Widely Tunable (2.47–2.64 µm) Hybrid Laser Based on GaSb/GaInAsSb Quantum-Wells and a Low-Loss Si3N4 Photonic Integrated Circuit

Photonic integrated circuits fabricated using a Si3N4 waveguide platform exhibit low losses in a wide wavelength region extending from visible to beyond 2 µm. This feature is exploited to demonstrate a high-performance integrated laser exhibiting broad wavelength tuneability near a 2.6 µm wavelength region. The laser is based on a Si3N4 photonic integrated circuit incorporating a tunable reflector and a AlGaInAsSb/GaSb quantum-well gain element. A tuning range of 170 nm (2474–2644 nm) and single-mode CW operation with a maximum power of 6.4 mW at room temperature are demonstrated. The performance is enabled by exploitation of several essential building blocks realized in Si3N4, namely low-loss Y-branches, inverse tapers, and a double-ring resonator with a free spectral range of ≈160 nm. Moreover, the limits of wavelength coverage are explored using Si3N4 waveguides and show that the platform supports low propagation loss up to 3.5 µm. Finally, the possibility to achieve improved mode matching between Si3N4 and GaSb waveguides is analyzed, further enabling enhancing the performance of such a hybrid laser platform and supporting wavelength extension beyond a 3 µm range.publishedVersionPeer reviewe

Integrated Photonic Platforms for Quantum Technology: A Review

Quantum information processing has conceptually changed the way we process and transmit information. Quantum physics, which explains the strange behaviour of matter at the microscopic dimensions, has matured into a quantum technology that can harness this strange behaviour for technological applications with far-reaching consequences, which uses quantum bits (qubits) for information processing. Experiments suggest that photons are the most successful candidates for realising qubits, which indicates that integrated photonic platforms will play a crucial role in realising quantum technology. This paper surveys the various photonic platforms based on different materials for quantum information processing. The future of this technology depends on the successful materials that can be used to universally realise quantum devices, similar to silicon, which shaped the industry towards the end of the last century. Though a prediction is implausible at this point, we provide an overview of the current status of research on the platforms based on various materials.Comment: 48 pages, 3 figure

Controlling phonons and photons at the wavelength-scale: silicon photonics meets silicon phononics

Radio-frequency communication systems have long used bulk- and surface-acoustic-wave devices supporting ultrasonic mechanical waves to manipulate and sense signals. These devices have greatly improved our ability to process microwaves by interfacing them to orders-of-magnitude slower and lower loss mechanical fields. In parallel, long-distance communications have been dominated by low-loss infrared optical photons. As electrical signal processing and transmission approaches physical limits imposed by energy dissipation, optical links are now being actively considered for mobile and cloud technologies. Thus there is a strong driver for wavelength-scale mechanical wave or "phononic" circuitry fabricated by scalable semiconductor processes. With the advent of these circuits, new micro- and nanostructures that combine electrical, optical and mechanical elements have emerged. In these devices, such as optomechanical waveguides and resonators, optical photons and gigahertz phonons are ideally matched to one another as both have wavelengths on the order of micrometers. The development of phononic circuits has thus emerged as a vibrant field of research pursued for optical signal processing and sensing applications as well as emerging quantum technologies. In this review, we discuss the key physics and figures of merit underpinning this field. We also summarize the state of the art in nanoscale electro- and optomechanical systems with a focus on scalable platforms such as silicon. Finally, we give perspectives on what these new systems may bring and what challenges they face in the coming years. In particular, we believe hybrid electro- and optomechanical devices incorporating highly coherent and compact mechanical elements on a chip have significant untapped potential for electro-optic modulation, quantum microwave-to-optical photon conversion, sensing and microwave signal processing.Comment: 26 pages, 5 figure

A Review of Capabilities and Scope for Hybrid Integration Offered by Silicon-Nitride-Based Photonic Integrated Circuits

