A Dispersion Measuring System

Abstract

The invention belongs to the technical field of measurement, and discloses a dispersion measuring method. The dispersion measuring method is used for measuring a dispersion value of an optical fiber link and is characterized by comprising the following steps of generating an optical carrier signal through a stable and continuous light source, adopting a radio-frequency signal for modulating the optical carrier signal into a double-sideband optical spectrum, sending the double-sideband optical spectrum to the optical fiber link to be measured, conducting photovoltaic conversion on an optical signal at the output end of the optical fiber link to be measured to convert the optical signal into an electric signal, monitoring the power value of the electric signal in real time, adjusting the scanning frequency of the radio-frequency signal, determining the scanning frequency fnull generated when the power of the electric signal is the minimum, and calculating a dispersion value obtained when the scanning frequency fnull is generated. According to the dispersion measuring method, the double-sideband optical spectrum detects the optical signal and is sent to the optical fiber link to be measured and then converted into periodical power changes of the electric signal, accurate positioning is achieved, data sampling is optimized, and therefore the measuring precision is improved; then the measuring frequency is reduced, efficiency is improved, and the measurement range is extended.

Description

technical field [0001] The invention relates to the technical field of measurement, in particular to a dispersion measurement system. Background technique [0002] At present, there are many studies on link dispersion measurement of optical transmission systems, such as online dispersion measurement based on time-domain pulse group velocity delay difference detection method. This solution requires the use of high-speed photodetectors, high-sensitivity RF power detectors and Other high-speed auxiliary measurement equipment requires strict clock synchronization between the transmitting end and the receiving end. The system cost is high and the accuracy fluctuates greatly. It is not suitable for the measurement of long-distance optical fiber link dispersion. On-line dispersion monitoring based on time-domain asynchronous sampling method, this type of method requires the use of high-speed photoelectric devices, such as light-speed photodetectors, high-speed analog-to-digital con...

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Problems solved by technology

[0002] At present, there are many studies on link dispersion measurement of optical transmission systems, such as online dispersion measurement based on time-domain pulse group velocity delay difference detection method. This solution requires the use of high-speed photodetectors, high-sensitivity RF power detectors and Other high-speed auxiliary measurement equipment, and require strict clock synchronization between the transmitting end and the receiving end, the system cost is high, and the accuracy fluctuates greatly, so it is not suitable for the measurement of long-distance optical fiber link dispersion

On-line dispersion monitoring based on time-domain asynchronous sampling method, this type of method requires the use of high-speed photoelectric devices, such as light-speed photodetectors, high-speed analog-to-digital converters, high-speed signal analyzers and other devices or equipment, the system cost is extremely high, and the dispersion measurement The range is limited and the accuracy is not high. It is suitable for monitoring the change of link dispersion within a certain range, but not suitable for the actual measurement of link dispersion. Format-dependent, a scheme can only target a specific modulation format

Dispersion monitoring based on RF spectrum analysis based on phase-sensitive detection, this type of method has similar shortcomings to the above-mentioned schemes, requires high-speed optoelectronic devices and expensive spectrum analysis instruments, the measurement range is too small, and the measurement system is too large to achieve Real-time measurement of dispersion in the optical transmission system; the measurement system has poor anti-noise performance, low measurement accuracy, high system cost, measurement results are greatly affected by device performance, and the consistency of multiple measurement results is poor, resulting in extremely low efficiency

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