2024/12/31 by Takuma Nakamura, Nakamura, Takuma, Dahyeon Lee +9 · 2 citations
Computer Science · Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Optics (physics.optics) #Photonic and Optical Devices #Quantum Information and Cryptography #Semiconductor Quantum Structures and Devices
paper · pdf · doi:10.48550/arxiv.2501.00545
openalex publication_date 2024/12/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate short pulse illumination of a high-speed extended-InGaAs photodiode at cryogenic temperatures towards its use in control and readout of superconducting qubits. First, we demonstrate high detector responsivity at 1550 nm illumination at 20 mK, a wavelength band unavailable to cryogenic standard InGaAs detectors due to the temperature-dependent bandgap shift. Second, we demonstrate an improved signal-to-noise ratio (SNR) at the shot noise limit for cryogenic short optical pulse detection when compared to conventional modulated continuous-wave laser detection. At 40 uA of photocurrent and a detector temperature of 4 K, short pulse detection yields an SNR improvement of 20 dB and 3 dB for phase and amplitude quadratures, respectively. Lastly, we discuss how short pulse detection offers a path for signal multiplexing, with a demonstration of simultaneous production of microwave pulses at two different carrier frequencies. Together, these advancements establish a path towards low noise and power efficient multiplexed photonic links for quantum computing with a large number of superconducting qubits.