Ironside C. Semiconductor integrated optics for switching light

Bristol: IOP Publishing, 2021. — 96 p.This book has its genesis in research work on all-optical switching in semiconductors. After sifting through many types of materials and device configurations the author and his collaborators were guided by the theory of optical waveguiding, twophoton absorption and the strongly related theory of the pure optical Kerr effect in semiconductors and arrived at semiconductor waveguide devices for ultrafast switching. There is a strong emphasis on III–V semiconductors. In particular for optical communications wavelengths, it turns out that one of the best materials is based on AlGaAs semiconductor alloys. Specifically, at for example optical communications wavelengths in the so-called C band around 1550 nm, then with Al fraction in AlxGa1-xAs around x = 0.18 in the core of semiconductor waveguides, then this leads to the best semiconductor devices for ultrafast all-optical switching.
Much of the book is dedicated to explaining why this is the case and discussing the evidence for this conclusion. Special thanks go to Professor J Stewart Aitchison, now of the University of Toronto, who came with idea of using the Al0.18Ga0.82As alloy. There are some interesting aspects of the effect of electric fields on the optical properties of semiconductors covered along the way. These include the linear electro-optic effect, electroabsorption and electrorefraction and how these relate to the second and third order nonlinear optics of semiconductors. The cascaded second order nonlinear optical effect, associated with linear electro-optic effect, can lead to a nonlinear refractive index normally associated with the third order nonlinear optical effect. Further, the theory of two-photon gain in semiconductors is derived by combining simple semiconductor laser theory with two-photon absorption theory. Two-photon gain in semiconductors has now been observed by some research groups.
The author hopes that the reader finds the same amount of enjoyment in reading about this work as the author and his collaborators (see the acknowledgements) found in doing the work.
The first edition has been revised and extended. It has been expanded by including a chapter on semiconductor optical amplifier (SOAs) and Python Jupyter notebooks have been included that can be run on Google’s colab computing platform.