GAIN CHANGE AND THRESHOLD REDUCTION OF DIODE-LASER BY INJECTION LOCKING

Injected optical signals change many of the characteristics of diode l asers. The frequency and the intensity of the injected signal determin e the effect. We present a systematic study of the change in laser gai n and hence threshold when the injected signal frequency is such that the locking point appears slightly below or above the threshold of the free running slave laser. Our results support the recent theoretical predictions where it was seen that spontaneous emission plays an impor tant role near the threshold and the gain change due to injection lock ing is maximum at the threshold. (C) 1998 Elsevier Science B.V. All ri ghts reserved.