1.3 μ m Ga0.11In0.89As0.24P0.76∕Ga0.27In0.73As0.67P0.33 compressive-strain multiple quantum well with n-type modulation-doped GaInP intermediate-barrier laser diodes

Abstract

The authors report on fabricating and characterizing a 1.3-μm Ga0.11In0.89As0.24P0.76∕Ga0.27In0.73As0.67P0.33 compressive-strain multiple quantum well with n-type modulation-doped GaInP intermediate-barrier laser diodes (LDs). The barrier region contains a 20Å Si-doped modulation-doped GaInP intermediate layer and two 40Å undoped Ga0.11In0.89As0.24P0.76 surrounding layers. The modulation-doped GaInP intermediate barrier can increase the optical gain by the modulated-electron Fermi-Dirac distribution function, and stop the electron overflow by the inherent barrier height. The surrounding layer serves as a buffer layer to prevent the overflow of Si dopant into the well; but it also alleviates the tensile strain of the modulation-doped GaInP intermediate barrier to maintain a compressive-strain quantum well. We measured the threshold current density, differential quantum efficiency, internal quantum efficiency, and internal optical loss as a function of cavity length and doping concentration of the modulation-doped GaInP intermediate barrier. The theoretical and experimental results show that the optimal doping concentration of the modulation-doped GaInP intermediate barrier is 3×1018cm−3. With this optimal condition, the 4μm ridge-stripe and 600μm cavity LDs without facet coating will exhibit the best performance, including a lower threshold current of 29mA, a higher slope efficiency of 0.215W∕A, a higher characteristic temperature of 87.6K, and a wavelength swing of 0.28nm∕K for the LDs operated in a temperature range of 10–80°C under continuous-wave operation.