Frequency division multiplexing (FDM) is a readout technique for transition edge sensor-based bolometer arrays used on telescopes including SPT-3G, POLARBEAR-2, and LiteBIRD. Here we present the latest progress and plans for development of a minimal-parasitic FDM architecture. This technology will enable ultra-large focal planes for future instruments such as CMB-S4. Reduced wiring length between the MHz resonators and series SQUID array ameliorates parasitic impedances which contribute to crosstalk and limit operation of low-resistance bolometers. We have demonstrated improved electrical performance including reduced stray inductance and reduced stray resistance. This will enable operation of low-resistance bolometers and higher multiplexing factors in future arrays. Operating bolometers at lower resistance will decrease the contribution of readout noise to the total NEP by decreasing the required voltage bias. Ongoing work seeks further improvement in circuit parasitics and a laboratory demonstration of this architecture integrated with low-resistance bolometers.
|Student (Ph.D., M.Sc. or B.Sc.)||N|
|Less than 5 years of experience since completion of Ph.D||Y|