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 ϕ_o = kn_eff δL. For optimum linearity ϕ_o = 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.

© 1988 Optical Society of America