Abstract

Four-wave mixing (FWM) in optical fibers has been widely investigated as a technique of realizing wavelength tunable light sources,¹–³ and, at the same time, as a source of noise that must be eliminated in wavelength-division-multiplexed transmission systems.⁴–⁶ FWM has also been demonstrated as a means of measuring fiber properties, such as the third-order nonlinearity in a fiber,⁷ the intermodal dispersion in a two-mode fiber,⁸ and the refractive-index profile of a graded-index fiber.⁹ Recently, we observed a new FWM process in a birefringent fiber, where a distinct frequency-shifted beam was produced as a result of mixing a laser beam with a spectrum of superfluorescent light.¹⁰ In this paper, we outline a theory to explain why this process is possible, and present experimental results to compare with the theory.

© 1998 Optical Society of America