Four-channel polarization-insensitive optically transparent wavelength converter

Multichannel wavelength converters may be important components in the crossconnects in future wavelength-division multiplexed (WDM) transport networks. We demonstrate a multichannel, polarization-insensitive, optically transparent wavelength converter, based on four-wave mixing in two semiconductor optical amplifiers in a polarization-diversity arrangement. Bit-error-rate (BER) measurements with four input 2.5-Gb/s WDM channels, spaced by 2 nm, show penalties for wavelength conversion less than 2.6 dB at 10(-9) BER. Changes in the state of polarization of the input signals cause the output power to change by less than 1.2 dB, and the corresponding power penalties change by less than 0.9 dB.