JP2001168804A - Laser communication system capable of automatically aligning optical axis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser communication system, adaptable to requirements of the system that is adjusted by automatically varying the optical axis through only moving the laser transmission section or laser reception section, without having to move the entire laser communication system because an external force causes the optical axis to be twisted in laser communication resulting in causing a communication fault. SOLUTION: This laser communication system is provided with the laser reception section that receives a laser beam and converts it into an electrical signal, the laser transmission section that converts the electrical signal into a laser beam to emit it, a motor section that adjusts a position of the laser transmission section, a speed reducer section that reduces the speed of a motor to minutely adjust the motion of the laser transmission section, and a control section that monitors the transmission reception state to control the motion of the laser transmission section and the motor section. On the occurrence of a communication defect between the laser communication systems due to twisted optical axis, the laser reception section is fixed and the position of the laser transmission section is moved to correct the optical axis thereby automatically aligning the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser communication system, and more specifically, an optical axis is distorted (displaced) by an external factor during communication between laser communication equipment.
The present invention relates to a laser communication system capable of performing auto-alignment to prevent such a problem.

[0002]

2. Description of the Related Art FIG. 1 is a block diagram schematically showing a configuration of a conventional laser communication system. Referring to FIG. 1, a conventional laser communication system (10A, 10B) includes a laser receiving unit that receives a laser signal and converts the laser signal into an electric signal.
(30A, 30B), a laser transmitting unit (20A, 20B) that converts an electric signal into a laser signal and transmits the same, and the laser receiving unit (30A,
30B) and a control unit (50A, 50B) for controlling and managing the laser transmission unit (20A, 20B), and a laser reception unit (30A, 30B), a laser transmission unit (20A, 20B) and a housing part (40A, 40B) for fixing the control part (50A, 50B) therein, whereby an electric signal (for example, voice used in mobile telephone and data communication) inputted to the laser communication system is provided. And all electrical signals including data, etc.) are converted to laser signals and transmitted, and the corresponding partner laser communication device is
This laser signal is received, converted into a corresponding electric signal, and communication using a laser is performed.

The process of adjusting the direction of the laser diode of the transmitting unit so that the beam emitted from the laser diode of the transmitting unit is accurately received by the photodiode of the receiving unit on the other side is called alignment.

[0004] First, when a laser communication system is installed, alignment is manually performed in both directions, and normal transmission and reception are performed. However, due to the external environment, fine movement of the equipment itself may occur, the alignment may be twisted, and normal transmission and reception may not be performed, and the position where the equipment is installed may be near the road where there are many vehicles If the equipment is located in a place where the temperature changes rapidly or the equipment for fixing the equipment is unstable, the alignment will often be twisted, and in each case, a large number of personnel will perform the alignment work for a long time, resulting in a huge amount of work. Maintenance is required. The reason why misalignment frequently occurs is that the margin for allowing the misalignment is small.

Considering this in detail, it is preferable that the optical axis of the laser transmitting unit of the transmitting laser communication system and the optical axis of the laser receiving unit of the receiving laser communication system be exactly matched. Since the laser communication devices and the like involved in transmission and reception are so far apart (about 1 km or more), it is practically almost impossible to exactly match the optical axes.

[0006] Generally, the margin in which the laser beam to be transmitted can be received by the receiving unit varies depending on the thickness of the laser beam. For example, the separation distance is 1 km, the diameter of the receiving lens is 125 mm, and the diameter of the transmitting beam. Is about 5 m in the upper and lower directions and about 10 m in the left and right sides in consideration of the fact that the signal intensity decreases even if the diameter of the laser beam increases as the distance increases. Therefore, it is necessary to adjust the optical axis so as to be maintained within the margin.

This will be concretely examined with reference to FIG.
FIG. 2 is a diagram illustrating a calculation related to an angle error and a distance error of an optical axis in a laser communication system.

