Paper
9 December 1999 Measurement of Brillouin gain spectrum distribution along an optical fiber by direct frequency modulation of a laser diode
Takemi Hasegawa, Kazuo Hotate
Author Affiliations +
Abstract
A novel scheme for measuring Brillouin gain spectrum distribution along an optical fiber is developed. This scheme utilizes direct frequency modulation of a laser diode for two purposes: generation of the pump and probe lightwaves, and position-selective excitation of stimulated Brillouin scattering. A laser diode is modulated with a rectangular-wave signal, so that the pump and probe lightwaves for Brillouin gain spectrum measurement are generated in time-division manner. A sinusoidal-wave signal is mixed with the modulation signal for spreading the spectra of the pump and probe lightwaves. Because of the spread spectra, stimulated Brillouin scattering occurs in a small section of the fiber where the two lightwaves are highly correlated. The Brillouin gain spectrum at the section is obtained selectively. The section to be measured is chosen by varying the period of the sinusoidal modulation. Experimental result of measurement of the Brillouin spectrum distribution with a spatial resolution of 70 cm is presented. As a comparison, another system is demonstrated, where the probe lightwave is generated by intensity modulation with LN modulator. Spatial resolution of about 6.5 cm is achieved.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Takemi Hasegawa and Kazuo Hotate "Measurement of Brillouin gain spectrum distribution along an optical fiber by direct frequency modulation of a laser diode", Proc. SPIE 3860, Fiber Optic Sensor Technology and Applications, (9 December 1999); https://doi.org/10.1117/12.372976
Lens.org Logo
CITATIONS
Cited by 11 scholarly publications and 1 patent.
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Modulation

Frequency modulation

Spatial resolution

Semiconductor lasers

Fermium

Optical fibers

Scattering

Back to Top