JPH09107330A - Optical transmitter-receiver, optical axis alignment method therefor and optical radio system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical axis alignment method for an optical transmitter-receiver in which optical axis alignment for communication light with directivity sent by optical transmitter-receiver sets is easily attained. SOLUTION: A master set 15 is provided with a communication use light emitting section 21 for usual optical communication and a search use light emitting section 22 to provide an output of a light with a wide directive angle for optical axis adjustment. In order to start the optical alignment of a slave set 16, the search use light emitting section 22 of a master set 15 is lighted to conduct optical axis alignment of the slave set 16 by using the light with the wide directive angle. Then idle lights sent from communication use light emitting sections 21 of the master set 15 and the slave set 16 are used to adjust the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transceiver for easily adjusting an optical axis, an optical axis adjusting method for an optical transceiver, and an optical wireless system.

[0002]

2. Description of the Related Art An optical wireless system is widely used in which optical transceivers having directivity are opposed to each other in a one-to-one manner and optical communication is performed between them. In the optical wireless system, as shown in FIG. 14, when the two optical transceivers 50A and 50B have the same communication direction (hereinafter referred to as an optical axis), communication is possible. As shown, if the optical axes of the optical transceivers 50A and 50B and the optical axis of the other optical transceiver 50 do not match, communication becomes impossible.

Therefore, in the optical wireless communication system, FIG.
As shown in FIG. 4, it is necessary to adjust the optical axes of the respective optical transmitters / receivers 50 so as to face each other in the communication direction.

The adjustment of the optical axis of the optical wireless communication system is generally performed in the following procedure. First, while transmitting an optical signal from one optical transceiver 50A, its optical axis is changed, and one optical transceiver 50A is temporarily fixed in a state where the receiving sensitivity of the other optical transceiver 50B is highest. Next, while transmitting an optical signal from the other optical transceiver 50B, its optical axis is changed, and the other optical transceiver 50B is temporarily fixed in a state where the receiving sensitivity of the one optical transceiver 50A is the highest. After the optical axes of the optical transmitters / receivers 50A and 50B are aligned in this way, both optical transmitters / receivers 50A and 50B are firmly fixed.

Generally, the adjustment of the optical axis of the optical transmitter / receiver 50 having directivity becomes more delicate as the directivity becomes stronger,
Manual adjustment also increases the time required for adjustment. In particular, in the case of the optical transmitter / receiver 50 having a strong directivity such that the directivity angle θ is several degrees or less, it is very difficult to manually adjust the optical axis.

In order to solve this problem, a technique for automatically adjusting the optical axis is disclosed in Japanese Patent Application No. 4-304638 and Japanese Patent Application No. 5-304638.
No. 277854 is proposed. According to the present invention, the installation time of the optical transmitter / receiver 50 is shortened, and the person who does not have the optical axis adjustment technique can install the optical transmitter / receiver 50.

[0007]

However, even if the optical axis adjustment itself is automated, it is necessary to manually signal the start of the optical axis adjustment. Further, regardless of whether or not the optical axis adjustment is automatically performed, it is necessary to perform the optical axis adjustment once for each of the one optical transmitter / receiver and the other optical transmitter / receiver, for a total of two optical axis adjustments.

Therefore, the following problems occur.
In the following description, in order to facilitate understanding, one of the pair of optical transceivers 50 is the master device 50A and the other is the slave device 50.
The operation of matching the optical axis by searching for the location of the communication partner is referred to as search.

(1) The initial search is difficult. When the optical axis of the child device 50B is directed to the parent device 50A in the first search, if the child device 50B exists within the directivity angle θ of the parent device 50A, as shown in FIG.
The light from can be received. However, as shown in FIG. 15, when the child device 50B is located outside the directivity angle θ of the parent device 50A, the child device 50B cannot find the direction of the parent device 50A.

As described above, the optical axis of the master unit 50A is the slave unit 50.
It is a prerequisite for adjusting the optical axis that the direction B is aligned to some extent. However, since the directivity angle θ of the master device 50A is small, it is difficult to align the optical axis of the master device 50A with the slave device 50B. The same problem occurs when the optical axes of the master unit 50A and the slave unit 50B are once aligned and then the optical axes are displaced for some reason, and the optical axes are adjusted again.