In this review we present some of the recent advances in the field of silicon nitride photonic integrated circuits. The review focuses on the material deposition techniques currently available, illustrating the capabilities of each technique. The review then expands on the functionalisation of the platform to achieve nonlinear processing, optical modulation, nonvolatile optical memories and integration with III-V materials to obtain lasing or gain capabilities

Wavelength Tunable Monolithic InP Receivers and Switches for Optical Communication Systems

Demand for information technology continues to grow, and with it the need for continuous improvement in telecommunication infrastructure. Recent interest in coherent modulation schemes, wavelength conversion, and large scale photonic integration for feasible, cost-effective scaling of existing network infrastructure has generated an intriguing area idea in which several technologies are combined at once to create a solution more capable than any individual approach. By leveraging these technologies together, a scalable path capable of providing sustainable growth in the telecommunication field may be realized. This dissertation explores this concept by the applying principles of monolithic integration to coherent receiver and optical switch technology with the goal of improving the size, cost, and performance of existing communication components as well as drive forward the state of the art in photonic integration. To this end, a monolithic coherent receiver was developed by integrating local oscillator, mixer, and high speed detection functions together on a single chip in an architecture capable of supporting polarization multiplexing and phase shift keying modulation formats. With an integrated local oscillator, the receiver’s capability is scalable, supporting higher capacity modulation formats through the use of more advanced feedback electronics and digital signal processing.In addition, a monolithic all-optical switch was developed by integrating both wavelength conversion and wavelength filtering functions onto a single chip. The architecture is capable of high speed switching of optical signals without costly optical-electrical conversion by utilizing an array of optical-optical modulators with scalable channel capacity and a static arrayed-waveguide grating router. By integrating these functions on the same chip, costly packaging issues may be avoided, greatly reducing development and production costs.By moving an increased number of components onto single die while maintaining similar performance to discrete solutions, the coherent receiver and all-optical switch devices presented in this work advance the state of the art by improving the cost and manufacturability of optical communication devices. Even more, these technologies represent a path toward manageable growth of optical communication systems for long haul, datacenter, and short reach solutions by demonstrating scalable architectures for each application. Development of such technology is not only vital but essential for the continued growth of the telecommunications industry. The novel application of photonic integration, coherent modulation, and optical switching technologies are a viable solution to maintaining sustainable growth in the telecommunications field

Modelling and characterization of hybrid integrated lasers in 2 to 3 µm wavelength band

Hybrid integrated silicon photonic lasers functioning at mid-IR wavelengths have recently emerged as a solution for developing compact optical sensors targeted at trace gas spectroscopy. This thesis concerns a measurement and simulation combined approach to characterize Silicon Nitride photonic integrated circuits (PICs) equipped to work as such lasers. Seven PICs from the same process are first aligned in an end-fire coupling scheme with the III-V gain chip using a closed-loop piezo stage. The gain chip consists of an AlGaInAsSb/GaSb type-I quantum well reflective semiconductor optical amplifier (RSOA). The PICs contain narrow-band long rectangular spiral and round spiral shaped distributed Bragg reflectors (DBRs) which work as external cavities allowing periodic feedback to the gain element. Intensity vs. current sweeps and measurements of the spectra of the uncooled 2 µm lasers demonstrate narrow full-width half-maximum (FWHM) linewidths and remarkable power outputs in continuous wave operation at room temperature. The measurements also give insight into process variation and design reliability, and have led to a recent submission to Optica for publication. A commercial eigenmode expansion solver is used to verify the experimental results as well as to explore the design space for Bragg reflectors at 2 µm and 2.7 µm with a view to optimizing the packing ratio, linewidth and side-mode suppression ratio of the devices for improved laser performance. The rapid and efficient end-fire based optical testing method presented in this work is expected to set a base-line for optimization of mid-IR tunable hybrid lasers

2022 Roadmap on integrated quantum photonics

AbstractIntegrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

This is the final version. Available on open access from IOP Publishing via the DOI in this recordData availability statement: The data that support the findings of this study are available upon reasonable request from the authors.Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.National Science Foundation (NSF)NAS