JP2000321541A - Light output control method and light output controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make loads not to be imposed on a control circuit and circuits of next stages when there is an excessive light input by allowing an optical attenuation means to output an output light having a fixed level while increasing an attenuation amount when a driving current is decreased and reducing the attenuation amount when the driving current is incerased. SOLUTION: The light outputted via an optical attenuator(OATT) 10 is branched by an optical coupler 20 and a photodiode(PD) 30 inputs an output light from the coupler 20 and converts it into a current and a monitoring circuit 40 converts this current into a voltage to output it as the power of a light output. A driving current control circuit 50 controls the value of the driving current of a circuit driving the heater of the OATT 10 so that the power of the light output becomes a fixed value. Hereupon, the OATT 10 outputs the output light by attenuating an optical signal which is inputted and the attenuation factor of the OATT 10 has a characteristic in which the attenuation amount becomes the maximum when the driving current which is to be outputted by the circuit 50 is '0' or near '0' and the attenuation becomes smaller as the driving current is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical output control method and an optical output control device used in an optical communication system and the like. The present invention belongs to a technology related to a light output control method and a light output control device for preventing an abnormal operation of a control circuit of a stage.

[0002]

2. Description of the Related Art Conventionally, in an optical communication system or the like, when the drive current of an optical attenuator is "0" or close to "0" as shown in the drive current / attenuation characteristic curve of FIG. A control method using the characteristics of an optical attenuator, in which the amount of attenuation gradually increases with an increase in current, has been used.

In an optical communication system or the like, multiple channels (wavelengths)
It is necessary to simultaneously control the light levels of all the channels at the next stage after the stage provided with the optical attenuator, assuming that the input light enters at a constant level in all the channels (wavelengths). That is being done.

[0004]

However, the prior art has the following problems. In this optical output control method, in a state where the attenuation of the optical attenuator is small, the power of the circuit or the device is turned “OFF” under some conditions or the drive current is controlled due to a failure of the drive current control circuit. If the light stops suddenly and there is excessive light input at that time, or if the input light is at a high level that is out of the standard of the control circuit of the next stage, excessive light power is also input to the next stage and the next stage There has been a problem that the control circuit may be damaged or failed.

In an optical communication system or the like, a multi-CH
(Wavelength) light level must be controlled at the same time. In the next stage after the stage having the function of optical attenuation, it is assumed that the input light enters at a constant level for all CHs (wavelengths), and the light level is common to all CHs. Since the control to keep the output light level constant is not working, when the light level becomes extremely high by only 1CH (wavelength) at the next stage, the circuit at the next stage is adjusted according to the high light level. Attenuates the light and accordingly all C
The light level of H decreases. As a result, the low level light is further attenuated, and the low level light becomes a light level that cannot be detected by the monitor circuit, and the CH (wavelength) of the low level light is detected as a signal interruption. There was also a problem that.

[0006] The present invention has been made in view of the above problems, and a purpose thereof is to provide a control circuit and a next-stage circuit in an optical communication system or the like when an excessive optical input is made. Another object of the present invention is to provide a technique relating to a light output control method and a light output control device that do not burden the user.

[0007]

