Amplifier Package Research Articles

Three-micrometer-diameter needle electrode with an amplifier for extracellular in vivo recordings

Microscale needle-electrode devices offer neuronal signal recording capability in brain tissue; however, using needles of smaller geometry to minimize tissue damage causes degradation of electrical properties, including high electrical impedance and low signal-to-noise ratio (SNR) recording. We overcome these limitations using a device assembly technique that uses a single needle-topped amplifier package, called STACK, within a device of ∼1 × 1 mm2 Based on silicon (Si) growth technology, a <3-µm-tip-diameter, 400-µm-length needle electrode was fabricated on a Si block as the module. The high electrical impedance characteristics of the needle electrode were improved by stacking it on the other module of the amplifier. The STACK device exhibited a voltage gain of >0.98 (-0.175 dB), enabling recording of the local field potential and action potentials from the mouse brain in vivo with an improved SNR of 6.2. Additionally, the device allowed us to use a Bluetooth module to demonstrate wireless recording of these neuronal signals; the chronic experiment was also conducted using STACK-implanted mice.

Collective synchronization and phase locking of fs fiber amplifiers: Requirements and potential solutions

Active coherent beam combination (CBC) of femtosecond pulses requires knowledge of the absolute phase between all the optical pulses: pulse synchronization and phase locking are both mandatory and must be measured and controlled. To assess controller requirements, we study fiber amplifier phase noise for various packaging and power levels. The main contributors are thermal noise (with large amplitude phase noise and frequencies below 5 Hz) and vibrations (with low amplitude phase noise and frequencies from 5 Hz to 2 kHz), leading to a woofer/tweeter pair of actuator. The amplifier packaging is of major importance: a simple PID model shows that in order to achieve a residual phase error of λ/100, the required controller bandwidth ranges from 0.5 Hz to 1 kHz, mostly depending on amplifier packaging. We also shortly review common phase locking techniques either based on pupil-plane sensor or focal-plane sensor. Common focal-plane techniques as SPGD or LOCSET are not directly compatible with pulsed femtosecond operation. Pupil-plane fringe-sensor techniques are more promising and route towards collective synchronization for femtosecond regime are proposed. Following the example of telescope interferometry, the final system might include both a pupil-plane, fringe-sensor and a focal-plane phase-diversity sensor, with pupil-plane sensor for synchronization and phase lock, and focal-plane sensor to control and maintain required focalized beam quality.

Power Amplification at 0.65 THz Using InP HEMTs

In this paper, progress toward developing solid-state power-amplifier modules at 0.65 THz is reported. This work is enabled by a >;1 THz fMAX InP HEMT transistor with a 30-nm gate and an integrated circuit process specifically tailored for circuits operating at frequencies approaching 1 THz. The building block of the reported amplifier modules is an eight-stage terahertz monolithic integrated circuit (TMIC) amplifier. The first six stages of the TMIC use 20- transistors, while the final two output stages rely on two power-combined 20-μm transistors to increase the output power. For operation at 0.65 THz, the TMIC also relies on integrated electromagnetic transitions for direct coupling with the WR1.5 waveguide of the amplifier package. Two modules are reported, with the first module containing a single TMIC and demonstrating a peak saturated output power of 1.7 mW at 640 GHz with a measured small-signal gain ≥10 dB from 629 to 638 GHz. The second module features two power-combined TMICs to increase output power. This is done using a waveguide Y-junction as both the combiner and splitter. In test, this power-combined module reached a peak output power of 3 mW at 650 GHz and measured small-signal gain ≥10 dB from 625 to 640 GHz.

Ultracompact Gain Block with Bi2O3-Based Erbium-Doped Fiber

An ultracompact gain block with Bi2O3-based erbium-doped fiber (Bi-EDF) is presented. The ultracompact gain block includes two pump LDs, two isolators, a photodiode, dichromatic mirrors and a Bi-EDF 23 cm long in the amplifier package with a size of only 45×43×10 mm. We can obtain a net gain of 25 dB and output power of 10 dBm at 1560 nm in the C-band region.

Passive alignment of second generation optoelectronic devices

This paper details how expanded-mode semiconductor devices and passive alignment techniques can be used to realize low-cost high-performance fiber grating laser and laser amplifier packages for future generations of optical telecommunication systems.

