Superconducting nanowire single-photon detectors (SNSPD) have the advantages of high maximal counting rate (MCR), high detection efficiency, and low dark count rate. They play an important role in the fields of optical quantum communication, optical quantum computing, laser ranging, and imaging. The MCR (i.e. detection speed) of SNSPD can be affected by the front-end readout circuit. To increase MCR, it is usually necessary to use a cryogenic DC-coupled readout circuit with a broad bandwidth. This study reports an SNSPD cryogenic DC-coupled amplification readout circuit based on a commercial high-speed operational amplifier chip OPA855. We systematically characterize its performance parameters in a temperature range from a room temperature of 300 K to a low temperature of 4.2 K. We address the problem of bandwidth loss of the circuit in a low-temperature environment by increasing the operating voltage of the OPA855 chip. For example, at 40 K, the operating voltage increases from ±2.5 V to ±4.9 V, and the quiescent current is about 8 mA, which is equivalent to a power consumption of 78 mW; meanwhile, the gain of this readout circuit is 16.7 dB, and the –3 dB cutoff bandwidth is ~2.7 GHz. We further install a cryogenic DC-coupled readout circuit based on the OPA855 amplifier at 40 K and characterize the performance parameters of the SNSPD at 2.2 K, such as the switching current, system detection efficiency, and MCR. The comparison with the conventional AC-coupled readout circuit at room temperature shows that the MCR increases about 1.3 times after using the DC-coupling circuit. Our study provides the interesting information about the OPA855 amplifier’s performance at low temperatures which facilitates its application in cryogenic environments and related fields.
Superconducting nanowire single-photon detectors (SNSPD) have the advantages of high maximal counting rate (MCR), high detection efficiency, and low dark count rate. They play an important role in the fields of optical quantum communication, optical quantum computing, laser ranging, and imaging. The MCR (i.e. detection speed) of SNSPD can be affected by the front-end readout circuit. To increase MCR, it is usually necessary to use a cryogenic DC-coupled readout circuit with a broad bandwidth. This study reports an SNSPD cryogenic DC-coupled amplification readout circuit based on a commercial high-speed operational amplifier chip OPA855. We systematically characterize its performance parameters in a temperature range from a room temperature of 300 K to a low temperature of 4.2 K. We address the problem of bandwidth loss of the circuit in a low-temperature environment by increasing the operating voltage of the OPA855 chip. For example, at 40 K, the operating voltage increases from ±2.5 V to ±4.9 V, and the quiescent current is about 8 mA, which is equivalent to a power consumption of 78 mW; meanwhile, the gain of this readout circuit is 16.7 dB, and the –3 dB cutoff bandwidth is ~2.7 GHz. We further install a cryogenic DC-coupled readout circuit based on the OPA855 amplifier at 40 K and characterize the performance parameters of the SNSPD at 2.2 K, such as the switching current, system detection efficiency, and MCR. The comparison with the conventional AC-coupled readout circuit at room temperature shows that the MCR increases about 1.3 times after using the DC-coupling circuit. Our study provides the interesting information about the OPA855 amplifier’s performance at low temperatures which facilitates its application in cryogenic environments and related fields.
The superconducting nanowire single-photon detector (SNSPD) is a leading technology for quantum information science applications using photons, and is finding increasing uses in photon-starved classical imaging applications. Critical detector characteristics, such as timing resolution (jitter), reset time, and maximum count rate, are heavily influenced by the readout electronics that sense and amplify the photon detection signal. We describe a readout circuit for SNSPDs using commercial off-the-shelf amplifiers operating at cryogenic temperatures. Our design demonstrates a 35 ps timing resolution and a maximum count rate of over 2 × 107 counts per second, while maintaining <3 mW power consumption per channel, making it suitable for a multichannel readout.
Superconducting nanowire single-photon detectors (SNSPDs) are integral to the fields of quantum information and quantum communication, offering high efficiency, low dark count rate, high count rate, and minimal timing jitter. However, a common challenge with SNSPDs is their propensity for latching and nonlinear count rate increase under high incident photon fluxes due to the traditional external readout circuitry. This issue is primarily caused by large dynamic inductance and the ac-coupled effects of the bias and amplifier capacitors. In this study, we carefully selected a commercial SNSPD with an efficiency of over 95%. To address the aforementioned challenges, we implemented a resistor–inductor-type filter structure, which is directly coupled to a low-temperature amplifier, and their operating temperature is 40 K. Experimental results revealed that the enhanced SNSPD readout circuit achieves a count rate that is approximately 3.5 times greater than that of the traditional circuit. Moreover, the timing jitter of the SNSPD was optimized, decreasing by approximately 3.6 times under high incident photon fluxes. These performance enhancements could significantly improve high-speed optical communication and quantum precision measurement.