The gist of the present invention described in claim 1 is used in an optical communication system or the like, and the optical attenuator reduces the amount of attenuation of the input light in accordance with the drive current input from the drive current controller. A light output control method for outputting output light by performing attenuation control, wherein the amount of attenuation is determined by the drive current control unit,
Alternatively, the optical attenuator is preset so as to be maximum in a non-operating state, and the optical coupler receives the output light from the optical attenuator and performs a branching process in two directions. The output light is output to the next stage, the other output light is output to a photodiode, and the photodiode converts the output light from the optical coupler into a current and outputs the current to a monitor circuit. Converting the current converted from light into voltage and outputting it as output optical power, wherein the driving current control means inputs the voltage-converted output optical power and outputs the output light output from the optical attenuation means. A predetermined voltage value set in advance based on the level and the output optical power are compared with each other. If the output optical power is higher than the predetermined voltage value, the drive current is reduced, and the output optical power is reduced. Is greater than the predetermined voltage value When the drive current is low, the drive current is increased and output, and the optical attenuator increases the attenuation when the drive current is reduced, and decreases the attenuation when the drive current is increased. And outputting a predetermined level of the output light. The gist of the present invention according to claim 2 is that an optical output control device including the drive current control unit, the optical attenuating unit, the optical coupler, the photodiode, and the monitor circuit has not been activated or has just been activated. 2. The apparatus according to claim 1, wherein the amount of attenuation of the light attenuating means is maximized in the state.
The present invention resides in the described light output control method. The gist of the present invention described in claim 3 is that the optical attenuator maximizes the amount of attenuation in a state where the input light is not input. Be in the way. Claim 4
The gist of the invention described is that the optical attenuator maximizes the amount of attenuation when the input light is out of a high-level or low-level standard with respect to a standard set in the optical output control device. A light output control method according to any one of claims 1 to 3, characterized in that: The gist of the present invention according to claim 5 includes a drive current control means and a light attenuation means, wherein the drive current control means outputs a drive current for controlling the light attenuation means, and the light attenuation means according to the drive current. The means is an optical output control device that controls the amount of attenuation of the input light and supplies the attenuation-controlled output light to the next stage, and includes an optical coupler, a photodiode, and a monitor circuit, wherein the optical coupler is Inputting the output light attenuated by the light attenuating means, branching the light output to the next stage and the photodiode, the photodiode converts the light output from the optical coupler into a current, The monitor circuit converts the current output from the photodiode into a voltage and outputs the converted current as optical output power, and the drive current control means sets in advance based on the level of output light output from the optical attenuation means. A predetermined voltage value is compared with a voltage value of the optical output power from the monitor circuit, and the optical output power that increases or decreases with the output light output from the optical attenuating means is a predetermined voltage value. Controlling and outputting the value of the drive current so as to be equal to, and the optical attenuating means controlling the amount of attenuation of the input light according to the drive current and outputting to the optical coupler,
The present invention resides in a light output control device wherein the attenuation is set to be maximum in a state where the drive current control means or the light attenuation means is not operating. The gist of the present invention according to claim 6 is that the light attenuating means is set so that the amount of attenuation becomes maximum when the light output control device is not operated or immediately after the operation. An optical output control device according to claim 5 is provided.
The gist of the present invention according to claim 7, wherein the optical attenuator is set so that the amount of attenuation becomes maximum in a state where the input light is not input. 6. The optical output control device according to item 6. The gist of the present invention according to claim 8, wherein the optical attenuator is configured such that, when the input light is out of a high-level or low-level standard with respect to a standard set in the optical output control device, Is set to be the maximum.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, an optical output control device 1 according to the present embodiment includes an optical attenuator (optical attenuator, hereinafter, referred to as OATT) 10, an optical coupler 20, a photodiode (hereinafter, referred to as PD) 30, Monitor circuit 40
And a drive current control circuit (drive current control means) 50.

As shown in FIG. 1, the light output via OATT 10 is split by optical coupler 20, one of which is output light to the next stage, and the other is output light to PD 30. The PD 30 receives the output light from the optical coupler, converts the light into a current, and outputs the converted current to the monitor circuit 40. The monitor circuit 40 converts the current output from the PD 30 into a voltage and outputs it as optical output power. The drive current control circuit 50 compares the optical output power from the monitor circuit 40 with a preset value, so that the drive current of the circuit that drives the heater of the OATT 10 so that the optical output power becomes a constant value. Control the value of. By repeating this series of controls, the output light from the OATT 10 is kept constant.

The OATT 10 attenuates an input optical signal and outputs the attenuated optical signal. The attenuation factor can be controlled by the drive current output by the drive current control circuit 50.
The drive current control circuit 50 has a characteristic that the attenuation becomes maximum when the drive current increases and the drive current increases when the drive current is increased. , Both high and low levels), a function to reduce the drive current and increase the amount of attenuation.

