Broad tuning of whispering-gallery modes in silicon microdisks

Abstract

Silicon microdisks with dynamically-tunable resonance spectra are achieved with nanoscale, in-plane silicon electrical contacts in a single lithographic step. Electrical current is passed through the devices to enable thermal tuning via joule heating. A 14nm wavelength shift is demonstrated with 1.6mW power consumption in devices with >20nm free spectral ranges and quality factors exceeding 20,000. Spectral shifts equal to a full width at half maximum can be achieved with approximately 10microW tuning power for a mode with quality factor of 20,000.

Whispering gallery modes in semiconductor optical fibres and optical bottle microresonators

“…2, revealing a full width at half maximum (FWHM) linewidth of 0.11 nm, corresponding to a loaded Q factor of Q l = r /FWHM=1.4x10 4 (where  r is the resonant wavelength). In spite of the improved surface quality, the loaded Q factor is of a similar magnitude to that reported in microdisks [16], due to the bulk material loss of a-Si:H and the method of coupling. Several measurements of different microresonators showed similar Q factors.…”

“…Recent advances in silicon photonics have accelerated interest in the fabrication of high Q silicon WGM microresonators [14][15][16]. Silicon is an excellent material for photonics applications, owing to its high optical damage threshold, large nonlinearities and its broad transmission window (~1.2-7 m).…”

Semiconductor optical fibres for infrared applications: A review

“…Figure 9(a) shows a typical transmission spectrum measured for a 6 µm diameter a-Si:H fibre resonator when launching into the WGMs via a standard tapered silica fibre coupler approach [52]. This spectrum reveals Q-factors on the order of 10 4 , which are comparable to the best values reported in planar-based single crystal silicon resonators [54], and these could be improved further by optimizing the material and coupling conditions. Significantly, as these WGM resonators are essentially free-standing, for appropriate choices of the starting fibre core diameter they are capable of operating across the full infrared transmission window of the semiconductor material.…”

Silicon emission in and out resonant coupling with high Q optical mode

“…Finite-difference frequency-domain (FDFD) simulations 6 The large thermooptic coefficient of silicon α (α =1.86*10 -4 1/K), due to the temperature dependence of the silicon bandgap 7 , is used to enable thermal modal tuning. This temperature dependence leads to the shift of the central wavelength of this mode as the temperature increases (Fig.…”