Wave propagation and group velocity

Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the reduction of size, weight, cost and power consumption. This article reviews the recent advances in this emerging field which is dubbed as integrated microwave photonics. Key integrated MWP technologies are reviewed and the prospective of the field is discussed.

Integrated microwave photonics

Recent advances in photonic integration have propelled microwave photonic technologies to new heights. The ability to interface hybrid material platforms to enhance light–matter interactions has led to the development of ultra-small and high-bandwidth electro-optic modulators, low-noise frequency synthesizers and chip signal processors with orders-of-magnitude enhanced spectral resolution. On the other hand, the maturity of high-volume semiconductor processing has finally enabled the complete integration of light sources, modulators and detectors in a single microwave photonic processor chip and has ushered the creation of a complex signal processor with multifunctionality and reconfigurability similar to electronic devices. Here, we review these recent advances and discuss the impact of these new frontiers for short- and long-term applications in communications and information processing. We also take a look at the future perspectives at the intersection of integrated microwave photonics and other fields including quantum and neuromorphic photonics. This Review discusses recent advances of microwave photonic technologies and their applications in communications and information processing, as well as their potential implementations in quantum and neuromorphic photonics.

The growing maturity of integrated photonic technology makes it possible to build increasingly large and complex photonic circuits on the surface of a chip. Today, most of these circuits are designed for a specific application, but the increase in complexity has introduced a generation of photonic circuits that can be programmed using software for a wide variety of functions through a mesh of on-chip waveguides, tunable beam couplers and optical phase shifters. Here we discuss the state of this emerging technology, including recent developments in photonic building blocks and circuit architectures, as well as electronic control and programming strategies. We cover possible applications in linear matrix operations, quantum information processing and microwave photonics, and examine how these generic chips can accelerate the development of future photonic circuits by providing a higher-level platform for prototyping novel optical functionalities without the need for custom chip fabrication. The current state of programmable photonic integrated circuits is discussed, including recent developments in their building blocks, circuit architectures, electronic control and programming strategies, as well as different application spaces.

https://biblio.ugent.be/publication/8677857/file/8677861.pdf

Programmable photonic circuits.

Photonic systems for high-performance information processing have attracted renewed interest. Neuromorphic silicon photonics has the potential to integrate processing functions that vastly exceed the capabilities of electronics. We report first observations of a recurrent silicon photonic neural network, in which connections are configured by microring weight banks. A mathematical isomorphism between the silicon photonic circuit and a continuous neural network model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, a simulated 24-node silicon photonic neural network is programmed using “neural compiler” to solve a differential system emulation task. A 294-fold acceleration against a conventional benchmark is predicted. We also propose and derive power consumption analysis for modulator-class neurons that, as opposed to laser-class neurons, are compatible with silicon photonic platforms. At increased scale, Neuromorphic silicon photonics could access new regimes of ultrafast information processing for radio, control, and scientific computing.

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Neuromorphic photonic networks using silicon photonic weight banks.

One of the key research topics of the Telecommunication Engineering (TE) Group at the University of Twente (UT) is RF Photonics. The aim of this field is to develop schemes that utilize the advantages of optical technology for performing RF functions in wireless communication systems. Examples of such functions are high-frequency filtering, frequency conversion, antenna remoting, and beam forming for phased array antennas. The TE Group is currently involved in several Senter and NIVR projects on RF Photonics that are related to phased array antenna applications.

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RF photonics technology for phased array antenna applications

A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our goal is to deliver large bandwidth Ku-band connectivity between antennas, mount conformal to the airplane fuselage and on a geostationary satellite, respectively.This way it would be possible to bring live DVB-S television to airplane passengers. In this paper, we present recent research conducted on a 4 × 1 ring resonator-based OBFN test set-up. This OBFN has four optical input ports and one optical output port. It is tuned to provide the desired signal combination with optimal constructive interference between the modulated input signals from the PAA. Therefore, combining circuitry and delay elements are required. The OBFN is tuned by electrically heating tunable true time delay (TTD) elements. These are built using optical ring resonators (ORRs). By cascading multiple ORRs with different resonance frequencies, it is possible to create a TTD with a large bandwidth. Optical beam forming is used because it provides advantages over traditional beam forming methods. These advantages are: large bandwidth, EMI resistance, and, when integrated onto a single chip, compactness and low costs. The OBFN is created using planar optical waveguide technology and consists of the following building blocks: waveguides, Mach-Zehnder interferometers, (MZIs) couplers and ORRs. The tuning of the OBFN is done by an electronic control system using a microcontroller. Communication with a PC is possible using USB. To our knowledge, this is the first integrated ORR-based OBFN circuit for PAA satellite reception.

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Design of a ring resonator-based optical beam forming network for phased array receive antennas

Electro-Photonics combines the best of both electronics and optics to tackle the challenges of next generation optical communication networks in terms of capacity, flexibility, and energy efficiency. The optimal sharing of the processing work load between the electrical and optical domain brings considerable benefits to communication system complexity, performance, and construction as well as operational cost. As a key technology, photonic integrated circuits (PICs) play a critical role for the implementation of signal processing in the optical domain, serving for signal generation, switching, and acquisition. PICs point to advancing of network devices such as transmitters, receivers, and switches with desirable features of large bandwidth, high stability, precise control, easy tuning, and potential for low-cost fabrication by enabling miniaturization of complex optical systems on a chip scale. In this paper, we review the PIC research progress of the Monash Electro-Photonics Laboratory and its major contributions to the fields of optical communications and microwave photonics. We focus on applications in optical orthogonal frequency division multiplexing (O-OFDM), Nyquist wavelength division multiplexing (N-WDM), optical pulse manipulation, and programmable optical processors. The results of these works underline not only hardware fabrication capability and performance improvement for electrophotonics, but, more importantly, a new engineering paradigm that stimulates innovations in information and communication technologies.

Electro-photonics: An emerging field for photonic integrated circuits

The CMOS compatible fabrication equipment, the transparency from UV to IR and the capability of batch processing make the TriPleXTM waveguide platform very suitable for a large variety of applications. In this paper a description of the technology and examples of applications in different wavelength ranges are given. These applications exploit the low loss properties at relatively high index contrasts in the TriPleXTM technology

TriPlextm photonic platform technology: Low-loss waveguide platform for applications from UV to IR

Adding a ring-resonator-assisted MZI for preprocessing improves the selectivity of ROADMs, enabling cascades of ROADMs to process N-WDM superchannels. We experimentally investigate the N-WDM superchannels performance with high-order QAM after filtered by cascaded enhanced ROADMs.

Leimeng Zhuang

Papers

RF photonics technology for phased array antenna applications

Design of a ring resonator-based optical beam forming network for phased array receive antennas

Electro-photonics: An emerging field for photonic integrated circuits

TriPlextm photonic platform technology: Low-loss waveguide platform for applications from UV to IR

Investigation of performance-enhanced ROADMs for N-WDM superchannels carrying high-order QAM