Other

Nippon Telegraph and Telephone Corporation

Ando Electric Company

Junzo Yamada

Mitsuru Shinagawa

Tadao Nagatsuma

Katsushi Ohta

Akishige Ito

Toshiyuki Yagi

Jun Kikuchi

Nobuaki Takeuchi

Yoshiki Yanagisawa

Yoshio Endou

Fumio Akikuni

Nobukazu Banjo

Tsuneo Mano

Tsuneo Matsumura

Junichi Inoue

Takakuni Douseki

Yasuyuki Matsuya

Nobutaro Shibata

Noriyuki Toriyama

Nobukazu Banjou

Shinichirou Mutou

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

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

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.

Probe for electro-optic sampling oscilloscope

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.

Light receiving circuit for use in electro-optic sampling oscilloscope

An electro-optical probe used for an oscilloscope (e.g., electro-optic sampling oscilloscope) is mainly constructed by a probe head and a probe unit. The probe head contains a metal pin and an electro-optical element having a reflector at its terminal surface. The probe unit contains a reduced number of optical parts, which are arranged such that an optical axis of incoming beams of the electro-optical element differs from a optical axis of outgoing beams of the electro-optical element. That is, laser beams output form a laser diode are subjected to convergence by a converging lens to produce converged beams, which are incident on the electro-optical element as its incoming beams. The incoming beams are subjected to reflection by the reflector to produce reflected beams, which are output from the electro-optical element as its outgoing beams. Then, the reflected beams are converted to parallel beams by a collimator lens, or they are converged by a converging lens. A polarization detector performs separation on input beams from the lens to produce separated components of beams, optical axes of which differ from each other. Those components of beams are respectively supplied to photodiodes, wherein they are converted to electric signals. Thus, it is possible to measure a waveform of a measured signal based on differences between the electric signals, which reflect changes of polarization states of the beams in the electro-optical element.

Electro-optical probe for oscilloscope measuring signal waveform

A probe for an electrooptic sampling oscilloscope in which an electric field generated by a measured field is coupled with an electrooptic crystal. A beam is incident on this electrooptic crystal, and by the polarization state of the incident beam, the form of the measured signal is measured. The electrooptic element is supported form the end terminal side of the probe body by a probe head member that serves as the end terminal of the probe body. An insertion hole is formed from the outside up to the reflecting film on the probe head member. One end thereof is in contact with a reflecting film, the other end thereof is inserted so as to protrude from the probe head member, and at the same time, the external radial diameter of the insertion hole is formed so as to be large compared to the radial dimension of the reflected film.

Electrooptic probe

An electro-optic sampling probe used for observing a waveform of a test signal based on the change of the polarization state of a light pulse caused when the light pulse generated based on a timing signal is entered in an electro-optic crystal that is coupled by an electric field generated by the test signal. The electro-optic sampling probe includes an electro-optic crystal having a stopper portion at its upper portion, an electro-optic crystal supporting portion for supporting the electro-optic crystal by the stopper portion so as not to fall and capable of moving the electro-optic crystal vertically and an electro-optic crystal driving portion formed by a base and a board, to which the electro-optic crystal supporting portion is attached which moves on the base, for rectilinearly moving the electro-optic crystal along the direction of an optical axis.

Electro-optic sampling probe

An electrooptic probe which can facilitate replacement of a metallic pin. A probe head constituting a tip end portion of a probe body including a head body for retaining an electrooptic element and a tip member detachably provided on the head body for retaining the metallic pin.

An electro-optic probe having a laser diode for generating a laser beam based on a control signal from an oscilloscope body; a collimator lens for making the laser beam into a parallel beam; an electro-optic element having on an end face thereof a reflective coating, with 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, which passes a laser beam generated by the laser diode and isolates a reflected beam which is reflected by the reflective coating; and photodiodes which convert the reflected beam isolated by the isolator into electrical signals. The electro-optic element is integrally affixed to a probe head which is rotatable with respect to a probe body on which the probe head is mounted.

Disclosed herein is an electro-optic sampling probe in which the quantity of light incident on the electro-optic sampling system module can be adjusted. The probe includes an electro-optic element that has a reflective face, an optical system for transmitting a laser beam received from an external source and an electro-optic sampling optical system module as well as unit for attenuating the quantity of light of the laser beam that is received by the optical system.

Growing community of inventors

Ebina, Japan

Junzo Yamada