Other

Nippon Telegraph and Telephone Corporation

Ando Electric Company

Ntt Docomo, Inc.

Tadao Nagatsuma

Mitsuru Shinagawa

Junzo Yamada

Katsushi Ohta

Akishige Ito

Toshiyuki Yagi

Jun Kikuchi

Yoshiki Yanagisawa

Nobuaki Takeuchi

Yoshio Endou

Fumio Akikuni

Nobukazu Banjo

Kazuyoshi Matsuhiro

Hakaru Kyuragi

Noriyuki Toriyama

Katsuyuki Machida

Shinji Uebayashi

Ryo Yamaguchi

Hiromu Ishii

Hiroyoshi Togo

Teruo Onishi

Shouji Yagi

Ken Takeya

Kunio Saito

Makoto Yaita

Naofumi Shimizu

Sanjay Gupta

Nobukazu Banjou

A biological tissue equivalent phantom unit to be used by the specific absorption rate measuring system for evaluating absorption of electromagnetic wave energy includes a biological tissue equivalent phantom for absorbing an electromagnetic wave. In addition, two or more electro-optical crystals are arranged at two or more measurement points in the biological tissue equivalent phantom. The electro-optical crystals have a dielectric constant that is approximately equal to that of the biological tissue equivalent phantom. Two or more optical fibers are laid in the biological tissue equivalent phantom for optically connecting each of the electro-optical crystals to an external destination.

Specific absorption rate measuring system, and a method thereof

An electro-optic sampling apparatus is provided to enable measurement on potentials of signals on the conductor of coaxial cable with high precision and with ease. Herein, an electric input connector inputs a measured electric signal, which is introduced to a conductive path such as a microstrip line. An electro-optic material (e.g., Bi SiO ) that provides electro-optic effect such as Pockel's effect is fixed to a bare portion of the conductive path and is varied in birefringence ratio in response to strength of electric field caused by the conductive path through which the measured electric signal transmits. The conductive path is then terminated by a terminal device. Now, a laser beam is radiated toward the electro-optic material, wherein it is varied in polarization in response to variations of the birefringence ratio. Then, the laser beam is reflected by a dielectric mirror and is separated into two beams by a polarization beam splitter. Photodiodes are provided to convert the two beams to electric signals representing potentials. Thus, the apparatus measures voltage of the measured electric signal based on the electric signals.

Electro-optic apparatus for measuring signal potentials

An electro-optic probe has a laser diode for emitting a laser beam in accordance with a control signal from a measuring instrument main body, an electro-optic or magneto-optic element provided with a reflection film on an end surface thereof, a separator provided between the laser diode and electro-optic or magneto-optic element which is pervious the laser beam emitted from the laser diode and separates a beam reflected from the reflection film and two photodiodes which transform the beam reflected by the separator. A member of weak dielectric material, such as a glass plate, overlies the electro-optic or magneto-optic element at the end of the probe to protect the element, or the element is at the end of the probe and is exposed.

Electro-optic probe and magneto-optic probe

An electro-optic sampling oscilloscope (or EOS oscilloscope) uses an electro-optic probe containing an electro-optic crystal, which is placed under effect of an electric field caused by a measured signal. Laser pulses are supplied to the electro-optic crystal wherein they are subjected to polarization. Then, measurement data representative of a waveform of the measured signal are produced in response to polarization states of the laser pulses and are stored in a measurement data storage. A user can select specific measurement data by using a list of files of multiple measurement data which is displayed on a screen. Then, the EOS oscilloscope displays an outline waveform which is created based on a reduced number of sample points extracted from the selected measurement data. Comments and/or measurement conditions can be stored in the measurement data storage in relation to the measurement data, so that they are adequately displayed on the screen.

