JP2626486B2 - Spatial optical transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial light transmission device,
In particular, the present invention relates to a spatial light transmission device having a function of outputting a transmission light beam with an offset angle added to a reception optical axis.

[0002]

2. Description of the Related Art Conventionally, a laser beam is used for communication with a remote station at a long distance, and the optical axis of a received light is tracked so that the remote station moves like a satellite station. Various spatial light transmission devices that emit (laser light) with an offset angle added to the reception optical axis have been proposed (for example, Japanese Patent Application Laid-Open Nos. 2-18631 and 2-198234).

FIG. 4 is a block diagram showing an example of this type of conventional spatial light transmission device. As shown in FIG. 1, a conventional spatial light transmission device includes a light beam transmitter 1 for outputting transmission light, a light tracking sensor 2 for detecting an angular deviation of a reception optical axis, and a two-axis beam deflector driving circuit 3 A two-axis beam deflector 4 for correcting the angle deviation of the reception optical axis, a beam splitter 5 for separating the transmission light and the reception light, and an offset beam deflector driving circuit to which the transmission beam offset angle data d is input. 8
And an offset beam deflector 9 for adding an offset angle to the reception optical axis to direct transmission light.

The operation of the conventional spatial light transmission device will be described. The transmission light emitted from the optical beam transmitter 1 is incident on an offset beam deflector 9 where the offset beam deflector driving circuit 8 Is added to the receiving optical axis based on the transmission beam offset angle data d.
It is transmitted from the axial beam deflector 4 to the opposite station.

On the other hand, the received light obtained by receiving the light beam from the opposite station passes through the biaxial beam deflector 4 and is incident on the beam splitter 5, where it is reflected and incident on the optical tracking sensor 2. Is done. The optical tracking sensor 2 generates and outputs a photoelectric conversion signal corresponding to the shift of the receiving optical axis with respect to the center, and inputs this signal to the biaxial beam deflector 4 through the biaxial beam deflector driving circuit 3. Thus, tracking control is performed so that the receiving optical axis is input to the center of the optical tracking sensor 2.

[0006]

However, the above-mentioned conventional spatial light transmission device directs the transmission light at an angle obtained by adding a desired offset angle to the reception optical axis input to the center of the optical tracking sensor 2. Since the offset beam deflector 9 is provided on the transmission optical axis, two sets of beam deflectors 4 and 9 are combined with the two-axis beam deflector 4 for tracking the reception optical axis, and the beam deflector driving circuit 3 and 8, there is a problem in that there is a limitation in miniaturization of the device.

[0007] The present invention has been made in view of the above points,
A spatial light transmission device that solves the above-mentioned conventional problems by providing drive control of a two-axis beam deflector based on data obtained by subtracting offset angle data added to transmission light from angle data detected by an optical tracking sensor. The purpose is to:

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light beam transmitter for outputting transmission light, an optical tracking sensor for detecting an angle deviation of a reception optical axis, and an emission of transmission light. A two-axis beam deflector for deflecting the angle of the receiving optical axis, and a transmission light from a light beam transmitter is incident on the two-axis beam deflector, and a received light from the two-axis beam deflector is optically tracked. A beam splitter incident on the sensor, a subtraction circuit for subtracting a detection signal from the optical tracking sensor from transmission beam offset angle data, and a biaxial beam for controlling a deflection angle of the biaxial beam deflector based on an output signal of the subtraction circuit And a deflector driving circuit.

[0009]

According to the present invention, the deflection angle of the two-axis beam deflector is controlled by a subtraction circuit based on a difference signal obtained by subtracting a detection signal from the optical tracking sensor from predetermined transmission beam offset angle data. Therefore, the reception optical axis can be corrected so that the reception optical axis is incident on a predetermined position of the optical tracking sensor, and the transmission light of the optical axis added to the reception optical axis by the offset angle based on the transmission beam offset angle data is transmitted. Can be output. That is, in the present invention, the correction of the reception optical axis and the pointing with the offset angle of the transmission light can be simultaneously performed by one two-axis beam deflector.

[0010]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the same components as those in FIG. 4 are denoted by the same reference numerals.
As shown in FIG. 1, in the present embodiment, an optical beam transmitter 1, an optical tracking sensor 2, a two-axis beam deflector drive circuit 3, a two-axis beam deflector 4, and a beam splitter 5 for separating transmission light and reception light. By providing the subtraction circuit 6 in the configuration including the following, the offset beam deflector 9 provided between the conventional light beam transmitter 1 and the beam splitter 5 and the drive circuit of the offset beam deflector 9 8 is deleted.

Here, the subtraction circuit 6 subtracts the transmission beam offset angle data from the angle data from the optical tracking sensor 2 and inputs the obtained difference signal (subtraction data) to the two-axis beam deflector driving circuit 3. It is a configuration to do. As a result, a closed loop is formed by the two-axis beam deflector drive circuit 3, the two-axis beam deflector 4, the beam splitter 5, the optical tracking sensor 2, and the subtraction circuit 6.

