Y. Tsuchiya

Non-Contact Picosecond Electro-Optic Sampling Utilizing Semiconductor Laser Pulses

Non-contact picosecond electro-optic sampling utilizing semiconductor laser pulses, which is compact, easy to use and inexpensive, is described focusing on the recent improvements such as reduction of system noise, adoption of a longitudinal E-0 probe and its advantages, monitoring system of the measurement point, and improvement of the space dependent sensitivity. We demonstrate the equivalent input noise of 125mV/IHz with a temporal resolution of 45ps at a distance of 20gm between the probe tip and the device under test, with a 4.5s measuring time. We also discuss the possibility of absolute voltage measurement.

How the electro-optic probing system can contribute to LSI testing?

The electro-optic (E-O) probing system using laser diode (LD) for measuring the voltage waveform at internal nodes of high speed LSI is described comparing performance to other electric instruments. The voltage sensitivity was improved by using an external ZnTe E-O probe and a low noise LD. Two kinds of E-O probing systems have been developed; a sampling system using a pulsed LD has the frequency bandwidth of 10 GHz and the minimum detectable voltage of 430 /spl mu/V/spl radic/Hz, and a real time system using a CW LD and a high speed photo detector has 480 MHz and 23 mV with 700 accumulations. Each system is based on mechanical prober and a microscope. Approach of the E-O probe to the electrode is computer-controlled. The advantages of high temporal resolution, noncontact and noninvasive method have realized measurements for microwave devices and passivated electrodes. Dependency of the output signal on the space between E-O probe and electrode is discussed as well as that on the electrode width.<<ETX>>

Infrared Sensitive Universal Streak Camera For Use In 1.0 To 1.6 µm Wavelength Region

An infrared sensitive synchroscan streak camera for use in the wavelength region of 1.0 to 1.6 μm is described, including system configuration, absolute photocathode sensitivity, system dynamic range, and its application. Linear (y=1) dynamic ranges of more than 103 at 1.3 and 1.5 μm wavelength have been demonstrated to confirm a single photon reaction in the photocathode at the practical power density level, using ultrashort light pulses from laser diodes. Applications of the system for direct and linear measurement such as picosecond time-resolved spectroscopy of diode laser pulses at 1.3 and 1.5 μm wavelength are also discussed. The system works in single-shot mode as well as synchroscan, by changing a plug-in. This new technique can be widely utilized for direct, linear, real-time and multichannel measurement of ultrafast optical phenomena in the wavelength range of 1.0 to 1.6 μm.

Laser Pulse Tomography Using A Streak Camera

Non-destructive tomographic images for a semi-transparent bottle and fingers of man have been obtained in real time by using HAMAMATSU C1587 synchroscan streak camera and a colliding pulse mode locked ring dye laser which emits 615nm laser pulses with 100 femtosecond duration, as a probe. This new technique, Laser pulse tomography, has been invented by adopting the streak camera to analyze time delays of reflected and transmitted light from/through the object. Experimentally, spatial resolutions of approx. 1 mm for the tomographic direction and approx. 0.4 mm for the spatial direction on the objects have been achieved for the first time.

Sampling Optical Oscilloscope

A conceptually new sampling optical oscilloscope has been developed based on the streak camera technology. This is analogous to a conventional sampling oscilloscope but entirely electron-optical in operation and can potentially analyze picosecond optical signals directly. The sampling optical oscilloscope makes use of a photoelectron tube so-called sampling streak tube. This tube is not only a photodetector but also an ultrafast electron sampling device. Optical signals are converted into Photoelectrons, which is the replica of the incident optical signals, at the photocathode. These photoelectrons are then accelerated and deflected to perform traversing of the replica for the purpose of sampling. Part of the electron replica is incident on a Phosphor screen, where it is converted into an optical signal. A ohotomultiplier tube is used to detect the radiation of the screen to analyze the incident signal. The entire waveform of the input signal is obtained by gradu-ally changing the deflection or sampling timing. This unique system permits direct detec tion, digitization and analysis of optical signals in the 350-850 nm region with rise and fall time of 10 ps. It provides a dynamic ranee of > 1000:1, sampling rate of up to 2 MHz, sensitivity of photomultipliers, and breaks the distortion such as overshoot, rincino, cable mismatches or other instrument distortion.

Characterization Of Photon-Counting Streak Camera

An excellent photon counting streak camera (PCSC) which can detect single photoelectron with high temporal resolution has been developed. PCSC is adopting a photon counting streak tube (POST) which incorporates tandem micro-channel-plates (MCPs). Using this camera, single photoelectron images can be obtained with high gain and high S/N ratio. And Spatial resolution is measured to be about 11 1p/mm at supplying voltage 1800V to MCPs. Further, by detecting center of gravity for each photoelectron image, spatial resolution of 30 1p/mm has been achieved. Temporal resolution is evaluated to be better than 2 ps at single shot operation and 12 ps at synchroscan operation. Therefore PCSC will be useful for many fields, for example, time resoluved Raman scattering, the life time of fluorescence, photon statistics, and so on.

Tunable picosecond all solid-state Cr:LiSAF laser

Many kinds of experiments about all solid-state Cr:LiSAF laser have been made for the purpose of generating tunable femtosecond pulses. For the first time, a tunable all solid-state cw laser having tunability over more than 100 nm was developed by using new spectrum selection self-injection locking (SSSIL) method in 1992. We report that we have realized tunable picosecond radiation from an all solid-state laser with 146/spl sim/200 ps pulses in a 88 nm range. Also, 70 fs pulse generation was achieved using a Kerr-lens mode-locking pumped with an Ar/sup +/ laser.<<ETX>>

Sampling Optical Oscilloscope Using A Traveling-Wave Semiconductor Laser Amplifier

Optical sampling with a traveling-wave semiconductor laser amplifier driven by short electrical current pulses is experimentally investigated for the purpose of designing a simple, compact and sensitive solid-state sampling optical oscilloscope.The temporal resolution of about 350 ps with the chip gain of 10 dB is demonstrated. The minimum detectable power is about 45 nw, which corresponds to input optical energy less than 0.01 fRpuise. The larger chip gain of 23 dB with aperture time of 110 ps for optical sampling is obtained if the laser amplifier is driven near the dynamic threshold level, however unexpected output signals where the intensity variation is inverted are observed.

Optical Oscilloscope Capable Of Measuring Picosecond Electrical Waveforms

We have developed a new system for measuring picosecond electrical waveforms, where the advantages of electro-optic sampling are maintained, but the need for a complex short-pulse-laser is eliminated. The system utilizes two advanced technologies; an optical oscilloscope which is a conceptually new optical waveform analyzer with picosecond time resolution, and an electro-optic modulator for electric to optical signal convertor. Using this system, the waveform of the driving current and optical pulses from a laser diode have been simultaneously measured with the temporal resolution of < 25 ps.

A New Sampling Optical Oscilloscope Based on Streak Camera Technology

Fundamental technology for advanced measurement seems to be switching over to photonics from traditional electronics. It may be due to the critical limit of electronics in ability of high speed, multichannel processing and so on. On the other hand, an ultrafast streak camera is well known as one of the most versatile instruments for measureing the dynamic behavior of luminous events in the picosecond and subpicosecond region.1