High-Speed Low-Noise InAs/InAlGaAs/InP 1.55-$\mu{\rm m}$ Quantum-Dot Lasers

We present the static and dynamic properties of InAs quantum-dot (QD) lasers emitting near 1.55 μm. The used laser material comprises four QD layers and exhibits a high modal gain of about 40 cm
^-1
. The 340-μ.m-long lasers show a room temperature threshold current of 38 mA and a maximum output power of 16 mW. The small signal modulation response is highly damped and carrier transport limited with a moderate 3-dB bandwidth of 5 GHz. This is accompanied by a flat relative intensity noise spectrum at a low level of -150 dBc/Hz. Neverthe- less, the laser exhibits record large signal modulation capabilities for a 1.5-μ.m QD laser: 15 Gb/s with a 4-dB on/off ratio.