High-Speed Modulation of Semiconductor Lasers by Optical Injection Locking

Semiconductor lasers are an integral part of high-speed telecommunications. The push for higher modulation frequencies, thereby allowing greater data rates, has motivated the scientific community for several decades. However, as the field matured, the maximum speed of traditional directly-modulated lasers has reached a fundamental limit. Recently, optical injection locking has been proven to enhance the bandwidth and resonance frequency of directly-modulated semiconductor lasers. The injection locking technique allows the lasers to exceed their fundamental modulation speed limit, allowing for greater communication speeds. This book first develops theoretical insight into the nature of resonance frequency and bandwidth enhancement by optical injection locking. The design parameters of resonance frequency enhancement are described and these results are generalized to oscillators of all kinds. High-speed resonance frequencies well over 100 GHz and 3-dB modulation bandwidths in excess of 50 GHz are fundamentally possible. Various types of modulation formats are implemented as well. This book will be useful to anyone interested in the forefront of high-speed optical communications."