Superconducting nanowire single photon detectors (SNSPDs) have demonstrated advantages over traditional detectors in many fields [1]. Most fiber-coupled SNSPDs are coupled to single mode fibers, limiting their usability for applications where large surface area detectors are needed, for example fluorescence detection and satellite-based quantum communication [2][3]. Other important requirements for many applications are broadband detection efficiency, and low timing jitter [4]. So far, the increased meander length of multimode detectors, and the therefore increased kinetic inductance and number of imperfections due to film inhomogeneities have limited the timing jitter [5]. Moreover, combining low timing jitter with high detection efficiency and low dark count rate in one device is challenging due to the tradeoffs between different properties of SNSPDs [6]. In this paper, we achieved high efficiency and strong saturation over a broad wavelength range with a low timing jitter of 16.99 ps while maintaining a low dark count rate of < 0.2 Hz for an SNSPD coupled to a 50 µm core multimode fiber. To enhance the broadband absorption from 405 nm to 830 nm, detectors were fabricated on an optimized SiO2 cavity and Aluminum mirror. The geometry of the nanowire was also tuned to reach a good internal saturation of efficiency over the visible/NIR range but also to carry high current to get a large signal. Furthermore, a cryogenic readout amplifier was optimized to improve the signal to noise ratio and thus lead to high time resolution. Our devices can be readily used to enable higher resolution and faster quantum optics, bio-imaging, laser ranging and other optical experiments.
Scalable, high speed data transfer between cryogenic (0.1-4 K) and room temperature environments is instrumental in a broad range of fields including quantum computing, superconducting electronics, single photon imaging and space-based communications. A promising approach to overcome the limitations of conventional wire-based readout is the use of optical fiber communication. Optical fiber presents a 100-1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and is also immune to electromagnetic interference, which allows routing of sensitive signals with improved robustness to noise and crosstalk. Most importantly, optical fibers allow for very high bandwidth densities (in the Tbps/mm2 range) by carrying multiple signals through the same physical fiber (Wavelength Division Multiplexing, WDM). Here, we demonstrate for the first time optical readout of a superconducting nanowire single-photon detector (SNSPD) directly coupled to a CMOS photonic modulator, without the need for an interfacing device. By operating the modulator in the forward bias regime at a temperature of 3.6 K, we achieve very high modulation efficiency (1000-10,000 pm/V) and a low input impedance of 500 Ω with a low power dissipation of 40 μW. This allows us to obtain optical modulation with the low, millivolt-level signal generated by the SNSPD. Optical communication is becoming the preferred I/O solution in modern, room temperature high performance systems, and this work demonstrates its suitability for scalable cryogenic readout, which could help achieve the full potential of superconducting technologies.
Abstract Scalable, low power, high speed data transfer between cryogenic (0.1–4 K) and room temperature environments is essential for the realization of practical, large-scale systems based on superconducting technologies. A promising approach to overcome the limitations of conventional wire-based readout is the use of optical fiber communication. Optical fiber presents a 100–1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and is also immune to electromagnetic interference, which allows routing of sensitive signals with improved robustness to noise and crosstalk. Most importantly, optical fibers allow for very high bandwidth densities (in the Tbps/mm2 range) by carrying multiple signals through the same physical fiber (Wavelength Division Multiplexing, WDM). Here, we demonstrate for the first time optical readout of a superconducting nanowire single-photon detector (SNSPD) directly coupled to a CMOS photonic modulator, without the need for an interfacing device. By operating the modulator in the forward bias regime at a temperature of 3.6 K, we achieve very high modulation efficiency (1,000–10,000 pm/V) and a low input impedance of 500 Ω with a low power dissipation of 40 μW. This allows us to obtain optical modulation with the low, millivolt-level signal generated by the SNSPD.
Scalable, low power, high speed data transfer between cryogenic and room temperature environments is essential for the realization of practical, large-scale systems based on superconducting technologies. Optical fiber presents a 100–1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and allows for very high bandwidth densities by carrying multiple signals through the same physical fiber. By operating a CMOS modulator in the forward bias regime at a temperature of 3.6 K, we have demonstrated the optical readout of a superconducting nanowire single-photon detector (SNSPD) without the need for an interfacing device.