Adv Antest Corporation

Tomoyu Yamashita

Akiyoshi Irisawa

Motoki Imamura

Eiji Kato

Shigeki Nishina

Kodo Kawase

Takeshi Ozeki

Provided is a light beam incident device including an off-axis parabolic mirror that receives parallel light beams and converges the parallel light beams at one point on an object to be measured, and an incident-side light reception surface of a mirror that feeds the parallel light beams to the off-axis parabolic mirror. An angle (incident angle) between the object to be measured and converged light beams obtained by converging the parallel light beams changes in accordance with a light reception portion at which the off-axis parabolic mirror receives the parallel light beams. The incident side light reception surface of the mirror can change the light reception portion by moving with respect to the off-axis parabolic mirror.

Light beam incident device and reflected light measurement device

A pulse light source includes: a master laser that outputs a master laser light pulse whose repetition frequency is controlled to a predetermined value; a slave laser that outputs a slave laser light pulse; a phase comparator that detects a phase difference between an electric signal having a frequency of the predetermined value, and an electric signal based on a light intensity of the slave laser light pulse; a loop filter; an adder that adds a repetition frequency control signal having a certain repetition cycle, to an output from the loop filter; and a phase comparator that measures a pulse phase difference which is a phase difference between the master laser light pulse and the slave laser light pulse. A magnitude of the repetition frequency control signal is controlled such that the measured pulse phase difference matches with a target value of the pulse phase difference.

Pulse light source, and method for stably controlling phase difference between pulse laser lights

An electromagnetic wave measurement device includes an electromagnetic wave outputter that outputs an electromagnetic wave having a frequency equal to or more than 0.01 THz and equal to or less than 100 THz toward a device under test. An electromagnetic wave detector detects the electromagnetic wave which has transmitted through the device under test. A relative position changer changes a relative position of an intersection of an optical path of the electromagnetic wave transmitting through the device under test and the device under test, with respect to the device under test, so that the intersection is at a predetermined relative position due to the refraction of the electromagnetic wave by the device under test. A characteristic value deriver derives a characteristic value of the electromagnetic wave based on a detection result of the electromagnetic wave detector, the characteristic value being associated with the predetermined relative position.

Electromagnetic wave measuring apparatus, measuring method, program, and recording medium

According to the repetition frequency control device, a master laser outputs a master laser light pulse the repetition frequency of which is controlled to a predetermined value. A slave laser outputs a slave laser light pulse. A reference comparator compares a voltage of a reference electric signal the repetition frequency of which is the predetermined value and a predetermined voltage with each other, thereby outputting a result thereof. A measurement comparator compares a voltage based on a light intensity of the slave laser light pulse and the predetermined voltage with each other, thereby outputting a result thereof. A phase difference detector detects a phase difference between the output from the reference comparator and the output from the measurement comparator. A loop filter removes a high-frequency component of an output from the phase difference detector.

Repetition frequency control device

A frequency converter includes a first direct digital synthesizer that receives a signal having a predetermined frequency f_master as a clock signal and further an internal frequency setting signal, and outputs an internal signal having a frequency based on the internal frequency setting signal, and a second direct digital synthesizer that receives the internal signal as a clock signal, and further an output frequency setting signal, and outputs an output signal having a frequency f_slave (=f_master&#x2212;&#x394;) based on the output frequency setting signal. A difference between the predetermined frequency f_master and the frequency of the internal signal is larger than a difference between the predetermined frequency f_master and the frequency f_slave of the output signal.

Signal output device, and output apparatus of signal source of signals and of laser beam pulses

A detector detects an electromagnetic wave having a frequency of 0.01 THz&#x2266;f&#x2266;100 THz and transmitted through a device under test (DUT). A changer changes a relative position of an intersection of an optical path of the electromagnetic wave and the DUT, with respect to the DUT. A deriver derives a characteristic value of the electromagnetic wave based on a detection result of the detector, while the characteristic value is associated with an assumed relative position, which is the relative position if the electromagnetic wave is not refracted by the DUT. A corrector changes the assumed relative position to an actual relative position, which is the relative position if the refraction of the electromagnetic wave by the DUT is considered. A corrected deriver derives the characteristic value associated with a predetermined relative position based on an output from the corrector.

According to the present invention, an electromagnetic wave measurement device includes an electromagnetic wave output device, an electromagnetic wave detector, a relative position changing unit, a delay period recording unit, a phase deriving unit, a delay-corrected phase deriving unit, a sinogram deriving unit, and an image deriving unit. The electromagnetic wave output device outputs an electromagnetic wave having a frequency equal to or more than 0.01 THz and equal to or less than 100 THz toward a device under test and a container storing at least a part of the device under test.

