Hugo W. Chan

A three-terminal semiconductor-superconductor transimpedance amplifier

The authors report an improved hybrid three-terminal transimpedance amplifier (TIA) with significant current gain. The TIA consists of a semiconductor diode configured for injection of electrons into a thin base electrode (<25 nm) superconductor-insulator-superconductor junction, whose response is read out by low-impedance superconductive electronics. An input dynamic impedance greater than 10/sup 11/ Omega , an output dynamic impedance of approximately 10/sup -3/ Omega a current gain of 20, and an effective input noise current less than 10/sup -14/ A/ square root Hz were achieved. The TIA was operated in a sensor test bed with an extrinsic silicon infrared (IR) detector and superconductive analog-to-digital (A/D) converter. This device permits matching state-of-the-art semiconductor IR detectors with superconductive A/D converters, enabling a fully digital cryogenic focal plane array sensor with high sensitivity and speed but reduced power consumption.<<ETX>>

Application of superconductive electronics to LWIR sensor systems

One of the key issues in the development of IR focalplane systems is the need for low-noise and low-power read- out circuitry which is compatible with the detector technology. Superconductive circuitry offers several advantages over more conventional circuitry. These include much lower power consumption and the possibility of unique circuit topologies relevant for developing advanced monolithic detectors. On-chip signal processing through A/D conversion with digital gamma-ray suppression and digital integration appears possible. This paper reviews the progress that TRW has made in developing several of the key components of such a superconductive read-out system. We have developed a semi- conductor/Josephson-junction 3-terminal device for direct interfacing to semiconductor detectors as well as thin-film superconductive detectors. The 3-terminal device has a current gain of : 500 and provides an optimum interface to further superconductive stages. Performance when coupled to a SQUID read-out will be discussed.

Potential architectures for superconductive IR focal plane sensors

Extremely low power superconductive electronics (SCE) (low noise preamplifier, analog to digital converter, multiplexer, etc.) for very large focal plane arrays can significantly reduce the overall sensor system power, hence its weight and volume, thus reducing overall mission cost. The general architecture for a Z-plane, all-superconducting technology focal plane signal processor is presented illustrating the functional elements and their general configurations. The low noise and speed of the TRW developed SCE permits unique solutions to focal plane array signal processing issues such as in-line gamma suppression and digital signal integration.