Optical fibre modulator based on electrostatic attraction

A fibre-based electrostatic deflector is described that enables modulating the optical signal in fibre systems. A 2.5-cm long fibre length was gold coated and deflected through the application of voltage between the fibre and an external electrode. Static measurements showed that the device is suitable for e-field sensing, and 100% power modulation was obtained for resonant frequencies ∼1 kHz. A peak voltage as low as 2 V gave a 15% modulation depth with 65 μm diameter fibre, and the maximum frequency measured for a 65 μm fibre was ∼40 kHz. In a proof-of-principle experiment, a 1.61-μm wavelength Er 3+/Yb 3+ fibre laser was Q-switched by placing the electrostatic fibre modulator inside the cavity, generating pulses of 4-μs duration.