Repeated Wavelength Conversion of 10 Gbit/s Signal Using Wavelength-Tunable Semiconductor Lasers

Repeated wavelength conversion of 10 Gbit/s pseudo-random non-return-to-zero signals is demonstrated using superstructure grating distributed Bragg reflector lasers operating in the 1.55-μm wavelength region. Error-free and very low-power-penalty wavelength conversion can be achieved in both first and second wavelength conversion for a fixed converted wavelength over a broad wavelength range from 1.486 to 1.573 µm (about 90-nm wide). The power penalty of the transmitted signal light through the first wavelength conversion device increases when the converted wavelength is switched from 1.544 to 1.573 µm periodically at a repetition frequency of 40 MHz. The increase in power penalty, however, is less than 6 dB even when the bit error rate is 10-12.