JP5534464B2 - Optical transceiver and optical signal optimization method thereof - Google Patents

Description

  The present invention relates to an optical transceiver and an optical signal optimization method thereof, and more particularly, to an optical transceiver capable of detecting degradation of an optical transmission signal and correcting the degradation, and an optical signal optimization method thereof.

  2. Description of the Related Art An optical transmitter / receiver in which an optical signal transmitter (optical transmitter) and an optical signal receiver (optical receiver) are integrated is known as a device that performs optical communication.

  Conventionally, as a method for monitoring a deterioration state of an optical signal transmitted and received between optical transceivers and transmitting an optimum optical signal on the transmitter side, for example, one optical transceiver (hereinafter referred to as “device A”) In a system that receives an optical signal transmitted from the other optical transceiver (hereinafter referred to as “device B”), the optical signal received by device B is monitored for deterioration state (characteristic deterioration), and the monitoring information is A method for controlling an optical signal transmitted from device A is known.

JP 2010-40969 A

  However, the degradation state of the optical signal monitored by this conventional method includes the characteristics of the optical transmitter of device A, the characteristics of the optical transmission path for transmitting the optical signal between device A and device B, and the characteristics of device B. Since the optical signal is a deterioration state that combines all the characteristics of the optical receiver, whether the optical signal characteristic deterioration is that of the optical transmitter of the device A, the optical transmission line, or the optical receiver of the device B However, there was a problem that it was not possible to distinguish whether it was a combination of these. For example, when the characteristics of the optical transmitter of device A are good and there is a problem with the optical transmission path or the optical receiver of device B, or there is a problem with both the optical transmission path and the optical receiver of device B, device A Even if the optical signal transmitted by the optical transmitter is adjusted, the problem is not solved.

  Conventionally, there exists a system having a means for optimizing an optical signal transmitted by the optical transmitter of device A, a means for optimizing an optical signal received by device B, or both. In the state where the cause of the optical transmitter, the optical transmission line, and the optical receiver cannot be separated, it is not possible to optimize each of them. In addition, as the optical communication speed increases, it is increasingly required to secure a margin for the received optical signal. In this conventional method, the optical signal transmitted by the optical transmitter of device A and the device B Since the optical signal received by the optical receiver cannot be in the best state, the maximum signal margin cannot be ensured, and there is a limit to the speeding up.

  As another conventional method, there is a method in which the outgoing light of the optical signal from the optical transmitter is branched into two, one is used for normal communication, and the other is used for monitoring the deterioration state of the optical signal. Are known. However, in this method, a part of the laser diode emission light is constantly used for monitoring, so in order to ensure the optical output necessary for optical communication, it is necessary to increase the output of the laser diode. This is not preferable because it affects the life of the laser diode.

  Therefore, in view of such circumstances, the present invention is a new optical transmission / reception capable of monitoring an optical signal degradation state by separating an optical transmitter, an optical transmission line, and an optical receiver and transmitting an optimal optical signal on the transmitter side. And an optical communication optimizing method thereof.

An optical transceiver according to the present invention is an optical transceiver comprising an optical transmitter for transmitting an optical signal and an optical receiver for receiving an optical signal, wherein the optical path of the optical signal transmitted by the optical transmitter is changed to another An optical path switching unit that switches between a first optical path during optical communication that performs optical communication with an optical transceiver and a second optical path during monitoring that receives and monitors the optical signal with the optical receiver; The switching unit reflects at least two mirrors that reflect an optical signal transmitted by the optical transmitter during the monitoring and guides the optical signal to the optical receiver, a casing that holds the at least two mirrors, and drives the casing A drive mechanism that switches between the first optical path and the second optical path depending on whether or not the at least two mirrors are positioned on an optical path of an optical signal transmitted by the optical transmitter; Transmitted from the optical transmitter A measurement unit that measures an error rate of an optical signal received by the optical receiver, and a setting unit that calculates and sets an optimal optical communication parameter of the optical transmitter based on the measurement result. A controller is further provided.
The optical transceiver according to the reference example is an optical transceiver including an optical transmitter that transmits an optical signal and an optical receiver that receives the optical signal, and the optical path of the optical signal transmitted by the optical transmitter An optical path switching unit that switches between a first optical path during optical communication that performs optical communication with an optical transceiver and a second optical path during monitoring that receives and monitors the optical signal with the optical receiver; The switching unit reflects at least two mirrors that reflect an optical signal transmitted by the optical transmitter during the monitoring and guides the optical signal to the optical receiver, a casing that holds the at least two mirrors, and drives the casing And a drive mechanism that switches between the first optical path and the second optical path depending on whether or not the at least two mirrors are positioned on an optical path of an optical signal transmitted by the optical transmitter.

