Tunable laser with suppression of spontaneous emission

摘要

A laser apparatus and method with compact cavity design that provides suppression of source spontaneous emission (SSE) and amplified spontaneous emission (ASE) light with minimal loss. The laser comprises a gain medium emitting a light beam along an optical path, a tuning element positioned in the optical path and configured feed back light of a selected wavelength to the gain medium and configured to define a first output beam directed along a first output path, a partial reflector located in the optical path and positioned to create a second output beam directed along a second output path substantially parallel to the first output path; and having a spontaneous emission component that is spatially separated from the selected wavelength. The second output beam can be coupled into optical fiber and produce a coherent light source with high spectral purity and tunable wavelengths.