An all-optical multi-wavelength converter using absorption modulation of an injection-locked Fabry-Perot laser diode (FP-LD) is demonstrated at 2.5Gb/s. The multi-wavelength converter can simultaneously provide 1 to 4 channel outputs and support both inverted and non-inverted conversion. By optimizing the wavelength of pump signal and polarization states of pump, probes, and the FP-LD, all converted outputs show high extinction ratio and negligible crosstalk power penalty. The results guarantee to increase the number of output channels. The proposed scheme can be applied to multicasting functions as well as 1xN wavelength conversion in an all-optical wavelength division multiplexed network.