High-frequency performance of triple quantum well GaInNAs/GaAs ridge waveguide lasers emitting at 1.35 mu m

Static performances and high-frequency characterisation of a GaInNAs/GaAs laser diode emitting at 1.35 mum are reported. Optimised molecular beam epitaxial (MBE) growth has allowed the achievement of a triple quantum well stack for improved dynamic properties. Broad area lasers exhibit a transparency current density of 642 A/cm(2) at 20degreesC under pulsed operation and a characteristic temperature T-0 of 80 K. Single-mode narrow-ridge waveguide devices emitting at 1.34 mum demonstrate a low threshold current of 26 mA under continuous wave (CW) operation at 25degreesC for an HR/as-cleaved cavity. The maximum output power reaches 9 mW with a slope efficiency of 0.13 W/A under CW operation. Intrinsic dynamic properties of the devices have been evaluated through relative intensity noise (RIN) measurements and small signal modulation. The dependence of the relaxation frequency on the bias current shows a slope of 0.92 GHz/mA(1/2). The evolution of the damping factor against the squared relaxation frequency gives a K factor of 0.44 ns. RIN measurements yield a record relaxation frequency of 7.4 GHz for this triple-QW device. Small signal modulation shows a 3 dB bandwidth of 9.7 GHz for this new material system, compatible with 10-Gbit/s applications.