A novel all-optical wavelength converter based on the transverse-magnetic (TM)-mode absorption modulation of a Fabry-Perot laser diode (FP-LD) is proposed and demonstrated. An FP-LD shows absorption nulls for TM mode probe beam, which are red-shifted by an additional optical pump injection. Using this, the transmission of the continuous-wave probe beam can be optically controlled and wavelength conversion is, thus, achieved. The proposed scheme is simple and cost-effective, and can be used for very wide-range wavelength conversion. Bit-error-rate measurements at 2.5 Gb/s were performed, and the power penalties of 2 and 6 dB were observed, respectively, for noninverted and inverted wavelength conversion.