Slab-coupled waveguide laser was theoretically analyzed by E. A. J. Marcatili  in the 1970's, based on which, we recently demonstrated a high power slab-coupled waveguide laser with buried hetero-structure. The laser lases around 1525.5 nm, with 3.4 μm*4.4 μm (FWHM) spatial mode shape. With improved current blocking mechanism, the output power reaches 326mW per facet, the coupling efficiency to the single mode fiber (SMF) is 80%, the horizontal and vertical far field angles are 10°, 18° respectively. Electron blocking layer will be implemented to improve internal quantum efficiency. Epi-side down bonding will be used to improve heat dissipation and output power.
The incorporation of carbon into In0.53Ga0.47As, In0.52Al0.48As and In0.52Al0.2Ga0.28As lattice matched to InP was investigated using carbon tetrabromide (CBr4) as the carbon source in Metalorganic Chemical Vapor Depositions growth. The parameters and growth conditions are optimized to get high p-type doping for photonic device applications. This is among the first few studies on C-doping in InAlAs and InAlGaAs, and the results show that the presence of Al also efficiently helps to obtain high p-type carbon doping.
Bulk InGaAs and InGaAsP and quantum well structure were grown on different oxide pattern. The material composition varies with the width of oxide pattern. The PL peak wavelength of the grown SAG quantum well is determined by the variation of both the material composition and the well width. We have experimentally identified the ratio of the contribution from the two sources, which agree well with the theoretical calculation from the measured thickness changes.
GaAs/AlAs superlattices (SLs) were grown by MOCVD. The temperature dependence of photoluminescence was measured. The type II-transition dominated PL spectrum was achieved by controlling the layers thickness of GaAs and AlAs at low temperature. Such SLs with long carrier lifetime is very attractive for low crosstalk semiconductor optical amplifier applications.
The method of using Si delta doping to obtain high n-type doping for InP and In0.53Ga0.47As lattice matched to InP was studied. With the multiple delta doping, we can obtain ~1019 cm-3 N-type doping for both the InP and InGaAs materials by using TMI, PH3, Si2H6 and TEGa precursors in Metalorganic Chemical Vapor Depositions growths. Current results show that the delta doping technique is critical for getting extremely high N-type doping in InP and InGaAs.
Bulk InGaAs and InGaAsP and quantum well structure have been grown on different oxide pattern by MOCVD. We found that because of material composition variation caused by the oxide pattern compressive strain s built, so that the PL intensity is reduced. By introducing tensile strain to compensate for the compressive strain caused by the SAG effect, the PL intensity has been improved. Active and passive integrated devices can be fabricated without significantly suffering the material degradation by using this method.
In1-xGaxAsyP1-y nipi Structure has been grown by MOCVD and been characterized by photoluminescence. The two PL profiles from the direct and the indirect recombination channels were clearly observed. The excitation intensity and temperature dependence of the PL profiles are studied. A calculated carrier lifetime, as long as 71μs is possible to be realized. With such a long carrier lifetime, we can push the XT noise out of the signal band down to frequencies < f=f=1/(2πτ)=2.2kHz. Equivalently, the XT is eliminated.