As shown in FIG. 2A, even if the angle of the lens axis of one of the transmission units is actually twisted by 1 °, the other party receiving at a distance of 1 km ahead has a twist of 17.5 m in the distance. Occurs. As shown in FIG. 2B, if the diameter of the laser beam is 60 cm at a distance of 1 km and the diameter of the lens of the receiving unit is 10 cm, if the optical axis is twisted by 60 cm, the receiving unit You will not be able to receive. It is 0.0344 ° in angle (when moving from the actual center to the left or right, the transmission angle is half of that, 0.0172 °). Therefore, it is recognized that the probability of misalignment occurring due to external or internal factors is extremely high.

Therefore, there is a problem in that the optical axis of the laser communication system is distorted due to factors such as external force, which is a problem of the conventional laser communication system, and communication failure occurs.

As a conventional method for solving this problem, there is a method of manufacturing the housing portions (40A, 40B) so as to be firmly fixed by using a fixing support. Although the force increases, if the optical axis is deviated, there is a problem that the entire laser communication system must be moved together with the fixing support to compensate for the deviation.

As another conventional method, after the optical axis is fixed, it is firmly fixed, and when the position is deviated, in order to correct the optical axis, the fixing is released and the position is manually moved. Although there is a method of providing an equipment part and correcting the optical axis due to external force, it is basically insufficient to eliminate the current situation where the beam is twisted, and it requires a lot of manpower, cost and time. There is.

As another conventional method, there is a method of increasing the size of a transmitted beam (3 to 5 m based on 1 km) in order to solve the problem of the optical axis being twisted. When it becomes large, there is a problem that the density of the light quantity becomes low and the transmission distance becomes short.

Further, as another conventional method, there is a method of starting communication while gradually reducing the beam size from the maximum size to finding the optical axis by the original laser size. In the method, it is practically difficult to vary the size of the laser,
There is a problem that practical use is difficult.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to automatically change the optical axis, and to operate a laser transmitter or a laser receiver without moving the entire laser communication system. Simplify the overall configuration of the laser communication system and ensure stable service by moving only the unit, preferably by fixing the laser receiving unit and automatically allowing the laser transmitting unit to move automatically. Optimized and minimized beam size by automatically adjusting the optical axis to enable communication and improve signal stability and extend transmission distance It is to provide a simple laser communication system.

[0015]

In order to achieve the above object, the present invention provides a laser diode unit which converts an input electric signal into a laser beam and emits the laser beam, and a laser beam emitted from a partner. A photodiode unit that receives and converts it into an electrical signal, a motor unit that adjusts the direction of the laser diode unit, a deceleration unit that reduces the speed of the motor to reduce the movement of the laser diode unit, and monitors the communication state A control unit for controlling the motor unit is provided.

In the laser communication system according to the present invention, the photodiode (receiver) is fixed, and only the laser diode (transmitter) can be adjusted by the motor to move the optical axis.

Further, in the laser communication system according to the present invention, the laser diode section (transmitting section) can freely move up, down, left and right by the motor section.

According to the present invention, in a communication system using a laser, the direction of a laser diode in a transmitting unit is automatically adjusted using a motor so that a receiving unit on the other side can receive the signal accurately. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 3 is a block diagram schematically illustrating a configuration of a laser communication system according to the present invention.

As shown in FIG. 3, in the laser communication system according to the present invention, a laser diode unit (100A, 100B) for converting an input electric signal to be transmitted into a laser beam and emitting the laser beam, Photodiode section (200A, 200B) that receives the emitted laser beam and converts it into an electric signal, motor section (300A, 300B) that adjusts the direction of the laser diode section (100A, 100B), reduces the speed of the motor Reducer unit (400A, 400B) that finely adjusts the movement of the laser diode unit (100A, 100B), and control unit (500A, 500B) that monitors the transmission and reception state and controls the motor unit (300A, 300B) ).