(2) The accuracy of the optical axis adjustment is limited. When each of the search for the master device 50A and the slave device 50B is performed once, the optical axis of the slave device 50B is matched with the optical axis of the master device 50A, and then the optical axis of the master device 50A is aligned with the optical axis of the slave device 50B. Will match. For this reason, after adjusting the optical axis of the slave unit 50B, the optical axis of the master unit 50A is moved, and strictly speaking, the optical axes of the slave unit 50B and the master unit 50A do not match.

(3) The entire search operation of a plurality of times is not automated. Further, the entire optical axis adjustment process is not automated. Therefore, if the number of searches is increased in order to improve the adjustment accuracy, the time and effort for the adjustment are increased. Will increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical transceiver capable of automating optical axis adjustment, an optical axis adjusting method, and an optical wireless system.
Another object of the present invention is to provide an optical transceiver capable of easily and accurately adjusting the optical axis, an optical axis adjusting method, and an optical wireless system.

[0014]

In order to achieve the above object, the optical axis adjusting method for an optical transmitter / receiver according to the first aspect of the present invention is directed to a communication light having directivity emitted by each optical transmitter / receiver. In an optical axis adjusting method of an optical transmitter / receiver for performing optical axis alignment, one optical transmitter / receiver emits search guide light having a larger directivity angle than the communication light, and the other optical transmitter / receiver is aimed at the search guide light. Is to perform the first optical axis adjustment.

The optical axis adjusting method for an optical transmitter / receiver according to a second aspect of the present invention is an optical axis for an optical transmitter / receiver for performing optical axis alignment of communication light having directivity generated by each optical transmitter / receiver. In the adjusting method, one optical transceiver emits light of a specific pulse pattern having a larger directivity angle than the communication light, and the other optical transceiver starts optical axis adjustment by receiving the light, and the other. Optical transmitter / receiver emits light, and one optical transmitter / receiver receives light from the other optical transmitter / receiver to adjust the optical axis between both optical transmitters / receivers, and the optical axis adjustment reaches a predetermined level. At this stage, light having a pulse pattern having a waveform different from that of the light having the specific pulse pattern is transmitted to the other party, and the optical axis adjustment is completed.

The optical axis adjusting method for an optical transmitter / receiver according to a third aspect of the present invention aligns the optical axis of communication light intensity-modulated with a predetermined frequency having directivity emitted by each optical transmitter / receiver. In the optical axis adjusting method for an optical transmitter / receiver that performs a plurality of times, the optical axis of the communication light between the optical transmitters / receivers is set to a target with a search guide light having a larger directivity angle than the communication light emitted by the optical transmitter / receiver. In addition to the adjustment, the frequency of the intensity modulation of the communication light is switched between the transmitting side and the receiving side each time the optical axes are adjusted.

An optical transmitter / receiver according to a fourth aspect of the present invention is a communication light emitting section for emitting communication light having a predetermined directivity angle, and a search guide having a larger directivity angle in the optical transmitter / receiver than the communication light. A search light-emitting unit that emits light, a light-receiving unit that receives external light, the search light-emitting unit emits light when the optical axis is adjusted, and the communication light-emitting unit emits light when communicating to adjust its own optical axis. And a control unit for integrally controlling the directing directions of the communication light emitting unit, the search light emitting unit, and the light receiving unit so that the amount of light received by the light receiving unit is maximized.

An optical transmitter / receiver according to a fifth aspect of the present invention is an optical wireless transmitter / receiver for performing optical wireless communication between optical transmitters / receivers by performing optical axis alignment of communication light having directivity emitted from each other. In the system, the optical transmitter / receiver is provided with a search light emitting section for emitting search guide light having a larger directivity angle than the communication light and a search light receiving section for receiving light from the other party, and the other party's search light emitting section emits light. The optical axis of the communication light between the optical transmitters and receivers is adjusted by receiving the search guide light by the light receiving unit for search.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An optical transceiver, an optical axis adjusting method, and an optical wireless system according to embodiments of the present invention will be described in detail below.

