US 10,594,405 B2Granted

Optical receiver and method of controlling optical receiver

AssigneeSumitomo Electric Industries, Ltd.

InventorHideki Oe

Life of this patent

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Abstract

In an optical receiver, a control unit determines an SOA current set value such that an SOA current becomes a maximum value ISOA_MAXwhen a VOA voltage is smaller than a first threshold value VVOA_LOW, determines the SOA current set value such that the SOA current becomes smaller than the maximum value ISOA_MAX and larger than a minimum value ISOA_MIN when the VOA voltage is equal to or larger than the first threshold value VVOA_LOW and is smaller than a second threshold value VVOA_HIGH, and determines the SOA current set value such that the SOA current is fixed to the minimum value ISOA_MIN when the VOA voltage is equal to or larger than the second threshold value VVOA_HIGH.

Claims20

Dependent claims

An optical receiver for receiving an optical reception signal, the optical receiver comprising:

a variable optical attenuator configured to output a first optical signal obtained by attenuating the optical reception signal with an attenuation amount increasing or decreasing in accordance with a first control signal;
a semiconductor optical amplifier configured to output a second optical signal obtained by amplifying the first optical signal with a gain increasing or decreasing in accordance with a second control signal;
an optical receiving unit configured to convert the second optical signal into an electrical signal and output a monitor signal in accordance with the electrical signal;
a comparison circuit configured to compare the monitor signal with an output set signal and generate the first control signal in accordance with a result of the comparison;
and
a control unit configured to generate the second control signal and the output set signal in accordance with the first control signal, wherein
the comparison circuit makes the first control signal larger as a difference between the monitor signal and the output set signal becomes larger when the monitor signal is larger than the output set signal, and outputs an output value within a predetermined range as the first control signal when the monitor signal is smaller than the output set signal,
the variable optical attenuator makes the attenuation amount larger when the first control signal becomes larger and makes the attenuation amount smaller when the first control signal becomes smaller,
the semiconductor optical amplifier makes the gain larger when the second control signal becomes larger and makes the gain smaller when the second control signal becomes smaller, and wherein the control unit
increases the second control signal by a first increase value within a first range smaller than a first upper limit value, and increases the output set signal in accordance with the first increase value within a second range smaller than a second upper limit value set in accordance with the first upper limit value, when the first control signal is smaller than a first threshold value,
decreases the second control signal by a first decrease value within a third range larger than a first lower limit value smaller than the first upper limit value, and decreases the output set signal in accordance with the first decrease value within a fourth range larger than a second lower limit value set in accordance with the first lower limit value, when the first control signal is within an active range larger than a second threshold value larger than the first threshold value, and
maintains the second control signal and the output set signal when the first control signal falls within an inactive range equal to or larger than the first threshold value and equal to or smaller than the second threshold value.

9 more elements

A method of controlling an optical receiver configured to receive an optical reception signal, and including:

a variable optical attenuator configured to output, in response to a first control signal, a first optical signal obtained by attenuating the optical reception signal with an attenuation amount becoming larger as the first control signal is larger and becoming smaller as the first control signal is smaller,
a semiconductor optical amplifier configured to output, in response to a second control signal, a second optical signal obtained by amplifying the first optical signal with a gain becoming larger as the second control signal is larger and becoming smaller as the second control signal is smaller,
an optical receiving unit configured to convert the second optical signal into an electrical signal and output a monitor signal in accordance with the electrical signal,
a comparison circuit configured to compare the monitor signal with an output set signal and generate the first control signal in accordance with a result of the comparison, and
a control unit configured to generate the second control signal and the output set signal in accordance with the first control signal,
the method comprising:
making the first control signal larger as a difference between the monitor signal and the output set signal becomes larger when the monitor signal is larger than the output set signal, and outputting an output value within a predetermined range as the first control signal when the monitor signal is smaller than the output set signal;
increasing the second control signal by a first increase value within a first range smaller than a first upper limit value and increasing the output set signal in accordance with the first increase value within a second range smaller than a second upper limit value set in accordance with the first upper limit value when the first control signal is smaller than a first threshold value;
decreasing the second control signal by a first decrease value within a third range larger than a first lower limit value smaller than the first upper limit value and decreasing the output set signal in accordance with the first decrease value within a fourth range larger than a second lower limit value set in accordance with the first lower limit value when the first control signal is within an active range larger than a second threshold value larger than the first threshold value;
and
maintaining the second control signal and the output set signal when the first control signal falls within an active range equal to or larger than the first threshold value and equal to or smaller than the second threshold value.

