160 GHz mode-locked laser diode stabilized by subharmonic-frequency optical pulse injection

Subharmonic-frequency optical pulse injection (subharmonic synchronous mode-locking, SSML) is a promising way of stabilizing ultrafast passively mode-locked laser diodes (PML-LD) because the application is not limited by the bandwidth of drive sources. In this paper, we report on stabilizing 160 GHz PML-LD by the SSML method. Timing jitter reduction was evaluated quantitatively by a newly-developed all-optical down converting technique of ultrafast optical pulses using the optical fiber's nonlinearity. Timing jitter was reduced to 0.26 ps at an injection power of 57 /spl mu/W, comparable to that of injected pulses.