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Electrically pumped, surface-emitting distributed feedback lasers were for the first time demonstrated without any facet reflections. The devices contained second-order gratings etched into a thin p-AlGaAs cladding layer surface. A gold ohmic contact deposited directly onto the p-AlGaAs grating surface provided strong coupling to the waveguide mode. Single spatial mode devices with low divergence output beams and single frequency spectra were obtained at room temperature.
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Macomber et al. (1987) studied this question.
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