Wavelength tuning of quantum well heterostructure lasers using an external grating

摘要

The method of and apparatus for tuning the wavelength using an external diffraction grating is accomplished with a quantum well injection laser wherein the range of operating wavelength selection is extended beyond the expectations of wavelength selection in fundamental emission spectrum of conventional bulk-crystal heterostructure lasers to include wavelength selection at the multiple carrier recombination transition energies possible in the conduction band sub-bands and valence band sub-bands present in quantum well heterostructures of single or multiple quantum well lasers. Quantum well heterostructure lasers have a unique advantage over previous tuned semiconductor lasers, as exemplified in the previously cited prior art, in that the active region of the quantum well laser can be bandfilled to well above the bulk crystal band edge at moderate current densities indicative of excellent candidates for broad band tuning through a wide range of the quantum well sub-bands of the quantum well structure.