US 5,969,341 AGranted

Optical integrated voltage sensor for optically measuring the magnitude of a voltage

AssigneeKabushiki Kaisha Toyota Chuo Kenkyusho

InventorsHiroshi Ito, Tadashi Ichikawa, Satoru Kato

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Abstract

A compact voltage sensor with stable characteristics is provided. A measuring beam that is incident from an optical fiber is branched into first and second modulation-inducing waveguides of a wave branching/combining section within an optical integrated circuit. Phase changes of opposite sign are induced in the measuring beams propagating within the first and second modulation waveguides by applying voltages of mutually opposite sign to modulation-inducing electrodes, to induce a phase difference between the two. By reflecting the measuring beams from a reflective surface, propagating them back in the opposite direction within the first and second modulation waveguides, and passing them through the optical intensity modulation section again, thus applying a further phase modulation thereto, the phase difference between the measuring beams proceeding in the opposite direction within the first and second modulation waveguides can be made to be substantially twice the phase difference of the measuring beams before they are reflected by the reflective surface. The sensor also has a function to protect a sensor section thereof from dielectric breakdown caused by the accidental input of a high voltage.

Claims13

Dependent claims

An optical integrated voltage sensor comprising:

measuring beam generation means for outputting a measuring beam;
an optical fiber for guiding said measuring beam;
sensor means for modulating the intensity of said measuring beam in accordance with a measurement voltage and outputting said modulated measuring beam back towards said optical fiber;
branching means provided between said measuring beam generation means and said optical fiber, for passing said measuring beam from said measuring beam generation means and branching said measuring beam modulated by said sensor means into a given direction;
and
signal processing means for calculating said measurement voltage, based on the intensity of the measuring beam branched by said branching means;
wherein said sensor means comprises an optical integrated circuit, which comprises:
a waveguide formed at one end as a measuring beam incident section and at the other end as a measuring beam reflection section;
and
an optical intensity modulation section for modulating and outputting the intensity of said measuring beam propagating within said waveguide in accordance with said measurement voltage wherein said waveguide comprises a first modulation-inducing waveguide and a second modulation-inducing waveguide which are branched off at a wave branching/combining section;
said measuring beam reflection section is formed at the other end of each of said first and second modulation-inducing waveguides;
said optical intensity modulation section is provided with a pair of electrodes for applying oppositely polarized voltages to said first and second modulation-inducing waveguides, thereby modifying the phases of the measuring beams propagating within each of said modulation-inducing waveguides, and causing constructive interference between the modified measuring beams at said wave branching/combining section so as to output a measuring beam of an intensity that has been modified in accordance with said measurement voltage;
and
said optical intensity modulation section is provided with a voltage-divider circuit for dividing the voltage of a signal, and a voltage that corresponds to a voltage-division ratio thereof is applied to said electrodes.

11 more elements

An optical integrated voltage sensor comprising:

measuring beam generation means for outputting a measuring beam;
an optical fiber for guiding said measuring beam;
sensor means for modulating the intensity of said measuring beam in accordance with a measurement voltage and outputting said modulated measuring beam back towards said optical fiber;
branching means provided between said measuring beam generation means and said optical fiber, for passing said measuring beam from said measuring beam generation means and branching said measuring beam modulated by said sensor means into a given direction;
and
signal processing means for calculating said measurement voltage, based on the intensity of the measuring beam branched by said branching means;
wherein said sensor means comprises an optical integrated circuit, which comprises:
a waveguide formed at one end as a measuring beam incident section and at the other end as a measuring beam reflection section;
and
an optical intensity modulation section for modulating and outputting the intensity of said measuring beam propagating within said waveguide in accordance with said measurement voltage
a voltage-measurement terminal section which is provided on a far end surface side of said optical integrated circuit, for contacting a voltage measurement section of an object to be measured and supplying said measurement voltage to said voltage-divider circuit;
wherein said voltage-divider circuit divides a voltage from said terminal section and applies said divided voltage to said electrodes.

9 more elements

Dependencies are inferred from the claim text.