An optical communication optimizing method according to the present invention is an optical communication optimizing method for an optical transceiver including an optical transmitter that transmits an optical signal and an optical receiver that receives the optical signal, and is transmitted by the optical transmitter. The optical path of the optical signal is received from the first optical path at the time of optical communication in which optical communication is performed with another optical transceiver, and the transmitted optical signal is received by the optical receiver to monitor the optical signal. A step of switching to a second optical path, a step of setting a parameter as a set value for changing a light emission waveform of an optical signal transmitted by the optical transmitter, and an optical signal transmitted from the optical transmitter and received by the optical receiver Measuring the error rate of the optical transmitter, and calculating and setting an optimal optical communication parameter of the optical transmitter based on the measurement result, and the switching step includes the step of: The optical receiver transmitted from the optical transmitter In comprising a step of measuring the error rate of the received optical signal, based on the measurement result, and setting to calculate the optimal optical communication parameters of the optical transmitter, a.
An optical communication optimizing method according to a reference example is an optical communication optimizing method for an optical transceiver including an optical transmitter that transmits an optical signal and an optical receiver that receives the optical signal, and is transmitted by the optical transmitter. The optical path of the optical signal is received from the first optical path at the time of optical communication in which optical communication is performed with another optical transceiver, and the transmitted optical signal is received by the optical receiver to monitor the optical signal. A step of switching to a second optical path, a step of setting a parameter as a set value for changing a light emission waveform of an optical signal transmitted by the optical transmitter, and an optical signal transmitted from the optical transmitter and received by the optical receiver Measuring an error rate of the optical transmitter, and calculating and setting an optimum optical communication parameter of the optical transmitter based on the measurement result.

  According to the optical transceiver and the like of the present invention configured as described above, the optical transmitter, the optical transmission line, and the optical receiver are separated to monitor the deterioration state of the optical signal, and the optimal optical signal is transmitted on the transmitter side. Can be sent. As a result, since the optical signal transmitted by the optical transmitter can be optimized, a signal margin can be ensured, and the communication speed of optical communication can be further increased.

It is a block diagram which shows schematic structure of the optical transmitter / receiver of this embodiment. It is a figure for demonstrating operation | movement of the optical path switching part of the optical transmitter-receiver of this embodiment. It is a flowchart which shows the processing content of the optical signal optimization method implemented using the optical transmitter-receiver of this embodiment. It is a figure which shows an example of the graph of the error rate produced with the controller of this embodiment. It is a schematic diagram which shows the state which observed the optical signal at the time of optical communication with the measuring device. It is a figure for demonstrating the characteristic of a laser diode.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an optical transceiver 1 according to an embodiment of the present invention.

  As shown in FIG. 1, the optical transceiver 1 includes an optical path switching unit 2, an optical transmitter 3, an optical receiver 4, and a controller 5. The optical fibers 6a and 6b shown in FIG. 1 serve as a transmission path for optical communication between the two optical transceivers 1 and 1 ′. The optical fiber 6a is an optical transmitter of the optical transceiver 1. 3 is arranged to transmit an optical signal to the optical receiver 4 ′ of the other optical transceiver 1 ′, and the optical fiber 6 b is connected to the optical receiver 4 of the optical transceiver 1 with the light of the other optical transceiver 1 ′. Arranged to receive the optical signal transmitted from the transmitter 3 '.

  The optical path switching unit 2 has a function of switching the optical path (traveling direction) of the optical signal (transmission signal) transmitted from the optical transmitter 3, and includes mirrors 2a and 2b that reflect the transmission signal and change the optical path. A housing 2c that holds the mirrors 2a and 2b, and a drive mechanism 2d that slides (position changes) the housing 2c itself in a direction perpendicular to or substantially perpendicular to the traveling direction of the transmission signal from the optical transmitter 3. Composed.