(First Embodiment) FIG. 1 shows a configuration example of an optical wireless system according to an embodiment of the present invention. This communication system includes a cable 11 and a plurality of LAN connection devices 13 connected to the cable 11 and having a communication function.
A cable 12, a plurality of LAN connection devices 14 connected to the cable 12 and having a communication function, and a cable 11.
And a second optical transceiver 16 connected to the cable 12, and a part of the wired LAN is connected to the first optical transceiver 15 and the second optical transceiver. It has a configuration in which it is replaced with an optical wireless LAN composed of the device 16.

The first optical transceiver 15, as shown in FIG. 2 (A), a communication light emitting section 21 for outputting an optical signal for optical communication directivity angle theta _0, greater than the directivity angle theta ₀ The light emitting unit 22 for searching, which emits the search guide light SG for adjusting the optical axis having the directivity angle θ ₁ , and the light receiving unit 23 are provided. As shown in FIG. 2B, the second optical transmitter / receiver 16 includes a communication light emitting unit 21 that outputs an optical signal for optical communication with the directivity angle θ ₀ , and a light receiving unit 23.

As shown in FIG. 3, the first optical transceiver 15 includes a CPU 31, a memory 32, a communication control unit 33, and
It is composed of a stage 34, a stage drive unit 35, a driver circuit 36, and an internal bus 37.

The CPU 31 performs a search operation (optical transmitter / receiver 15) which will be described later in accordance with a program stored in the memory 32.
And 16 optical axis aligning operations) and communication operations are controlled. The memory 32 stores the operation program of the CPU 31 and the like.
The communication control unit 33 controls data communication between the cable 11 and the optical transmitter / receiver 15. The communication light emitting unit 21, the search light emitting unit 22, and the light receiving unit 23 are fixed to the stage 34. The stage drive unit 35 adjusts the orientation of the stage 34 under the control of the CPU 31 so that the optical axes of the communication light emitting unit 21, the search light emitting unit 22, and the light receiving unit 23 (hereinafter, simply referred to as optical axes). Scan in the X-axis and Y-axis directions. Under the control of the CPU 31, the driver circuit 36 drives (lights) the communication light emitting unit 21, drives the search light emitting unit 22, and sends the reception signal of the light receiving unit 23 to the communication control unit 33 via the internal bus 37. Forward.

The second optical transmitter / receiver 16 has substantially the same structure as the first optical transmitter / receiver 15 shown in FIG. 3 except that the search light emitting section is not provided.

Next, the operation of the optical transmitters / receivers 15 and 16 having such a configuration will be described. During normal operation, the CPU 31 of the optical transmitter / receiver 15 or 16 drives the communication light emitting unit 21 via the driver circuit 36 and opposes the signals supplied from the lines 11 and 12 via the communication control unit 33 to the opposite light source. It transmits to the transceivers 16 and 15. Further, the light receiving section 23 receives the optical signal transmitted from the optical transceivers 16 and 15 which face each other, and transfers this to the lines 11 and 12 via the communication control section 33.

Next, the operation and procedure for aligning the optical axes of the optical transceivers 15 and 16 will be described with reference to the flowchart of FIG. In the following description, the first optical transmitter / receiver 15 is used as a master device, the second optical transmitter / receiver 16 is used as a slave device, and a search is made for an operation in which the communication partner is located and the optical axis is aligned with that direction. To call.

First, the CPU 31 of the master device 15 is instructed to start the optical axis adjustment processing by an external switch or the like (not shown). In response to this instruction, the CPU 31 of the parent device 15 turns on the search light emitting section 22 via the driver circuit 36 and turns on the search guide light SG (step S1). Since the directivity angle θ1 of the search guide light SG is large, if the orientations of the master unit 15 and the slave unit 16 are adjusted to some extent, the slave unit 16 can receive the search guide light SG as shown in FIG.

