JP3052905B2 - Optical space 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 an optical space transmission apparatus used for spatial transmission of an optical signal.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of a conventional optical space transmission apparatus. In FIG. 1, reference numeral 1 denotes an optical transmitter that converts a transmission signal SS into an optical signal PS, and has an electric / optical conversion function. Reference numeral 2 denotes an optical antenna for transmitting and receiving the spatial light P, which outputs the optical signal PS output from the optical transmitter 1 as the spatial light P, and receives the spatial light P and outputs it as the optical signal PR.

[0003] Reference numeral 3 denotes a beam splitter disposed on the right side of the optical antenna 2 for guiding the optical signal PS output from the optical transmitter 1 to the optical antenna 2 and the optical signal PS output from the optical antenna 2. Transmit PR. Reference numeral 4 denotes a relay lens disposed on the right side of the beam splitter 3, and condenses the optical signal PR transmitted through the beam splitter 3. 5 is
An optical receiver disposed on the right side of the relay lens 4, and converts the optical signal PR collected by the relay lens 4 into a reception signal SR.
Convert to That is, the optical receiver 5 has a light / electric conversion function.

In the above configuration, when the transmission signal SS is input to the optical transmitter 1, the optical transmitter 1 outputs an optical signal PS. After the optical signal PS is guided to the optical antenna 2 by the beam splitter 3, the optical signal
Are transmitted as spatial light P toward an optical antenna on the receiving side (not shown).

When the spatial light P transmitted from an optical antenna on the transmitting side (not shown) is received by the optical antenna 2, an optical signal PR is output from the optical antenna 2. After passing through the beam splitter 3, the optical signal PR is condensed by the relay lens 4 and further received by the optical receiver 5. As a result, the optical receiver 5 outputs a reception signal SR corresponding to the optical signal PR.

[0006]

By the way, in the conventional optical space transmission device, if the transmission distance of the spatial light P is long,
Since the spatial light P spreads during transmission, there is a disadvantage that the optical antenna 2 on the receiving side can receive only weak spatial light P. Then, in the conventional optical space transmission device,
It is conceivable to improve the antenna gain by increasing the diameter of the optical antenna 2 on the receiving side, but this method is difficult to realize for the following reasons. The first reason is that the required surface accuracy is close to the limit of the manufacturing accuracy because the wavelength of the spatial light P is very short, so that it is not possible to manufacture the high-gain large-diameter optical antenna 2. . The second reason is that the driving mechanism for driving the large-diameter optical antenna 2 becomes heavy and does not meet the demand for weight reduction. Here, it is known that the weight of the driving mechanism is proportional to about the fourth power of the diameter of the optical antenna 2. The present invention has been made under such a background, and an object of the present invention is to provide an optical space transmission apparatus capable of receiving spatial light at a high level while suppressing an increase in the weight of the apparatus.

[0007]

According to the first aspect of the present invention, there is provided an optical spatial transmission apparatus used for spatial transmission of an optical signal.
There are, a transmitting means for outputting an optical signal to be transmitted, a first optical antenna for transmitting and receiving spatial light, juxtaposed to said first optical antenna <br/> Na, a second transmitting and receiving the spatial light An optical antenna, the output light of the first optical antenna, and the second optical antenna;
At least one of the output light of the antenna
And the output light of the first optical antenna and the second optical
Output light reflecting means for combining in a space the output light of the tena;
Receiving means for receiving the optical signal synthesized by the output light reflecting means and converting it into a received signal; based on the receiving means, the phase of the output light of the first optical antenna and the second
As the output light of the phase of the optical antenna is in phase, and the phase control means for controlling the output light of the phase of said second optical antenna is disposed in the vicinity of the first optical antenna, said feeding
Transmitting the optical signal output by the communication means to the first optical antenna
On the other hand, the output light of the first optical antenna is sent to the receiving means.
And a guiding beam splitter .
The invention according to claim 2 is used for spatial transmission of an optical signal.
In optical space transmission equipment, optical signals to be transmitted are
Transmitting means for outputting, and a first optical amplifier for transmitting and receiving spatial light.
A tena and the first optical antenna, the spatial light
A second optical antenna for transmitting / receiving the first optical antenna;
Out of the output light of the antenna and the output light of the second optical antenna.
To reflect either one of the first optical antenna
And the output light of the second optical antenna are combined in space.
Output light reflecting means, and the output light reflecting means.
Receiving means for receiving the generated optical signal and converting it into a received signal
And the first optical antenna based on the receiving means.
The phase of the output light and the phase of the output light of the second optical antenna
Of the output light of the second optical antenna so that
Phase control means for controlling a phase, and the second optical antenna
And the optical signal output by the transmitting means.
To the second optical antenna, while the second output light
And a beam splitter for guiding the light to the phase control means.
It is characterized by that .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the free-space optical transmission device according to the first embodiment of the present invention. In this figure, reference numeral 10 denotes an optical transmitter that converts a transmission signal SS into an optical signal PS, and has an electric / optical conversion function. 1
Reference numeral 1 denotes a first optical antenna that transmits and receives the first spatial light P1, and has the same configuration as the optical antenna 2 (see FIG. 3). That is, the weight and size of the optical transmitter 10 are the same as the weight and size of the optical antenna 2. Also,
The first optical antenna 11 outputs the optical signal PS output from the optical transmitter 10 as a first spatial light P1, and receives the first spatial light P1 transmitted from a not-shown transmitting-side optical antenna. This is output as the first optical signal PR1.

