Optical Frequency Combs Generated by Acousto-Optic Frequency-Shifting Loops

Abstract

A recirculating loop that includes an acousto-optic frequency shifter (AOFS) constitutes a versatile procedure to generate an optical frequency comb (OFC) from a continuous wave (cw) laser. This scheme, implementable with conventional fiber equipment, is capable of producing spectra composed of at least hundreds of coherent lines using a single-stage system. In this paper, we summarize the method to generate these acousto-optic frequency combs and briefly describe a simple model to optimize their performance. We also overview their main reported applications, paying special attention to those based on the peculiarities exhibited by the optical field at the output of the fiber loop.

Flexible Tunable Nyquist Pulse Generation Using Recirculating Frequency Shift Loop

“…According to the theory of temporal integer Talbot effect [24], [25], when the condition f m τ r = k (k integer) is satisfied by adjusting the loop delay, the phase difference Δϕ between adjacent spectral lines is fixed as:…”

Integrated microwave acousto-optic frequency shifter on thin-film lithium niobate

“…An active acousto-optic frequency shifting loop, also known as frequency-shifted feedback laser [36] can be used for optical frequency combs and pulse generation [37][38][39]. Moreover, this approach is of interest for various applications in optical real-time Fourier transformations [40], photonic microwave channeling [41], and optical frequency domain ranging [42].…”

Dual optical frequency combs generation with frequency-shifted feedback laser, method, and applications

“…Usually, it is the electro-optic (EO) modulator, 9,10 or, seldom, an acousto-optic (AO) molulator. [11][12][13][14][15] It was shown 16,17 that the AO tunable filter (AOTF) may be used as the SSB modulator as any AO device shifts the optical radiation frequency due to the Doppler effect. The AOTF application allows to control all OFC spectral characteristics by changing the parameters of AO diffraction.…”