Calculation of optical power emitted from a fibre grating laser

Abstract

The optical power that can be obtained from the facets of a fibre grating laser is calculated in the paper. This calculation is based on the effective transmission coefficient of the compound cavity of the device. The dependence of slope efficiency (of power per facet) on the reflectivities of the diode facets and grating, length of the laser diode and grating, and emission wavelength are considered. A configuration is suggested which allows the largest amount of optical power to be obtained from the back facet of the device when fibre gratings with strong reflectivities are used. It is also shown that a reduction in facet reflectivity results in significant reduction of the variation of output power slope efficiency due to changes in emission wavelength or length of the external cavity.