High-speed short cavity strained-layer multiple quantum well lasers

The high-speed response and optical properties of strained-layer In/sub 0.3/Ga/sub 0.7/As four and five quantum-well ridge waveguide lasers fabricated by chemically-assisted ion beam etching (CAIBE) are presented. The threshold current variation with cavity length is very similar for the two-layer designs, but the differential gain decreases more quickly with optical loss in the four quantum-well devices. Consequently, whereas the 200-400 mu m cavity length lasers from the four quantum-well wafer are superior to those from the five quantum-well layer in terms of high speed performance, the 50- and 100- mu m long devices are nearly identical. A CW 3-dB bandwidth of 22 GHz and a record 3-dB bandwidth of 26 GHz under pulsed bias have been measured on 50 mu m long lasers. 100- mu m cavity length lasers exhibit excellent modulation efficiency with a typical 3-dB bandwidth of 20 GHz.<
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