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Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 1, p. 33, January, 1989.     

A temperature-stable semiconductor laser based on coupled waveguides

The design of a stripe semiconductor laser with a composite waveguide formed of two tunneling-coupled waveguides, one of which is narrow and contains the active medium and the other of which is wide and forms the optical mode is considered. It is shown that temperature stabilization of the lasing wavelength can be attained with such a semiconductor laser design. Stabilization of the wavelength can be brought about by lasing in antiresonance conditions of coupling of two waveguides; these conditions arise in a narrow range of wavelengths that depends on temperature only slightly. Calculations performed at the parameters characteristic of the InAlGaAsP laser system show that it is possible to reduce the temperature dependence of the lasing wavelength by a factor of 3 in the temperature range with the width of 60 K.     

Effect of active-region modulation doping on simultaneous ground-state and excited-state lasing in quantum-dot lasers

The lasing spectra and light-power characteristics of lasers based on InAs/InGaAs quantum dots with p-type modulation doping are studied over a broad range of pump currents. It is shown that p-type doping leads to a significant increase in the threshold current for the onset of lasing at the excited-state transition and makes it possible to attain higher output powers for lasing at the ground-state transition as compared to lasers with an undoped active region. An explanation for the observed features of two-level oscillation in quantum-dot lasers is suggested.