Photonic RF and microwave fractional differentiation, integration, and Hilbert transforms with Kerr optical micro-combs

Abstract

Integrated Kerr micro-combs are a powerful source of multiple wavelength channels for photonic radio frequency (RF) and microwave signal processing, particularly for transversal filter systems. They offer significant advantages featuring a compact device footprint, high versatility, large numbers of wavelengths, and wide Nyquist bands. We present our recent progress on photonic RF and microwave high bandwidth temporal signal processing based on Kerr micro-combs with comb spacings from 49GHz to 200GHz. We focus on integral and fractional Hilbert transforms, differentiators as well as integrators. The future potential of optical micro-combs for RF photonic applications in terms of functionality and ability to realize integrated solutions is also discussed.

High-frequency broadband radar signal generation based on optical frequency comb

“…The first technical approach is based on the pulse shaping: an ultra-short pulse (responding to a broad spectrum in the frequency domain) is modulated through the shaping system and following passes through the photodetector (PD) for achieving photoelectric conversion to obtain the target waveform [9][10][11][12][13][14][15] . The key to this technical approach lies in the pulse shaping scheme, for which there are currently multiple methods to choose from.…”

“…The light of each tap is modulated and introduced with different time delays. After being combined, the desired waveform is obtained [13][14] . Alternatively, the target signal can be achieved based on signal analysis principles, as shown in Figure 2(c), the frequency-domain information of the target signal with arbitrary time-domain shape can be obtained by performing a short-time Fourier transform or Hilbert transform.…”

“…OFCs generate a multitude of phase-locked frequency lines, making them attractive multi-wavelength laser sources for applications in signal generation and processing, which has attracted wide attention and became an increasingly hot topic. Quite a lot of findings have been published in such field domestically and internationally [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] . The OFCs provide excellent characteristics of ultra-short pulse in the time domain and broad spectrum in the frequency *uestctqg@163.com; phone 18091195355 domain and at the same time enormous narrow linewidth, coherent frequency comb lines with equal intervals, which make it able to provide significant support for the generation of instantaneous wide bandwidth, multi-waveforms in different frequency bands at the high operating frequency.…”