Advances in facet design for buried lasers and amplifiers

A new approach is presented for calculating the facet reflectivity of semic onductor lasers and waveguides buried at a finite distance below an upper s emiconductor-air interface. The full three-dimensional nature of the wavegu ide is considered, and the effect of the air-semiconductor boundary on the facet reflectivity is fully explored for both TE and TM polarizations, incl uding the use of coated and angled facets. It is clearly shown that the pro ximity of the semiconductor-air interface cannot be neglected without compr omising accuracy, especially in the practically important case of coated fa cets, Furthermore, the novel method described here is easy to implement, as well as being accurate and fast.