Tunable and reconfigurable photonic microwave filter based on stimulated Brillouin scattering

Abstract

A high Q-factor photonic microwave filter showing tuning and reshaping capabilities and based on stimulated Brillouin scattering is demonstrated. The filter bandpass can be continuously tuned, changing the microwave oscillator used to generate the pump power, and the filter shape can be modified by modulating the microwave tone. A single bandpass over the microwave spectrum can be obtained by using single-sideband suppressed carrier modulation. Experimental results demonstrate the wide tuning range of the filter, its reshaping capability, and Q factor of 670.

Large Brillouin amplification in silicon

“…Using this physics, the rapidly growing field of silicon-based Brillouin-photonics has produced new frequency agile RFphotonic notch filters [8,10,13,14] and multi-pole bandpass filters [12] as the basis for radio-frequency photonic (RF-photonic) signal processing. Beyond these specific examples, the potential impact of such Brillouin interactions is immense; frequency combs [13,15,16], ultra-low phasenoise lasers [17][18][19], sensors [9,12,20], optical isolation [21][22][23][24], and an array of signal processing technologies [8,[12][13][14][25][26][27]] may be possible in silicon with further progress.However, strong Brillouin amplification-essential to many new Brillouin-based technologies-has yet to be realized in silicon photonics. Despite the creation of strong Brillouin nonlinearities in a range of new structures [6,7], nonlinear losses and free carrier effects have stifled attempts to demonstrate net optical amplification.…”

Low-power, chip-based stimulated Brillouin scattering microwave photonic filter with ultrahigh selectivity

“…Although SBS has been widely studied in optical fibers, recently there has been a growing interest in harnessing SBS in nanophotonic waveguides [22][23][24][25][26][27]. The ability to control the coherent interaction of photons and acoustic phonons in chip-sized devices (as opposed to in optical fibers many kilometres long) promises not only fascinating new physical insights, but also opens the path to realising key technologies on-chip including slow light [28,29]; narrow linewidth lasers [30]; optical frequency combs [31,32]; RF signal processing [33][34][35] and filtering [36][37][38][39][40]. In particular, SBS filters can exhibit linewidths of the order of 10-100 MHz.…”

Opto-acoustic phenomena in whispering gallery mode resonators

“…It has very useful application in many fields such as sensors, [2,3] narrow linewidth lasers, [4,5] slow and fast light, [6,7] light storage, [8] high resolution optical spectrometry [9,10] and microwave signal processing [11,12] . The harnessing of this effect includes the choice of proper materials for both light and acoustic waves and the optical enhancement structure.…”

“…Optical fibers with the ability of confining light in a small mode area and a long distance have been successfully used to enhance and study the SBS processes. SBS has thus been demonstrated in traditional fibers, [2][3][4][5][6][7][8][9][10][11][12] photonics crystal fibers [13] and sub-wavelength microfibers [14] . On-chip optical waveguides are also very promising platforms for integrated solutions to harvest the SBS effect [15][16][17] .…”