Temporal jitter in free-running InGaAs/InP single-photon avalanche detectors

A versatile photon counting system with active afterpulse suppression for free-running negative-feedback avalanche diodes

InGaAs/InP-based negative-feedback avalanche diodes (NFADs) have been demonstrated to be an excellent option for photon detection at telecom wavelengths in quantum communication applications, where photon arrival times are random. However, it is well-known that the operation of NFADs at low temperatures (193 K or below) is crucial to minimize the effects of afterpulsing and high dark count rates (DCRs). In this work, we present a new versatile readout electronics system with active afterpulse suppression that also offers flexible cooling options. Through the characterization of two NFAD detectors from Princeton Lightwave, Inc. and a thorough evaluation of our electronics' performance under various operating conditions, we demonstrate the effectiveness of this readout system in improving the performance of NFAD-based photon detectors. At the optimal bias for NFADs, our electronics were able to significantly reduce the afterpulsing probability by a factor of 200 for dead times ranging from 5 to 20 µs following each detection event. This helps to keep the total DCRs at around 100 counts per second or less for a 20 µs hold-off time. The versatility of our detection system makes NFADs a cost-effective alternative to more complex detectors, such as superconducting nanowire single-photon detectors, in the research of long-distance quantum communications and low-noise single photon detectors at telecommunication wavelengths.

Timing measurements with silicon single photon avalanche diodes: principles and perspectives [Invited]

Picosecond timing of single photons has laid the foundation of a great variety of applications, from life sciences to quantum communication, thanks to the combination of ultimate sensitivity with a bandwidth that cannot be reached by analog recording techniques. Nowadays, more and more applications could still be enabled or advanced by progress in the available instrumentation, resulting in a steadily increasing research interest in this field. In this scenario, single-photon avalanche diodes (SPADs) have gained a key position, thanks to the remarkable precision they are able to provide, along with other key advantages like ruggedness, compactness, large signal amplitude, and room temperature operation, which neatly distinguish them from other solutions like superconducting nanowire single-photon detectors and silicon photomultipliers. With this work, we aim at filling a gap in the literature by providing a thorough discussion of the main design rules and tradeoffs for silicon SPADs and the electronics employed along them to achieve high timing precision. In the end, we conclude with our outlook on the future by summarizing new routes that could benefit from present and prospective timing features of silicon SPADs.

Free-Running Single-Photon Detection via GHz Gated InGaAs/InP APD for High Time Resolution and Count Rate up to 500 Mcount/s

Free-running InGaAs/InP single-photon avalanche photodiodes (SPADs) typically operate in the active-quenching mode, facing the problems of long dead time and large timing jitter. In this paper, we demonstrate a 1-GHz gated InGaAs/InP SPAD with the sinusoidal gating signals asynchronous to the incident pulsed laser, enabling free-running single-photon detection. The photon-induced avalanche signals are quenched within 1 ns, efficiently reducing the SPAD's dead time and achieving a count rate of up to 500 Mcount/s. However, the timing jitter is measured to be ~168 ps, much larger than that of the SPAD with synchronous gates. We adjust the delay between the gating signals and the incident pulsed laser to simulate the random arrival of the photons, and record the timing jitter, respectively, to figure out the cause of the jitter deterioration. In addition, the effects of the incident laser power and working temperature of the APD on the time resolution have been investigated, broadening the applications of the GHz gated free-running SPAD in laser ranging and imaging, fluorescence spectroscopy detection and optical time-domain reflectometry.

Advances in Chip-Based Quantum Key Distribution

Quantum key distribution (QKD), guaranteed by the principles of quantum mechanics, is one of the most promising solutions for the future of secure communication. Integrated quantum photonics provides a stable, compact, and robust platform for the implementation of complex photonic circuits amenable to mass manufacture, and also allows for the generation, detection, and processing of quantum states of light at a growing system's scale, functionality, and complexity. Integrated quantum photonics provides a compelling technology for the integration of QKD systems. In this review, we summarize the advances in integrated QKD systems, including integrated photon sources, detectors, and encoding and decoding components for QKD implements. Complete demonstrations of various QKD schemes based on integrated photonic chips are also discussed.

High performance planar germanium-on-silicon single-photon avalanche diode detectors

Single-photon detection has emerged as a method of choice for ultra-sensitive measurements of picosecond optical transients. In the short-wave infrared, semiconductor-based single-photon detectors typically exhibit relatively poor performance compared with all-silicon devices operating at shorter wavelengths. Here we show a new generation of planar germanium-on-silicon (Ge-on-Si) single-photon avalanche diode (SPAD) detectors for short-wave infrared operation. This planar geometry has enabled a significant step-change in performance, demonstrating single-photon detection efficiency of 38% at 125 K at a wavelength of 1310 nm, and a fifty-fold improvement in noise equivalent power compared with optimised mesa geometry SPADs. In comparison with InGaAs/InP devices, Ge-on-Si SPADs exhibit considerably reduced afterpulsing effects. These results, utilising the inexpensive Ge-on-Si platform, provide a route towards large arrays of efficient, high data rate Ge-on-Si SPADs for use in eye-safe automotive LIDAR and future quantum technology applications.

By incorporating germanium, single-photon avalanche diode detectors using silicon-based platforms are applied to infrared light detection. Here, a cost-effective planar detector geometry is presented yielding high detection efficiency suitable for applications such as sparse photon imaging or LIDAR.

1.25 GHz sine wave gating InGaAs/InP single-photon detector with a monolithically integrated readout circuit

InGaAs/InP single-photon detectors (SPDs) are the key devices for applications requiring near-infrared single-photon detection. The gating mode is an effective approach to synchronous single-photon detection. Increasing gating frequency and reducing the module size are important challenges for the design of such a detector system. Here we present for the first time, to the best of our knowledge, an InGaAs/InP SPD with 1.25 GHz sine wave gating (SWG) using a monolithically integrated readout circuit (MIRC). The MIRC has a size of 15  mm×15  mm and implements the miniaturization of avalanche extraction for high-frequency SWG. In the MIRC, low-pass filters and a low-noise radio frequency amplifier are integrated based on the technique of low temperature co-fired ceramic, which can effectively reduce the parasitic capacitance and extract weak avalanche signals. We then characterize the InGaAs/InP SPD to verify the functionality and reliability of the MIRC, and the SPD exhibits excellent performance with 27.5% photon detection efficiency, a 1.2 kcps dark count rate, and 9.1% afterpulse probability at 223 K and 100 ns hold-off time. With this MIRC, one can further design miniaturized high-frequency SPD modules that are highly required for practical applications.