Injection locking characteristics of an AlGaAs semiconductor laser

Injection locking of an AlGaAs double-heterostructure laser was studied with respect to locking frequency width and locking gain. The relation of the locking bandwidth versus the ratio of locked laser to injected power was consistent with the analysis on injection locking phenomena by Adler. Measured maximum locking bandwidth was 3 GHz, when locking gain was 23 dB. The 40 dB maximum gain was observed with the 500 MHz locking bandwidth. By measuring the beat notes between two temperature-stabilized free running AlGaAs lasers, the linewidth was estimated as 10 MHz.