Next, the operation of the light output control device according to the present embodiment will be described with reference to FIG. The optical coupler 20 is
The OATT output light 110 output from the ATT 10 is branched, and one is output to the next stage, and the other is output to the PD 30. The PD 30 performs a process of the light / electricity conversion 120 on the input light, converts the light into a current, and outputs the current to the monitor circuit 40. The monitor circuit 40 converts the current into the current / voltage conversion 13
0, and outputs the optical output power to the drive current control circuit 50. The drive current control circuit 50 reads this optical output power as a digital value, compares it with a predetermined voltage value (light level) set in advance, and drives the drive current 140 so that the required OATT output light 110 becomes constant. And outputs it to OATT10. The OATT 10 controls the amount of attenuation of the input light based on the drive current 140.

In the state where the power of the light output control device 1 is "OFF", the state where the power is "ON" and immediately after the start of control, and the state where the drive current control circuit 50 is not operating, the drive current
40 is “0” or close to “0”.
The OATT output light 110 from the OATT 10 has a low output in this state. After the power of the light output control device 1 is turned on, as the light output control device 1 repeats the control operation, the amount of attenuation of the OATT 10 decreases, and the OATT output light 110 changes to a high output. OAT until value
The amount of attenuation at T10 is controlled to decrease. Specifically, when the output optical power converted from the detected current becomes higher than a desired value, the monitor circuit 40 reduces the drive current 140 to increase the amount of attenuation of the OATT 10. Then, control is performed so that the amount of attenuation increases until the output light power reaches a predetermined value, and when the output light power becomes lower than a desired value, the reverse control is performed.

The drive current control circuit 50 decreases the drive current 140 and increases the amount of attenuation when nonstandard light (similarly at low and high levels) is input.

As described above, O which constitutes the light output control device
With the ATT and the drive current control circuit stopped,
When there is a high level of optical input, the attenuation of OATT is maximized, which suppresses excessive optical input to the next stage, prevents breakage and deterioration, and enables the optical output control device to perform control. When started, the amount of OATT attenuation gradually decreases,
The light output changes from a low output to a high output, and it is possible to prevent an abnormal operation of the next-stage control circuit due to a sudden increase in the light level.

As shown in FIG. 2, the relationship between the driving current 140 for the OATT 10 and the attenuation of the input light is as follows.
When 40 is close to “0” or “0”, the amount of attenuation reaches a maximum value, indicating that the characteristic has a characteristic that the amount of attenuation decreases as the drive current 140 increases.

The light output control device according to the embodiment is configured as described above, and has the following effects.
Even when a high level light is suddenly input from a state where no optical signal is input or a state where a low level optical signal out of the standard is detected, the OATT output light gradually increases the optical level from the low level to the high level. Since the adjustment can be performed, it is possible to prevent a control failure of the next-stage circuit due to a sudden level change.

Conventionally, it has been necessary to increase the drive current in order to maximize the amount of attenuation of a channel that does not contain a signal. However, in the present embodiment, "0" or "0" is used.
Since the control is performed with a drive current close to 0 ", the current consumption can be reduced, the power consumption of the optical attenuator can be reduced, and the characteristic change of the circuit constituting the optical output control device due to temperature rise can be prevented. .

In the present embodiment, the present invention is not limited to this, and can be applied to a light output control method and a light output control device suitable for applying the present invention.

The number, position, shape, and the like of the above-mentioned constituent members are not limited to the above-described embodiment, but can be set to a number, position, shape, and the like suitable for carrying out the present invention.

In each of the drawings, the same components are denoted by the same reference numerals.

[0021]

Since the present invention is configured as described above, the following effects can be obtained. Even if a high-level optical power is suddenly input to the optical output control device from a state where the power of the optical output control device or the drive current control circuit is “OFF”, the attenuation of the OATT is sufficiently large.
The light output level to the next stage can be reduced. For this reason, it is possible to prevent damage due to excessive input of optical power to the next-stage circuit and occurrence of abnormal operation in the next-stage control circuit due to a sudden increase in light level.

