Frequency offset monitoring device and optical coherent receiver
AssigneeFujitsu Limited
InventorsZhenning TAO, Huijian Zhang, Takeshi Hoshida, Lei Ll
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Abstract
The present invention provides a frequency offset monitoring device and an optical coherent receiver. A low speed frequency offset monitoring device comprises a signal speed lowering section, for lowering the speed of an inputted signal and outputting the speed lowered signal, and a frequency offset monitor, for monitoring frequency offset of the speed lowered signal outputted by the signal speed lowering section.
Claims6
An optical coherent receiver, comprising:
- the low speed frequency offset monitoring device according to claim 1, for monitoring a frequency offset of an inputted optical signal;
- a control logic, for outputting a first control signal and a second control signal in accordance with the frequency offset to control the frequency offset;
- a local oscillator, for supplying a local oscillator optical signal;
- a first optical frequency shifter, for shifting a frequency of the local oscillator optical signal in accordance with the first control signal from the control logic;
- a second optical frequency shifter, for shifting a frequency of the inputted optical signal in accordance with the second control signal from the control logic;
- an optical hybrid, for mixing the inputted optical signal having been shifted frequency with the local oscillator optical signal having been shifted frequency;
- first and second twin photoelectric detectors, for converting the optical signal outputted from the optical hybrid into electrical base band signals;
- and
- a signal processing device, for processing the converted signal to obtain a data output;
- wherein the low speed frequency offset monitoring device monitors the frequency offset of the inputted optical signal in accordance with the converted signal.
The optical coherent receiver according to claim 7, further comprising:
- first and second A/D converters, for respectively converting the base band electrical signals outputted from the first and the second twin photoelectric detectors into digital signals;
- wherein the first and second A/D converters are respectively connected between the first and second twin photoelectric detectors and the low speed frequency offset monitoring device.
The optical coherent receiver according to claim 8, further comprising:
- first and second A/D converters, for respectively converting the base band electrical signals outputted from the first and the second twin photoelectric detectors into digital signals;
- wherein the first and second A/D converters are respectively connected between the first and second twin photoelectric detectors and the low speed frequency offset monitoring device.
The optical coherent receiver according to claim 9, further comprising:
- first and second A/D converters, for respectively converting the base band electrical signals outputted from the first and the second twin photoelectric detectors into digital signals;
- wherein the first and second A/D converters are respectively connected between the first and second twin photoelectric detectors and the low speed frequency offset monitoring device.
Dependencies are inferred from the claim text.