Reference numeral 12 denotes a beam splitter disposed to the right of the first optical antenna 11, which guides the optical signal PS output from the optical transmitter 10 to the first optical antenna 11, while The first optical signal PR1 output from the optical antenna 11 is transmitted. Reference numeral 13 denotes a relay lens disposed on the right side of the beam splitter 12, and condenses the first optical signal PR1 transmitted through the beam splitter 12.

Reference numeral 14 denotes a first total reflection mirror disposed on the right side of the first relay lens 13, which converts the first optical signal PR1 collected by the first relay lens 13 into an optical signal to be described later. The light is totally reflected to the receiver 19 side. Reference numeral 15 denotes a second optical antenna provided in addition to the first optical antenna 11,
It has the same configuration as the first optical antenna 11. The second optical antenna 15 receives the second spatial light P2 transmitted from the transmitting-side optical antenna (not shown), and outputs this as a second optical signal PR2.

Reference numeral 16 denotes a relay lens disposed on the right side of the second optical antenna 15 for condensing the second optical signal PR2 output from the second optical antenna 15. Reference numeral 17 denotes an optical phase controller which is output from the second relay lens 16 so as to match the phase of the first optical signal PR1 output from the first relay lens 13 based on the control signal SC. The phase of the second optical signal PR2 is controlled. Reference numeral 18 denotes a second total reflection mirror disposed on the right side of the optical phase controller 17, and totally reflects the second optical signal PR 2, whose phase is controlled by the optical phase controller 17, to the optical receiver 19 side. Let it.

The optical receiver 19 includes a first total reflection mirror 14.
To convert the first optical signal PR1 totally reflected by the second optical signal PR2 and the second optical signal PR2 totally reflected by the second total reflection mirror 18 into a received signal SR. The optical phase controller 20 controls the optical phase controller 17 so that the level of the received signal SR supplied from the optical receiver 19 becomes the maximum value.
Is output.

Next, the operation of the space optical transmission apparatus according to the first embodiment will be described. In FIG. 1, when the transmission signal SS is input to the optical transmitter 10, the optical transmitter 10
Outputs an optical signal PS. Then, the optical signal PS is guided to the first optical antenna 11 by the beam splitter 12, and then transmitted from the first optical antenna 11 to the optical spatial transmission device (not shown) as the first spatial light P1.

When spatial light is transmitted from an optical spatial transmission device (not shown), the spatial light is converted into a first spatial light P1 and a second spatial light P2 by the first optical antenna 11 and the second spatial light P2. Each is received by the optical antenna 15. As a result, the first optical signal PR1 is output from the first optical antenna 11, and the first optical signal PR1 is condensed by the first relay lens 13 after passing through the beam splitter 12. . Then, the first optical signal PR1 collected by the first relay lens 13 is totally reflected by the first total reflection mirror 14, and then guided to the optical receiver 19.

On the other hand, from the second optical antenna 15,
The second optical signal PR2 is collected by the second relay lens 16 and then input to the optical phase controller 17. Thereby, the second optical signal P
After the phase is controlled by the optical phase controller 17, R2
Is totally reflected by the total reflection mirror 18 and is guided to the optical receiver 19.

As a result, the first optical signal PR1 totally reflected by the first total reflection mirror 14 and the second optical signal PR2 totally reflected by the second total reflection mirror 18 are combined and combined. The combined optical signal thus received is received by the optical receiver 19. Here, it is assumed that the phase of the first optical signal PR1 is different from the phase of the second optical signal PR2. Therefore, the level of the combined optical signal input to the optical receiver 19 is
Not the maximum value. Then, the optical receiver 19 outputs a reception signal SR corresponding to the composite optical signal.

As a result, the optical phase control circuit 20 outputs a control signal SC to the optical phase controller 17 so that the received signal SR has a maximum value. Thereby, in the optical phase controller 17, the phase of the second optical signal PR2 becomes the same as the phase of the first optical signal PR1, and the received signal SR becomes the maximum value. That is, in the optical space transmission apparatus according to the first embodiment, the feedback control is performed by the optical phase controller 17, the optical receiver 19, and the optical phase control circuit 20 so that the received signal SR becomes the maximum value. is there.

As described above, according to the optical space transmission apparatus according to the first embodiment of the present invention, the first optical signal output from the two first optical antennas 11 and the second optical antenna 15 By making the phases of PR1 and the second optical signal PR2 the same, the level of the combined optical signal in the optical receiver 19 can be theoretically reduced as compared with the case where one optical antenna 2 (see FIG. 3) is used. Can be doubled. That is, according to the optical spatial transmission device according to the above-described first embodiment, the first spatial light P1 and the second spatial light P2 can be received at a high level.