The laser diode section (100A, 100B) receives an electric signal for transmission, is controlled by a control section (500A, 500B), converts the input signal into a laser beam, and converts the converted laser beam. Fire a beam. The photodiode units (200A, 200B) receive the laser beams emitted in this manner, are controlled by the control units (500A, 500B), and convert the received laser beams into electric signals.
The motor unit (300A, 300B) is usually a stepping motor, and the laser diode unit (100A, 100B) is connected to the laser diode unit (100A, 100B) via the reduction gear unit (400A, 400B) so that the laser diode unit (100A, 100B) can be moved. ), And the motor part (300A, 300B) and the reduction gear part (400A, 400B) are directly connected to each other, and even if the moving angle of the motor part (300A, 300B) is large, the speed is reduced. The mechanical section (400A, 400B) divides it into smaller movement angles, and the laser diode section (100A, 100B)
Not only can B) be finely moved, but it also serves to increase the torque. Motor part (300A, 300B)
It is preferable that two motor parts are provided, and one motor part moves the laser diode part (100A, 100B) in the horizontal direction, and the other motor part moves the laser diode part (100A, 100B) in the vertical direction. You can make it move. That is, the control unit (500A, 500B) transmits a signal (angle compensation signal) for correcting the optical axis of the laser diode unit (100A, 100B) to the motor unit (300A, 300B), and when the motor rotates. The laser diode section (100A, 100B) can move freely up, down, left and right,
The predetermined direction in which (100A, 100B) moves can be moved in any direction based on the combination of up, down, left, and right.

Therefore, the motor units (300A, 300B) can move the laser diode units (100A, 100B) up, down, left, and right by the control signals of the control units (500A, 500B).
The control unit (500A, 500B) according to the present invention, unlike the conventional example, monitors the transmission / reception state, and when the signal power is attenuated, in order to compensate for it, the motor unit (100A, 100B)
And the laser diode is connected by a structure that moves the laser diode up, down, left, and right along the axis so as to maintain communication in an optimal state.

Referring to FIG. 3, the connection between the components will be described. The control unit (500A, 500B) includes a motor unit (300A, 3A).
00B), and is electrically connected so as to be able to receive a feedback signal (this feedback signal may be generated from an encoder via a speed reducer). The photodiode units (200A, 200B) and the laser diode units (100A, 100B) are electrically connected for transmitting and receiving control signals. The motor section (300A, 300B) and the reduction gear section (400A, 400B)
(400A, 400B), mechanically connected around the shaft so that the control angle (shaft rotation angle) of the motor unit can be finely adjusted. The reduction gear unit (400A, 400B) is a laser diode unit (100A, 100B) via a mechanism that moves vertically and horizontally according to the rotation angle of the reduction gear unit (400A, 400B).
When the control unit (500A, 500B) sends a pulse control signal to the motor unit (300A, 300B), the motor unit is driven (the shaft rotates), and thereby the mechanism moves horizontally and vertically, respectively. Depending on the body, the laser diode (1
00A, 100B) can be changed. The photodiode units (200A, 200B) have their positions fixed forward, and convert laser signals into electric signals under the control of the control units (500A, 500B).

The operation of each component according to the present invention will be specifically described.
When a laser signal is transmitted from (00A) to the laser communication system (600B), an electric signal input to the laser communication system (600A) is input to the laser diode unit (100A), and the laser diode unit (100A) , Control unit
(500A) converts the input signal into a laser signal of a certain level, and emits a laser through a transmission lens (not shown). The laser signal includes information on the position of the laser diode unit (100A) as well as the converted input signal.

The emitted laser signal is input to a photodiode unit (200B) of a laser communication system (600B) and reconverted into an original electric signal. The converted input signal included in the signal is combined with the laser signal. Diode part (100A)
Is reproduced by the control unit (500B). At this time, the photodiode unit (200B) is fixed, and the laser emitting direction of the laser diode unit (100A) is controlled by the motor unit (300A) and the reduction gear unit (400A). The motor section (300A, 300B) uses a stepping motor,
It is driven by a pulse signal received from the control unit (500A). At this time, two motors are used, one for up and down control and one for left and right control.

One of the reduction gear unit (400A) is a motor unit (300A)
And the other is moved up and down and left and right, respectively, to adjust the laser emission angle of the laser diode unit (100A). Actually, when there is no speed reducer (400A), the fine adjustment of the angle of the laser diode (100A) must be performed in the motor (300A) itself. There is a disadvantage that it becomes.

