Integrated line-by-line optical pulse shaper for high-fidelity and rapidly reconfigurable RF-filtering

Abstract

We present a 32 channel indium phosphide integrated pulse shaper with 25 GHz channel spacing, where each channel is equipped with a semiconductor optical amplifier allowing for programmable line-by-line gain control with submicrosecond reconfigurability. We critically test the integrated pulse shaper by using it in comb-based RF-photonic filtering experiments where the precise gain control is leveraged to synthesize high-fidelity RF filters which we reconfigure on a microsecond time scale. Our on-chip pulse shaping demonstration is unmatched in its combination of speed, fidelity, and flexibility, and will likely open new avenues in the field of advanced broadband signal generation and processing.

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

“…To date, a number of photonic chip implementations of AWG have been reported with promising results [18,32,42]. One straight-forward way to synthesize a particular electrical waveform is to use the time-domain impulse response of a tapped delay line filter.…”

“…AWGRs are able to perform M × N Fourier transforms, and therefore, their use has been investigated in optical communication and spectroscopic systems [30,31]. While AWGRs can be used as building blocks in more complex systems [32][33][34][35], their rigid topology limits their functional flexibility. In contrast, topologies comprising coupler arrays and delay lines offer design flexibility and easy incorporation of tuning elements [36][37][38][39].…”

A Review of Photonic Generation of Arbitrary Microwave Waveforms

“…Notable results include the demonstration of Silicon based on-chip electrical tuning spectral shaper using chirped waveguide Bragg gratings [37], the demonstration of on-chip line by line pulse shaper with 25 GHz resolution and sub-microsecond reconfigurability [38,39] and the realisation of a reconfigurable photonic integrated signal processor that is capable of performing integration, differentiation and Hilbert transform of different orders [40]. These recent developments consequently open new avenues in the field of arbitrary waveform generations and broadband signal processing.…”

“…There is also a significant interest in the frequency chirp generations using Fourier pulse shaping and frequency to time mapping, especially the demonstration compact photonic integration [43], flexible tuning of chirp rate [37], control of chirp sign [44] and the ability of shaping the waveform envelop [45]. There are also applications of arbitrary waveform generation for measuring and compensating for multipath channel propagation that overcomes inter-symbol interference [46] and for rapidly reconfigurable RF filtering [38,47]. There are also significant activities in the field of waveform generation based on microwave photonic filtering, particularly the generation of triangular wave train [48,49].…”

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

“…Although showing a great range of functions, implementing RF signal processing in microwave photonics may require a complex optical system that comprises a combination of many of these functions. In a broad sense, integrating such systems on monolithic chips [28,29] or by means of micro-assembly of multiple chips [30][31][32][33] is a key for the proliferation of their large-scale application in real-world systems. To that scope, we need to simultaneously address the issues of device size, power consumption, and performance stability, as compared with all-electronics solutions [34].…”