LOW-NOISE 65O-NM-BAND ALGAINP VISIBLE LASER-DIODES WITH A HIGHLY DOPED SATURABLE ABSORBING LAYER

Stable self-sustained pulsating and low-noise 650-nm-band AlGaInP visi ble laser diodes were demonstrated by adopting a novel structure, whic h has a highly doped saturable absorbing (SA) layer. Short carrier lif etime, which is indispensable for self-pulsation, was realized by appl ying high doping concentration to the p-type SA layer, 500-mu m-long d evices with 51%/51% coated facets were fabricated, resulting in the th reshold current of 75 mA at 20 degrees C. The temporal output power wa s measured at the average output power of 5 mW and the stable self-pul sation was observed up to an ambient temperature of 60 degrees C. Ther efore, the relative intensity noise (RIN) was kept about -140 dB/Hz in temperature ranging from 20 degrees C to 60 degrees C. Since the refr active index difference could be kept large and the optical mode could be confined effectively, the astigmatism in this work was below 3 mu m at 5 mW against dc injection current. The lasers operated over 1350 h under the average output power of 5 mW at 60 degrees C.