Improved Performance of 2.2- $\mu{\rm m}$ InAs/InGaAs QW Lasers on InP by Using Triangular Wells

InP-based InAs/InGaAs quantum well (QW) lasers emitting at wavelength about 2.2 μm have been demonstrated. To study the effects of triangular QWs on laser performance, lasers grown with digital alloy triangular QWs are discussed and rectangular InAs QW lasers are presented for reference. The use of triangular QWs improves laser performance in terms of threshold current density, output power, characteristic temperature, maximum operation temperature, quantum efficiency, and internal optical loss coefficient. By using triangular QWs, the threshold current density decreases from 2.58 to 1.42 kA/cm² under continuous-wave driving condition at 300 K, and the output power increases from 3.6 to 10.4 mW/facet at an injection current of 400 mA. The maximum operation temperature reaches up to 330 K, about 20 K higher than the value of the laser with rectangular-shaped QWs.