High resolution relatively short fiber length measurement system based on microwave photonic link

Abstract A high resolution relatively short fiber length measurement system is proposed, which based on the phase modulation microwave photonic link. It is based on analysis of the free spectrum range (FSR) of the microwave photonic link with high resolution vector network analyzer. Compared with the traditional method, there's no need costly and high-performance laser for the system, no dead zone and can improve the precision millimeter. The smallest relative length of fiber is 3 mm with the existed high resolution vector network analyzer, and the error can be controlled within 0.05 mm when the relative fiber length is 100 m.