Optical and Quantum Sensing and Precision Metrology II
Strategies and components for quantum limited precision measurement in integrated quantum photonics
Jonathan Frazer, Joel F. Tasker, Jake Biele, Alexandre Belsley, Matthew Stafford, Giacomo Ferranti, Euan J. Allen, Sabine Wollmann, F. Brunel, Sébastien Tanzilli, Virginia D’Auria, Animesh Datta, Joshua W. Silverstone, Jonathan C. F. Matthews
Integrated photonics is providing a compelling route for quantum limited and quantum enhanced technologies, including computing communications and optical sensing. This is because chip-scale integrated photonics can offer miniaturization as well as possible scalability in manufacture. Here we will discuss recent results in developing integrated homodyne detection integrated in silicon photonics. We discuss its combination with integrated electronics to demonstrate high bandwidth performance and its use to measure squeezed light over a broad bandwidth, out to 9GHz. This demonstrates a performance enhancement that is relevant to quantum technology and is due to miniaturization. We will discuss possible applications of of integrated quantum noise listed homodyne detection, including a strategy to perform quantum limited absorption estimation using integrated photonics and coherent states.
Integrated photonics is providing a compelling route for quantum limited and quantum enhanced technologies, including computing communications and optical sensing. This is because chip-scale integrated photonics can offer miniaturization as well as possible scalability in manufacture. Here we will discuss recent results in developing integrated homodyne detection integrated in silicon photonics. We discuss its combination with integrated electronics to demonstrate high bandwidth performance and its use to measure squeezed light over a broad bandwidth, out to 9GHz. This demonstrates a performance enhancement that is relevant to quantum technology and is due to miniaturization. We will discuss possible applications of of integrated quantum noise listed homodyne detection, including a strategy to perform quantum limited absorption estimation using integrated photonics and coherent states.
Photonic quantum technology can be enhanced by monolithic fabrication of both the underpinning quantum hardware and the corresponding electronics for classical readout and control. Together, this enables miniaturisation and mass-manufacture of small quantum devices---such as quantum communication nodes, quantum sensors and sources of randomness---and promises the precision and scale of fabrication required to assemble useful quantum computers. Here we combine CMOS compatible silicon and germanium-on-silicon nano-photonics with silicon-germanium integrated amplification electronics to improve performance of on-chip homodyne detection of quantum light. We observe a 3 dB bandwidth of 1.7 GHz, shot-noise limited performance beyond 9 GHz and minaturise the required footprint to 0.84 mm. We use the device to observe quantum squeezed light, from 100 MHz to 9 GHz, generated in a lithium niobate waveguide. This demonstrates that an all-integrated approach yields faster homodyne detectors for quantum technology than has been achieved to-date and opens the way to full-stack integration of photonic quantum devices.
Complimentary metal-oxide semiconductor (CMOS) integration of quantum technology provides a route to manufacture at volume, simplify assembly, reduce footprint, and increase performance. Quantum noise-limited homodyne detectors have applications across quantum technologies, and they comprise photonics and electronics. Here, we report a quantum noise-limited monolithic electronic-photonic integrated homodyne detector, with a footprint of 80 micrometers by 220 micrometers, fabricated in a 250-nanometer lithography bipolar CMOS process. We measure a 15.3-gigahertz 3-decibel bandwidth with a maximum shot noise clearance of 12 decibels and shot noise clearance out to 26.5 gigahertz, when measured with a 9-decibel-milliwatt power local oscillator. This performance is enabled by monolithic electronic-photonic integration, which goes below the capacitance limits of devices made up of separate integrated chips or discrete components. It exceeds the bandwidth of quantum detectors with macroscopic electronic interconnects, including wire and flip chip bonding. This demonstrates electronic-photonic integration enhancing quantum photonic device performance.
Squeezed light underpins quantum-enhanced sensing and continuous-variable quantum information processing, and integrated photonics offers a route to producing it at scale. Universal to these applications are squeezed-light generation and measurement. Importantly, quantum measurements serve not only as readout but also as active operations in quantum-state evolution. However, integrating squeezed-light generation and photodetection on the same photonic chip has remained challenging because they impose fundamentally conflicting material requirements: low optical loss to preserve quantum correlations, but efficient photon absorption for photodetection. Here, we demonstrate squeezed-light generation, routing, and balanced homodyne detection integrated on a single photonic chip through heterogeneous integration. A two-mode squeezed quantum microcomb comprising 34 quantum modes is measured with approximately 3 dB squeezing. Our work establishes a scalable architecture for fully integrated squeezed-light quantum photonic systems, unifying quantum-state generation, processing, and detection on a single chip.
Silicon photonics is rapidly evolving as an advanced chip framework for implementing quantum technologies. With the help of silicon photonics, general-purpose programmable networks with hundreds of discrete components have been developed. These networks can compute quantum states generated on-chip as well as more extraordinary functions like quantum transmission and random number generation. In particular, the interfacing of silicon photonics with complementary metal oxide semiconductor (CMOS) microelectronics enables us to build miniaturized quantum devices for next-generation sensing, communication, and generating randomness for assembling quantum computers. In this review, we assess the significance of silicon photonics and its interfacing with microelectronics for achieving the technology milestones in the next generation of quantum computers and quantum communication. To this end, especially, we have provided an overview of the mechanism of a homodyne detector and the latest state-of-the-art of measuring squeezed light along with its integration on a photonic chip. Finally, we present an outlook on future studies that are considered beneficial for the wide implementation of silicon photonics for distinct data-driven applications with maximum throughput.
Integrated quantum photonic applications, providing physically guaranteed communications security, subshot-noise measurement, and tremendous computational power, are nearly within technological reach. Silicon as a technology platform has proven formidable in establishing the micro-electronics revolution, and it might do so again in the quantum technology revolution. Silicon has taken photonics by storm, with its promise of scalable manufacture, integration, and compatibility with CMOS microelectronics. These same properties, and a few others, motivate its use for large-scale quantum optics as well. In this paper, we provide context to the development of quantum optics in silicon. We review the development of the various components that constitute integrated quantum photonic systems, and we identify the challenges that must be faced and their potential solutions for silicon quantum photonics to make quantum technology a reality.
Silicon photonics is a dynamic research field of integrated optics. It allows to miniaturize numerous optical functionalities such as lasers, electro-optical modulators, routers, detectors, for telecom wavelengths, LIDAR, sensor, metrology or even spectroscopy, all while been able to propose large scale production high precision technologies. On another side, quantum optics suffers from difficulties to scale optical systems, requires extreme stability, perfect alignment, and many bulky optical elements, while solving these issues follows a natural path in integrated photonics. Development of integrated quantum photonics can thus open the door to cheap, powerful, and scalable systems for quantum cryptography, telecoms, and computation. In a significant way, quantum requirements are not the ones of classical circuits with respect to photonic components and circuits. The generation of quantum states indeed requires more than 100dB of pump laser rejection, while being able to manage ultra-low useful optical signals and get rid of on-chip optical noise. In this context, this thesis is dedicated to the study, dimension, realization, and characterization of silicon photonic components and circuits for quantum optics on a chip. The target goal is to generate entangled states in energy-time and manipulate them on chip. The qualification of the quantum properties is also explored to better understand the limitations of the silicon platform in the followed objectives. Another choice of this work is to stay in telecoms wavelength and aligned with the standard channels (ITU grid), to only use off-the-shelf components, all while been CMOS compatible and compliant with standard fabrication process, this to allow the possibility to produce on large scale.