Temporal locking of pulses in injection locked oscillators

We demonstrate a novel injection-locking effect in oscillators, which is obtained in both the time and frequency domains. The "temporal-locked" oscillator generates an ultra-low phase noise continuous-wave (CW) signal, accompanied by an ordered train of short [Formula: see text] phase pulses with precise timing, where both signals are phase-locked to an external sinusoidal source. Remarkably, even when the cavity delay drifts, the period of the temporal-locked pulses remains constant. Furthermore, the instantaneous phase and the timing of the minimum and maximum amplitudes within part of the pulse remain approximately constant. These unexpected results stem from the nonlinear effect of strong injection on the waveform of the phase pulses. In particular, this effect leads to the self-adaptation of the instantaneous frequency to delay variations, thereby preserving the periodicity of the pulses. We theoretically show that a simple and general setup can accurately model the pulse propagation within the cavity. We experimentally demonstrate the effect in an optoelectronic oscillator (OEO). The pulse timing inherits the stability of the external CW source. The combination of an ultra-low phase noise CW signal with precisely timed pulses is important for various applications that require accurate measurements in both the time and frequency domains.