Tapered waveguide InGaAs/InGaAsP multiple-quantum-well lasers

The use of ultrathin etch-stop techniques to expand the vertical optical mode size adiabatically in 1.5- mu m InGaAs/InGaAsP MQW lasers using a tapered-core passive intracavity waveguide structure is discussed. 30% differential quantum efficiency out the tapered facet, far-field FWHM of approximately 12 degrees and a butt-coupling efficiency into a cleaved fiber of -4.2 dB, with -1-dB alignment tolerances of approximately +or-3 mu m, were achieved.<
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