Programmable optical processor chips: toward photonic RF filters with DSP-level flexibility and MHz-band selectivity

Abstract

Integrated optical signal processors have been identified as a powerful engine for optical processing of microwave signals. They enable wideband and stable signal processing operations on miniaturized chips with ultimate control precision. As a promising application, such processors enables photonic implementations of reconfigurable radio frequency (RF) filters with wide design flexibility, large bandwidth, and high-frequency selectivity. This is a key technology for photonic-assisted RF front ends that opens a path to overcoming the bandwidth limitation of current digital electronics. Here, the recent progress of integrated optical signal processors for implementing such RF filters is reviewed. We highlight the use of a low-loss, high-index-contrast stoichiometric silicon nitride waveguide which promises to serve as a practical material platform for realizing high-performance optical signal processors and points toward photonic RF filters with digital signal processing (DSP)-level flexibility, hundreds-GHz bandwidth, MHz-band frequency selectivity, and full system integration on a chip scale.

Photonic integrated field-programmable disk array signal processor

“…Flat-top filtering. Optical filters with a flat top can find wide applications in optical communications and interconnect systems for signal processing and routing 26,27 . The FPDA can be reconfigured as a flat-top optical filter.…”

Picosecond optical pulse processing using a terahertz-bandwidth reconfigurable photonic integrated circuit

“…The advance in photonic integrated circuit (PIC) technologies has enabled the implementation miniaturization of optical components [6][7][8][9][10][11][12][13][14][15][16]. PICs can be controlled accurately and are stable.…”

“…Regarding integrated optical signal processors using PICs, previous research has made great contributions in terms of circuit design and implementing various processing functions, with a wide range of applications having been demonstrated [17][18][19][20][21][22][23][24]. The constant development of essential components and building blocks such as splitters(combiners) [25,26], (de)multiplexers [23,27], couplers [4,7], delay lines [8,28] and phase shifters [16,22] have shown promising results of performance in terms of size, loss, bandwidth, coupling efficiency, control power consumption and fabrication accuracy. On the circuit level, a well-studied circuit topology is the arrayed waveguide grating router (AWGR) [29], which joins two slab couplers with an array of linearly incremental waveguide delays.…”

Orbital Angular Momentum Multiplexed Free-Space Optical Communication Systems Based on Coded Modulation

“…Optical communication systems are usually deployed over fiber-optic links [1][2][3], free-space optical (FSO) links [4][5][6], or hybrid FSO-fiber links [7]. Recent advances in photonics integrated circuits (PIC) have been greatly pushing forward the worldwide application of optical communications [8][9][10]. Although they have enabled a capacity-approaching communication [11][12][13], fiber-optic links may be too fragile or costly to be deployed in some environments, e.g., seismic belts.…”