Structural design and fabrication of 830 nm GaAsP/AlGaAs low polarization superluminescent diode with tensile-strained wells

In this paper, super luminescent diode (SLD) at 830 nm with high power efficiency and low polarization was reported. The mode gain of tensile-strained GaAsP/AlGaAs double-quantum well (DQW) was calculated by the Lüttinger–Kohn Hamiltonian, including confinement effects and tetragonal strain. The results showed that the transverse-electric polarized mode gain was almost the same with transverse-magnetic polarized mode gain of the device with GaAs_0.92P_0.08 quantum well. Tensile-strained GaAs_0.92P_0.08/Al_0.25Ga_0.75As DQW SLD was prepared by Metal–organic Chemical Vapor Deposition. The SLD of ridge wave guide structure was fabricated with “J-shape” absorbing region structure with a tilt angle of 7°. The stack layers of TiO₂ and SiO₂ were coated on two facets as anti-reflection films, with residual facet reflectivity less than 1%. The SLD testing result showed the degree of polarization was 4%, optical power was 11.2 mW and peak wavelength of 824 nm at injection current was 100 mA. The experimental results were in good agreement with theoretical calculation results.