JPH0784186A - Optical communication device - Google Patents

Abstract

PURPOSE:To enable optical communication with good condition by emitting a beacon beam through a light passing area provided on a sub-mirror, thereby effectively emitting the beacon beam with high intensity and making the distribution of light intensity to the opposite party of communication uniform. CONSTITUTION:A beacon beam from the opposite party communication is successively reflected and converged by a main mirror 1 and a sub-mirror 2, reflected by a beam splitter 4 through a collimator lens 3 and a pointing means 7 and converged on a beacon beam receiving part 17 by means of a convex lens 5. The light beam converged by the convex lens 5 is reflected by the beam splitter 4, converged on a position S by means of the collimator lens 3 through the pointing means 7, passes through a through hole 2b provided on the sub- mirror 2 and emitted to the opposite party of communication. By calculating the diameter of the through hole 2b opened on the center of the optical axis of the sub-mirror 2 from the diameter of the beacon beam flux, a distance from a final lens surface to the sub-mirror and a distance from the final lens surface to the converged position of the beacon beam, the uniformly spread beacon beam is effiectively transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication optical device,
Especially, the communication light is supplemented by using the marker light flux for notifying the communication partner of his / her position, and the optical communication is always performed in a good condition, for example, the optical communication between the artificial satellite and another artificial satellite or The present invention relates to an optical communication optical device suitable for optical communication between an artificial satellite and a ground station.

[0002]

2. Description of the Related Art Generally, in optical communication performed between artificial satellites or between an artificial satellite and a ground station, in order to ensure a good communication state, a direction of a communication light beam emitted from a transmitting side and a receiving antenna are used. The orientations of must match exactly.

At this time, the communication light flux used for signal transmission has a spread of about 1 / th in order to increase the antenna gain.
It is used after being narrowed down to about 1000 seconds. On the other hand, the attitude control capability of the artificial satellite is about 1/10 to 1/100 seconds, and it is almost impossible to match the emission direction of the communication light flux with the direction of the receiving antenna as it is.

Therefore, in addition to the communication light flux, a beacon light beam is used to detect the position of the communication partner, and the communication light flux is emitted toward the communication partner (by so-called pointing operation) based on the detection result. There is.

That is, in order for the receiver side to inform the sender of his / her exact position, the transmitter side emits a light beam with a slight spread so that the sender can easily capture it, as a beacon beam, and the transmitter side outputs this. The direction of arrival of the beacon beam is detected accurately, and the communication light beam is emitted in that direction.

FIG. 4A is an optical path diagram of a main part of a conventional optical communication optical device 30, and FIGS. 4B and 4C are enlarged explanatory views of a part of FIG. 4A.

In the figure, reference numeral 31 is a main mirror, which is a parabolic reflecting surface having a concave surface facing the communication partner. 21 is a secondary mirror,
A convex reflecting surface is arranged facing the main mirror 31 side. Primary mirror 3
1 and the sub mirror 21 constitute a so-called Cassegrain type reflection optical system 32. Reference numeral 22 denotes a collimator lens having a positive power, which is arranged so that the focal position coincides with the focal position P of the reflective optical system 32 on the optical axis La.

Reference numeral 33 is a pointing means, which has total reflection mirrors 28 and 29. Pointing means 3
Reference numeral 3 indicates the optical axis Lb formed by optical elements after the total reflection mirror 29, the reflection optical system 32, and the collimator lens 2 by inclining the total reflection mirror 28 and the total reflection mirror 29 relatively.
The inclination of the optical axis La formed by 2 is adjusted, and the direction of the outgoing communication light flux is accurately directed to the direction of the communication partner.

Reference numeral 24 denotes a beam splitter which splits a light beam into a transmitted light and a reflected light depending on the wavelength. In the figure, a communication light beam is transmitted and a marker light beam is reflected.

Reference numeral 26 is a convex lens, and 23 is a communication light flux transmitting / receiving means. The communication light flux transmitting / receiving means 23 is a communication light flux receiving unit 3
4, the communication light flux transmitter 35, the half mirror 39, and the like. The communication light flux from the communication partner is converged by the convex lens 26 and transmitted through the half mirror 39, and the communication light flux receiver 3
It is condensed on 4 and photoelectrically converted. The communication light flux from the communication light flux transmitter 35 is reflected by the half mirror 39 and made into a parallel light flux by the convex lens 26.