The photodiode section (200B) receives the laser beam generated and emitted by the laser diode section (100A) on the other side and converts it into an electric signal. At this time, although the level changes due to the strength of the received signal, a constant level is always maintained by the AGC circuit (which is included in the photodiode unit but may be included in the control unit). Is done. When there is a change in the signal level of the received laser signal, the difference in the level is detected by the AGC circuit, and the detection signal is transmitted to the control unit (500B).

The control unit (500B) constantly monitors the intensity of the light received by the photodiode unit (200B) based on this signal. The control unit (500B) includes a laser diode interface (502B) used to notify the control unit (500A) of its own state to the other control unit, a motor interface (504B) for operating the motor, and a photodiode unit. Equipped with a photodiode interface (506B) that monitors the light detection value and monitors the alarm status, comprehensively analyzes the above conditions and operates the motor, and the laser beam is accurately transmitted to the receiver (200A) on the other side. It is configured to be able to receive.

The light output of the laser diode unit (100B) is monitored via the photodiode unit (200A), the received level is monitored, and data is transmitted to the equipment of the other party when an alarm condition occurs. When the light intensity below the set level is detected or communication failure with the other party occurs,
You will try to auto-align.

Hereinafter, the above-described auto-alignment method will be described in detail with reference to FIGS. FIG.
FIG. 5 is a flowchart illustrating a method of performing auto-alignment of an optical axis according to the present invention. FIG. 5 is a diagram illustrating scanning of a laser beam in the entire region, FIG. 6 is a diagram illustrating scanning locally adjusting a laser beam, and FIG. FIG. 3 is a view showing fine adjustment scanning of a laser beam. Before describing the method of performing the auto-alignment of FIG. 4, terms used particularly in the auto-alignment method according to the present invention will be described.

First, the coordinate initialization step (S622) refers to a step in which the range that can be moved by the motor unit of the laser diode determined during the design and production of the system is set by the control unit or manually. I do. That is, when the apparatus is turned on, at this stage, the current position of the laser diode unit and the movable range are calculated as rectangular coordinate values.

The global adjustment step (S650) is a step of scanning and searching the entire range in which the laser diode can move when communication with the other party is not performed.

In the local adjustment step (S640), the whole area adjustment step is performed.
This is a stage in which adjustment is performed more finely than (S650) and in a wider range than the fine adjustment stage (S630) described later.

Finally, the fine adjustment step (S630) refers to a step of performing adjustment while moving very finely in order to search for an optimal alignment state.

Hereinafter, a method of performing auto-alignment according to the present invention will be described with reference to FIG. 4 (a success and a failure referred to below mean that communication is performed in a good state and that communication is not performed, respectively). Means.).

When the power of the laser communication system is turned on (S610), it is determined whether the coordinate values of the movable range of the laser diode units (100A, 100B) and the current position are calculated as rectangular coordinate values (that is, coordinate setting is not performed). Is determined) (S620).

If the coordinates have been set, the process proceeds to a step (S624) of judging whether the signal output of the receiving section satisfies a predetermined value, otherwise, the coordinates initialization step Proceed to (S622). In the coordinate initialization stage (S622),
Laser diode section (100A, 100B) is motor section (300A, 300B
The range that can be moved according to B) and the current position are calculated as rectangular coordinate values. This calculation is performed by the control unit (500A, 500A
B) Laser diode interface (502A, 502
B).

If such coordinate setting is not performed, it is recognized that a problem has occurred in the motor units (300A, 300B). However, if the coordinate setting is performed, the process proceeds to a step of determining whether the signal output of the receiving unit satisfies a predetermined value (S624). In the step (S624), it is determined whether or not the electric signal in the receiving unit satisfies a predetermined power value.If the electric signal is equal to or more than the predetermined power value, it is determined that the optical axis adjustment is not necessary. Because there is
It is not necessary to perform an auto-align operation. However, if the predetermined power value has not been reached, in order to perform the auto-alignment operation, the process is performed in a fine adjustment step (S
Proceed to 630).

