We demonstrate a simple, novel technique for measurement of the Raman gain spectrum in optical fibers. We measure the stimulated Raman scattered power generated by a square pulse as a function of its pulse width. Because of fiber dispersion, increasing the pulse width increases the interaction length of the pump and Stokes pulses and leads to a higher Stokes power. The dependence of growth rate of Stokes power on pulse width gives the Raman gain coefficient. Our technique does not require calibration against a standard or absolute measurement of the Stokes signal. We show that gain values obtained with this technique agree well with direct pump-probe measurements.
© 1996 Optical Society of America
Daniel Mahgerefteh, Douglas L. Butler, Julius Goldhar, Brian Rosenberg, and Geoffrey L. Burdge, "Technique for measurement of the Raman gain coefficient in optical fibers," Opt. Lett. 21, 2026-2028 (1996)