Electro-optic sampling oscilloscope

The present invention relates to an electro-optic probe, which includes the following components: a laser diode for emitting a modulating laser light according to control signals generated in a main body of the electro-optic sampling oscilloscope; a first lens for converting the modulating laser light to a parallel beam; a second lens for focusing the parallel beam; an opto-electronic element having a reflection film at a reflection-end; an isolator device disposed between the first lens and the second lens for transmitting the modulating laser light and separating a reflected beam produced at the reflection film into signal beams; and photo-diodes for converting optical energies of the signal beams separated by the isolator device into respective electrical signals; wherein, the signal beams to enter the photo-diodes are directed to propagate towards the laser diode, and the photo-diodes are disposed in a longitudinal direction of a probe casing.

Electro-optic probe

An electro-optic sampling probe is disclosed, by which both faces of an IC wafer can be measured without moving the IC wafer. In the probe, an excitation optical system is provided at the back face side of a back-face excitation type IC wafer. The back face of the IC wafer is irradiated by light output from the excitation optical system, and simultaneously, the electric signal transmitted through wiring on the IC wafer is measured by using light output from an electro-optic sampling optical system provided at the front face side of the IC wafer. If the excitation optical system is substituted with an electro-optic sampling optical system, an IC wafer having wiring in both faces can also be measured.

Electro-optic sampling probe and measuring method using the same

In a pattern forming method, a trench is formed on a flat base. A pattern material is arranged only in and around the trench so as to project upward from the surface of the base and to be larger than the opening of the trench. The pattern material projecting from the surface of the base is removed by chemical mechanical polishing (CMP) so as to be flush with the upper surface of the base.

Pattern forming method

An electro-optic sampling probe is provided, capable of irradiating a plurality of excitation light beams on a plurality of light receiving portions mounted on an IC wafer which is an object for measurement. The electro-optic sampling probe comprises a plurality of excitation optical system modules which commonly uses an objective lens for condensing the excitation light beams on the IC wafer and a detachable portion for attaching and detaching the excitation optical system module, a second probe body for covering the optical path of a light beam emitted from the excitation optical system module is provided at the rear side of the IC wafer, and at least one of the plurality of excitation optical system modules have an optical axis which differs from those of other modules; thereby at least two excitation light beams can be irradiated on the light receiving portions on the IC wafer surface.

Probe for electro-optic sampling oscilloscope

An electro-optic sampling probe includes an electro-optic element which is to be positioned to contact wiring on an IC wafer surface which is a measurement target and whose optical characteristics are changed depending on an electric field applied via the wiring and an electro-optic sampling optical system module having a polarized beam splitter, a wave plate, and a photo diode. The module separates light, which is transmitted through the electro-optic element and is reflected by a surface of the electro-optic element from laser light emitted from the outside and converts the separated light into an electric signal, and includes an optical axis adjuster attached to a detachable portion of an optical fiber that emits the laser light for adjusting the optical axis of the laser light and a light receiving surface adjuster attached to the detachable portion of the photo diode for adjusting the position of a light receiving surface of the photo diode.

Electro-optic sampling probe and a method for adjusting the same

In order to maintain accuracy of measurement, a temperature-insensitive electro-optic probe has a laser diode provided to emit a laser beam based on a control signal of an oscilloscope body, a collimator lens provided to convert the laser beam into a parallel beam; an electro-optic element having on an end face thereof a reflective coating, with the optical characteristics which are changed by propagating an electrical field via a metal pin provided at the end face on the reflective coating side, an isolator provided between the collimator lens and the electro-optic element, and adapted to transmit the laser beam emitted from the laser diode, in order to separate a light reflected by the reflective coating from the laser beam, a photodiode provided to convert the reflected light separated by the isolator into an electrical signal, a temperature detection section arranged to be in contact with optical components consisting the isolator, and to detect the temperature of the optical components and output the result of the detection, a temperature adjustment section arranged to be in contact with the laser diode, and to adjust the temperature of the laser diode based on the result of the temperature detection, and a temperature control unit provided to control the temperature adjustment section based on the result of the temperature detection.