Reference numeral 27 is a convex lens, and 25 is a marker light beam transmitting / receiving means. The marker light flux transmitting / receiving unit 25 is a marker light flux receiving unit 36.
It has a marker light flux transmitter 37, a half mirror 38, and the like. Beacon beam from communication partner is convex lens 2
Half mirror 3 of the labeled light flux transmitting / receiving means 25 converged by 7
Then, the light is focused on the marker light beam receiving unit 36 via 8 and photoelectrically converted.

The marker light beam transmitter 37 is arranged at a position slightly shifted from the focal position of the convex lens 27 in the optical axis direction, and the beacon beam emitted from the marker light beam transmitter 37 is reflected by the half mirror 38 to be convex lens 27. It is a parallel light beam with a little spread. The convex lens 27 is provided so as to be movable in the direction of the optical axis L ', and the beam width of the beacon beam can be changed by changing the focal position with respect to the marker light beam transmitting unit 37.

In the case of optical communication, first, the orbital position and the posture direction of the communication partner and that of the communication partner are calculated, and the posture control is performed so that the device 30 is oriented substantially in the direction of the communication partner.

Next, the receiving side emits a beacon beam in order to convey its exact position to the transmitting side. And the sender who received the beacon beam seeks the position of the receiver,
The deviation between the position of the receiver and the optical axis of the communication light beam to be transmitted is calculated, and the pointing means 33 is adjusted to correct the deviation of the optical axis to emit the communication light beam for optical communication. There is.

[0015]

In the optical communication optical device shown in FIG. 4, the beacon beam has a slight spread so that the transmitting side can easily receive it. Therefore, as shown in FIG. There is a problem that the outside of the light flux is limited and the usable area of the primary mirror 31 is limited, so that a primary mirror with a large area is required to compensate for this and the size of the entire apparatus becomes large.

Further, the center of the beacon beam is blocked by the secondary mirror 21, and the intensity distribution in a plane perpendicular to the optical axis becomes so-called donut shape in which the intensity is strong in the peripheral portion and weak in the central portion. In particular, there is a problem in that the total output is significantly reduced due to the shadow around the center of the light flux, which is originally strong.

Further, when the communication partner performs the pointing operation using the beacon beam, it is necessary to consider that it is in a donut shape, which has a drawback that it greatly affects the algorithm of the pointing operation.

According to the present invention, the beacon beam is emitted through the light passage area provided in the secondary mirror, so that the beacon beam can be emitted efficiently and with high intensity, and the light intensity distribution given to the communication partner is made uniform and always good. An object of the present invention is to provide an optical communication optical device that enables optical communication in a state.

[0019]

An optical communication optical device of the present invention is a reflection optical system in which a sub-mirror is arranged opposite to a main mirror having a concave surface facing the communication partner, and a communication light beam from the communication partner is reflected by the reflection optical system. A communication light flux receiving unit that performs optical communication by reflecting and receiving in order the primary mirror and the secondary mirror of the optical system, and a reflection light beam that notifies the communication partner of its own position through the light passage area provided in the secondary mirror. And a marker light beam transmitter that emits light to a communication partner side in substantially the same direction as the optical axis of the optical system.

In addition, a reflection optical system in which a sub-mirror is arranged to face a main mirror having a concave surface facing the communication partner, and a communication light beam from the communication partner is reflected in the order of the main mirror and the sub mirror of the reflection optical system. A communication light beam receiving unit for receiving and receiving optical communication, and a marker light beam for notifying the communication partner of his / her position to the communication partner side substantially in the same direction as the optical axis of the reflection optical system and the marker light beam lens system and the secondary mirror. And a marker light beam transmitting unit that emits light through the light beam passing area provided in the second mirror, the diameter of the light beam passing area of the secondary mirror is D2, and the marker light beam passing through the final lens surface on the secondary mirror side of the marker light beam lens system. The diameter of the marker light beam is D1, the distance on the optical axis from the final lens surface to the sub-mirror is L, and the distance between the final lens surface and the converging position of the marker light beam passing through the final lens surface is X. When I did

[0021]

[Equation 2] It is characterized by satisfying.

[0022]

Embodiment 1 FIG. 1 is a schematic view of the essential portions of Embodiment 1 of the present invention. In this embodiment, for example, optical communication is performed between artificial satellites using a communication light beam, and the position of a communication partner is confirmed by a beacon light beam having a wavelength different from that of the communication light beam to perform a pointing operation. There is.

