Abstract: The electric field measuring device measures an electric field intensity of an electromagnetic wave generated from equipment under test 8 in an area for detecting an electromagnetic wave. An antenna 1 and an optical intensity modulator having a Mach-Zehnder type optical waveguide are inside the area and an output signal of the antenna is supplied to a modulation electrode of the optical intensity modulator. A light source unit, a light receiving unit, and a DC bias control unit controlling a DC bias voltage supplied to the optical intensity modulator are outside the area. An optical wave is guided to the optical intensity modulator from the light source unit, and is guided to the light receiving unit from the optical intensity modulator via an optical fiber 4. The DC bias voltage is supplied to the optical intensity modulator from the DC bias control unit via a power supply line 4.

Abstract: Provided is an optical receiver which accurately demodulates an optical signal obtained by the differential phase shift modulation method. The optical receiver includes: an interferometer which branches the inputted optical signal into two parts and gives a one-bit phase difference to the resultant two optical signals so that the two optical signals after addition of the phase difference are made to interfere each other to output two output lights; reflection means which reflects one of the output lights from the interferometer so as to return to the interferometer; detection means which detects the return light which has been reflected by the reflection means and propagates through the interferometer in the different direction from the inputted optical signal, for output; and phase difference control means which adjusts the phase difference given by the interferometer according to the intensity of the return light detected by the detection means.

Abstract: The present invention relates to an optical receiver, and particularly, to an optical receiver by which a DQPSK-modulated optical signal is demodulated to a multilevel phase-modulated signal.

Abstract: An optical modulator is provided which includes: an optical splitting part that splits an input light wave into two light waves; two optical waveguides that propagate the two light waves into which the input light wave is split, respectively; a first SSB modulating part that is provided in one of the two optical waveguides and modulates a light wave, which propagates into the first SSB modulating part, with a carrier frequency so that the light wave is converted into a different light wave having a single side band; a second SSB modulating part that is provided in the other of the two optical waveguides and modulates a light wave, which propagates into the second SSB modulating part, with a data signal in order to generate a signal light wave having a different single side band; and an optical combining part that combines the light wave modulated by the first SSB modulating part with the signal light wave generated by the second SSB modulating part.

Abstract: The present invention provides an optical modulation element module which is capable of the optical modulation for analog transmission with a low driving voltage and low chirp.

Abstract: An optical waveguide element having a plurality of surface waveguide portions. A connecting portion for connecting the surface waveguide portions. An output light-outputting waveguide portion connected to the connecting portion each on a dielectric substrate. An output light optical fiber connected to an output end of the output light-outputting waveguide portion. A reinforcing capillary for a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiver. The reinforcing capillary has a hole or groove for supporting the output light optical fiber, a connecting face bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face. The light outputted from the optical waveguide element, therethrough to the outside of the capillary.

Abstract: The present invention offers an optical modulator capable of efficiently transmitting electric signals to an interaction part of a signal electrode with acting on an optical waveguide even when the electric signals are in a high frequency zone, and capable of performing high frequency broad-band operation. The optical modulator comprises a substrate 1 formed of a material having electro-optical effect, an optical waveguide formed on the substrate, and an electrode 3 for modulating the light passing through the optical waveguide.

Abstract: An optical waveguide monitor equipped with an output light monitor having a decreased restriction in the dimensions and form thereof, a high reliability and a low production cost includes an optical waveguide element (having a plurality of surface waveguide portions, a connecting portion for converging and connecting the surface waveguide portions and an output light-outputting waveguide portion connected to the connecting portion each formed on a dielectric substrate plate; an output light optical fiber connected to an output end of the output light-outputting waveguide portion, a reinforcing capillary for reinforcing a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiving means, wherein the reinforcing capillary has a hole or groove for containing and supporting the output light optical fiber therein, a connecting face thereof bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face, to thereby enable

Abstract: An optical modulator which magnifies a modulation index and reduces affection of SBS by suppressing a light source carrier component in an equivalent light source spectral width and performs more long-distance transmission by suppressing one of sideband spectrums generated by a modulation signal to reduce affection of fiber dispersion, having a light branch means that branches input light having a carrier component into two light waves; a SSB modulation means that modulates one branched wave and generates a wave having the carrier component and one sideband spectrum; an intensity adjustment means that adjusts intensity of the carrier component of the other wave; a phase adjustment means that adjusts the phase of the carrier component with respect to at least one of the two waves; and a multiplexing means that multiplexes the two waves passing through the modulation means, and the intensity and phase adjustment means, and emits output light.

Abstract: An optical modulator in which stabilized driving is realized over a long time by relaxing stress generated in a recess formed in the surface of a substrate in the optical modulator and controlling deterioration of optical modulation control caused by stress-strain in the substrate including an optical waveguide. The optical modulator comprises a substrate of a material exhibiting electrooptic effect, an optical waveguide (4) provided on the substrate, and control electrodes (20-25) for controlling the phase of light being guided through the optical waveguide characterized in that a recess (12) is provided in the surface of the substrate for forming the control electrodes, and the control electrode (24) being formed on the recess is provided with a stress relaxing means.

Abstract: An optical modulator is provided which includes: an optical splitting part that splits an input light wave into two light waves; two optical waveguides that propagate the two light waves into which the input light wave is split, respectively; a first SSB modulating part that is provided in one of the two optical waveguides and modulates a light wave, which propagates into the first SSB modulating part, with a carrier frequency so that the light wave is converted into a different light wave having a single side band; a second SSB modulating part that is provided in the other of the two optical waveguides and modulates a light wave, which propagates into the second SSB modulating part, with a data signal in order to generate a signal light wave having a different single side band; and an optical combining part that combines the light wave modulated by the first SSB modulating part with the signal light wave generated by the second SSB modulating part.

