Abstract

Opto-electronic oscillators (OEOs) are sources of radio-frequency (RF) tones with low phase noise [1], which serve in radars, coherent communication and precision metrology. OEOs consist of hybrid cavities: light is modulated by an RF waveform and propagates over a length of fiber. Light at the fiber output power is detected, and the recovered signal is then fed back to modulate the optical source [1]. Optical fibers support a broad variety of guided acoustic modes, at radio-frequencies between hundreds of MHz and several GHz [2]. These modes may be stimulated by light, and scatter light, in processes known as guided acoustic waves Brillouin scattering (GAWBS) [2]. Photonic crystal fibers and micro-structured fibers, for example, exhibit ultra-high opto-mechanical coupling. GAWBS processes in such fibers were used to obtain self-oscillations and spectral combs generation at radio-frequencies [3,4]. The effect in standard single-mode fiber (SMF), however, is orders-of-magnitude weaker.

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