High precision chromatic dispersion measuring method and automatic dispersion compensating optical link system that uses this method
First Claim
1. A method of measuring chromatic dispersion of an optical transmission line, comprising:
- transmitting on the optical transmission line a single digital optical signal generated by using a single light source on an optical transmission line, the digital optical signal being a carrier suppressed RZ encoded optical signal generated using a carrier suppressing device and binary NRZ code or partial response code, a carrier suppressed clock signal generated using a carrier suppressing device and a clock signal, an NRZ encoded optical signal, an RZ encoded optical signal, or an optical clock signal;
receiving the same single digital optical signal transmitted on the optical transmission line;
optically separating at least two band components of different frequencies from the received same single digital optical signal;
extracting at least two pieces of phase information of basebands from the at least two band components;
comparing at least two of the at least two extracted pieces of phase information to obtain information about a relative phase difference between at least two of the at least two extracted band components; and
calculating a chromatic dispersion value for the optical transmission line;
based on the information about the relative phase difference extracted from the at least two band components of different frequency optically separated from the original transmitted single digital optical signal.
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Accused Products
Abstract
The present invention relates to an automatic dispersion compensating optical link system. Carrier suppressed RZ encoded optical signals generated using carrier suppressing means and binary NRZ code or partial response code, or carrier suppressed clock signals generated using carrier suppressing means and clock signals are transmitted on an optical transmission line. Two bands of the carrier suppressed RZ encoded optical signals or carrier suppressed clock signals transmitted on the optical transmission line are each divided into bands and are received. Phase information of the respective basebands is extracted from the binary NRZ code components or partial response code components or clock signals in each band and the relative phase difference thereof is detected. The chromatic dispersion value of the optical transmission line is then calculated from the relative phase difference.
44 Citations
39 Claims
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1. A method of measuring chromatic dispersion of an optical transmission line, comprising:
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transmitting on the optical transmission line a single digital optical signal generated by using a single light source on an optical transmission line, the digital optical signal being a carrier suppressed RZ encoded optical signal generated using a carrier suppressing device and binary NRZ code or partial response code, a carrier suppressed clock signal generated using a carrier suppressing device and a clock signal, an NRZ encoded optical signal, an RZ encoded optical signal, or an optical clock signal; receiving the same single digital optical signal transmitted on the optical transmission line; optically separating at least two band components of different frequencies from the received same single digital optical signal; extracting at least two pieces of phase information of basebands from the at least two band components; comparing at least two of the at least two extracted pieces of phase information to obtain information about a relative phase difference between at least two of the at least two extracted band components; and calculating a chromatic dispersion value for the optical transmission line;
based on the information about the relative phase difference extracted from the at least two band components of different frequency optically separated from the original transmitted single digital optical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An automatic dispersion compensating optical link system comprising:
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an optical signal transmission device that transmits a single digital optical signal generated by using a single light source on an optical transmission line which connects an optical transmitting apparatus and an optical receiving apparatus with the digital signal being a carrier suppressed RZ encoded optical signal generated using a carrier suppressing device and binary NRZ code or partial response code, a carrier suppressed clock signal generated using a carrier suppressing device and a clock signal, an NRZ encoded optical signal, an RZ encoded optical signal, or an optical clock signal; an optical signal receiving device that receives the same single digital optical signal transmitted on the optical transmission line, and optically separates at least two band components of different frequency from the received same single digital optical signal; and a chromatic dispersion value calculation device that extracts at least two pieces of phase information of basebands from the at least two band components, and compares at least two of the at least two extracted pieces of phase information to obtain information about a relative phase difference between at least two of the at least two extracted band components, and calculates a chromatic dispersion value for the optical transmission line, based on the information about the relative phase difference extracted from the at least two band components of different frequency optically separated from the original transmitted single digital optical signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An optical receiving apparatus comprising:
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a device which receives a single digital optical signal, which is a carrier suppressed RZ encoded optical signal generated using a carrier suppressing device and binary NRZ code or partial response code, a carrier suppressed clock signal generated using a carrier suppressing device and a clock signal, an NRZ encoded optical signal, an RZ encoded optical signal, or an optical clock signal, and which single digital optical signal is generated by using a single light source and which is transmitted on an optical transmission line, optically separates at least two optical spectrum components from the received same single digital optical signal, extracts at least two components of different frequency from among the optical spectrum components and extracts at least two pieces of phase information of basebands from the at least two components of different frequencies; a phase comparing device which detects a relative phase difference between the extracted frequency components based on the phase information for each of the frequency components; a chromatic dispersion measuring device which calculates a chromatic dispersion amount of the digital optical signal due to the optical transmission line based on the relative phase difference obtained from the phase comparing device; and a dispersion compensating device which compensates chromatic dispersion of the optical transmission line based on a measurement result of the chromatic dispersion measuring device. - View Dependent Claims (39)
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Specification