  An example of the position change of the optical path switching unit 2 will be described with reference to FIG. When the optical transmitter / receiver 1 performs normal optical communication with another optical transmitter / receiver 1 ′, the optical path switching unit 2 includes mirrors 2a and 2b of the optical path switching unit 2 as shown in FIG. It arrange | positions so that it may become a position retracted | retracted from the optical path used for optical communication (1st arrangement | positioning). In this state, the optical signal transmitted by the optical transmitter 3 travels along the optical path (first optical path) from the optical transmitter 3 to the optical fiber 6a, and enters and is transmitted to the optical fiber 6a. The optical signal received from the optical fiber 6 b travels on the optical path from the optical fiber 6 b to the optical receiver and enters the optical receiver 4.

  On the other hand, when the optical path switching unit 2 monitors the optical transmission waveform transmitted by the optical transmitter 3, the mirrors 2a and 2b of the optical path switching unit 2 are transmitted from the optical transmitter 3 as shown in FIG. The second optical signal is slid from the first arrangement so that the optical path of the optical signal can be switched (second arrangement). In this state, the optical signal transmitted from the optical transmitter 3 travels the optical path (second optical path) from the optical transmitter 3 to the optical receiver 4 via the mirrors 2a and 2b. Then, the light is sequentially reflected by the mirror 2 a and the mirror 2 b and enters the optical receiver 4. Therefore, the optical path switching unit 2 drives the housing 2c and determines whether the two mirrors 2a and 2b are positioned on the optical path of the optical signal transmitted by the optical transmitter 3 or not. The optical path can be switched. The number of mirrors provided in the optical path switching unit 2 may be two or more as long as the optical signal transmitted by the optical transmitter 3 can be reflected and guided by the optical receiver 4.

  The optical transmitter 3 includes a laser diode 3a and a laser diode driver 3b. The laser diode driver 3b has a function of changing the drive waveform of the laser diode 3a, and the setting value of the drive waveform can be changed by a command from the controller 5.

  The optical receiver 4 includes a photodiode 4a and an amplifier 4b, and receives the received optical signal with the photodiode 4a, and converts the optical signal into an electrical signal with the amplifier 4b. The converted electrical signal is sent to the controller 5 for processing.

  The controller 5 has a function to slide control the position of the optical path switching unit 2 (slide control unit), a function to set the drive waveform of the laser diode driver 3b (drive waveform setting unit), and an error from the optical signal received by the optical receiver 4 A function for measuring a rate (error rate) (measuring unit), a memory function (storage unit), a function for processing data stored in the memory, and calculating and setting optimum optical communication parameters of the optical transmitter 3 ( A setting unit). The controller 5 includes, for example, a processor for performing various operations and controls, a RAM that temporarily stores data and functions as a working area during image processing, a ROM that stores programs, and peripheral circuits. . The controller 5 may be a part of the configuration of the optical transceiver 1 or may be configured separately from the optical transceiver 1.

  Here, conventionally, a module in which an optical transmission / reception portion using an optical fiber such as a fiber channel is detachable has been standardized by a manufacturer and has been widely commercialized, for example, SFP, GBIC, Modules such as XNEPAK, XPAC, and XFP are known. The components (for example, the optical path switch 2, the optical transmitter 3, and the optical receiver 4) that constitute the optical transceiver 1 of the present embodiment can be incorporated in this module. Thus, by including the components (for example, the optical path switch 2, the optical transmitter 3, and the optical receiver 4) as a set in the module, the features of the module can be utilized to the maximum. That is, it can be applied to modules standardized in the industry, and usually there are many modules in a certain system, but it can be determined independently from the system in units of modules, and analysis is easy. Only defective modules can be repaired by replacing the module that is the smallest replacement unit.

  Next, an optical signal optimization method for obtaining an optimal optical signal waveform performed by the optical transceiver 1 will be described with reference to the flowchart of FIG. Note that the processes can be executed in any order or in parallel as long as the process contents do not contradict each other.

  First, the controller 5 drives the drive mechanism 2d to change the housing 2c holding the mirrors 2a and 2b from the normal communication side arrangement (the first arrangement described above) to the emission waveform confirmation side arrangement (the second arrangement described above). (Step S100). By moving the housing 2c from the first arrangement to the second arrangement, the optical path of the optical signal transmitted from the optical transmitter is changed from the first optical path at the time of optical communication to optically communicate with other optical transceivers. The optical receiver switches to the second optical path at the time of monitoring in which the optical signal is received and monitored.

