Quantum key distribution (QKD) technology is progressively transitioning from experimental research to industrial development. The development of highly integrated and stable QKD modules has thus emerged as a new research direction. Current integrated QKD research primarily focuses on the integration of optical systems, with relatively few studies addressing optoelectronic co-integration. Due to the more stringent demands of QKD systems on driving signal amplitude, noise, and bandwidth, the driving electronics become more complex and power-intensive, making it difficult to achieve the level of optoelectronic integration seen in classical optical communication systems. We propose a hybrid optoelectronic integrating scheme for QKD modules based on chip-on-board technology, which co-packages the QKD-encoding photonic chip and its required electronic driver chips within a compact, centimeter-scale module. By optimizing the layout structure, incorporating thermal management, and implementing active temperature control, the module temperature can be stabilized within a set range. Simulation and experimental results demonstrate that the module has a total power consumption of 7.69 W and can maintain a stable temperature of 45°C for extended periods when the thermoelectric cooler is active. This effectively ensures the stable operation of the photonic chip and supports long-term QKD functionality, thereby providing technical support for advancing hybrid optoelectronic integrated QKD systems.
Quantum key distribution (QKD) technology is progressively transitioning from experimental research to industrial development. The development of highly integrated and stable QKD modules has thus emerged as a new research direction. Current integrated QKD research primarily focuses on the integration of optical systems, with relatively few studies addressing optoelectronic co-integration. Due to the more stringent demands of QKD systems on driving signal amplitude, noise, and bandwidth, the driving electronics become more complex and power-intensive, making it difficult to achieve the level of optoelectronic integration seen in classical optical communication systems. We propose a hybrid optoelectronic integrating scheme for QKD modules based on chip-on-board technology, which co-packages the QKD-encoding photonic chip and its required electronic driver chips within a compact, centimeter-scale module. By optimizing the layout structure, incorporating thermal management, and implementing active temperature control, the module temperature can be stabilized within a set range. Simulation and experimental results demonstrate that the module has a total power consumption of 7.69 W and can maintain a stable temperature of 45°C for extended periods when the thermoelectric cooler is active. This effectively ensures the stable operation of the photonic chip and supports long-term QKD functionality, thereby providing technical support for advancing hybrid optoelectronic integrated QKD systems.
Quantum key distribution (QKD) offers the highest possible levels of communication secrecy. Using the laws of quantum mechanics, QKD protocols allow two distant parties to establish symmetric encryption keys that can be proven information theoretically secure. In order to make this technology accessible to a wide range of sectors, it is essential to address the questions of cost, volume production and compatibility with standard Telecom/Datacom infrastructures. While over the last few years, a number of works were devoted to the demonstration of photonic integrated circuits for quantum communications, a practical solution to interface these chips in a complete system remained an elusive goal. We review our efforts in integrating the core optical functions of quantum key distribution onto quantum photonic chips and in demonstrating the first standalone photonic integrated QKD system. Our approach tackles various system integration challenges related to packaging, optoelectronic design and power consumption. The quantum hardware is assembled in pluggable interconnects that guarantee efficient thermal management and forward compatibility of a same host electronics with successive generations of chips. Autonomous operation and long-term stability are demonstrated in realistic operation conditions. Our work offers new pathways for practical implementations of QKD and its viable deployment at large scales.
We review our efforts in integrating optical hardware for quantum key distribution onto photonic chips and in engineering the first standalone photonic integrated QKD system. Our approach tackles various system integration challenges related to packaging, optoelectronic design and power consumption. The quantum hardware is assembled in pluggable interconnects that guarantee efficient thermal management and forward compatibility of a same host electronics with successive generations of chips. Autonomous operation and long-term stability are demonstrated in realistic operation conditions. Our work offers new pathways for practical implementations of QKD and its viable deployment at large scales.
Quantum Key Distribution (QKD) has garnered significant attention due to its unconditional security based on the fundamental principles of quantum mechanics. While QKD has been demonstrated by various groups and commercial QKD products are available, the development of a fully chip-based QKD system, aimed at reducing costs, size, and power consumption, remains a significant technological challenge. Most researchers focus on the optical aspects, leaving the integration of the electronic components largely unexplored. In this paper, we present the design of a fully integrated electrical control chip for QKD applications. The chip, fabricated using 28 nm CMOS technology, comprises five main modules: an ARM processor for digital signal processing, delay cells for timing synchronization, ADC for sampling analog signals from monitors, OPAMP for signal amplification, and DAC for generating the required voltage for phase or intensity modulators. According to the simulations, the minimum delay is 11ps, the open-loop gain of the operational amplifier is 86.2 dB, the sampling rate of the ADC reaches 50 MHz, and the DAC achieves a high rate of 100 MHz. To the best of our knowledge, this marks the first design and evaluation of a fully integrated driver chip for QKD, holding the potential to significantly enhance QKD system performance. Thus, we believe our work could inspire future investigations toward the development of more efficient and reliable QKD systems.
Abstract In photonic quantum information processing, the generation, manipulation, and detection of photonic quantum states inherently depend on electronic control devices. As a core enabling technology, on-chip optoelectronic hybrid integration drives optical quantum devices toward higher density, lower power consumption, and enhanced stability while pushing the application and performance limits of quantum information processing. This review summarizes the progress in chip-integrated optoelectronic technologies and their applications in key quantum information scenarios-quantum communication, quantum photonic source engineering, optical frequency conversion, and linear optical quantum information processing. We also discuss key challenges and future directions, envisioning optoelectronic integration as the pivotal bridge from lab demonstrations to practical, scalable quantum photonic systems.
Quantum key distribution (QKD) is a rapidly maturing quantum photonic technology that allows for the distribution of secure cryptographic keys under no assumptions of the attacker's computing power. A key hurdle for its large-scale adoption is the reduction of its hardware size and cost, for which photonic integration is a promising solution. However, there exists no perfect material platform for this task, and for QKD this leads to either design compromises or core functionalities left off-chip. This thesis makes the assertion that hybrid integrated photonics, where one combines two chip materials into one structure, can resolve some of these issues. Firstly, we present an edge-coupled hybrid transceiver that combines a silicon nitride waveguide chip with an indium phosphide modulator chip. Secondly, we pursue the hybrid integration of the single photon detectors. However, the appropriate solution of fast-gated telecom-wavelength avalanche diodes did not exist, and so in the second experimental chapter of this thesis we develop and characterise a linear array of GHz-gated InGaAs/InP SPADs. Finally, we demonstrate a hybrid integrated QKD receiver, consisting of a silica waveguide chip with the aforementioned SPAD array. This represents the first integrated QKD receiver without requiring either external single photon detectors or cryogenic cooling. The results support the benefits of hybrid integration for quantum key distribution, but also more widely for quantum photonic technology as it continues to emerge.
Abstract Quantum key distribution (QKD) has made significant advancements over the past few decades and is gradually transitioning from laboratory to industrial domain. This transformation process poses urgent demands for integrated, cost‐effective, and mass‐producible QKD devices. Here, by interfacing a laser diode, a QKD encoding photonics chip, and their associated electronics driver chips, the QKD transmitter has been condensed from several bulky discrete components to integrated modules with dimensions of a few centimeters, while the modulation rate of the transmitter has been enhanced to 3.33 GHz. Based on this transmitter, QKD is demonstrated over a 100 km standard fiber channel, capable of generating secure keys at a record high key rate of 2.82 Mbps over this distance. This work demonstrates the feasibility of high‐speed integrated QKD transmitters, thereby further propelling the research on QKD in practical applications.