Reconfigurable photonic RF filters based on integrated Kerr frequency comb sources

TL;DR

This paper presents integrated Kerr micro-comb based photonic RF filters that achieve high spectral resolution, large bandwidth, and reconfigurability, advancing compact and versatile RF filtering technologies.

Contribution

It introduces two types of microcomb-based RF filters with enhanced resolution, bandwidth, and reconfigurability, demonstrating significant improvements over traditional methods.

Findings

Achieved RF spectral resolution of 117 MHz

Demonstrated RF bandwidth of 4.64 GHz

Enabled programmable RF transfer functions

Abstract

We demonstrate two categories of photonic radio frequency (RF) filters based on integrated optical micro-combs. The first one is based on the transversal filtering structure and the second one is based on the channelization technique. The large number of wavelengths brought about by the microcomb results in a significantly increased RF spectral resolution and a large instantaneous bandwidth for the RF filters. For the RF transversal filter, we demonstrated Q factor enhancement, improved out-of-band rejection, tunable centre frequency, and reconfigurable filtering shapes. While a high resolution of 117 MHz, a large RF instantaneous bandwidth of 4.64 GHz, and programmable RF transfer functions including binary-coded notch filters and RF equalizing filters with reconfigurable slopes are demonstrated for the RF channelized filter. The microcomb-based approaches feature a potentially much smaller cost and footprint, and is promising for integrated photonic RF filters.