Simple and highly accurate technique for time delay measurement in optical fibers by free-running laser configuration.
A novel and simple technique for the measurement of time delay in the optical fiber by a free-running laser is proposed and demonstrated. The fiber to be measured was spliced to an erbium-doped fiber so as to form a ring-cavity laser. The mode beating frequency of the laser was measured to determine the round-trip time delay. This precise and efficient technique has an accuracy of 10(-8) for a fiber length of 100 km and of 10(-6) for a several-meters-long one.
Yun
Ke
K
Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, China. keyun@stanford.edu
Li
Jing
J
Zhang
Guangxiao
G
Chen
Lingling
L
Yang
Weijian
W
Zhang
Zhigang
Z