Tunable Programmable Microwave Photonic Filters Based on an Optical Frequency Comb

Abstract

We demonstrate advanced transversal radio frequency (RF) and microwave functions based on a Kerr optical comb source generated by an integrated micro-ring resonator. We achieve extremely high performance for an optical true time delay aimed at tunable phased array antenna applications, as well as reconfigurable microwave photonic filters. Our results agree well with theory. We show that our true time delay would yield a phased array antenna with features that include high angular resolution and a wide range of beam steering angles, while the microwave photonic filters feature high Q factors, wideband tunability, and highly reconfigurable filtering shapes. These results show that our approach is a competitive solution to implementing reconfigurable, high performance and potentially low cost RF and microwave signal processing functions for applications including radar and communication systems.

Integrable microwave filter based on a photonic crystal delay line

“…MWP signal processors reported so far [12][13][14][15][16] have relied on discrete optoelectronic devices and standard optical fibre delay lines, and components leading to bulky, expensive and powerconsuming architectures. Typical delay line footprints range from several tens of centimetres when using fibre Bragg gratings (FBGs) to a few kilometres when using standard optical fibres.…”

Reconfigurable broadband microwave photonic intensity differentiator based on an integrated optical frequency comb source

“…Such a large FSR enables an increased Nyquist zone of ∼100 GHz, which is challenging for mode-locked lasers and externallymodulated comb sources. [40][41][42] The advantages of our platform for nonlinear OPOs include ultra-low linear loss (∼0.06 dB cm 1 ), a moderate nonlinear parameter (∼233 W 1 km 1 ), but most of all a negligible nonlinear loss up to extremely high intensities (∼25 GW cm 2 ). 34,35 After packaging the input and output ports of the device with fibre pigtails, the total insertion loss is ∼3.5 dB.…”

Reconfigurable Filter-free Sinc-shaped RF Photonic Filters Based on Rectangular Optical Frequency Comb

“…(1), f m = 20 GHz with φ2 = -1020 ps/nm dispersion results in a 163 ps delay between adjacent comb lines, corresponds to a free-spectral-range (FSR) of 6.1 GHz. Thus, the first main passbands of the filters are centered at 6.1 GHz for all cases, operating at the first Nyquist zone (DC to 10 GHz) free of spurious frequency [1,7]. The RF photonic filter responses are measured by vector network analyzer (VNA), shown in Fig.…”

“…Radio frequency (RF) filters based on optical frequency comb and dispersive propagation enable RF signal processing in the photonic domain [1,2]. Compared to its electrical counterpart, this approach is favored due to the broad bandwidth and low losses rendered by optical fibers, as well as arbitrary RF filter shape empowered by lineby-line shaping of the optical frequency comb [2,3].…”