SBIR-STTR Award

Laser optical communications offer the potential to dramatically increase the link bandwidth and decrease the emitter power in long-range space communications. Newest system designs require photon-counting arrays operated at high detection efficiency, tens of picoseconds temporal resolution, and capability to handle high detection rates at the wavelength of the laser beam. We propose to develop a novel photon-counting detector array in near infrared, operated with moderate cooling, high-detection efficiency, high saturation counting rate, and capable of high timing resolution. In Phase I, we will investigate methods to integrate photon absorption enhancement techniques into the photon detector process flow and demonstrate the elements of the technology yielding photon-counting detector arrays with high detection efficiency at 1064 nm, high bandwidth and saturation-counting rate. In Phase II, we will integrate the new process flow with readout electronics into compact photon-counting arrays using hybrid and monolithic integration technologies. Detector and readout circuit design will be improved to meet the detection efficiency, noise, timing resolution, and linearity requirements.

Long-range optical telecommunications (LROT) impose challenging requirements on detector array sensitivity at 1064nm and arrays timing bandwidth. Large photonic arrays with integrated beam acquisition, tracking and/or communication capabilities, and smart pixel architecture should allow the implementation of more reliable and robust LROT systems. Integration of smart pixel technology for parallel data acquisition and processing is currently available in silicon. Current silicon photon-counting detector arrays benefit from a worldwide manufacturing and R&D infrastructure but their response at 1064nm is not suitable for LROT.In Phase I we proposed to verify the feasibility of increasing the responsivity of aPeak's silicon photon counting arrays at 1064nm by increasing their quantum absorption efficiency and demonstrating sub-nanosecond timing resolution. Phase I resulted in photon counting arrays with enhanced response at 1064 nm. Modules to be implemented into the readout IC (ROIC) have been fabricated in compact ASIC designs, suitable for integration into the smart pixel fabric – they have demonstrated 100ps timing jitter and have exceeded the dynamic range requirements. Noise, timing resolution, and linearity requirements meet updated program requirementsPhase II program builds upon Phase I results and previous smart pixel development at aPeak Inc with the aim to develop photon-counting arrays with enhanced 1064nm response and integrated counters at pixel level, capable of high - timing resolution and high counting rate. We propose to develop the photon counting detector arrays, associated ROIC arrays in ASIC, technology to assemble the detector and ROIC arrays, as well as in process ASIC mapping and maskless correction methods critical for the detector fabrication. Detector array design will be improved to meet the detection efficiency at 1064nm, while preserving or improving the detector noise, timing resolution, and linearity demonstrated in Phase I