The CPU 31 of the slave unit 16 is also instructed to start the optical axis adjustment processing by an external switch or the like (not shown). In response to this instruction, the CPU 31 of the child device 16 starts the search operation. That is, the stage drive unit 35 causes the stage 34
Is scanned, and the optical axis of the handset 16 is controlled so that the amount of light received by the light receiving unit 23 is maximized (step S2). In this state, as shown in FIG. 5, the optical axis of the slave unit 16 substantially coincides with the direction of the master unit 15.

Next, the search light-emitting unit 22 of the master unit 15 is turned off, the communication light-emitting unit 21 of the slave unit 16 is turned on, and the light intensity modulated (IM) at a specific frequency (hereinafter referred to as idle light). Call I is transmitted (step S3). The CPU 31 of the parent device 15 performs a search operation and controls the tilt angle of the stage 34 via the stage driving unit 35 so that the amount of light received by the light receiving unit 23 is maximized, and the optical axis of the parent device 15 is set to the child device 16.
Is adjusted so as to face (step S4).

With the above processing, as shown in FIG.
The optical axis of 5 and the optical axis of the handset 16 are substantially aligned.
Next, the communication light emitting unit 21 of the master device 15 is turned on to transmit the idle light I (step S5). CPU of handset 16
Reference numeral 31 controls the tilt angle of the stage 34 via the stage drive unit 35 so that the amount of light received by the light receiving unit 23 becomes maximum, and adjusts the optical axis of the slave unit 16 to face the direction of the master unit 15 ( Step S6).

After that, when the same operation is repeated a predetermined number of times, the optical axis adjusting process is ended.

As described above, according to the communication system of this embodiment, since the search light-emitting section 22 of the master unit 15 transmits the search guide light SG having a large directivity angle, the master unit is adjusted when the optical axis is adjusted. The process of matching the optical axes of 15 and the slave unit 16 to each other to some extent can be simplified, and the optical axis adjustment process can be easily performed.

In the above description, the base unit 1 is searched in the first search.
Although only the search light emitting section 22 of No. 5 is turned on, both the search light emitting section 22 and the communication light emitting section 21 may be turned on. In this case, the optical axis of the slave unit 15 can be roughly adjusted by the search guide light SG, and then the optical axis of the slave unit 16 can be relatively accurately aligned with the master unit 15 by using the idle light I.

(Second Embodiment) Master device 15 and slave device 16
When the optical axis of the slave unit 16 and the optical axis of the slave unit do not match, or when the matched optical axes of the slave unit 16 do not match, the idle light I from the communication light receiving and emitting unit 21 of the slave unit 16 is Since the light emitting unit 23 of 15 does not reach, the parent device 15 cannot detect the idle light I from the child device 16. Therefore, the master unit 15 and the slave unit 16
It is impossible to communicate with and the optical axis must be adjusted. Therefore, when the light receiving unit 23 of the parent device 15 cannot receive the idle light I from the child device, the search light emitting unit 22 may be forced to emit light.

In this case, the CPU 31 of the base unit 15 monitors the output signal of the light receiving unit 23 via the driver circuit 36, and when the received signal level of the light receiving unit 23 falls below a predetermined threshold value, the driver circuit 36 is driven. The search light emitting section 22 is caused to emit light via the light source.

Thus, when the optical axes do not match,
By forcibly emitting the search guide light SG, the optical axis adjustment process can be directly started on the slave unit 16 side. Further, when the optical axes are coincident with each other and communication is performed between the master unit 15 and the slave unit 16, the search guide light SG is not emitted, and the communication is not hindered.

(Third Embodiment) In the first embodiment, the communication light emitting section 21 and the search light emitting section 22 of the parent device 15 are separately arranged. The light emitting unit 22 may be shared.

FIG. 7 shows an example of the structure of a shared light emitting section, which is composed of a light emitting element 41, an optical system 42 including lenses, and a control section 43. During optical communication between the master unit 15 and the slave unit 16, the control unit 43 controls the optical system 42 to generate the idle light I having the directivity angle θ ₀ . On the other hand, during the optical axis adjustment (or during non-communication), the CPU 31 controls the optical system 42 via the driver 36 to widen the directivity angle θ1 (widen the directivity) to generate the search guide light SG. .

