All-optical coding of mode-locked semiconductor laser pulse trains for high bit rate optical communications

We demonstrate an all-optical scheme for coding high frequency mode-locked semiconductor laser pulse trains. The scheme is experimentally demonstrated by optically modulating a high frequency pulse train at 38 GHz generated by a subharmonic synchronous mode-locked semiconductor laser with binary information contained in multiple low bit rate optical data signals (3.8 Gb/s). Synchronization between the two signals is achieved through optical injection into the mode-locked laser while high speed modulation is achieved via a nonlinear optical loop mirror made of dispersion shifted fiber. The coding scheme has advantages over existing passive multiplexing schemes in generating high data rate optical signals due to its regeneration and wavelength conversion functionality. [Copyright &y& Elsevier]