Bartley, Tim

Cryogenic Integrated Optoelectronics for Photonic Quantum Technology

Tim Bartley - University of Paderborn, Germany

Abstract: Quantum photonics relies on interfacing different technologies under mutually compatible operating conditions. While integrated optics is well suited for scalable quantum photonics at room temperature. Nevertheless, the most reliable measurements at the single photon level are performed by superconducting nanowire single photon detectors (SNSPDs), which require cryogenic operating temperatures. Due to its inherent nonlinear and electro-optic properties, lithium niobate is a promising platform to generate and manipulate quantum optical states in a cryogenic environment at high speed and with minimal heat dissipation.

We have previously shown quantum light generation [1,2], frequency conversion [3], and a variety of electro-optic modulators [4,5] in the titanium in-diffused lithium niobate (Ti:LN) platform that are fully functional at low temperatures. More recently, we have begun to interface the outputs of SNSPDs with both lasers [6] and integrated photonic modulators [7], demonstrating low-power cryogenic opto-electronic signal processing. We use titanium in-diffused waveguides in lithium niobate as our nonlinear and electro-optic integration platform, which is very useful for cryofenic prototyping and informs the design of more scalable nonlinear and electro-optic integration platforms, in particular lithium niobate on insulator (LNOI).

In this talk I will discuss our latest results implementing a cryogenic feed-forward opto-electronic circuit, which can selectively manipulate a quantum state based on a desired measurement outcome [8]. The single photon detection with an SNSPD, amplification with CMOS ICs and electro-optic modulation in lithium niobate waveguides is performed entirely within a cryostat at 0.8K. The tight integration allows us to minimize the latency between the measurement result at the single photon level and the modulation.

References

[1] Lange et al., “Cryogenic integrated spontaneous parametric down-conversion,” Optica, 9(1), 108-111 (2022)
[2] Lange et al., “Degenerate photons from a cryogenic spontaneous parametric down-conversion source,” Physical Review A, 108(2), 023701 (2023)
[3] Bartnick et al., “Cryogenic second-harmonic generation in periodically poled lithium niobate waveguides,” Physical Review Applied, 15(2), 024028 (2021)
[4] Thiele et al., “Cryogenic electro-optic polarisation conversion in titanium in-diffused lithium niobate waveguides,” Optics express, 28(20), 28961-28968 (2020)
[5] Thiele et al., “Cryogenic electro-optic modulation in titanium in-diffused lithium niobate waveguides,”Journal of Physics: Photonics, 4(3), 034004 (2022)
[6] Thiele et al., “Optical Bias and Cryogenic Laser Readout of a Multipixel Superconducting Nanowire Single Photon Detector,” APL Photonics, 9(7) (2024)
[7] Thiele et al., “All optical operation of a superconducting photonic interface” Optics Express, 31(20), 32717-32726 (2023)
[8] Thiele et al., “Cryogenic Feedforward of a Photonic Quantum State.” arXiv preprint arXiv:2410.08908. (2024)