| Summary: | 碩士 === 國立成功大學 === 奈米科技暨微系統工程研究所 === 97 === In recent years, the development in the telecommunication business has increased and these applications include long-distance, short distance, and high-speed optical fiber communications systems, has increased the for significantly higher internet bandwidth used in these applications day by day. Semiconductor laser diode emitting at the wavelength of 1.3-1.55μm is one of the most important optoelectronic devices in optical-fiber communication due to their advantages of zero dispersion and lowest loss respectively. They are the most suitable transmission wavelength regions of long haul fiber communication. The long wavelength can be achieved by growing conventional InP-based lasers. Not only it is very expensive and the temperature characteristics are not good enough, but also not suitable to make VCSELs.
In this thesis, we try to grow GaAs-based QW lasers by MOVPE to replace InP-based long wavelength lasers. After optimization of the growth condition, highly strain GaAsSb/GaAs QWs can be grown on GaAs substrates by MOVPE successfully; we design various laser structures with strain compensation layer to improve the crystal quality of highly strained GaAsSb QW. Lasing wavelength of 1235nm with very low threshold current density of 220A/cm2 edge emitting lasers were demonstrated successfully. In addition, we also study GaAsP/GaAs MQB with strain-compensated effects. Device with this structure get the better opto-electronic and thermal characteristic, room temperature threshold current density is 65A/cm2 and the characteristic temperature is 102K.
In the future, we will try to grow GaAsSb/InGaAs bi-layer QW lasers. We believe the bi-layer QW laser has an advantage in lasing peak wavelength above 1.3-μm, even achieving 1.55-μm. Besides, GaAsSb QW VCSELs all grow by MOVPE is another challenge.
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