Further, according to the space optical transmission apparatus according to the above-described first embodiment, as compared with a case where a desired antenna gain is obtained by increasing the diameter of one optical antenna 2 (see FIG. 3). The weight of the receiving device (the first optical antenna 11 and the second optical antenna 15) can be relatively halved. That is, in the conventional optical space transmission apparatus, in order to obtain the same desired antenna gain as in the optical space transmission apparatus according to the first embodiment, the diameter of the optical antenna 2 (see FIG. 3) is √2 times, in other words, The weight needs to be quadrupled. On the other hand, in the optical space transmission apparatus according to the first embodiment, the receiving apparatus (the first optical antenna 11 and the second optical antenna 1
The weight of 5) is twice as large as that of one optical antenna 2 (see FIG. 3). Therefore, according to the optical space transmission apparatus according to the first embodiment described above, it is possible to receive spatial light at a high level while suppressing an increase in the weight of the apparatus.

<Second Embodiment> Next, the configuration of a free-space optical transmission apparatus according to a second embodiment of the present invention will be described with reference to FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG.
The beam splitter 12 shown in FIG.
5 and the second relay lens 16, and the optical transmitter 10 is disposed on the second optical antenna 15 side.

That is, the optical transmitter 10 shown in FIG. 2 outputs the optical signal PS when the transmission signal SS is input, and this optical signal PS is guided to the second optical antenna 15 by the beam splitter 12. . When the second spatial light P2 is received by the second optical antenna 15, a second optical signal PR2 is output from the second optical antenna 15, and the second optical signal PR2 is The light passes through the splitter 12 and is guided to the second relay lens 16. The operation of the free-space optical transmission apparatus according to the second embodiment is the same as the operation of the free-space optical transmission apparatus according to the above-described first embodiment, and a description thereof will be omitted.

[0022]

As described above, according to the first and second aspects of the present invention, the phase of the first output light and the phase of the second output light are made the same by the phase control means. Second
Since the phase of the output light is controlled, the level of the combined optical signal received by the receiving means can be doubled as compared with the conventional optical space transmission apparatus. Further, according to the first and second aspects of the present invention, the first and second optical antennas have a larger diameter than a conventional optical transmission space apparatus and a desired antenna gain can be obtained. When the desired antenna gain is obtained by using the second optical antenna, an increase in weight can be suppressed to half. That is, according to the first and second aspects of the present invention, it is possible to obtain an effect that spatial light can be received at a high level while suppressing an increase in the weight of the apparatus. Further, according to the first and second aspects of the present invention, since the transmitting means and the beam splitter are provided, the optical signal can be transmitted.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a free-space optical transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an optical free space transmission apparatus according to the second embodiment.

FIG. 3 is a block diagram showing a configuration of a conventional optical space transmission device.

[Explanation of symbols]

 Reference Signs List 10 optical transmitter 11 first optical antenna 12 beam splitter 13 first relay lens 14 first total reflection mirror 15 second optical antenna 16 second relay lens 17 optical phase controller 18 second total reflection mirror 19 Optical receiver 20 Optical phase control circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI H04B 10/22 10/26 10/28

Claims (2)

(57) [Claims] An optical spatial transmission used for spatial transmission of an optical signal.
A transmitting device that outputs an optical signal to be transmitted, a first optical antenna that transmits and receives spatial light, and a second optical antenna that is provided with the first optical antenna and transmits and receives the spatial light. , Output light of the first optical antenna, and the second optical antenna
At least one of the output light of
The output light of the first optical antenna and the output light of the second optical antenna
Output light reflecting means for combining the output light with the space, and receiving the optical signal combined by the output light reflecting means,
Receiving means for converting the received light into a received signal; and the second receiving means, based on the receiving means, such that the phase of the output light of the first optical antenna and the phase of the output light of the second optical antenna are in phase. of the phase control means for controlling the phase of the optical antenna of the output light, is arranged in the vicinity of the first optical antenna, said transmitting means
For guiding the optical signal output from the first optical antenna to the first optical antenna.
On the other hand, a beam for guiding the output light of the first optical antenna to a receiving means.
And a beam splitter. 2. An optical spatial transmission used for spatial transmission of an optical signal.
A transmitting device for outputting an optical signal to be transmitted, a first optical antenna for transmitting and receiving spatial light, and a transmitting and receiving device for transmitting and receiving the spatial light.
A second optical antenna, the output light of the first optical antenna, and the second optical antenna
At least one of the output light of
The output light of the first optical antenna and the output light of the second optical antenna
Output light reflecting means for combining the output light with the space, and receiving the optical signal combined by the output light reflecting means,
Receiving means for converting into a received signal, and an output of the first optical antenna based on the receiving means
The phase of the light and the phase of the output light of the second optical antenna are the same.
Phase of the output light of the second optical antenna so that
Control means for controlling the transmission means, and the transmitting means arranged near the second optical antenna
Guiding the optical signal output from the second optical antenna to the second optical antenna.
And a beam for guiding the second output light to the phase control means.
An optical space transmission device, comprising: a splitter .