Numerical Investigation into Optical and Electronic Performance of Crystal Orientation-dependent InGaAs/InP Near-Infrared Laser

Abstract The energy band dispersion profile and their dependence on crystal orientation for III-V zinc-blende compound quantum wells (QW) have earned significant attention in recent years due to reduced band mixing effects emerging from increased energy separation between valence subbands. So QW like InGaAs grown in non-conventional orientation seems to be quite optimistic to serve as active region in near-infrared optoelectronic applications due to small piezoelectric polarization, improved confinement of high energy states and increased favorable spectral range than traditional (1 0 0)-oriented growth. Here, crystal orientation-dependent electronic and optical performance of InGaAs-InP laser subjected to 1.60% compressive strain and emitting around 2 µm is studied numerically after working out an eight-band k.p Hamiltonian with the help of finite difference method and Tensor rotation technique. An equivalent circuit model using three-level laser rate equations is employed here to reveal optical output power and steady state frequency response. It is noticed that the wave functions of hole are more confined in (1 1 1) orientation than (1 0 0) orientation. Also, there is a noteworthy reliance of the energy band gap, optical gain spectra and output lasing power profile on change in crystal orientation. The estimated gains are found to be 4250, 3900, 3555, 3210 and 2950 cm−1 in (1 1 1), (1 0 0), (1 3 1), (1 1 0), and (1 1 3) orientations. The topmost lasing power and lowest threshold current are noted to be 56.4mW and 4.5 mA, respectively, in the (1 1 1) crystal orientation. Further, the highest optical emission point is observed to be moved towards longer wavelength for the alteration in crystal orientation from (1 3 1) to (1 1 1).