In the figure, reference numeral 1 denotes a primary mirror, which has a reflecting surface 1a consisting of a parabolic surface with a concave surface facing the communication partner. 2 is a secondary mirror, which has a reflecting surface 2a having a convex surface facing the primary mirror 1,
A through hole (light passage region) 2b is provided at a substantially central portion of the reflecting surface 2a.

The primary mirror 1 and the secondary mirror 2 constitute a so-called Cassegrain type reflection optical system 12.

Reference numeral 3 denotes a collimator lens having a positive power, which is arranged so that the focal position coincides with the focal position P of the reflective optical system 12 on the optical axis La.

A pointing means 7 has total reflection mirrors 8 and 9, and the total reflection mirror 8 and the total reflection mirror 9 are relatively bent to form an optical axis formed by optical elements after the total reflection mirror 9. By adjusting the inclination between Lb and the optical axis La formed by the reflection optical system 12 and the collimator lens 3, the outgoing communication light flux is accurately directed to the communication partner.

Reference numeral 4 denotes a beam splitter that splits a light beam into a transmitted light and a reflected light depending on the wavelength. In the present invention, the communication light beam is transmitted and the beacon beam is reflected.

Reference numeral 6 is a convex lens, and 11 is a communication light flux transmitting / receiving means. The communication light flux transmitting / receiving means 11 is a communication light flux receiving unit 13.
It has a communication light flux transmitter 14, a half mirror 15, and the like. The communication light flux from the communication partner is converged by the convex lens 6, passes through the half mirror 15, and is condensed on the communication light flux receiver 13 to be photoelectrically converted. Further, the communication light flux from the communication light flux transmitter 14 is reflected by the half mirror 15 and the convex lens 6
Is a parallel light flux.

Reference numeral 5 is a convex lens, and 16 is a marker light beam transmitting / receiving means. The marker light flux transmission / reception means 16 is a marker light flux transmitter 18
It also has a marker beam receiver 17, a half mirror 19, and the like. The convex lens 5 focuses on the beacon light receiving unit 17 from the communication partner side reflected by the beam splitter 4.
The convex lens 5 collects the beacon beam from the beacon light beam transmitter 18, and is provided movably in the direction of the optical axis L'to change its collecting position so that the beacon beam can be efficiently emitted to the communication partner. There is.

The convex lens 5 and the collimator lens 3 constitute one element of a marker light beam lens system for condensing the beacon beam at a position S substantially in the center of the through hole 2b of the secondary mirror 2.

When optical communication is performed in this embodiment, first, the orbital position and attitude direction of the communication partner and the communication partner are calculated,
Attitude control is performed so that the device 10 faces substantially the communication partner direction.

Next, the receiving side emits a beacon beam 18a from the beacon light beam transmitting section 18 in order to inform the transmitting side of its own accurate position. Then, the transmitting side that receives the beacon beam obtains an accurate position of the receiving side, calculates the deviation between the position of the receiver and the optical axis of the communication light beam to be transmitted, and corrects the deviation of the optical axis. Adjust the pointing means 7 to emit the communication light flux 14a from the communication light flux transmitter 14;
Optical communication is performed.

The communication light beam 14a at this time is shown by a solid line in FIG. The communication light flux from the communication partner is incident on the anti-slope 1a of the primary mirror 1, is reflected while converging in the incident direction, is then reflected by the reflective surface 2a of the secondary mirror 2, and is a focus position on the optical axis La. It is once condensed on P and is converted into a parallel light beam by the collimator lens 3.

Then, the light is transmitted through the beam splitter 4 via the pointing means 7, and is condensed on the communication light flux receiving means 13 by the convex lens 6 to be photoelectrically converted.

Further, the communication light beam transmitted to the communication partner is reflected by the communication light beam transmitter 14 by the half mirror 15 and made into parallel light by the convex lens 6 and follows an optical path substantially opposite to that at the time of reception.

On the other hand, the beacon beam from the communication partner is reflected and condensed in the order of the primary mirror 1 and the secondary mirror 2, is reflected by the beam splitter 4 via the collimator lens 3 and the pointing means 7, and is projected by the convex lens 5. It is focused on the marker light beam receiving unit 17.

Further, the beacon beam 18a emitted to the other party of communication is indicated by a dotted line in FIG.
It is further emitted, passes through the half mirror 19, and is condensed by the convex lens 5.

