Independent and Simultaneous Delay Control of Two 10-Gb/s Channels Using a Single Optical Delay Element

We demonstrate a single tunable delay element based on wavelength conversion and dispersion for independent dual-channel operation. The two signals are sent bidirectionally to a single piece of highly nonlinear fiber for wavelength conversion by four-wave mixing. The converted signals are then sent to a chirped fiber Bragg grating to utilize its wavelength-dependent delay characteristic. We demonstrate up to 400-ps delay for return-to-zero and nonreturn-to-zero modulated signals at 10 Gb/s. The amount of delay for each channel is controlled by the wavelength of a pump signal, and is completely independent of the presence of the other one. The quality of the delayed signals is also independent of the presence of the other; this is verified by bit-error-rate measurements.