Abstract

Using a nonlinear phase shift in a signal wave by means of cross-phase modulation (XPM) from a synchronized pump wave, we can detune transmission spectra of long-period fiber gratings (LPFG’s) [1]. Thus, the transmission loss fringe in Fig 1 shifts to longer wavelengths when the effective index for a signal wave increases by a nonlinear phase shift due to XPM from a pump wave. Utilizing a narrow spectral loss band from an LPFG pair [2], we could reduce the operation intensity to less than 5 GW /cm². In Fig. 2, we demonstrated for the first time to the best of our knowledge that a signal wave can be gated all-optically by means of a pump wave in LPFG’s.

© 2000 IEEE