This presentation will describe Canada’s silicon photonics rapid prototyping consortium, SiEPICfab, and how it can accelerate silicon photonics research and development in quantum information processing. We use electron beam lithography (EBL) to fabricate either individual chips or wafers ranging from 100 mm to 200 mm in size. Fabrication includes waveguides, high-efficiency thermo-optic phase shifters, silicon doping for modulators/heaters/defect-mediated detectors, Bragg grating filters, and NEMS-tunable photonic crystals. Rapid prototyping also allows us to fabricate advanced devices not available in foundries, such as single photon detectors. Finally, successful demonstration of silicon photonic circuits requires testing and packaging - both electrical and optical - and we describe our plans for photonic wire bonding of silicon photonic chips to optical fibres and III-V chips.
This presentation will describe Canada’s silicon photonics rapid prototyping consortium, SiEPICfab, and how it can accelerate silicon photonics research and development in quantum information processing. We use electron beam lithography (EBL) to fabricate either individual chips or wafers ranging from 100 mm to 200 mm in size. Fabrication includes waveguides, high-efficiency thermo-optic phase shifters, silicon doping for modulators/heaters/defect-mediated detectors, Bragg grating filters, and NEMS-tunable photonic crystals. Rapid prototyping also allows us to fabricate advanced devices not available in foundries, such as single photon detectors. Finally, successful demonstration of silicon photonic circuits requires testing and packaging - both electrical and optical - and we describe our plans for photonic wire bonding of silicon photonic chips to optical fibres and III-V chips.
Silicon-on-insulator (SOI) wafers have been developed for electronic integrated circuits, but are also one of the most promising platforms in photonic integrated circuits due to its low loss, high refractive index, ability to fast phase modulation, and well-developed fabrication technologies. With advantages to handle light with a small volume and high modulation speed, silicon photonics has been intensively investigated as the next generation platform of signal processing, interconnection, and communication devices. Recently, silicon photonics has been attracted great interests in quantum optics communities as optical quantum systems for linear optical quantum computing are achievable using silicon photonic components including beam splitters, phase modulators, and filters and the small footprint of a silicon photonic quantum system has unprecedented performances of high stability and scalability. Here we show our recent results on the fabrication of silicon photonic elements for quantum applications. We fabricated low-loss optical waveguides, efficient fiber-to-waveguide grating couplers, resonator-based optical filters, and tunable beam splitters and tested their performances. A micro-sized heater is attached on a Mach-Zehnder interferometer, showing stable operation as a slow phase modulator. In addition, phase modulators using plasma dispersion effects are under investigation. Finally, the quantum characteristics of photon pairs generated by spontaneous four-wave mixing in silicon waveguides are investigated. These results will be an essential cornerstone for the realization of quantum optical computing and quantum communication devices.
Integrated photonic circuits offer great promise for quantum technologies. However, due to the rapid propagation of light, many envisioned applications require efficient on-chip quantum memories with a programmable delay, compact footprint, and high fidelity. Implementing this based on standard semiconductor processing technology is an outstanding challenge. Here, we realize such memories using erbium-doped silicon waveguides, fabricated as part of a multi-wafer project by a nanophotonic foundry. We demonstrate light storage with a 44.2(9)MHz bandwidth and a programmable delay exceeding 1μs in a device with a footprint of only 1.5×10−2mm2, outperforming on-chip delay lines by many orders of magnitude. The phase of the read-out light field is preserved with a visibility of 91.3(30)%. The efficiency of 1.89(28)×10−8 can be improved in future devices through resonator enhancement and higher dopant concentrations. With this, the demonstrated approach will pave the way towards applications in photonic quantum computing based on scalable silicon processing technology.