  The controller 5 sets the parameter (X) as a set value for changing the light emission waveform of the laser diode driver 3b (step S101). For example, the parameter (X) in the present embodiment is variable in five steps within a variable range, and X is set to -2, -1, 0, 1, 2 with a default value = 0. Note that the parameter (X) is not limited to the above-described five stages, and can be appropriately varied such as three stages and ten stages.

  The controller 5 measures the error rate of the signal emitted from the optical transmitter 3 and received by the optical receiver 4 (step S102), and stores the measurement result in the memory (step S103). Specifically, for example, as an issuance condition, first, X = -2 is set, the error rate is measured, and the measurement result is stored in the memory. Next, X = -1 is set, the error rate is measured, and the measurement result is stored in the memory. Thereafter, X = 0, 1, and 2 are sequentially set to measure the error rate, and each measurement result is stored in the memory.

  The controller 5 calculates a parameter that optimizes the error rate (step S104). For example, the controller 5 creates a graph as shown in FIG. 4 from the error rate for each laser diode issuance condition stored in the memory, and uses this created graph to determine a parameter for which the error rate is optimal. calculate.

  The controller 5 sets the optimum parameter calculated as the light emission condition of the diode laser driver 3b (step S105). If the graph shown in FIG. 4 is created, the controller 5 can set the parameter (X = 1) that minimizes the error rate as the light emission condition of the diode laser driver 3b.

  The controller 5 moves the optical path switching unit 2 from the arrangement on the light emission waveform confirmation side (the second arrangement described above) to the normal communication side (the first arrangement described above) (step S106).

  As described above, according to the optical signal optimization method of the present embodiment, light emission is performed in a state where the characteristics of the optical transmitter 3 are separated from the performance of the optical transmission path or the optical receiver 4 that actually receives the signal. Waveform optimization can be achieved. As a result, since the optical signal transmitted by the optical transmitter can be optimized, a signal margin can be ensured and the communication speed of the optical signal can be further increased.

  The effects of applying the optical transceiver 1 and the optical signal optimization method of the present embodiment will be further described with reference to FIGS.

  FIG. 5A shows an example of a schematic diagram of each optical signal optimized by applying the present embodiment, and FIG. 5B shows a schematic diagram of each optical signal when the laser diode is deteriorated with time. An example of the figure is shown. Each schematic diagram shown in FIGS. 5A and 5B shows optical signals having communication speeds of 2 Gbps, 4 Gbps, 8 Gbps, and 10 Gbps from the top. In FIG. 5, the optical signal is indicated by a solid line, and the mask is indicated by black on the first-stage 2 Gbps signal and the fourth-stage 10 Gbps signal. The mask is an index for measuring the signal and measuring whether the quality is ensured. The state in which the signal quality is secured means that the signal does not interfere with the area of the mask (the area where the signal is indicated by the mask). It does not cross).

  Here, the laser diode is an element that outputs light in proportion to the current. For example, as shown in FIG. 6, it is known that the characteristics of the laser diode change, such as temperature change and deterioration with time. If the laser diode is caused to emit light under the same driving conditions in spite of such a characteristic change, the rising speed and falling speed of the light emission waveform become a factor. In this case, the optical signal is represented as shown in FIG. 5B. By applying this embodiment, the rising speed and falling speed of the signal are improved as shown in FIG. 5A. In particular, it is possible to improve that a high-speed transmission of 10 Gbps cannot secure a margin and cannot perform good communication.

<Modification>
The preferred embodiments of the present invention have been described above. However, the present invention should not be limited to the above embodiments, and does not depart from the spirit and scope expressed in the claims. Various modifications, additions, and omissions are possible by those skilled in the art.

  For example, the optical path switching unit 2 is not limited to the one described above, and another mechanical means can be applied, and an optical means can also be applied.

  Also, it is not necessary to use one parameter for optimizing the light emission waveform, and it is possible to apply to optimization of a plurality of parameters.

  Furthermore, it is more effective to optimize the characteristics of the receiver that actually receives the light after performing the signal optimization of the optical transmitter 3 by the above method.

