We experimentally demonstrate an optical circuit capable of mulliwavelength conversion. The circuit structure is intrinsically stable and polarization independent. It may thus be a practical solution for wavelength-division multiplexing multicasting applications. Its working principle relies on synchronous double-stage cross-gain modulation in SOAs between an incoming data-modulated signal and several local continuous wave lasers. We report the simultaneous wavelength conversion of an input 10 Gb/s nonreturn-to-zero to eight 200-GHz-spaced output channels. The obtained signals show only a moderate optical signal-to-noise ratio penalty.