The light beam condensed by the convex lens 5 is reflected by the beam splitter 4, is condensed at the position S by the collimator lens 3 through the pointing means 7, passes through the through hole 2b provided in the secondary mirror 2, and is transmitted to the communication partner side. It is ejecting.

Here, in order to efficiently emit the beacon beam 18a, it is necessary to pass through the through hole 2b without being blocked by the reflecting surface 2a of the secondary mirror 2.

Therefore, the diameter of the through hole 2b formed in the center of the optical axis of the secondary mirror 2 is D2, and the lens surface on the most position S side of the marker light beam lens system for condensing the beacon beam 18a at the position S (hereinafter simply referred to as "the lens surface"). The final lens surface is the lens surface 3a of the collimator lens 3 in this embodiment.) The beacon luminous flux diameter at the collimator lens 3 is D1, and the final lens surface 3a.
To the secondary mirror 2 on the optical axis is L, and the final lens surface 3
When X is the distance from a to the focus position S of the beacon beam, it is desirable to satisfy the following equation.

[0041]

[Equation 3] With this configuration, in the present embodiment, a beacon beam that has no shadow in the center and is uniformly spread is efficiently emitted.

In this embodiment, the total reflection mirror 8 may be a beam splitter, the beam splitter 4 may be a total reflection mirror, and the marker light beam transmission / reception means 16 may be arranged behind it.

2 and 3 are optical path diagrams of the second embodiment of the present invention. 2 shows an optical path of a communication light beam from a communication partner, and FIG. 3 shows an optical path of a beacon beam emitted to the communication partner.

In the figure, reference numeral 40 denotes a primary mirror, which has a reflecting surface 40a which is a parabolic surface having a concave surface facing the communication partner. Four
Reference numeral 1 denotes a secondary mirror, which is a reflecting surface 41 having a concave surface facing the primary mirror 40.
a, and a through hole (light passage region) 41b is provided substantially in the center of the reflecting surface 41a.

The primary mirror 40 and the secondary mirror 41 constitute a so-called Gregory type reflection optical system 55, and are arranged so that the spherical centers of the reflection surfaces 40a and 41a coincide with each other at one point on the optical axis.

Reference numeral 42 is a beam splitter having a through hole 42b in the central portion for splitting an incident light beam into a transmitted light and a reflected light according to a wavelength, which transmits a beacon beam and reflects a communication light beam.

Reference numeral 56 is a pointing means having total reflection mirrors 43 and 44. The pointing means 56 adjusts the inclination between the optical axis Lb formed by the optical elements after the total reflection mirror 44 and the optical axis La formed by the reflection optical system 55 by tilting the total reflection mirror 43 and the total reflection mirror 44 relatively. Then, the emitted communication light beam is accurately directed to the communication partner.

Reference numeral 45 is a convex lens, and 46 is a communication light flux transmitting / receiving means. The communication light flux transmitting / receiving means 46 is the communication light flux receiving unit 4.
7, a communication light flux transmitter 48, a half mirror 49, and the like. The communication light flux from the communication partner is a convex lens 45.
And the communication light flux receiving unit 4 through the half mirror 49.
It is condensed on 7 and photoelectrically converted. Further, the communication light flux from the communication light flux transmitter 48 is reflected by the half mirror 49 and made into a parallel light flux by the convex lens 45.

Reference numeral 50 denotes a convex lens (lens system for labeled light flux),
Reference numeral 53 is a marker light flux transmitting / receiving means. The marker light flux transmitting / receiving unit 53 includes a marker light flux receiver 51, a marker light flux transmitter 52, a half mirror 54, and the like. The convex lens 50 focuses the beacon luminous flux from the communication partner on the beacon luminous flux receiver 51. Further, the convex lens 50 focuses the beacon beam from the beacon light flux transmitter 52 at a position S on the optical axis La.

In the present embodiment, the communication light flux from the communication partner enters the anti-slope 40a of the main mirror 40, is reflected, and passes through the through hole 42b of the beam splitter 42 while converging in the incoming direction. , Is incident on the secondary mirror 2. Then, the light is reflected by the reflecting surface 2 a of the secondary mirror 2 to be substantially parallel light, and then reflected by the beam splitter 42.

The communication light beam reflected by the beam splitter 42 passes through a pointing means 56 and then a convex lens 45.
The light is condensed on the communication light flux receiver 47 and photoelectrically converted.

Further, the beacon beam emitted to the communication partner is emitted from the beacon light beam transmitting section 52, reflected by the half mirror 54, enters the convex lens 50, and is converged by the convex lens 50 so as to be condensed at the focal position S. Through hole 41b of mirror 41
It passes through and is emitted to the other party.

