Advances in facet design for buried lasers and amplifiers

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