Figure 2: Experimental results for waveguide-pump–cavity-probe system.

(a) Schematic diagram of the pump-probe characterization setup used in the experiment. The cavity resonance was probed using a tunable laser (Santec TLS 510) and a fast, sensitive InGaAs detector (New Focus). Another tunable laser was used as the pump and was amplified using a high-power output EDFA (L Band Manlight). The input and output WDM (wavelength division multiplexer; MicroOptics) ports were designed to operate in the 1,470–1,565 nm and 1,570–1,680 nm ranges. The mechanical response of the devices was studied using a real-time spectrum analyser (Tektronix RSA 3300). De-MUX, de-multiplexer; DUT; device under test; EDFA, erbium-doped fibre amplifier; MUX, multiplexer; PC, polarization controller; PD, photo detector; SA, spectrum analyser; TF: tunable filter; TLS, tunable laser source. (b) A transmission spectrum of the fabricated cavity. The transmission has been normalized to the maximum value outside the bandgap. The fundamental even mode is found to be near 1,507 nm with a Q of 15,000. The shaded region shows the operating range of the EDFA used to amplify the pump. The pump has a waveguide-like mode profile (see Supplementary Fig. S6) as it is outside the bandgap and is used to induce mechanical deformation to detune the even mode cavity resonance. (c) Cavity resonance was tuned from 1,507.72 to 1,508.19 nm when 6 mW of pump power at 1,583 nm was used. Red and blue curves correspond to 0 and 6 mW of pump power. The transmission in this case has been normalized to the maximum value of the cavity resonance. Cavity tuning was due to contribution from thermo-optical, nonlinear optical and optomechanical effects.