Emma Lazzeri

Bio: Emma Lazzeri is an academic researcher from Sant'Anna School of Advanced Studies. The author has contributed to research in topics: Optical amplifier & Photonics. The author has an hindex of 11, co-authored 58 publications receiving 1004 citations. Previous affiliations of Emma Lazzeri include Ericsson.

A fully photonics-based coherent radar system

Abstract: The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system.

Photonic Processing for Digital Comparison and Full Addition Based on Semiconductor Optical Amplifiers

Abstract: An N bit all-optical comparator and an all-optical full adder are presented. These complex circuits, which perform photonic digital processing, are implemented cascading a unique basic gate that exploits cross gain modulation and cross-polarization rotation in a single semiconductor optical amplifier (SOA). Since the interacting signals are counterpropagating in the SOA, they can be set at the same wavelength. Photonic processing improves the speed of the optical networks by reducing the packet latency time to the time-of-flight in the nodes. Digital comparison and full-addition are key functionalities for the processing of the packet labels. Integrated realizations are crucial, thus, SOAs represent a suitable mean both because they allow hybrid integrated solutions and fast operation speed. The performances of the basic gate, the comparator, and the full adder are investigated both in terms of bit error rate and eye opening. To the best of our knowledge this is the first time it is reported on the implementation of an all-optical comparator able to compare patterns longer than 1 bit. Previous works demonstrate the comparison of 1 bit patterns. Only few works report on an all-optical full adder implementation, but with different schemes. In our implementation, sum and carry out do not depend directly on the carry in, thus potentially improving the output signal quality when cascading multiple full adders.

Photonics in Radar Systems: RF Integration for State-of-the-Art Functionality

Abstract: The cross-fertilization between photonics and microwave systems is setting new paradigms in radio technologies, promising improved performance and new applications, with strong benefits for communication systems broadly as well as for public safety specifically In particular, the use of photonics in radar systems is leading to a new generation of multifunctional systems that can manage multiple simultaneous coherent radio signals at different frequencies, thus enabling multispectral imaging for advanced surveillance In fact, thanks to its tenability and huge bandwidth, photonics matches the flexibility requirements urgently needed in future software-defined radar architectures It also guarantees system compactness because a single shared transceiver can be used for multiband operations with the added potential of photonic integration

Multi-Frequency Lidar/Radar Integrated System for Robust and Flexible Doppler Measurements

Abstract: A new architecture for an integrated fully coherent radar–lidar system based on a single mode-locked laser is proposed and demonstrated. The lidar exploits a multi-frequency optical signal with tunable tones separation allowing a dynamic tradeoff among robustness and sensitivity of measurements. The radar that is based on photonics technologies employs the mode-locked laser for generating the radio frequency signals in the X-band and Ku-band, simultaneously with the lidar. Velocity measurements for different tones separation are demonstrated with good agreement among the values measured with the lidar and radar.

Optical xor for Error Detection and Coding of QPSK I and Q Components in PPLN Waveguide

Abstract: An all-optical scheme based on periodically-poled lithium niobate (PPLN) waveguide for signal processing of the in-phase (I) and quadrature (Q) components of an input quadrature phase shift keying (QPSK) signal is presented. The device is able to work on the I and Q components without any additional demodulation stage, and makes use of cascaded second harmonic and difference frequency generation in the PPLN to obtain the logical operation xor (I, Q). A single continuous wave signal is needed in addition to the input signal to generate the output signal, in which the information is coded in a binary phase shift keying modulation. The logical xor (I, Q) potentially enables data coding, error detection, and encryption of sensitive information in all-optical networks. Bit error rate measurements are provided to evaluate the system performance for a 20-Gb/s differential-QPSK input signal, and tunability of the output wavelength has been attested with almost constant optical signal-to-noise-ratio penalty along the C-band.

Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages

Abstract: Electro-optic modulators translate high-speed electronic signals into the optical domain and are critical components in modern telecommunication networks1,2 and microwave-photonic systems3,4. They are also expected to be building blocks for emerging applications such as quantum photonics5,6 and non-reciprocal optics7,8. All of these applications require chip-scale electro-optic modulators that operate at voltages compatible with complementary metal–oxide–semiconductor (CMOS) technology, have ultra-high electro-optic bandwidths and feature very low optical losses. Integrated modulator platforms based on materials such as silicon, indium phosphide or polymers have not yet been able to meet these requirements simultaneously because of the intrinsic limitations of the materials used. On the other hand, lithium niobate electro-optic modulators, the workhorse of the optoelectronic industry for decades9, have been challenging to integrate on-chip because of difficulties in microstructuring lithium niobate. The current generation of lithium niobate modulators are bulky, expensive, limited in bandwidth and require high drive voltages, and thus are unable to reach the full potential of the material. Here we overcome these limitations and demonstrate monolithically integrated lithium niobate electro-optic modulators that feature a CMOS-compatible drive voltage, support data rates up to 210 gigabits per second and show an on-chip optical loss of less than 0.5 decibels. We achieve this by engineering the microwave and photonic circuits to achieve high electro-optical efficiencies, ultra-low optical losses and group-velocity matching simultaneously. Our scalable modulator devices could provide cost-effective, low-power and ultra-high-speed solutions for next-generation optical communication networks and microwave photonic systems. Furthermore, our approach could lead to large-scale ultra-low-loss photonic circuits that are reconfigurable on a picosecond timescale, enabling a wide range of quantum and classical applications5,10,11 including feed-forward photonic quantum computation. Chip-scale lithium niobate electro-optic modulators that rapidly convert electrical to optical signals and use CMOS-compatible voltages could prove useful in optical communication networks, microwave photonic systems and photonic computation.

Dissipative Kerr Solitons in Optical Microresonators

Abstract: The development of compact, chip-scale optical frequency comb sources (microcombs) based on parametric frequency conversion in microresonators has seen applications in terabit optical coherent communications, atomic clocks, ultrafast distance measurements, dual-comb spectroscopy, and the calibration of astophysical spectrometers and have enabled the creation of photonic-chip integrated frequency synthesizers. Underlying these recent advances has been the observation of temporal dissipative Kerr solitons in microresonators, which represent self-enforcing, stationary, and localized solutions of a damped, driven, and detuned nonlinear Schrodinger equation, which was first introduced to describe spatial self-organization phenomena. The generation of dissipative Kerr solitons provide a mechanism by which coherent optical combs with bandwidth exceeding one octave can be synthesized and have given rise to a host of phenomena, such as the Stokes soliton, soliton crystals, soliton switching, or dispersive waves. Soliton microcombs are compact, are compatible with wafer-scale processing, operate at low power, can operate with gigahertz to terahertz line spacing, and can enable the implementation of frequency combs in remote and mobile environments outside the laboratory environment, on Earth, airborne, or in outer space.

Dissipative Kerr solitons in optical microresonators

Abstract: This chapter describes the discovery and stable generation of temporal dissipative Kerr solitons in continuous-wave (CW) laser driven optical microresonators. The experimental signatures as well as the temporal and spectral characteristics of this class of bright solitons are discussed. Moreover, analytical and numerical descriptions are presented that do not only reproduce qualitative features but can also be used to accurately model and predict the characteristics of experimental systems. Particular emphasis lies on temporal dissipative Kerr solitons with regard to optical frequency comb generation where they are of particular importance. Here, one example is spectral broadening and self-referencing enabled by the ultra-short pulsed nature of the solitons. Another example is dissipative Kerr soliton formation in integrated on-chip microresonators where the emission of a dispersive wave allows for the direct generation of unprecedentedly broadband and coherent soliton spectra with smooth spectral envelope.

Integrating photonics with silicon nanoelectronics for the next generation of systems on a chip.

Abstract: Electronic and photonic technologies have transformed our lives-from computing and mobile devices, to information technology and the internet. Our future demands in these fields require innovation in each technology separately, but also depend on our ability to harness their complementary physics through integrated solutions1,2. This goal is hindered by the fact that most silicon nanotechnologies-which enable our processors, computer memory, communications chips and image sensors-rely on bulk silicon substrates, a cost-effective solution with an abundant supply chain, but with substantial limitations for the integration of photonic functions. Here we introduce photonics into bulk silicon complementary metal-oxide-semiconductor (CMOS) chips using a layer of polycrystalline silicon deposited on silicon oxide (glass) islands fabricated alongside transistors. We use this single deposited layer to realize optical waveguides and resonators, high-speed optical modulators and sensitive avalanche photodetectors. We integrated this photonic platform with a 65-nanometre-transistor bulk CMOS process technology inside a 300-millimetre-diameter-wafer microelectronics foundry. We then implemented integrated high-speed optical transceivers in this platform that operate at ten gigabits per second, composed of millions of transistors, and arrayed on a single optical bus for wavelength division multiplexing, to address the demand for high-bandwidth optical interconnects in data centres and high-performance computing3,4. By decoupling the formation of photonic devices from that of transistors, this integration approach can achieve many of the goals of multi-chip solutions 5 , but with the performance, complexity and scalability of 'systems on a chip'1,6-8. As transistors smaller than ten nanometres across become commercially available 9 , and as new nanotechnologies emerge10,11, this approach could provide a way to integrate photonics with state-of-the-art nanoelectronics.

Integrated microwave photonics

Abstract: 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.