Low-Timing Jitter Single-Frequency Pulse Output from a Passively Q-Switched Monolithic Non-Planar Ring Oscillator

A low-timing jitter passively Q-switched monolithic non-planar ring oscillator (NPRO) with diffusion-bonded Cr⁴⁺: YAG in a single-frequency operation was realized. The pulse parameters were controlled by a Cr⁴⁺: YAG saturable absorber, while the single-frequency operation was ensured by the unidirectional ring cavity structure. The pulse trigger was actively provided by a gain switcher utilizing a composite pumping scheme. The dependence of the timing jitter between the output pulse and the trigger signal on the parameters of the composite pumping scheme was investigated both theoretically and experimentally. Using this approach, we achieved a single-frequency pulsed laser output with a timing jitter of 14.568 ns (RMS) at a repetition rate of 100 Hz corresponding to a pulse width of 5.99 ns. This novel Q-switched monolithic NPRO, which integrates the benefits of both active and passive Q-switching, results in a simple and reliable structure that achieves a low-timing jitter single-frequency pulse output.