Temperature-insensitive electro-optic probe

An electro-optic probe is provided which is able to prevent unnecessary reflected light from optical components in the electro-optic probe from entering photodiodes. The optical components which constitutes an isolator are disposed inclining from an optical path of a parallel light emitted from a collimating lens , such that the unnecessary reflected light beams from these optical component surfaces are not incident to the photodiodes and . The inclination angle of these optical components are set within a range from an angle formed by an optical path from said optical component to a light receiving element in said photodiode, and the diameter of said light receiving element to an angle allowable for the optical component to maintain the transmittance thereof.

A probe for an electro-optic sampling oscilloscope is provided, capable of obtaining an improved accuracy in measurement of the test measuring signals by controlling a temperature of an electro-optic element so as to be maintained at a constant such that the refractive index of the electro-optic element does not change due to the temperature change. The probe for the electro-optic sampling oscilloscope comprises a reflecting film at one end and a metal pin provided on the surface of the reflecting film such that the optical property of the electro-optic film changes according to an electric field applied through the metal pin. The probe further comprises a temperature detecting portion, disposed so as to contact with the electro-optic element, for detecting and outputting the temperature of the electro-optic element, a temperature adjusting portion, disposed so as to contact with the electro-optic element facing the temperature detecting portion about the electro-optic element, and a temperature controlling portion for controlling the temperature adjusting portion based on the result of the temperature detection.

An electro-optic sampling probe for preventing noise from being transmitted to photodiodes and improving the measurement accuracy is disclosed. In the probe, the optical system module comprises wavelength plates and polarized beam splitters arranged along an optical path of the relevant laser beam, and photodiodes facing the polarized beam splitters, wherein each photodiode is fixed via an insulating material to the main frame of the optical system module.

Electro-optic sampling probe comprising photodiodes insulated from main frame of EOS optical system

An electro-optic sampling prober is used to measure a waveform of a measured signal applied to wiring of an IC wafer. Herein, a laser radiates laser beams, which are supplied to an optical module containing an optical isolator and photodiodes by way of an optical fiber. Then, the laser beams pass through an optical wavelength filter to propagate through a prober unit. The laser beams are incident on an electro-optical element, which is changed in polarization state in response to an electric field being caused by the measured signal. The laser beams are reflected by a surface mirror of the electro-optical element, so that reflected beams propagate back through the prober unit and are returned to the optical module by way of the optical wavelength filter. During the measurement, a human operator watches an image of a selected portion of the IC wafer presently placed beneath the prober unit to adjust a positional relationship between the prober unit and IC wafer. The image is produced by an infrared camera equipped with a halogen lamp and a monitor. Incidentally, the optical wavelength filter has an optical characteristic such that a center wavelength in transmission of light coincides with a wavelength of the laser beams whose intensities are maximal, so it is possible to prevent components of light, which are not required for measurement, from being unnecessarily returned to the optical module, and it is possible to improve a S/N ratio in measurement.

Electro-optic sampling prober

In a light receiving circuit for use in electro-optic sampling oscilloscope which receives first and second optical, photodiodes and are connected in series between a positive bias power supply P and a negative bias power supply N. The photodiodes and receive optical signals whose polarization state correspond to the voltage of a signal to be measured and convert the thus-received optical signals into electric signals. An amplifier amplifies an electric current appearing in a point of connection P between the photodiodes and A current monitor detects the electric signal converted by the photodiode and a current monitor detects the electric signal converted by the photodiode The electric signal detected by the current monitor is subjected to analog-to-digital conversion by an analog-to-digital converter and the electric signal detected by the current monitor is subjected to analog-to-digital conversion by an analog-to-digital converter A control section formed from a subtraction circuit controls a ratio of polarization between the optical signals such that the difference between the value of the current detected by the current monitor and the value of the current detected by the current monitor becomes smaller.

Growing community of inventors

Sagamihara, Japan

Tadao Nagatsuma