When optical communication is performed, first, the orbital position and posture direction of the communication partner and that of the communication partner are calculated, and the posture control is performed so that the device 20 faces substantially the direction of the communication partner. Next, the receiving side emits a beacon beam from the beacon light flux transmitting unit 52 in order to convey its own accurate position to the transmitting side, and the transmitting side which has received the beacon beam obtains the accurate position and direction of the receiving side, Calculate the deviation between the receiver and the optical axis of the communication light beam that he or she intends to transmit.

Then, the pointing means 56 is adjusted so as to correct the deviation of the optical axis, and the communication light beam is emitted to perform the optical communication.

Here, since the beacon beam does not pass through the pointing means 56, the optical axis La of the reflection optical system 55, etc.
Marker light flux transmitting / receiving means 53 by detecting the amount of movement and the moving direction of
It is advisable to control the position of (1) and link it with the movement of the optical axis La, or set the divergence angle of the beacon beam to be equal to or more than the optical axis movement amount of the communication optical system.

With this configuration, in this embodiment, the influence of the ghost that the beacon beam of the user has on the communication light beam receiving means 47 of the user is greatly reduced.

Further, in the present embodiment, the beacon beam can be efficiently emitted without being blocked by the secondary mirror 41, and the area of the primary mirror 40 and the output of the marker light beam transmitting section (laser diode etc.) 52 and the power consumption can be increased. It is possible to reduce the weight and extend the life of the satellite.

In this embodiment, the light passing area is the secondary mirror 41.
However, the present invention is not limited to this, and for example, the sub-mirror 41 is a transparent member and the surface 41a on the main mirror side is formed.
Alternatively, a reflection film may be formed on a part of the surface (a region corresponding to the through-hole 41b) and a beacon beam may be emitted through the opening or the half mirror surface. It is also possible to form a dichroic film, a semi-transmissive film, or the like on a part of the surface 41a of FIG. 1 to transmit the beacon beam and reflect the communication light flux.

[0059]

According to the present invention, by emitting the marker light beam (beacon beam) through the light passage area of the secondary mirror,
It is possible to efficiently emit a beacon beam with a high intensity, to make the light intensity distribution given to the communication partner uniform, and to achieve an optical communication optical device capable of always performing optical communication in a good state.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is an optical path diagram of a main part of a second embodiment of the present invention.

FIG. 3 is a main part optical path diagram of a second embodiment of the present invention.

FIG. 4 is a schematic view of a main part of a conventional optical communication optical device.

FIG. 5 is an optical path explanatory diagram of a conventional optical communication optical device.

[Explanation of symbols]

 1,40 Primary mirror 2,41 Secondary mirror 12,55 Reflective optical system 13,47 Communication luminous flux receiver 14,48 Communication luminous flux transmitter 17,51 Marked luminous flux receiver 18,52 Marked luminous flux transmitter 7,56 Pointing means

Claims (2)

[Claims] 1. A reflection optical system in which a sub-mirror is arranged so as to face a main mirror having a concave surface facing the communication partner, and a communication light beam from the communication partner is reflected in the order of the main mirror and the sub mirror of the reflection optical system. A communication light beam receiving unit that receives light by receiving light to perform optical communication, and a communication light beam in a direction substantially the same as the optical axis of the reflective optical system through a light passing region provided in the sub-mirror for transmitting a marker light beam that notifies the communication partner of its own position. An optical communication optical device, comprising: a marker light beam transmitting unit that emits to the side. 2. A reflection optical system in which a sub-mirror is disposed so as to face a main mirror having a concave surface facing the communication partner, and a communication light beam from the communication partner is reflected in the order of the main mirror and the sub mirror of the reflection optical system. And a communication light beam receiving unit for receiving light to perform optical communication, and a marker light beam for notifying the communication partner of his / her position to the communication partner side substantially in the same direction as the optical axis of the reflection optical system. And a marker light flux transmitter that emits through the provided light passage region,
The diameter of the light passage region of the secondary mirror is D2, and the diameter of the marker light flux passing through the final lens surface on the secondary mirror side of the marker light beam lens system is D.
1, the distance on the optical axis between the final lens surface and the secondary mirror is L,
When the distance between the final lens surface and the converging position of the marker light flux passing through the final lens surface is X, An optical communication optical device, characterized in that