  Furthermore, when there is a dependency relationship between the optimization parameter (X) of the optical transmitter and the optimization parameter (Y) of the optical receiver, a method of optimizing by changing these parameters simultaneously can be used.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

  (Supplementary note 1) An optical transceiver including an optical transmitter for transmitting an optical signal and an optical receiver for receiving an optical signal, wherein an optical path of the optical signal transmitted by the optical transmitter is different from that of another optical transceiver. An optical path switching unit that switches between a first optical path at the time of optical communication for optical communication and a second optical path at the time of monitoring to receive and monitor the optical signal by the optical receiver, the optical path switching unit, At least two mirrors that reflect the optical signal transmitted by the optical transmitter during the monitoring and guide the optical signal to the optical receiver, a casing that holds the at least two mirrors, and a drive of the casing to drive the at least two An optical transceiver comprising a drive mechanism for switching between the first optical path and the second optical path depending on whether or not two mirrors are positioned on an optical path of an optical signal transmitted by the optical transmitter.

  (Supplementary Note 2) At the time of the monitoring, a measurement unit that measures an error rate of an optical signal transmitted from the optical transmitter and received by the optical receiver, and an optimum of the optical transmitter based on the measurement result The optical transceiver according to appendix 1, further comprising a controller including a setting unit that calculates and sets a parameter for optical communication.

  (Supplementary note 3) The optical transceiver according to supplementary note 1 or supplementary note 2, wherein the optical transmitter, the optical receiver, and the optical path switching unit are configured as one module.

  (Appendix 4) An optical communication optimization method for an optical transmitter / receiver comprising an optical transmitter for transmitting an optical signal and an optical receiver for receiving the optical signal, wherein the optical path of the optical signal transmitted by the optical transmitter is: The step of switching from the first optical path at the time of optical communication for optical communication with another optical transceiver to the second optical path at the time of monitoring by receiving the transmitted optical signal by the optical receiver and monitoring the optical signal And setting a parameter as a set value for changing the light emission waveform of the optical signal transmitted by the optical transmitter; and measuring an error rate of the optical signal transmitted from the optical transmitter and received by the optical receiver And an optical signal optimization method comprising: calculating and setting an optimum optical communication parameter of the optical transmitter based on the measured result.

  The present invention can be used in an optical communication system using an optical transceiver.

  DESCRIPTION OF SYMBOLS 1 ... Optical transmitter / receiver, 2 ... Optical path switching part, 3 ... Optical transmitter, 4 ... Optical receiver, 5 ... Controller, 6a, 6b ... Optical fiber.

Claims (3)

An optical transceiver comprising an optical transmitter for transmitting an optical signal and an optical receiver for receiving an optical signal,
The optical path of the optical signal transmitted by the optical transmitter is a first optical path during optical communication in which optical communication is performed with another optical transceiver, and at the time of monitoring by receiving the optical signal with the optical receiver An optical path switching unit that switches between the second optical path and
The optical path switching unit includes: at least two mirrors that reflect an optical signal transmitted by the optical transmitter during the monitoring and guide the optical signal to the optical receiver; a housing that holds the at least two mirrors; and the housing A drive mechanism that drives and switches between the first optical path and the second optical path depending on whether or not the at least two mirrors are positioned on an optical path of an optical signal transmitted by the optical transmitter ;
At the time of monitoring, a measurement unit that measures an error rate of an optical signal transmitted from the optical transmitter and received by the optical receiver, and an optimal optical communication parameter of the optical transmitter based on the measurement result A controller including a setting unit for calculating and setting
Optical transceiver. The optical transceiver according to claim 1 , wherein the optical transmitter, the optical receiver, and the optical path switching unit are configured as one module. An optical communication optimization method for an optical transmitter / receiver comprising an optical transmitter for transmitting an optical signal and an optical receiver for receiving an optical signal,
An optical path of an optical signal transmitted by the optical transmitter is received by the optical receiver from the first optical path at the time of optical communication in which optical communication is performed with another optical transceiver. Switching to a second optical path during monitoring to monitor the signal;
Setting a parameter as a setting value for varying the light emission waveform of the optical signal transmitted by the optical transmitter;
Measuring an error rate of an optical signal transmitted from the optical transmitter and received by the optical receiver;
Calculating and setting optimum optical communication parameters of the optical transmitter based on the measured results; and
Equipped with a,
The step of switching comprises measuring an error rate of an optical signal transmitted from the optical transmitter and received by the optical receiver at the time of monitoring, and on the basis of the measurement result, an optimal light of the optical transmitter. Calculating and setting communication parameters, and
Optical signal optimization method.