Electric field sensor having sensor head with unbalanced electric field shield to shield branched optical waveguides against an applied electric field

摘要

An electric field sensor comprises a substrate 4, an incident optical waveguide 5 formed on the substrate 4, two branched optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 5 and having refractive indexes, which are variable in response to an electric field intensity applied thereto, an outgoing optical waveguide 7 formed on the substrate 4 to join the branched optical waveguides 6, and an electric field shielding member 8 formed in the vicinity of a part of the branched optical waveguides 6 for shielding an electric field. The substrate 4 may be provided with a reflection mirror 16 for reflecting light beams from the branched optical waveguides 6. The substrate 4 is made of a ferroelectric material and has polarization directions reverse to each other at portions where the two branched optical waveguides 6 are formed.