In the fine adjustment step (S630), as shown in FIG. 7, scanning is performed while finely moving the laser diode units (100A, 100B) vertically and horizontally to control the position where the signal level is maximum. (500A, 500B) and search and position setting.

If the fine adjustment is performed so as to be successful, which means that the two-way communication is good, the auto-align operation is completed (S660), and the control unit (500)
A, 500B) recognizes this and performs only monitoring of the communication state.

If the fine adjustment is not performed to be successful, the process proceeds to the local adjustment step (S640), where a wider range of scanning is performed. That is, as shown in FIG. 6, a wider range is scanned through a path different from the fine adjustment.

If the local adjustment is successful, the process returns to the fine adjustment step (S630) to perform the fine adjustment. If the local adjustment fails, the process proceeds to the global adjustment step (S630). Proceed to S650). As shown in FIG. 5, global adjustment scans a wider area through a different path than fine or local adjustment. In this global adjustment stage (S650), communication must be performed (ie, must be successful), so that the scanning range is considerably widened. Even if the global adjustment fails, there is no further progression stage, and the entire area is scanned until communication is performed (until successful). If successful, the process proceeds to the local adjustment stage (S640), and as a result, Then, the above steps are repeated to complete the auto-align operation (S660).

However, if the power level of the laser signal received by the other party decreases below the reference value even after the completion of the auto-alignment, the fine adjustment step (S63) is performed.
0) to perform fine adjustment, if the other party does not receive a laser signal, proceed to the local adjustment step (S640), by repeating the flow of the above steps again, the laser communication of the present invention The system (600A, 600B)
A good communication state can always be maintained via the auto-align.

In the following, the operation of the device for correcting a twist (displacement) in the direction of the laser communication device due to an external force or the like in the laser communication system will be described with specific examples. Here, two situations in which auto-alignment must be performed in a laser communication system are assumed and described with examples.

First, when transmission is possible but reception is not possible, or when reception is possible but transmission is not possible (that is, when communication is performed only in one direction), and second, transmission and reception are both performed. For the sake of simplicity, the former is referred to as a first case, and the latter is referred to as a second case.

The auto-align operation of the laser communication system according to the present invention in the first case will be described. Also,
In the following description, the first laser communication system (600
A) and the second laser communication system (600B) have the same configuration, and the components of the first laser communication system (600A) are "first" for simplicity of explanation. The prefix (for example, the first control unit (500A), the first laser diode unit (100A)), the second laser communication system (600
Components of B) are prefixed with “second” (for example, a second control unit (500B), a second laser diode unit).
(100B)).

The first laser communication system (600A) and the second
Considering the case where the first laser communication system (600B) communicates with each other, the first laser communication system (600B)
In A), it is assumed that the optical axis is twisted to some extent due to external force and other factors (that is, in the first laser communication system (600A), reception is good but transmission is bad, and the second laser communication system is poor). In a laser communication system (600B), it is assumed that transmission is good but reception is bad).

In the first case, the amount of light input to the photodiode of the photodiode unit (200B) of the second laser communication system (600B) during communication is significantly reduced or no longer detected. , Built-in
The AGC circuit outputs an electric signal of an amount to be compensated for maintaining the received signal at a constant level, and this output signal is sent to the control unit (500B) via the photodiode interface (506B). Is entered.

The photodiode interface (506B) of the control unit (500B), which constantly monitors the light detection value of the photodiode unit (200B) and monitors the alarm condition, senses that the signal is not received, and For the laser communication system (600A), the fact that the first laser communication system should perform auto-alignment is transmitted as an information signal included in the laser signal.

Thereafter, the first laser communication system (600
The photodiode section (200A) of (A) receives this laser signal and controls the control section (500) of the first laser communication system (600A).
The photodiode section interface (506A) of (A) recognizes that the optical axis of the laser diode section (100A) is twisted by a signal transmitted from the second laser communication system (600B), and thereby, during bidirectional communication, Since one-way communication is being performed, it is determined that there is no need to adjust (ie, scan) the entire area, and local adjustment is sufficient. Therefore, the first laser communication system (6
00A) starts local adjustment.