(Fourth Embodiment) In the first embodiment, although the optical axis of the handset 16 is aligned with the handset 15 after the first search for the handset 16 is completed, The optical axis of the base unit 15 is not yet aligned with the handset unit 15. Therefore, the receiving unit 23 of the parent device 15 may not be able to receive the idle light from the child device 16. In order to solve this problem, as shown in FIG. 8, a light receiving unit 24 having a wide directivity angle for searching may be arranged in the base unit 15 separately from the light emitting unit 23. By arranging the search light receiver 24, after the first search operation of the slave unit 16 is completed, as shown in FIG.
4 can be received. That is, the idle light I from the slave unit 16 can be obtained by performing the search operation of the slave unit 16 only once.
Can be received by the master unit 15 whose optical axis does not match the slave unit 16. Therefore, using this received signal, the base unit 1
It is possible to automatically start the operation of aligning the optical axis of 5 with the slave unit 16.

(Fifth Embodiment) In the first to third embodiments, it is necessary to individually activate each search operation in the master unit 15 and the slave unit 16. However, a series of search operations is performed. Can be automatically continued. Below, base unit 1
A system will be described in which the search operations of the slave unit 5 and the slave unit 16 are continued a plurality of times, and the search is terminated when the optical axes match each other with a certain degree of accuracy.

In this example, the slave unit 15 (or the master unit 16)
The master unit 16 (or the slave unit 15) sends a predetermined first pulse pattern by turning on / off the idle light I shown in FIG. 10 to notify the other party of the end of the search operation. In addition, when a plurality of searches are performed and the optical axes match with each other with a certain degree of accuracy, the second pulse pattern shown in FIG. 11 is transmitted to notify the other party of the end of the optical axis adjustment processing. This second
The ON / OFF cycle of the pulse pattern is sufficiently shorter than the ON period of the first pulse pattern, and can be easily identified.

A series of optical axis adjusting operations in this case will be described with reference to FIG. First, the master unit 15 and the slave unit 16 are externally instructed to start the optical axis adjustment processing. Respond to this instruction,
The CPU 31 of the parent device 15 controls the driver 36 to transmit the search guide light SG (step T1). On the other hand, the CPU 31 of the child device 16 controls its optical axis so that the intensity of the received light becomes the strongest (step T2). Cordless handset 16
When the search operation is completed, the CPU 31 drives the driver circuit 36 to transmit the idle light I including the first pulse pattern shown in FIG. 10 to the communication light emitting section 21 (step T3).

After emitting the search guide light SG, the CPU 31 of the base unit 15 compares the reception level of the light receiving section 23 with a predetermined threshold value, and waits for reception of the first pulse pattern shown in FIG. (Step T4). When it is determined in step T4 that the first pulse pattern has been received, the CPU 31 of the master device 15 turns off the search guide light and then starts the search operation using the idle light I from the slave device 16 (step T5). ).

Thereafter, the same operation is repeated to improve the alignment accuracy of the optical axis. The search operation is executed multiple times, and the base unit 1
When the optical axes of 5 and the slave unit 16 match with each other with a predetermined accuracy (when the search operation is performed a predetermined number of times), the CPU 31 of the master unit 15
The communication light emitting section 21 is caused to transmit the second pulse pattern, which is the end signal of the optical axis alignment, through the driver circuit 36 (step T6).

Subsequently, the CPU 31 of the base unit 15 shifts to the operation of normal optical communication processing (step T7). In addition, child unit 1
The CPU 31 of No. 8 detects the second pulse pattern in the output signal of the light receiving unit 23, determines that a series of optical axis adjustment processing is completed (step T8), and shifts to normal optical communication processing operation ( Step T9).

With such an operation, the subsequent series of optical axis aligning processes can be automatically executed only by giving an instruction at the time of starting the optical axis aligning process, and can be automatically ended under a certain condition. .

(Sixth Embodiment) Even if the base unit 15 does not have a light receiving section for searching, which has a wide directional angle, the base unit 15
If the signal for the first search operation of 1 is manually performed, the subsequent search operations of the master unit 15 and the slave unit 16 can be automatically started.