A repetition frequency control device includes a slave photoelectric conversion unit which converts a slave laser light pulse into a slave electrical signal, a master photoelectric conversion unit which converts a master laser light pulse into a master electrical signal, a frequency change unit which changes the repetition frequency of the master electric signal by a predetermined value, a phase comparator which detects a phase difference between the slave electric signal and the output from the frequency change unit, and a loop filter which removes a high frequency component of an output from the phase comparator, where the repetition frequency of the master laser does not undergo control based on one or both of the master electric signal and the slave electric signal.

An object is to enable a change in a frequency for which an electric signal based on an optical signal is measured by a spectrum analyzer. An optical measurement device includes a first photoconductive switch that receives predetermined pulse light from a first laser light source, and outputs terahertz light having the same repetition frequency as the repetition frequency of the predetermined pulse light. The optical measurement device also includes a second photoconductive switch that receives the terahertz light and a sampling light pulse, and outputs a signal corresponding to a power of the terahertz light at a time point when the sampling light pulse is received. The optical measurement device further includes an RF spectrum analyzer that measures a magnitude of the signal corresponding to a measured frequency that changes over time, an optical coupler that outputs a simultaneous light pulse when the predetermined pulse light and the sampling light pulse are simultaneously input, a photo detector that converts the simultaneous light pulse into an electric signal as a trigger signal, and an optical delay circuit that delays the trigger signal.

Optical measuring apparatus

According to the present invention, the CT is carried out based on parameters other than the absorption rate. An electromagnetic wave measurement device includes an electromagnetic wave output devicewhich outputs an electromagnetic wave at a frequency equal to or more than 0.01 [THz] and equal to or less than 100 [THz] toward a device under test, an electromagnetic wave detectorwhich detects the electromagnetic wave which has transmitted through the device under test, a relative position changing unitwhich changes a relative position of an intersectionat which an optical path of the electromagnetic wave transmitting through the device under testand the device under testintersect with respect to the device under test, a phase deriving unitwhich derives, based on a detected result by the electromagnetic wave detector, a phase in the frequency domain of the electromagnetic wave which has transmitted through the device under test, a sinogram deriving unitwhich derives a sinogram based on a derived result by the phase deriving unit, and a cross sectional image deriving unitthat derives, based on the sinogram, an image of a cross section of the device under testincluding a trajectory of the intersection

Electromagnetic wave measuring apparatus, measurement method, a program, and a recording medium

A frequency resolution for measuring transmission characteristics of a device under test is increased. With a measuring device including a first terahertz light generator that generates incident light, a second terahertz light generator that generates reference light having an optical frequency f&#x2212;f&#x2212;fdifferent from an optical frequency f&#x2212;fof the incident light by a constant difference frequency f, a terahertz light detector which outputs an light detection signal having the difference frequency fbased on response light obtained by making the incident light incident to an optical fiber and the reference light, and a network analyzer that receives the light detection signal, thereby measuring characteristics of the optical fiber, a spectrum of the incident light (terahertz light) incident to the optical fiber includes the carrier frequency (f&#x2212;f), but does not include sideband frequencies (f&#x2212;f&#xb1;f). It is thus possible to reduce the effective spectrum width of the incident light. As a result, the frequency resolution increases in the measurement of the transmission characteristics of the optical fiber.

Measuring device, method, program, and recording medium

A device for measuring &#x3c4;includes a polarization controller () that allows first (second) incident light, in a synthetic incident light to an object to be measured (), to be in line with a p-polarization (s-polarization) axis in a polarization separator (). The phase shift equivalent value (optical angle frequency differentiation) and amplitude equivalent value (square value) of a first (second) incident light component in an output from the polarization separator () measured by a first (second) measuring unit () are respectively the phase shift equivalent value and amplitude equivalent value of a first column T, T(second column T, T) when the transfer function matrix of the object () is a 2&#xd7;2 matrix to thereby allow a control unit () to determine the polarization mode dispersion &#x3c4;of the object ().

Polarization mode dispersion measuring device, method, recording medium

The object of the present invention is to provide an apparatus that can perform measurement of chromatic dispersion, even if the wavelength of variable-wavelength light source and that of fixed-wavelength light source for reference are identical with each other. The variable-wavelength light generated by a variable-wavelength light source is subjected to intensity modulation to a frequency f by a first optical modulator and transmitted from one end to the other end of an optical fiber The fixed-wavelength light generated by a fixed-wavelength light source is subjected to intensity modulation to a frequency f by a second optical modulator and transmitted from the other end to the one end of optical fiber Therefore, it is possible to separately obtain the variable-wavelength light and fixed-wavelength light transmitted through the optical fiber using a second directional coupler and a first directional coupler respectively, regardless of wavelengths thereof. Accordingly, it is also possible to perform the comparison of phase and measurement of chromatic dispersion, even if the wavelengths of variable-wavelength light source and fixed-wavelength light source for reference are identical with each other.

Growing community of inventors

Miyagi, Japan

Tomoyu Yamashita