In the local adjustment in the first laser communication system (600A), a motor control signal (pulse signal corresponding to only the rotation angle of the stepping motor) is transmitted to the motor unit (500A) via the motor unit interface (504A) of the control unit (500A). (A), the motor unit (300A) is operated by a control signal (pulse signal), and the scanning direction of the laser diode unit (100A) is shifted left and right within a narrow width by the method shown in FIG. Scanning is performed while reciprocating.

Thereafter, when the optical axes of the first and second laser communication systems start to coincide with each other to some extent through local adjustment (that is, communication with the photodiode unit (200B) on the other side starts), the second laser communication system starts. 1 laser communication system
The controller (500A) of the (600A) progresses from local adjustment to fine adjustment, and the laser diode interface (502A, 50A)
Through 2B), it becomes possible to exchange their own state with each other via laser communication.

The fine adjustment is performed while exchanging the state (light quantity and the position of the laser diode) between each other. In the fine adjustment step, the first laser communication system (600A) emits a laser while scanning, and the photodiode unit (200B) of the second laser communication system (600B), in the manner shown in FIG. The position of the maximum light amount is calculated by measuring the light amount detected from the first laser communication system, and the calculated position is transmitted to the first laser communication system (600A). The diode section (100A) is located at the calculated position.

This fine adjustment step is a step of automatically maintaining an optimum communication state in a state where communication is being performed. Considering the position calculation and the operation of transmitting the calculated position, the first step is as follows. The position of the laser diode unit (100A) of the laser communication system (600A) is transmitted to the control unit of the second laser communication system (600B) via the laser communication, and fine adjustment is performed.
The photodiode unit (200B) of (600B) measures the amount of light and transmits it to the second control unit (500B) via the second photodiode unit interface (506B). The second control unit (5
00B) compares the two pieces of input information with each other while associating the two pieces of information with each other, detects the one with the largest light quantity, and obtains the positional information transmitted corresponding thereto.

Thereafter, the obtained position information is transmitted via data communication to the first laser communication system (600A) requiring position correction. The first control unit (500A) receives the position information via the first photodiode unit (200A),
The first motor unit (300A) is driven via the first motor unit interface (504A) to move and fix the first laser diode unit (100A) to an optimal position. Considering the method of calculating the position information described here, the first laser diode section (100A) moves under the control of the motor section (300A). At this time, the first laser diode section (100A) moves. In 100A), the space that can be moved up, down, left, and right is limited to a rectangular space, but the size of the rectangular space can be changed by a designer. Therefore, the position is calculated using a rectangular coordinate system in which the center of gravity of the rectangular space in which the laser diode part can move is the origin, the left and right are x-axes, and the vertical is the y-axis.

Next, the step of performing auto-alignment in the second case will be described. The second case will further include a global adjustment step compared to the first case. In the global adjustment, since no communication is performed between two laser communication systems that require communication, scanning is performed in a much wider range than the other laser communication systems.

When misalignment occurs between the laser communication systems (600A, 600B), the amount of light input to the photodiodes (200A, 200B) of the first and second laser communication systems (600A, 600B) is detected. And constantly monitor the light detection value of the photodiode section (200A, 200B)
The photodiode interface (506A, 506B) of the control unit (500A, 500B) monitoring the alarm situation senses this, and decides to perform global adjustment.

Thereafter, in both the first laser communication system and the second laser communication system (600A, 600B), the whole area adjustment (ie, the whole area scanning) is started by the respective control units (500A, 500B). The whole area adjustment is performed by the control unit (500A, 50A
0B), a pulse signal for instructing the whole area adjustment is generated, transmitted to the motor unit (300A, 300B) via the motor unit interface (504A, 504B), and the laser diode unit (10
0A, 100B) by controlling the position.