(Seventh Embodiment) In the fifth embodiment, when the search light-emitting unit 22 and the communication light-receiving / light-emitting units 21 and 23 shown in FIG. 2 cannot be arranged concentrically, the master unit 15
When the optical axis of the slave unit 16 is directed to the slave unit 16 and the optical axis of the slave unit 16 is deviated from the master unit 15, the slave unit 16 executes the first search, and then the master unit 15 is first searched. The pulse pattern is transmitted, and the system enters the state of waiting for the end of the search of the master device 15.
However, because the optical axis of the base unit 15 is aligned with the handset 16,
When the level of the light received by the handset 16 exceeds the threshold value, the handset 16
Starts the second search. When the search for the predetermined number of times is completed, the slave unit 16 transmits the second pulse pattern to the master unit 15 and shifts to the normal communication state.

However, since the slave unit 16 searches twice for the search light emitting unit of the master unit 15, the communication light of the slave unit 16 hits the communication light receiving unit 23 of the master unit 15. I can't communicate. After that, the master unit 1 is manually operated.
5 does not receive the search termination signal of the handset 16 after the search operation is completed, even if the search operation is performed on the 5 unit (already sent)
As a result, communication is still not possible. That is, a sequence omission occurs in which only the slave unit continuously performs the search without waiting for the search of the master unit.

In order to solve this problem, the intensity of the idle light I is modulated by the master unit 15 and the slave unit 16 at different frequencies, and the transmission frequency and the reception frequency are exchanged each time one search is completed. The method is effective. With such a configuration, for example, when the first search for the slave 16 is completed, the transmission frequency of the slave 16 is switched and the master 1
Since it is different from the reception frequency of No. 5, it is possible to prevent the situation of starting the second search. Then, by the second pulse pattern signal indicating the end of the search, the original modulation and demodulation frequency is restored.

The operation of the communication system having such a configuration will be described with reference to FIG. In this example, the number of searches is one for the master unit 15 and two for the slave unit 16, the master unit 15 does not have the search light-receiving unit 24, and the first search of the master unit is manually started. Shall be. Further, f1 and f2 represent the intensity modulation frequencies of the idle light I and the search guide light.

First, the optical axes of the master unit 15 and the slave unit 16 coincide with each other, the master unit 15 transmits the idle light and the search guide light intensity-modulated at the frequency f2, and the slave unit 16 intensity-modulates at the frequency f1. It is assumed that, for some reason, only the optical axis of the handset 16 is shifted while the idle light is being transmitted.

In this case, since the optical axis of the slave unit 16 does not face the master unit 15, the master unit 15 cannot receive the idle light from the slave unit 16 and emits the search guide light SG (step P1). This search guide light SG is also an optical signal whose intensity is modulated at the frequency f2. The handset 16 executes the first search in response to a manual operation or the like (step C1).
When the search is completed, the child device 16 sets the modulation frequency of the idle light to be transmitted to f2 and the modulation frequency of the received light to f1. Then, it enters into a state of waiting for the end of the search of the master device 15 (step C2).

On the other hand, on the side of the base unit 15, the operator visually judges that the search operation of the handset 16 is completed, and in response to a manual operation, the modulation frequency of the idle light to be transmitted is set to f.
1, the master device 15 starts the search operation with the modulation frequency of the received light being f2 (step P2). When the search operation is completed, the master device 15 transmits the first pattern pulse to the slave device 16 and waits for the completion of the search operation of the slave device.

Since the first pulse pattern from the master unit 15 has the modulation frequency f1, it is received by the slave unit 16, and the slave unit 16 starts the second search operation (step C).
3).

When the second search is completed, the slave unit 16 transmits a second pulse pattern signal indicating the end of the search to the master unit 15 (step C4). Further, the idle light transmission frequency (amplitude modulation modulation frequency) is switched to f1 and the idle light reception frequency (amplitude modulation modulation frequency) is switched to f2 (step C4) to receive the communication optical signal from the master unit 15. Stand by (step C5).

