Abstract: A distributed Brillouin sensor system is provided. The system has two distributed feedback (DFB) lasers, which are locked at the Brillouin frequency of the optical fiber through offset locking method by coupler splitting into two parts. The split parts are sent to two photodiodes, the outputs of which are sent to a mixer. A PID controller means follows the mixer and a current controller follows the PID controller. The lasers have a wavelength of 1550 nm. The PID controller locks the frequency difference. An optical delay line is used to produce the frequency tuning of the two DFB lasers around the Brillouin frequency of the optical fibers. The lock-in amplifier is used to keep the DC level of the optical modulator at minimum.

Abstract: A distributed Brillouin sensor system is provided. The system has two distributed feedback (DFB) lasers, which are locked at the Brillouin frequency of the optical fiber through offset locking method by coupler splitting into two parts. The split parts are sent to two photodiodes, the outputs of which are sent to a mixer. A PID controller means follows the mixer and a current controller follows the PID controller. The lasers have a wavelength of 1550 nm. The PID controller locks the frequency difference. An optical delay line is used to produce the frequency tuning of the two DFB lasers around the Brillouin frequency of the optical fibers. The lock-in amplifier is used to keep the DC level of the optical modulator at minimum.

Abstract: A dispersion compensator has a linearly chirped fiber Bragg grating mounted at two ends of an elongated, channel-shaped heat distributor. The distributor has two thermo-electric coolers at two ends, a heating strip for uniform heating of the distributor, a temperature sensor mounted on the distributor in the middle of the grating region, and longitudinally variable heating means attached to the distributor and extending along its length for effecting a longitudinally varying heating of the grating region. The provision of the heating strip helps maintain linearity of the thermal gradient of the distributor while the longitudinally variable heaters facilitate relatively fast dithering of the temperature of the grating region.

Abstract: A dispersion compensator has a linearly chirped fiber Bragg grating mounted at two ends of an elongated, channel-shaped heat distributor. The distributor has two thermo-electric coolers at two ends, a heating strip for uniform heating of the distributor, a temperature sensor mounted on the distributor in the middle of the grating region, and longitudinally variable heating means attached to the distributor and extending along its length for effecting a longitudinally varying heating of the grating region. The provision of the heating strip helps maintain linearity of the thermal gradient of the distributor while the longitudinally variable heaters facilitate relatively fast dithering of the temperature of the grating region.