Title :
Experimental and theoretical investigations of coherent OFDR with semiconductor laser sources
Author :
Passy, R. ; Gisin, N. ; von der Weid, J.P. ; Gilgen, H.H.
Author_Institution :
Group of Appl. Phys., Geneva Univ., Switzerland
fDate :
9/1/1994 12:00:00 AM
Abstract :
Experimental and theoretical investigations of coherent optical-frequency-domain reflectometry using semiconductor laser sources are presented. Good agreement was found between the analysis of the signal-to-noise ratio due to the phase noise and the experimental results. The sensitivity limit due to the quantum noise is also described. Limitations due to the nonlinearity in the optical frequency sweep produced by the thermal-response time of the laser and mode hopping are investigated and compared with experimental results. Two interferometric methods to characterize the thermal-response time of the laser and their implementations are described. The effects of mode hopping in the optical-frequency sweep are compared to numerical simulations. A simple formula to predict the position of spurious peaks due to mode hopping are presented. A spatial resolution of 400 μm over 10 cm was obtained by correcting the nonlinearity in the optical-frequency sweep by using an auxiliary interferometer. The Rayleigh backscattering was observed for the first time over more than 400 m of fiber using a DFB laser coupled to an external cavity
Keywords :
Rayleigh scattering; backscatter; light coherence; light interferometry; light scattering; measurement by laser beam; optical fibre testing; reflectometry; semiconductor lasers; sensitivity; 400 m; DFB laser; Rayleigh backscattering; auxiliary interferometer; coherent OFDR; coherent optical-frequency-domain reflectometry; external cavity coupled laser; interferometric method; mode hopping; nonlinearity; numerical simulations; optical frequency sweep; optical-frequency sweep; phase noise; quantum noise; semiconductor laser sources; sensitivity limit; signal-to-noise ratio; spatial resolution; thermal-response time; Laser modes; Laser noise; Laser theory; Optical interferometry; Optical noise; Optical sensors; Reflectometry; Semiconductor lasers; Signal analysis; Signal to noise ratio;
Journal_Title :
Lightwave Technology, Journal of