The master unit 15 responds to the second pulse pattern from the slave unit 16 and sets the transmission frequency of the idle light to f2.
The reception frequency is changed to f1 and the reception of a communication optical signal from the handset 16 is awaited (step P4).

According to such a configuration, since the reception frequency and the transmission frequency of the idle light are changed for each search operation, the sequence omission can be prevented and the optical axis can be adjusted appropriately.

The present invention is not limited to the above embodiment, and various modifications and applications are possible. For example, the optical communication LAN system shown in FIG. 1, the external configuration of the optical transceiver shown in FIG. 2, the circuit configuration of the optical transceiver shown in FIG. Can be changed to. In addition, in the seventh embodiment,
Although the modulation frequency is changed for each search operation, the light frequency itself may be changed.

[0060]

According to the present invention, it is possible to easily adjust the optical axes of the optical transmitters / receivers using the light for adjusting the optical axes having a wide directional angle, and to automate the adjustment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an optical communication system according to a first embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing external configurations of the first and second optical transceivers shown in FIG. 1, respectively.

FIG. 3 is a block diagram showing a circuit configuration of a first optical transceiver shown in FIG.

FIG. 4 is a flowchart illustrating a procedure of optical axis adjustment processing according to the first embodiment.

FIG. 5 is a diagram for explaining a search operation of a child device.

FIG. 6 is a diagram for explaining a search operation of a parent device.

FIG. 7 is an explanatory diagram showing a structure of a light emitting unit and a directivity angle of transmitted light according to a third embodiment.

FIG. 8 is a diagram showing an external configuration of an optical transceiver according to a fourth embodiment.

FIG. 9 is an explanatory diagram showing a search state of the optical transceiver according to the fourth embodiment.

FIG. 10 is a diagram showing a first pulse pattern signal indicating the end of each search operation.

FIG. 11 is a diagram showing a second pulse pattern signal indicating the end of a series of search operations.

FIG. 12 is a sequence diagram showing a procedure of a search operation in the fifth embodiment.

FIG. 13 is a sequence diagram showing a procedure of a search operation in the seventh embodiment.

FIG. 14 is an explanatory diagram showing a communicable state between conventional optical transceivers.

FIG. 15 is an explanatory diagram showing a communication impossible state between conventional optical transceivers.

[Explanation of symbols]

 15 Optical Transceiver (Master Unit) 16 Optical Transceiver (Slave Unit) 21 Communication Light Emitting Section 22 Search Light Emitting Section 23 Light Receiving Section 24 Search Light Receiving Section 41 Light Emitting Element 42 Optical System I Idle Light SG Search Guide Light

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Nomoto 3-3 Toyosu, Koto-ku, Tokyo NTT Data Communications Co., Ltd. (72) Inventor Yoshinori Masumoto Toyosu, Koto-ku, Tokyo 3-3, NTT DATA Communications Co., Ltd. (72) Inventor Mika Iida 3-3-3, Toyosu, Koto-ku, Tokyo NTT DATA Communications Corporation (72) Inventor Masahiro Watanabe 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Victor Company of Japan, Ltd. (72) Inventor Yukitsu Sakurai 3-12 Moriya-cho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture (72) Inventor, Japan Takami Shiramizu 3-12 Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Japan Victor Company of Japan, Ltd. (72) Inventor Naoki Yamashita, next to Kanagawa 3-12 Moriya-cho, Kanagawa-ku, Hama-shi Victor Company of Japan, Ltd.