The first laser communication system (600A) and the second
When communication in at least one direction is performed during the bidirectional communication of the laser communication system (600B), that is, the first photodiode unit (200A) or the second photodiode unit (200B).
When the light amount is detected in B), the process returns to the first case, so that the process proceeds to the same local adjustment stage as in the first case, and the same operation as in the first case is performed.

[0060]

As described above, according to the present invention, in a communication system using a laser, a laser beam emitted from a laser diode of a transmitting unit is accurately received by a receiving lens of a receiving unit on the other side. To
The direction of the laser diode in the transmitting section can be automatically adjusted using a motor. Therefore, according to the present invention, the optical axis is caused by various factors such as mechanical sway, expansion and contraction due to temperature change, influence by wind, change due to external impact, etc., which occur when the laser diode of the transmission unit is fixed and used. Can be prevented from changing, and the optical axis is automatically adjusted without being affected by the communication, so that the designer can ensure the stability of laser communication and the ease of initial installation, This also has the effect of reducing maintenance for inputting and adjusting human power.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a conventional laser communication system.

FIG. 2 is a diagram showing a calculation related between an angle error of an optical axis and a distance error in a laser communication system.

FIG. 3 is a block diagram schematically showing a configuration of a laser communication system according to the present invention.

FIG. 4 is a flowchart illustrating a method of performing auto-alignment of an optical axis according to the present invention.

FIG. 5 is a diagram showing scanning for adjusting the entire area of a laser beam.

FIG. 6 is a diagram showing local adjustment scanning of a laser beam.

FIG. 7 is a diagram showing fine adjustment scanning of a laser beam.

[Explanation of symbols]

 100A, 100B Laser diode section 200A, 200B Photodiode section 300A, 300B Motor section 400A, 400B Reduction gear section 500A, 500B Control section 600A, 600B Laser communication system

Claims (5)

[Claims] A first laser beam receiving means for receiving a first laser beam;
A first laser receiving unit (200A) for converting the
A first laser communication system (600A) having a first laser transmitter (100A) for emitting a laser beam, and a second laser beam receiving the second laser beam. A second laser receiving unit (200B) that converts the signal into a third signal; and a second transmitting unit (100B) that converts the fourth signal into the first laser beam and emits a laser beam. 2 laser communication system (600B)
The first laser communication system (600A) includes: a motor adjustment unit (300A, 400A) that adjusts a position of the first laser transmission unit (100A) by a motor; A control unit (500A) that monitors the state of communication with the second laser communication system (600B) by the output signal of the first laser receiving unit (200A) and controls the motor adjustment unit (300A, 400A). The optical axis of the first laser transmitting unit (100A) is shifted from the optical axis of the second laser receiving unit (200B), and the first laser communication system (600A) and the second If communication failure occurs between the laser communication system (600B)
(500A) is based on the output signal of the first laser receiving unit (200A), by driving the motor adjustment unit (300A, 400A), the first laser transmission unit (100A),
While being positioned along a predetermined direction, the second laser beam is emitted, and the first laser transmitting unit (100A) with respect to the optical axis of the fixed second laser receiving unit (200B) is emitted. A laser communication system which automatically adjusts a shift of an optical axis. 2. The laser communication system according to claim 1, wherein the motor adjustment unit (300A, 400A) reduces the speed of the motor in conjunction with the motor, and finely adjusts the movement of the laser transmission unit. A laser communication system, further comprising a speed reducer unit (400A) for adjusting. 3. The laser communication system according to claim 1, wherein the first laser transmission unit (100A) can freely move up, down, left, and right by the motor adjustment unit (300A, 400A). The laser communication system according to claim 1, wherein the predetermined direction in which the first laser transmission unit (100A) is moved is an arbitrary direction based on the combination of up, down, left, and right. 4. The laser communication system according to claim 1, wherein said laser beam is supplied to said laser transmitting unit.
(100A, 100B) position information and the laser receiver (200A, 2
A laser communication system comprising information on the amount of light of 00B). 5. The laser communication system according to claim 4, wherein said position information is transmitted to said laser transmitting unit (100A, 10A).
0B) is obtained by rectangular coordinates formed in a rectangular area moved and moved by the motor units (300A, 300B).