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We report on a detailed analysis of the effect of CW injection in an actively mode-locked laser at 780 nm, on the noise performances of the laser. The optical properties of the emitted pulse train, and the phase and amplitude noise of the RF pulse train generated after photodetection have been characterized with respect to the laser pumping rate, and to the injected power. We show that when injected, the laser exhibits a dramatic improvement of both RF phase noise and power spectrum, but at the expense of a degraded optical relative intensity noise. [ABSTRACT FROM AUTHOR]

High repetition rate optical pulse trains are essential for a wide range of applications, including photonic-assisted sampling. Among the different solutions proposed so far, Talbot lasers, based on the generation of an optical frequency comb in a frequency shifting loop, are a simple yet efficient source of short transform-limited pulses. By controlling the comb spectral phase, the repetition rate is reconfigurable. It can be set to a (possibly large) multiple of the comb spacing and reach the GHz range, while only requiring a low bandwidth synthesizer (typ. 100 MHz). The noise characteristics of this pulse trains is a key factor for its application. Therefore, we investigate the phase noise properties of Talbot lasers. In particular, we prove theoretically and demonstrate experimentally that the phase noise at high offset frequency from the carrier, does not depend on the multiplication factor q. We also demonstrate that the phase noise at low offset frequencies, which increases as 20 log q, can be strongly reduced by a simple locking technique. Finally, we show that in addition to their reconfigurability, Talbot lasers can provide timing jitters at 8.2 GHz as low as 350 fs (integrated from 105 Hz to the Nyquist frequency), making them suitable candidates for time metrology applications. [ABSTRACT FROM AUTHOR]

We propose and demonstrate an improved Talbot laser including a regenerative RF feedback loop. This architecture greatly enhances both amplitude and noise performances of the pulsed laser, while preserving the broadband tunability of its repetition rate. The phase noise power spectral density of the associated RF signal is found to be independent of the repetition rate. For a 4.9 GHz repetition rate, the timing jitter is as low as 54 fs (integrated between 10 kHz and 100 MHz offset frequency). This architecture paves the way towards tunable high performances coupled opto-electronic microwave oscillators. [ABSTRACT FROM AUTHOR]