Claims (12)

[Claims] 1. A method of adjusting an optical axis of an optical transmitter / receiver for aligning optical axes of communication lights having directivities emitted from the optical transmitter / receivers, wherein a directivity angle from one optical transmitter / receiver is larger than that of the communication light. An optical axis adjusting method for an optical transmitter / receiver, characterized in that the search guide light is emitted and the other optical transmitter / receiver performs the first optical axis adjustment with the search guide light as a target. 2. The one optical transmitter / receiver emits the search guide light when the communication light from the other optical transmitter / receiver cannot be received, and the other optical transmitter / receiver targets the search guide light. The optical axis adjusting method for an optical transceiver according to claim 1, wherein the first optical axis is adjusted. 3. The other optical transmitter / receiver emits search guide light having a larger directivity angle than the communication light, and one optical transmitter / receiver performs optical axis adjustment with the search guide light as a target. The optical axis adjusting method for an optical transceiver according to claim 1 or 2. 4. The optical axis adjusting method for an optical transmitter / receiver according to claim 3, wherein the optical axis adjustments of both optical transmitters / receivers targeting the search guide light are repeated a plurality of times. 5. The optical axes of both optical transmitters / receivers do not coincide with each other, and when the optical transmitters / receivers are not communicating, the search guide light has a wider directivity angle than usual and emits light. Item 5. The optical axis adjustment method for an optical transceiver according to any one of Items 1 to 4. 6. A method of adjusting an optical axis of an optical transmitter / receiver for aligning optical axes of communication lights having directivities emitted from the optical transmitter / receivers, wherein a directivity angle from one optical transmitter / receiver is larger than that of the communication light. The light of a specific pulse pattern is emitted, and by receiving this light, the other optical transmitter / receiver starts optical axis adjustment, the other optical transmitter / receiver emits light, and the other optical transmitter / receiver emits the other light. By receiving light from the transmitter / receiver, the optical axis between the two optical transmitters / receivers is adjusted, and when the optical axis adjustment reaches a predetermined level, a pulse pattern of a waveform different from the light of the specific pulse pattern is generated. A method of adjusting an optical axis of an optical transmitter / receiver, which comprises transmitting light to the other party and ending the optical axis adjustment. 7. A method for adjusting an optical axis of an optical transmitter / receiver, wherein optical axis alignment of communication light intensity-modulated at a predetermined frequency having directivity emitted by the optical transmitter / receivers is performed a plurality of times. The optical axis of the communication light between the optical transmitters and receivers is adjusted with the aim of the search guide light whose directivity angle is larger than that of the communication light emitted from the device, and the frequency of the intensity modulation of the communication light is adjusted to each optical axis. An optical axis adjusting method for an optical transmitter / receiver, characterized in that the transmitting side and the receiving side are interchanged each time. 8. A light emitting unit for communication which emits communication light having a predetermined directivity angle, a light emitting unit for search which emits search guide light having a larger directivity angle than the communication light to an optical transceiver, and receives external light. The light-receiving unit and the search light-emitting unit emit light when adjusting the optical axis, and the communication light-emitting unit emits light during communication, and the communication is performed so that the light-receiving unit receives the largest amount of light for adjusting its own optical axis. An optical transmitter / receiver, comprising: a light emitting unit for search, a light emitting unit for search, and a control unit for integrally controlling the directing directions of the light receiving unit. 9. The light emitting unit for communication and the light emitting unit for search are constituted by a light source and an optical means for adjusting a directivity angle of light from the light source.
The optical transceiver according to. 10. The control means causes the search light emitting section to emit light for aligning the optical axis of a communication partner, and when the light receiving section receives a predetermined signal, a light source is provided. 9. The optical transmitter / receiver according to claim 8, comprising an optical unit for adjusting a directivity angle of light from the light source. 11. In an optical wireless system for performing optical wireless communication between optical transceivers by aligning optical axes of communication lights having directivities emitted from the optical transceivers with each other, the optical transmitter / receiver has a directivity angle larger than that of the communication light. The search light-emitting unit that emits a large search guide light and the search light-receiving unit that receives light from the other party are provided, and the search guide light emitted from the other party's search light-emitting unit is received by the search light-receiving unit. An optical wireless system characterized by adjusting an optical axis of communication light between a transmitter and a receiver. 12. An optical wireless system for performing optical wireless communication between optical transmitters and receivers by aligning optical axes of communication lights having directivities, the optical transmitter and receiver having a directivity angle larger than that of the communication light. Optical wireless system characterized in that a search light emitting section for emitting a large search guide light is provided, and the optical axis of communication light between optical transceivers is adjusted with the search guide light emitted by the search light emitting section as a target. .