Narrowband Optical Signal Denoising Through All-Fiber Temporal Talbot Effects

We propose and experimentally demonstrate an all-fiber Talbot-based method to denoise MHz-bandwidth optical signals buried under noise. The method achieves up to 9 dB of optical signal-to-noise ratio improvement for the multiple target signals. Additionally, our approach preserves an undistorted version of the input waveform with significantly improved quality. The method involves phase-only transformations in both the time and frequency domains, accomplished through appropriate temporal phase modulation and chromatic dispersion. These transformations effectively prepare the signal for noise removal, which is achieved through time-domain filtering. Subsequently, the inverse dispersion is applied to retrieve the processed and noise-filtered signal. The demonstrated technique is a promising solution for noise filtering in narrowband optical signals, with applications in microwave photonics and optical signal processing.