Whispering Gallery Modes From Silicon Microsphere in <inline-formula> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula>-Band

Abstract

We reported the observation of whispering gallery modes (WGMs) from silicon microspheres in $C$ -band with a biconical tapered fiber-microsphere coupled system. We experimentally studied the resonant transmission spectra with broadband light source and optical spectrum analyzer, and measured the X-ray diffraction pattern of silicon microspheres. We analyzed the WGMs of silicon microspheres, the full-width at half-maximum was 0.12 nm, and the dip of the transmission spectra was 3.5 dB (55% of the incident power). The $Q$ factor of the silicon microsphere was $1.3 \times 10 ^{4}$ . The Raman gain coefficient in silicon is rather strong and the energy density of microsphere resonator is rather high, so the silicon microsphere resonator possesses broad application prospect in optical communication fields, including filter, modulator, switch, wavelength converter, amplifier, Raman laser source, and so on.