We report on the experimental observations of a perioddoubling route to chaos and a total mode-locking between two lowest-order lateral modes of a GaAs ridge wave-guide diode laser at 795 nm. A selfstarting passively mode-locking was achieved in an extended-cavity diode laser (ECDL) operating in a gain saturation regime. In the period-doubling mode-locked state, the RF spectra associated with the coherently coupled lateral TE0 and TE1 modes, consisted of harmonics (nfrep/2, n is an integer) of the half of pulse repetition rate frep/2 and the period (2T) of the pulse train was two-times longer than the pulse round-trip time T. On the other hand, in the total mode-locked state, the RF spectra and the pulse train corresponding to the TE0 and TE1 modes had exactly the same features compared to those of the period-doubling mode-locked state, except the RF spectra and the pulse train of the TE1 mode were shifted by f ref/4 in frequency and by T in time, respectively, indicating the pulses actually traveled alternatively through two lateral modes. The total mode-locking and also chaotic pulsations were observed at slightly different operation parameters, e.g. at different feedback angle of the grating, which was used as an output coupler of the ECDL.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics