Author:
Bulmer C. H.,Howerton M.M.,Burns W.K.,Hiser S. C.
Abstract
An integrated-optical modulator is of use for electric field sensing as the active device can be small, minimally perturbing and highly sensitive. The behavior of a Ti-indiffused LiNbO3 modulator/sensor has previously been reported.1,2 The device is a channel waveguide Mach-Zehnder interferometer where a difference in arm lengths, δL, gives rise to an intrinsic phase bias ϕo = kneff δL. For optimum linearity ϕo = 90°, which corresponds to δL = 152 nm at the operating wavelength λ = 1.3 μm. The device is formed in X-cut, Y-propagating LiNbO3 in order to both avoid pyroelectric effects causing temperature instability3 and also obtain good voltage sensitivity.