Microwave frequency switching delays in phase-locked period-one dynamics of semiconductor lasers

Modern microwave switches require high switching speeds to rapidly route data over multiple radio channels while minimizing the routing delay. This Letter proposes a novel, to the best of our knowledge, microwave frequency switching system using phase-locked Period-one (P1) dynamics of semiconductor lasers. When a semiconductor laser is optically injected by microwave-modulated optical signals, which carry two-tone input microwaves at 29 and 37 GHz, with proper injection power controlled by dual-voltage control signals, P1 dynamics are excited in the semiconductor laser and subsequently phase-locked by one of the input microwave tones. We have observed positive and negative switching delays in the switching process. For instance, a positive delay is observed when the system requires additional optical power to transition from a phase-locked state at 29 GHz to an unlocked state. Conversely, a negative delay occurs when the unlocked P1 dynamics approach but do not reach a 37-GHz frequency and then rapidly lock to the tone, thereby surpassing the speed of the control signals. These dual delays are instrumental in enhancing the switching speed of our system, enabling it to surpass the voltage switching time of the control signals by a factor of 3.6. In addition, by leveraging these dual delays, the duration of the microwave tones can be further extended in the switching process.