10 KNbN DSP module for IR sensor applications

The authors report significant progress on infrared (IR) focal plane array (FPA) imaging signal processing circuits, built in NbN and operating at 10 K. The improvements to our NbN process are highlighted by the introduction of directly grounded junctions (DGJ). These DGJs substantially reduce paras itic inductance thereby compensating for the high sheet inductance of NbN f ilms. The circuits being developed include a 16-bit SFQ counting ADC and se veral digital signal processing (DSP) units. We report test results of grea tly improved ADC performance, which is the result of both improved designs and fabrication techniques. Signal processing units on individual chips hav e been designed, fabricated, and tested. They perform functions such as bac kground subtraction, gain and responsivity correction, and data reduction, We report test results of the DSP chips performing these functions. Ultimat ely, these chips will be integrated on a multi-chip-module (MCM) with high bandwidth, low impedance interconnects and integrated with an IR focal plan e array sensor.