Simultaneous probe and pump extinction ratio enhancement demonstration in all-optical noninverted wavelength shifting

We demonstrate the utility of a semiconductor optical amplifier SOA-based cross-gain compression two-stage wavelength shifter that provides the functions of: (1) an increased wavelength shifted output probe extinction ratio for both up-conversion and down-conversion; (2) a noninverted output probe data format; and (3) a simultaneous increase of the input pump extinction ratio. The additional feature of an increased pump extinction ratio may be beneficial when broadcasting to several λ-dependent destinations. We demonstrate this two-stage shifter when up-converting from a l-Gbit/s 1551-nm input pump to a 1558-nm output probe. We show that the pump and probe extinction ratios are simultaneously increased by 2.4 and 2.0 dB, respectively, relative to the single-stage case while incurring a probe power penalty of only ∼0.5 dB at 1 Gbit/s. We also show that the output probe is not inverted. This scheme can be extended to several cascaded stages and to higher rates.