Kerr nonlinear switching in a hybrid silica-silicon microspherical resonator

Abstract

A hybrid silicon-core, silica-clad microspherical resonator has been fabricated from the semiconductor core fiber platform. Linear and nonlinear characterization of the resonator properties have shown it to exhibit advantageous properties associated with both materials, with the low loss cladding supporting high quality (Q) factor whispering gallery modes which can be tuned through the nonlinear response of the crystalline core. By exploiting the large wavelength shift associated with the Kerr nonlinearity, we have demonstrated all-optical modulation of a weak probe on the timescale of the femtosecond pump pulse. This novel geometry offers a route to ultra-low loss, high-Q silica-based resonators with enhanced functionality.

Semiconductor optical fibers

“…2(a) shows all-optical modulation of a λ ∼ 1.55 µm signal that is circulating in a silicon fiber-based resonator. The on/off switching is induced by an ultrafast Kerr nonlinear index modulation when the silicon core is pumped with 720 fs pulse source [5]. This modulated signal was obtained for an average pump power of 10 mW, for which we obtained an extinction ratio of ∼ 6 dB.…”

Glass and Process Development for the Next Generation of Optical Fibers: A Review

“…Such micro-spheres and analogous micro-cylinders have proven useful for a variety of high-Q resonators [134,135], including tunable ones based on thermal and Kerr-related nonlinearities [136][137][138]. Additionally, the high refractive index, Raman gain and strong photoconductivity have permitted the realization of fiber-based anti-resonant reflecting optical waveguides (ARROW) [139], mid-infrared (MIR) light sources [140] and RF antennas [141].…”

Silicon optical fibres – past, present, and future

“…While not necessarily germane to cubic silicon, crystallographic control would be of great value to non-cubic, hence potentially χ (2) -active semiconductor core phases. More recent work on using controlled capillary instabilities to produce silicon-in-silica microspheres [32] and microspherical resonators [33] has provided an additional degree of flexibility to tailor the optical confinement, broadening the scope of the applications.…”