8 more elements

An optical receiver for receiving an optical reception signal having an optical input power, the optical receiver comprising:

a variable optical attenuator (VOA) configured to attenuate the optical reception signal by an attenuation amount variable in response to a first control signal and output an attenuated optical reception signal as a first optical signal;
a semiconductor optical amplifier (SOA) configured to amplify the first optical signal by a gain variable in response to a second control signal and output an amplified first optical signal as a second optical signal;
an optical receiving unit including an optical demultiplexer, a receiver optical sub assembly (ROSA), and a monitor circuit, the ROSA being configured to receive the second optical signal through the optical demultiplexer and convert the second optical signal into an electrical signal, the monitor circuit being configured to output a monitor signal in accordance with the electrical signal from the ROSA;
a comparison circuit configured to compare the monitor signal with an output set signal and generate the first control signal in accordance with a result of the comparison;
and
a control unit including an analog-to-digital converter (ADC), a central processing unit (CPU), a first digital-to-analog converter (DAC), a second DAC, and a drive circuit, the CPU being configured to monitor the first control signal through the ADC and generate the second control signal and the output set signal in accordance with the first control signal, the second control signal being provided to the SOA through the first DAC and the drive circuit, the output set signal being provided to the comparison circuit through the second DAC, wherein
the comparison circuit increases the first control signal as a difference between the monitor signal and the output set signal increases, and decreases the first control signal as the difference between the monitor signal and the output signal decreases when the monitor signal is larger than the output set signal, and outputs an output value within a predetermined range as the first control signal when the monitor signal is smaller than the output set signal,
the VOA increases the attenuation amount when the first control signal increases and decreases the attenuation amount when the first control signal decreases,
the SOA increases the gain when the second control signal increases and decreases the gain when the second control signal decreases, and
the control unit
sets the second control signal to a first upper limit value (ISOA_MAX) and increases the output set signal with an increase in the optical input power for keeping the first control signal within an inactive range between a first threshold value (VVOA_HIGH) and a second threshold value (VVOA_LOW) smaller than VVOA_HIGH, when the optical input power is in a first region smaller than a first boundary value (Pina),
decreases the second control signal from ISOA_MAX to a first lower limit value (ISOA_MIN) smaller than ISOA_MAX with an increase in the optical input power, and decreases the output set signal from a second upper limit value (PSOA_MAX) to a second lower limit value (PSOA_SAT) with the increase in the optical input power for keeping the first control signal within the inactive range, when the optical input power is in a second region between Pina and a second boundary value (Pinb) larger than Pina, and
maintains the second control signal to ISOA_MIN and the output set signal to PSOA_SAT against an increase in the optical input power for adjusting the first control signal in an active range larger than VVOA_HIGH, when the optical input power is in a third region larger than Pinb.

10 more elements

A method of controlling an optical receiver configured to receive an optical reception signal having an optical input power, and including:

a variable optical attenuator (VOA) configured to attenuate the optical reception signal by an attenuation amount variable in response to a first control signal and output an attenuated optical reception signal as a first optical signal,
a semiconductor optical amplifier (SOA) configured to amplify the first optical signal by a gain variable in response to a second control signal and output an amplified first optical signal as a second optical signal,
an optical receiving unit including an optical demultiplexer, a receiver optical sub assembly (ROSA), and a monitor circuit, the ROSA being configured to receive the second optical signal through the optical demultiplexer and convert the second optical signal into an electrical signal, the monitor circuit being configured to output a monitor signal in accordance with the electrical signal,
a comparison circuit configured to compare the monitor signal with an output set signal and generate the first control signal in accordance with a result of the comparison, and
a control unit including an analog-to-digital converter (ADC), a central processing unit (CPU), a first digital-to-analog converter (DAC), a second DAC, and a drive circuit, the CPU being configured to monitor the first control signal through the ADC and generate the second control signal and the output set signal in accordance with the first control signal, the second control signal being provided to the SOA through the first DAC and the drive circuit, the output set signal being provided to the comparison circuit through the second DAC,
the method comprising:
increasing the first control signal as a difference between the monitor signal and the output set signal increases, and decreasing the first control signal as the difference between the monitor signal and the output set signal decreases when the monitor signal is larger than the output set signal, and outputting an output value within a predetermined range as the first control signal when the monitor signal is smaller than the output set signal;
increasing the attenuation amount when the first control signal increases and decreasing the attenuation amount when the first control signal decreases,
increasing the gain when the second control signal increases and decreasing the gain when the second control signal decreases, and setting the second control signal to a first upper limit value (ISOA_MAX) and increasing the output set signal with an increase in the optical input power for keeping the first control signal within an inactive range between a first threshold value (VVOA_HIGH) and a second threshold value (VVOA_LOW) smaller than (VVOA_HIGH), when the optical input power is in a first region smaller than a first boundary value (Pina);
decreasing the second control signal from ISOA_MAX to a first lower limit value (ISOA_MIN) smaller than ISOA_MAX with an increase in the optical input power, and decreasing the output set signal from a second upper limit value (PSOA_MAX) to a second lower limit value (PSOA_SAT) with the increase in the optical input power for keeping the first control signal within the inactive range, when the optical input power is in a second region between Pina and a second boundary value (Pinb) larger than Pina;
and
maintaining the second control signal to ISOA_MIN and the output set signal to PSOA_SAT against an increase in the optical input power for adjusting the first control signal in an active range larger than VVOA_HIGH, when the optical input power is in a third region larger than Pinb.

9 more elements

Dependencies are inferred from the claim text.

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Abstract

An optical receiver for receiving an optical reception signal, the optical receiver comprising:

a variable optical attenuator configured to output a first optical signal obtained by attenuating the optical reception signal with an attenuation amount increasing or decreasing in accordance with a first control signal;
a semiconductor optical amplifier configured to output a second optical signal obtained by amplifying the first optical signal with a gain increasing or decreasing in accordance with a second control signal;
an optical receiving unit configured to convert the second optical signal into an electrical signal and output a monitor signal in accordance with the electrical signal;
a comparison circuit configured to compare the monitor signal with an output set signal and generate the first control signal in accordance with a result of the comparison;
and
a control unit configured to generate the second control signal and the output set signal in accordance with the first control signal, wherein
the comparison circuit makes the first control signal larger as a difference between the monitor signal and the output set signal becomes larger when the monitor signal is larger than the output set signal, and outputs an output value within a predetermined range as the first control signal when the monitor signal is smaller than the output set signal,
the variable optical attenuator makes the attenuation amount larger when the first control signal becomes larger and makes the attenuation amount smaller when the first control signal becomes smaller,
the semiconductor optical amplifier makes the gain larger when the second control signal becomes larger and makes the gain smaller when the second control signal becomes smaller, and wherein the control unit
increases the second control signal by a first increase value within a first range smaller than a first upper limit value, and increases the output set signal in accordance with the first increase value within a second range smaller than a second upper limit value set in accordance with the first upper limit value, when the first control signal is smaller than a first threshold value,
decreases the second control signal by a first decrease value within a third range larger than a first lower limit value smaller than the first upper limit value, and decreases the output set signal in accordance with the first decrease value within a fourth range larger than a second lower limit value set in accordance with the first lower limit value, when the first control signal is within an active range larger than a second threshold value larger than the first threshold value, and
maintains the second control signal and the output set signal when the first control signal falls within an inactive range equal to or larger than the first threshold value and equal to or smaller than the second threshold value.

9 more elements