Abstract: An optical waveguide monitor equipped with an output light monitor having a decreased restriction in the dimensions and form thereof, a high reliability and a low production cost includes an optical waveguide element (having a plurality of surface waveguide portions, a connecting portion for converging and connecting the surface waveguide portions and an output light-outputting waveguide portion connected to the connecting portion each formed on a dielectric substrate plate; an output light optical fiber connected to an output end of the output light-outputting waveguide portion, a reinforcing capillary for reinforcing a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiving means, wherein the reinforcing capillary has a hole or groove for containing and supporting the output light optical fiber therein, a connecting face thereof bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face, to thereby enable

Abstract: An optical waveguide monitor equipped with an output light monitor having a decreased restriction in the dimensions and form thereof, a high reliability and a low production cost includes an optical waveguide element (having a plurality of surface waveguide portions, a connecting portion for converging and connecting the surface waveguide portions and an output light-outputting waveguide portion connected to the connecting portion each formed on a dielectric substrate plate; an output light optical fiber connected to an output end of the output light-outputting waveguide portion, a reinforcing capillary for reinforcing a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiving means, wherein the reinforcing capillary has a hole or groove for containing and supporting the output light optical fiber therein, a connecting face thereof bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face, to thereby enable

Abstract: An optical modulator which magnifies a modulation index and reduces affection of SBS by suppressing a light source carrier component in an equivalent light source spectral width and performs more long-distance transmission by suppressing one of sideband spectrums generated by a modulation signal to reduce affection of fiber dispersion, having a light branch means that branches input light having a carrier component into two light waves; a SSB modulation means that modulates one branched wave and generates a wave having the carrier component and one sideband spectrum; an intensity adjustment means that adjusts intensity of the carrier component of the other wave; a phase adjustment means that adjusts the phase of the carrier component with respect to at least one of the two waves; and a multiplexing means that multiplexes the two waves passing through the modulation means, and the intensity and phase adjustment means, and emits output light.

Abstract: A method and a device for measuring the half-wave voltage of a Mach-Zehnder type optical modulator accurately and without depending on the bias variation of an optical modulator. The method of measuring the half-wave voltage of the Mach-Zehnder type optical modulator the steps of applying a high-frequency AC signal 34 and a monitoring low-frequency AC signal 35 in a superimposed manner to a Mach-Zehnder type optical modulator 1, or applying the both respectively to separately constituted electrodes, and observing the low-speed response of an output light from the optical modulator 1, wherein the half-wave voltage at a frequency to be measured of the Mach-Zehnder type optical modulator 1 is measured by using the voltage amplitude of the high-frequency AC signal 34 when the intensity change of an out put light by the monitoring low-frequency AC signal 35 is almost zero with the voltage amplitude of the high-frequency AC signal 34 kept variable.

Abstract: An optical modulator in which stabilized driving is realized over a long time by relaxing stress generated in a recess formed in the surface of a substrate in the optical modulator and controlling deterioration of optical modulation control caused by stress-strain in the substrate including an optical waveguide. The optical modulator comprises a substrate of a material exhibiting electrooptic effect, an optical waveguide (4) provided on the substrate, and control electrodes (20-25) for controlling the phase of light being guided through the optical waveguide characterized in that a recess (12) is provided in the surface of the substrate for forming the control electrodes, and the control electrode (24) being formed on the recess is provided with a stress relaxing means.

Abstract: An optical waveguide element having a plurality of surface waveguide portions. A connecting portion for connecting the surface waveguide portions. An output light-outputting waveguide portion connected to the connecting portion each on a dielectric substrate. An output light optical fiber connected to an output end of the output light-outputting waveguide portion. A reinforcing capillary for a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiver. The reinforcing capillary has a hole or groove for supporting the output light optical fiber, a connecting face bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face. The light outputted from the optical waveguide element, therethrough to the outside of the capillary.

Abstract: The present invention provides an optical modulation element module which is capable of the optical modulation for analog transmission with a low driving voltage and low chirp.

Abstract: An optical waveguide monitor equipped with an output light monitor having a decreased restriction in the dimensions and form thereof, a high reliability and a low production cost includes an optical waveguide element (having a plurality of surface waveguide portions, a connecting portion for converging and connecting the surface waveguide portions and an output light-outputting waveguide portion connected to the connecting portion each formed on a dielectric substrate plate; an output light optical fiber connected to an output end of the output light-outputting waveguide portion, a reinforcing capillary for reinforcing a connection between the optical waveguide element and the output light optical fiber and a monitoring light receiving means, wherein the reinforcing capillary has a hole or groove for containing and supporting the output light optical fiber therein, a connecting face thereof bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face, to thereby enable

Abstract: Present invention offers an optical modulator capable of efficiently transmitting electric signals to an acting portion of a signal electrode with acting on an optical waveguide even when the electric signals are in high frequency zone, and capable of performing high frequency broad band operation. The optic modulator comprises a substrate 1 formed of a material having electro-optical effect, an optical waveguide formed on the substrate, and an electrode 3 for modulating the light passing through the optical waveguide. The optical modulator is characterized in that an electric signal connection pad unit 6 is provided on a part of the electrode, and in that the thickness of the substrate which is located at least on a lower part of the electric signal connection pad unit 6 and directly or indirectly continuous to the electric signal connection pad unit 6 is thinner than the thickness of other parts of the substrate.