All optical mode locking of Fabry-Perot laser diode via mutual injection locking between two longitudinal modes

A method to mode lock a Fabry-Perot laser diode (F-P LD) by purely optical means is proposed. Two F-P modes are mutually injection locked with the aid of injected cw light at the center frequency of the two modes. The other F -P modes are cascadingly mode locked owing to the cavity-enhanced nondegene rate four-wave mixing in the F-P LD. The principle of the method was confir med by observing the linewidth narrowing of the lasing longitudinal modes a nd the generated optical pulse train at the repetition frequency of one F-P mode spacing. (C) 1999 American Institute of Physics. [S0003-6951(99)04927 -X].