Optical modulator

Abstract

An optical modulator which is capable of lowering the degree of chirping without deteriorating the extinction characteristic. An intermediate layer is interposed between a well layer and an n-side barrier layer and tensile strain is produced in the well layer, whereby a relationship Ew<Em<Eb is established between a band gap Eb (eV) of the barrier layer, the band gap Ew (eV) of the well layer, and the band gap Em (eV) of the intermediate layer. Another type of tensile strain quantum well structure having four kinds of layers may be formed by adding another layer to the above tensile strain quantum well structure having three kinds of layers. The band gap of an additional layer is set between the band gaps of the well layer and the intermediate layer or between the band gaps of the intermediate layer and the barrier layer.

Dependencies are inferred from the claim text.