Further, in the conventional OATT, the current value has a maximum attenuation at a certain value, and the value varies depending on the individual. Therefore, it takes a long time to detect the maximum attenuation, and a highly accurate set current value is required. Although required, in the control method of the present invention, when the drive current is “0” or near “0”, the OA
Since TT is set to be the maximum attenuation, it is easy to set a control current for controlling the maximum attenuation and the changing attenuation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a light output control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the drive current and the amount of attenuation in FIG.

FIG. 3 is a diagram illustrating an example of a relationship between a drive current and an amount of attenuation in a conventional light output control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical output control apparatus 10 Optical attenuator (optical attenuating means, OATT) 20 Optical coupler 30 Photodiode (PD) 40 Monitor circuit 50 Drive current control circuit (Drive current control means) 110 OATT output light 120 Optical / electrical conversion 130 Current / Voltage conversion 140 drive current

Claims (8)

[Claims] 1. An optical output control method used in an optical communication system or the like, wherein an optical attenuator controls an attenuation amount of an input light and outputs an output light according to a drive current input from the drive current controller. The drive current control means or the optical attenuator is preset so as to be maximum when the optical attenuator is not operating, and the optical coupler receives the output light from the optical attenuator. And performs a branching process in two directions, outputs one as output light to the next stage, outputs the other output light to a photodiode, and the photodiode converts the output light from the optical coupler into a current. The monitor circuit converts the current converted from light into a voltage and outputs it as output optical power, and the drive current control means converts the voltage-converted output optical power to the output current. Enter the light attenuation Comparing a predetermined voltage value set in advance based on the level of output light output from the means with the output light power, and when the output light power is higher than the predetermined voltage value,
The drive current is reduced, and when the output optical power is lower than the predetermined voltage value, the drive current is increased and output, and the optical attenuator is configured to reduce the amount of attenuation when the drive current is reduced. And outputting the output light at a constant level by decreasing the amount of attenuation when the drive current increases. 2. The optical attenuator according to claim 1, wherein said drive current control means, said optical attenuator, said optical coupler, said photodiode, and said monitor circuit are not operated, or said optical output control apparatus is in a state immediately after operation. 2. The light output control method according to claim 1, wherein said attenuation of said means is maximized. 3. The optical output control method according to claim 1, wherein the optical attenuator maximizes the attenuation in a state where the input light is not input. 4. The optical attenuator maximizes the attenuation when the input light is out of a high-level or low-level standard with respect to a standard set in the optical output control device. The light output control method according to claim 1. 5. A drive current control means and an optical attenuation means, wherein the drive current control means outputs a drive current for controlling the optical attenuation means, and the optical attenuation means attenuates input light according to the drive current. An optical output control device for controlling an amount and supplying an output light whose attenuation is controlled to a next stage, comprising: an optical coupler, a photodiode, and a monitor circuit, wherein the optical coupler is attenuated by the optical attenuation means. The controlled output light is input, the optical output is branched to the next stage and the photodiode, the photodiode converts the optical output from the optical coupler into a current, and the monitor circuit The current output from the photodiode is voltage-converted and output as optical output power, and the driving current control unit is configured to set a predetermined value based on the level of output light output from the optical attenuation unit. Is compared with the voltage value of the optical output power from the monitor circuit, so that the optical output power that increases or decreases with the output light output from the optical attenuation means is equal to a predetermined voltage value. Controlling and outputting the value of the drive current, and the light attenuating means controls the amount of attenuation of the input light in accordance with the drive current and outputs the same to the optical coupler, and the drive current control means, or The light output control device is set so that the amount of attenuation is maximized in a state where the light attenuation means is not operating. 6. The optical attenuator according to claim 5, wherein the optical output control device is set so that the amount of attenuation becomes maximum when the optical output control device is not operated or immediately after the operation. Light output control device. 7. The optical output control according to claim 5, wherein the optical attenuator is set so that the amount of attenuation becomes maximum when the input light is not input. apparatus. 8. The optical attenuator is configured to set the amount of attenuation to be maximum when the input light is out of a high-level or low-level standard with respect to a standard set in the optical output control device. The optical output control device according to any one of claims 5 to 7, wherein: