Advances in Mode-Locked Semiconductor Lasers

The chapter reviews the recent advances and the state of the art in the area of mode-locked semiconductor lasers. Starting with the principles and theoretical foundations of mode-locked semiconductor laser operation, the chapter reviews the recent advances in, and the modern state of, the mode-locked semiconductor theory, summarizing the main theoretical predictions and discussing the effects of the operating point and the main laser parameters on the laser performance. We proceed with reviewing recent experimental advances, showing how physical reasoning and theoretical predictions inform the strategies of improving the laser performance as regards output and peak power, pulse duration, repetition rate range, and jitter. The chapter discusses the recent novel paradigms of mode locking (ML) in semiconductor lasers, such as the use of low-dimensional materials, coherent saturable absorption effects, and self ML without a saturable absorber. The chapter concludes with a brief overview of prospective applications.