Abstract: An optical isolator comprises a Faraday rotator for non-reciprocally rotating a polarization plane of light, and two polarizers joined to both sides of the Faraday rotator. Each of the polarizers is processed into a spherical surface to form a lens for converging or diverging light passing through the polarizer to form a real image or a virtual image. The optical isolator is formed by joining the two polarizers with the Faraday rotator interposed therebetween and has a generally spherical shape as a whole. The two polarizers may be made of materials different in refractive index from each other.

Abstract: 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.

Abstract: A system comprises a substrate 4, an incident optical waveguide 5 formed on the substrate for receiving a light beam incident thereto, two phase-shift optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 4 for varying a phase of a transmitted light beam in response to an electric field intensity, an outgoing optical waveguide 7 formed on the substrate 4 to join the phase-shift optical waveguides 6. At least one of the phase-shift optical waveguides 6 has a reversely polarized portion 8 reversely polarized. A light transmission film may be formed at one or a plurality of portions on the phase-shift optical waveguides 6. A buffer layer 14 may be formed on a part on or in the vicinity of the phase-shift optical waveguides 6. A transparent substance film for imparting a stress to one of the phase-shift optical waveguides 6 may be formed on a part or a whole of a portion without the buffer layer 14.

Abstract: A system comprises a substrate 4, an incident optical waveguide 5 formed on the substrate for receiving a light beam incident thereto, two phase-shift optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 4 for varying a phase of a transmitted light beam in response to an electric field intensity, an outgoing optical waveguide 7 formed on the substrate 4 to join the phase-shift optical waveguides 6. At least one of the phase-shift optical waveguides 6 has a reversely polarized portion 8 reversely polarized. A light transmission film may be formed at one or a plurality of portions on the phase-shift optical waveguides 6. A buffer layer 14 may be formed on a part on or in the vicinity of the phase-shift optical waveguides 6. A transparent substance film for imparting a stress to one of the phase-shift optical waveguides 6 may be formed on a part or a whole of a portion without the buffer layer 14.

Abstract: 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.

Abstract: An optical electric field sensor comprises optical components 2 through 4 and 11 through 13 including an optical crystal and is for measuring the intensity of an electric field, spontaneously or forcedly generated, by the use of variation of at least one of an intensity, a phase, and a polarization direction of a light beam passing through the electric field. The above-mentioned optical components are arranged and sealed in a package 7 made of at least one of a glass material such as quartz, a ceramics material, and a plastic material such as vinyl chloride having an antistatic-treated surface. More effectively, a main portion of the surface of the package 7 is subjected to abrasion. On the other hand, the optical crystal having an electrooptical effect is fixedly surrounded by a heat insulation material. The entire surface of the optical crystal substrate is coated with conductive resin. Silicone is applied in an area between modulation electrodes.

Abstract: An electric field sensor comprises a sensor head 1, a package 13 accommodating the sensor head, and an antenna 14 attached to the outside of the package and connected to the sensor head 1. The sensor head 1 has a substrate 3 and an optical modulator 4 attached thereto. The optical modulator 4 has an incident optical waveguide 5 formed on the substrate 3, two phase-shift optical waveguides 6 which are formed on the substrate 3 to be branched from the incident optical waveguide 5 and each of which has a variable refractive index varying in response to an electric field intensity applied thereto, an outgoing optical waveguide 7 formed on the substrate 3 to join the phase-shift optical waveguides 6, and two modulation electrodes 8 formed on or in the vicinity of the phase-shift optical waveguides 6. The antenna 14 has two rod antenna elements 17 and 18.