Photon pairs and heralded single photons are a useful resource in quantum communication, computation, and measurement. Room-temperature microchip-scale integrated devices could enable scalability, robustness and low-cost deployment in practical applications. Silicon is an attractive integration platform, since pair generation by spontaneous four-wave mixing at 1.2 - 1.6 micron wavelengths requires optical power levels that can be delivered by compact electrically-driven laser diodes. However, silicon photonics lacks a native laser device, and the propagation losses are not especially low, although they are somewhat lower than III-V integrated optics, which does have an integrated laser. Nevertheless, silicon photonics can be expected to become a widely-adopted platform for photonics – both classical and quantum – because of the ability to leverage the mature fabrication processes using large-area silicon wafers inherited from the development of microelectronics. Moreover, scalable quantum optics requires electronics for control, drivers and readout circuits, which silicon microelectronic technology can supply. Our research is improving the performance of silicon photonics components for quantum optical communications, and is increasing the level of integration in the quantum silicon photonics toolkit, using microelectronic components and electrically-driven hybrid silicon lasers.
The emerging field of quantum technologies requires a range of photonic devices, many with demanding specifications. The area of quantum information processing requires scaling in order to increase the complexity of experiments, this has led researchers towards integrated photonic platforms. The key property of these single photon devices is low-loss operation and as a consequence glass and silica devices have been a dominant platform. Whereas atom chip sensors require stable compact systems for converting optical fibre modes to free space beams for atom trapping. In this talk I will present the photonic engineering undertaken at the University of Southampton to fabricate devices for the quantum technology community. The key fabrication approach is a direct UV writing technique, where a UV laser beam is used to define waveguides, splitters/couplers, Bragg gratings and 2D tilted gratings. The fabricated devices include cascaded arrays of Mach-Zehnder interferometers to preform photon-photon interactions, single photon sources via spontaneous four-wave mixing, integrated superconducting single photon detectors and 2D diffraction gratings. In addition to the inscription method I will describe the fabrication of the substrates required for the UV writing process which are generated via Flame Hydrolysis Deposition. I will discuss our most recent work on single photon linear optical networks constructed from a number of identical reconfigurable modules. The modules are characterised separately to produce an accurate model of the network and the cellular approach permits the replacement of modules that are deficient. Each module comprises of an array of 10 Mach-Zehnder interferometers with 40 thermo-optic phase shifters on each chip that control both the amplitude and phase of the optical modes. By concatenating modules any arbitrary N ×N unitary network can be realised. The channel waveguides are engineered to be mode matched to standard optical fibre producing excellent coupling efficiency. I will present our recent work in this area and other photonic devices for the field of quantum technology.
Direct UV-written silica-on-silicon provides an attractive platform for quantum optics, offering the key benefits of low propagation losses and excellent optical fibre compatibility. This work has aimed to develop the necessary techniques and components for completely integrated quantum optics experiments to be carried out using this platform, on a larger scale than previously possible. Arrays of matched on-chip photon sources based on birefringence-matched spontaneous four-wave mixing (FWM) are demonstrated, both at 800 nm and in the telecommunications C-band, along with progress towards further integration of these sources. Thermo-optic phase shifters, for use in room temperature quantum circuits, have been optimised via modelling, and a range of alternative modulator technologies have been explored. Further work has been concerned with the development of a modular system for quantum optics, comprising a set of duplicate reconfigurable modules and the necessary drive electronics and software, with the intent of simplifying the task of identifying and quantifying manufacturing imperfections in large integrated experiments. Efforts have also been made to improve the detection efficiency of on-chip transition edge sensor (TES) single photon detectors, including the use of longer absorbers and high reflectors for multiple absorption passes; this has resulted in the demonstration of a photon-number-resolving detector with a Bragg grating enhanced quantum efficiency of 87%. Approaches for further increasing the detection efficiency are considered and a device for on-chip Hong-Ou-Mandel and photon subtraction experiments using these detectors is reported.
All optical quantum information processing is an important developing field for understanding and exploiting quantum entanglement and offers opportunities in quantum computation, quantum sensing and quantum communication. The presentation will describe work on laser written devices in a silica on silicon platform. The devices can be used to create single photon sources, waveguide circuitry and number resolving detectors. Applications of the technology include boson sampling, quantum teleportation, on-chip number resolving detection and quantum simulation. The use of laser writing allows for rapid prototyping, and by including high quality Bragg gratings, it is possible to provide accurate measurements of device properties including losses and coupler variability. Furthermore, the ability to make accurate measurements of material properties such as dispersion and birefringence allows the creation of tailored devices with optimal properties for identical photon sources.