Abstract A precise and dead-zone-free method of optical fiber length measurement was proposed based on Gaussian optical pulses delay technique.Using optical fiber delay loop, two Gaussian pulses sequences with relative delay were observed in the high-speed oscilloscope.The two Gaussian pulses coincided with each other by adjusting the pulses frequency, and the optical fiber length could be calculated by the frequency.Frequency measurement errors would be induced if the two Gaussian pulses coincided incompletely.Complete coincidence could be judged by measuring the maximum amplitude according to delay-to-amplitude conversion. The frequency resolution achieved 0.1 Hz leading to high measurement accuracy. Experimental results showed that the uncertainty was 0.04 m for 2284.34 m G.652 single mode fiber (SMF), and 0.24 m for 12726.57 m SMF when wavelength of the optical source was 1296 nm.
2015, Vol. 36 
