0000000000377302
AUTHOR
Martin D. Dawson
showing 7 related works from this author
GaInNAs/GaAs Bragg-mirror-based structures for novel 1.3μm device applications
2004
We report the use of GaInNAs/GaAs material system for a range of 1.3 μm vertical-cavity devices namely VCSELs, VCSOAs, VECSELs and SESAMs. Using optical pumping, we demonstrate that up to 4 mW of 1290 nm output power can be fibre-coupled from a VCSEL. We also show that tayloring the VCSEL structure allows to produce a monolithic long-wavelength VCSOA with up to 16 dB of gain. We also report the first demonstration of a 1.3 μm VECSEL with more than 0.5 W of CW ouptut power. Finally, annealing effects on the properties of a GaInNAs SBR and modelocking of two Nd:doped solid state lasers using this element are described.
Effects of rapid thermal annealing on the optical properties of low-loss 1.3μm GaInNAs∕GaAs saturable Bragg reflectors
2004
We report studies of the effect of rapid thermal annealing (RTA) on the optical properties of a low-loss 1.3 mum saturable Bragg reflector (SBR), consisting of a GaInNAs/GaAs single quantum well embedded in an AlAs/GaAs Bragg reflector grown monolithically on a GaAs substrate. RTA gives rise to a blueshift of the photoluminescence (PL) peak (and therefore of the excitonic absorption peak) and an enhancement of PL intensity, while the reflectivity properties including peak reflectivity and bandwidth are not degraded. Temperature dependent photoluminescence measurements show that the RTA-induced blueshift of photoluminescence consists of two components: one originating from the increase of op…
Microreflectivity studies of wavelength control in oxidised AlGaAs microcavities
2003
Wet oxidation of GaAs/AlGaAs structures is an important technique in the processing of advanced devices such as vertical cavity surface emitting lasers (VCSELs). In one VCSEL application, the low-index and electrically-insulating AlxOy layers have been used to obtain high-reflectivity and broad bandwidth distributed Bragg reflector mirrors (DBRs). A further recent development has shown that combined lateral–vertical oxidation of intracavity AlGaAs layers can be used to tune the resonant wavelength of a semiconductor microcavity. The slow oxidation rate limits the lateral scale of practical wet oxidation to mesas structures of 50–100 μm in width. Therefore post-processing assessment of spect…
Selective modification of the band gaps of GaInNas/GaAs structures by quantum well intermixing techniques
2003
We report the unambiguous demonstration of controlled quantum well intermixing (QWI) in the technologically important GaInNAs/ GaAs 1.3 mum material system. QWI is a key technique to selectively modify the band gap of quantum wells, which has found broad application in semiconductor lasers and photonic integrated circuits (PICs). Extending such technology to GaInNAs/GaAs structures is highly desirable due to the technologically advantageous properties of this material system. Here, we investigate well-characterized GaInNAs quantum well material which has been annealed "to saturation" before QWI processing to allow unambiguous interpretation of results. After RTA at 700 degreesC for similar …
1.3 µm GaInNAs optically-pumped vertical cavity semiconductor optical amplifier
2003
A GaInNAs/GaAs vertical cavity semiconductor optical amplifier (VCSOA) is reported. This is believed to be the first monolithic VCSOA operating at 1.3 mum. Under continuous-wave optical pumping in a singlemode fibre coupled format, gain figures of up to 17.7 dB were achieved. Amplification with 12 GHz bandwidth,was obtained at 12.8 dB peak gain.
Long-wavelength monolithic GaInNAs vertical-cavity optical amplifiers
2004
We report on the continuous-wave amplification characteristics of an optically pumped 1.3-μm multiple-quantum-well GaInNAs-GaAs vertical-cavity semiconductor optical amplifier (VCSOA). The VCSOA structure was monolithically grown by molecular beam epitaxy and operated in reflection mode in a fiber-coupled system. The maximum on-chip gain attained, limited by the onset of laser action, was 15.6 dB at 196 mW of 980-nm pump power. For a chip gain of 10.4 dB, the optical bandwidth was 10.8 GHz and the saturation output power was -9 dBm. By varying the pump laser power, a maximum extinction ratio of 22.3 dB was obtained. Temperature-controlled tuneable operation of the device is also presented a…
Quantum well intermixing in GaInNAs/GaAs structures
2003
We report on the characteristics of quantum well intermixing in GaInNAs/GaAs structures of differing N content. Rapid thermal annealing combined with SiO2 caps deposited on the surface of the samples is used to disorder 1.3 mum GaInNAs/GaAs multiquantum wells which have been preannealed in-situ to the stage of blueshift saturation. The different effects of two capping layer deposition techniques on the interdiffusion of In-Ga have been compared, particular regarding the role of sputtering processes. The dependence of quantum well intermixing-induced photoluminescence blueshift on N concentration has provided extra information on the intrinsic properties of the GaInNAs/GaAs material system. …