Advanced code-division multiplexers for superconducting detector arrays

TL;DR

This paper introduces a new in-focal-plane code-division multiplexer for superconducting detector arrays, enabling scalable, compact, and power-efficient multiplexing suitable for larger future arrays in astrophysics and materials analysis.

Contribution

The paper presents a novel in-focal-plane code-division multiplexer with lithographic modulation elements that multiplex signals and bias voltages, reducing power and size for larger detector arrays.

Findings

Eliminates the shunt resistor in TES biasing.

Reduces power dissipation significantly.

Enables fitting all elements within a detector pixel.

Abstract

Multiplexers based on the modulation of superconducting quantum interference devices are now regularly used in multi-kilopixel arrays of superconducting detectors for astrophysics, cosmology, and materials analysis. Over the next decade, much larger arrays will be needed. These larger arrays require new modulation techniques and compact multiplexer elements that fit within each pixel. We present a new in-focal-plane code-division multiplexer that provides multiplexing elements with the required scalability. This code-division multiplexer uses compact lithographic modulation elements that simultaneously multiplex both signal outputs and superconducting transition-edge sensor (TES) detector bias voltages. It eliminates the shunt resistor used to voltage bias TES detectors, greatly reduces power dissipation, allows different dc bias voltages for each TES, and makes all elements sufficiently compact to fit inside the detector pixel area. These in-focal-plane code-division multiplexers can be combined with multi-gigahertz readout based on superconducting microresonators to scale to even larger arrays.