38-GHz-band high-power MMIC amplifier module for satellites on board use

The design and development results of 38-GHz high-power MMIC amplifier modules for use in the solid-state power amplifier (SSPA) to be carried aboard Engineering Test Satellite VI in 1993 are presented. This amplifier will be used in millimeter-wave intersatellite communication experiments. For the development of this amplifier, high-power, highly reliable FETs with 0.25- mu m-long gates were designed. The FET large-signal impedance was accurately measured using an improved load-pull method and MMIC transformers. The measurements were used to design two types of MMICs: one composed of two FET cells with 600- mu m-wide gates and the other of four FET cells with 400- mu m-wide gates. A two-stage amplifier package consisting of two of these MMICs that can be used at 38 GHz is also developed. A P/sub o/(1 dB) of 25 dBm and a gain of 11 dB are obtained. A 38-GHz test conducted during chip screening achieves a high production yield without circuits adjustment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High gain (21 dB) packaged semiconductor optical amplifiers

Record high gains of 20–21 dB have been reproducibly obtained using a new type of semiconductor optical amplifier package incorporating a 1.3 μm tilted-facet ridge amplifier. The package uses a novel two-temperature-zone design to achieve independent soldering of the input and output fibres.

Cryogenic performance of a GaAs MMIC distributed amplifier

A three-stage GaAs MMIC distributed amplifier chip which was specially packaged in a two-chip, six-stage amplifier for cryogenic operation from 1 to 10 GHz is discussed. When immersed in liquid nitrogen, a fourfold reduction in amplifier noise is observed over the 4-GHz to 8-GHz frequency range. The cryogenic amplifier package is described, and the test configuration is explained. The reduction in amplifier noise is in agreement with the generally observed scaling with ambient temperature (in Kelvin) for discrete GaAs FET amplifiers. >

565 Mbit/s 219 km transmission experiment using four gain controlled packaged semiconductor laser amplifiers

A 565 Mbit/s 219 km optical transmission system is investigated, using four gain controlled travelling wave semiconductor laser amplifier packages. The addition of gain control caused little deterioration in system performance, and allowed stabler operation against changes in signal polarisation and device temperature. Residual system output power fluctuations of less than 0•5 dB were observed over a 7 degree temperature range

Efficient circuit implementations of current conveyors, negative impedance converters and nonlinear impedance converters using operational transconductance amplifiers

This paper points out that a commercially available dual-operational trans-conductance amplifier package (CA3280) can be efficiently used as both positive and negative second-generation current conveyors, floating negative impedance converters and floating nonlinear impedance converters. In many situations, no other active devices are required to implement the above circuit functions.

Recent developments in ultra-low-noise broad-band TWT amplifiers

A low-noise traveling wave tube amplifier operating over the double band from 8-18 GHz with a maximum noise figure of 8.5 db has recently been developed. This amplifier has a nominal small signal gain of 30 db, a gain variation of less than 6 db and a saturated power output of +5 to +10 dbm. The low-noise figure and power output performance exceeds that of presently available Ku-Band amplifiers, and is comparable to presently available X-Band amplifiers as well. The amplifier package, consisting of tube, magnet and integral power supply, weighs 18 lb, has a maximum height of 4.75 in. and is 12 in. long.

A high efficiency - high quality audio frequency power amplifier

The development of the power amplifier discussed in this paper was undertaken with the objective of providing a large amount of good quality audio power in a small package at relatively low cost. The size of an amplifier package and its cost are dependent largely on the efficiency of operation and the power sensitivity of the output stage. Ream power tubes satisfy these two requirements more readily than triodes. The quality of the audio power is improved. by the use of push-pull operation and large amounts of feedback. The use of a suitable amount and type of feedback with beam power tubes eliminates the advantage of inherent low output impedance obtained with triodes. In Class A or Class AB operation the dynamic characteristics of the two tubes may be matched to obtain a reasonably linear characteristic, and while feedback is desirable its use may sometimes be avoided. In Class B operation it is not possible to match dynamic characteristics to get linear operation, and therefore a large

Some Designs and Applications for Packaged Amplifiers Using Subminiature Tubes

Design and construction details of d.c. and a.c. amplifier packages using subminiature tubes are given. In addition, applications to control and measurement circuits are shown. The purpose of these amplifiers is to decrease the time lost in the construction and repair of complicated electronic equipment for biophysical and other experiments.