident angle. 2. The optical transmission device according to claim 1, wherein band oscillation is corrected. 3. The optical transmission device according to claim 1, wherein said first correcting means and said second correcting means drive different optical elements to correct variations in said incident angle. 3. The optical transmission device according to claim 1, wherein said first correcting means and said second correcting means drive the same optical element to correct variations in said incident angle. 2. The imaging element is a lens movable in a direction perpendicular to the optical axis, and the optical element is a lens movable in a direction perpendicular to the optical axis or a reflecting element with a variable angle of reflection. 5. The optical transmission device according to any one of 1 to 4. 6. The light beam according to claim 5, wherein the movable range of the driven portion of the first correcting means and the movable range of the driven portion of the second correcting means are centered on the same position. transmission equipment. The amount of change in the incident angle with respect to the driving amount of the imaging element of the first correction means and the amount of change in the incident angle with respect to the amount of driving the optical element in the second correcting means are different from each other. 7. The optical transmission device according to any one of claims 3 to 6. 6. The light beam according to claim 5, wherein the movable range of the driven portion of the first correcting means and the movable range of the driven portion of the second correcting means are centered at different positions. transmission equipment. 3. The optical transmission device according to claim 2, wherein the center frequency of said second frequency band is ten times or more the center frequency of said first frequency band. When the driving amount of the driven part by the first correcting means and the driving amount of the driven part by the second correcting means are the same, the amount of change in the incident angle by the first correcting means is the second 8. The optical transmission device according to any one of claims 1 to 7, wherein the change amount of the incident angle by the correcting means is ten times or more. having an aperture stop,
11. The optical transmission device according to claim 1, wherein said second correction means is arranged between said aperture diaphragm and said light receiving means. a splitting optical element disposed between the second correcting means and the light receiving means for splitting the communication light into transmitted light and reflected light;
a detection means arranged in one of the optical paths of the transmitted light and the reflected light;
a control unit that controls driving of the first correcting means and the second correcting means based on information from the detecting means;
12. The optical transmission device according to any one of claims 1 to 11, characterized by comprising:

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