Patent ID: 8937978
Filing Date: 2015-01-20
Classification: B82Y,H01S

Abstract:
1. A semiconductor laser operable to output light at a lasing wavelength in response to supply of an electrical current, the semiconductor laser having an optical cavity comprising: an active region with a first band gap arranged such that a proportion of electrons and holes that recombine across the first band gap recombine to emit photons at the lasing wavelength, the proportion decreasing with increasing temperature of the optical cavity; and an additional structure with one or more additional band gaps, the first and one or more additional band gaps being arranged such that a ratio of electrons and holes that recombine across the first band gap to electrons and holes that recombine across the one or more additional band gaps increases with increasing temperature of the optical cavity, wherein, over a range of temperatures at which the semiconductor laser is intended to operate, the increasing ratio compensates for the decreasing proportion so as to reduce change with temperature of the optical cavity in the rate at which electrons and holes recombine across the first band gap to emit photons at the lasing wavelength.