High resolution wavelength locking technique for one- and two-dimensional arraysof semiconductor diode lasers

摘要

An external cavity semiconductor laser provided with a semiconductor laser diode array (40), a diffraction grating (32), and a mirror (34). The diode laser array (40) is positioned to illuminate the diffraction grating (32) and the mirror (34) to reflect selected wavelengths back into the cavity for plural wavelength locked beams with a single resonant cavity. The laser array (40) provides lasers (36, 38) at different spatial positions of the resonant cavity (30) for resonating laser beams at multiple wavelengths providing a cost effective approach for generating multiple wavelengths. A first semiconductor diode laser (36) of the array illuminates the diffraction grating with a first beam at a first angle of incidence, and a second semiconductor diode laser (38) of the array illuminates the diffraction grating with a second beam at a second angle of incidence. A mirror (34) positioned opposite the diffraction grating reflects the first beam (42) and the second beam (44) deflected from the diffraction grating (32) to provide a first select order of reflection from said diffraction grating back to the first laser (36) and the second laser (38) respectively. An output (46) couples a second select order of reflections from the diffraction grating (32). A modified Littman-Metcalf configuration is adapted to the implementation of a single external cavity to minimize the costs associated with multiple external cavity diode lasers and/or wavelength lockers for each of multiple semiconductor diode lasers. The described embodiments provide innovative applications of one- and two-dimensional, position-dependent wavelength feedback to lock arrays of semiconductor lasers at a particular, well-controlled wavelength, using the best attributes of crossed dispersion techniques (high resolution and two-dimensional dispersion) to achieve this goal.