Next, the operation of this embodiment will be described.
The transmission light emitted from the light beam transmitter 1 is transmitted through the beam splitter 5 and is incident on the biaxial beam deflector 4, where it is deflected by an offset angle described later and transmitted to the opposite station. This is because if the opposing station is a satellite, it moves at a very long distance at a high speed, and if the transmitted light is transmitted coincident with the receiving optical axis, the opposing station (that is, the satellite) may not be able to receive it. The transmission optical axis is deflected with respect to the reception optical axis by the offset angle whose position has been predicted and transmitted.

On the other hand, the received light obtained by receiving the light beam from the opposite station passes through the biaxial beam deflector 4 and is incident on the beam splitter 5, where it is reflected and incident on the optical tracking sensor 2. Is done. The optical tracking sensor 2 generates and outputs a photoelectric conversion signal (detection angle data) corresponding to the shift of the receiving optical axis with respect to the center, and makes this signal enter the subtraction circuit 6.

The subtraction circuit 6 receives the detection angle data from the optical tracking sensor 2 and the predetermined transmission beam offset angle data d, and subtracts the transmission beam offset angle data d from the detection angle data to obtain the obtained data. The obtained difference signal (subtraction data) is converted into a two-axis beam deflector driving circuit 3
To enter.

Here, the two-axis beam deflector drive circuit 3 controls the deflection angle of the two-axis beam deflector 4 so that the output difference signal of the subtraction circuit 6 becomes 0 by the closed loop. As a result, the optical axis of the transmission light is added to the reception optical axis by an offset angle determined by the transmission beam offset angle data d.

That is to say, this will be described in more detail. The light tracking sensor 2 converts the reception light separated from the transmission light by the beam splitter 5 into a condenser lens 11 (shown in FIG. 1) as shown in FIG. (Omitted) and has a light receiving unit 21 that is incident therethrough, and outputs a signal corresponding to the beam receiving position of the light receiving unit 21.

Accordingly, when the light receiving position of the light receiving section 21 is at the center position as shown in FIG. 3, the shift in the X-axis direction is 0 and the shift in the Y-axis direction is 0 (0, 0). )
Similarly, when light is received at the position shown in FIG. 3, a signal indicating the coordinate of (ΔX, ΔY) is output.

On the other hand, in the closed loop of FIG. 1, the deflection angle of the two-axis beam deflector 4 is controlled so that the input difference signal to the two-axis beam deflector drive circuit 3 becomes zero. When the receiving optical axis of the light receiving section 21 of FIG.
It can be seen that (0,0) should be given as, and when the position should be set to the above position, (−ΔX, −ΔY) should be given as the transmission beam offset angle data d.

In the case described above, the two-axis beam deflector 4
Is ΔX / f (rad) in the X direction and ΔY / f (rad) in the Y direction (where f is the focal length of the condenser lens 11). That is, the deflection angle of the two-axis beam deflector 4 can be changed based on the transmission beam offset angle data d, whereby the optical axis of the transmission light can be changed.

As described above, in the present embodiment, the closed optical path can be corrected by the above-described closed loop so that the received optical axis is incident on the predetermined position of the light receiving section 21 of the optical tracking sensor 2, and the transmission beam offset is corrected. Since the transmission light of the optical axis added to the reception optical axis by the offset angle according to the angle data d can be output, the offset beam deflector 9 conventionally provided between the optical beam transmitter 1 and the beam splitter 5 is provided. And the offset beam deflector drive circuit 8 can be eliminated.

[0021]

As described above, according to the present invention,
With one two-axis beam deflector, correction of the receiving optical axis and pointing with an offset angle of the transmitting light can be performed at the same time, eliminating the need for a beam deflector for offsetting the transmitting light and its driving circuit, which were conventionally required. Therefore, the configuration of the entire apparatus can be reduced in size and can be configured at a low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of FIG.

FIG. 3 is a diagram showing a light receiving surface of an optical tracking sensor for explaining an operation of a main part of the present invention.

FIG. 4 is a configuration diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 light beam transmitter 2 light tracking sensor 3 two-axis beam deflector drive circuit 4 two-axis beam deflector 5 beam splitter 6 subtraction circuit d transmission beam offset angle data

Claims (2)

(57) [Claims] An optical beam transmitter for outputting transmission light; an optical tracking sensor for detecting an angular deviation of a reception optical axis; a two-axis beam deflector for emitting transmission light and deflecting the angle of the reception optical axis; A beam splitter for transmitting light from the light beam transmitter to the two-axis beam deflector, and for receiving light from the two-axis beam deflector to enter the light tracking sensor; And a two-axis beam deflector driving circuit for controlling the deflection angle of the two-axis beam deflector based on the output signal of the subtraction circuit. Space optical transmission equipment. 2. An optical tracking sensor, a subtraction circuit, a two-axis beam deflector drive circuit, a two-axis beam deflector, and a beam splitter, wherein the output signal of the subtraction circuit becomes zero. 2. The spatial light transmission device according to claim 1, wherein a closed loop for controlling a deflection angle is formed.