Logan G Wright

NTT Research and Cornell University

As optical fiber communications and fiber lasers approach fundamental limits there is considerable interest in multimode fibers. In nonlinear science, they represent an exciting environment for complex nonlinear waves. As in single-mode fiber, solitons may be particularly important. Multimode solitons consist of synchronized, non-dispersive pulses...

Multimode fibres are of interest for next-generation telecommunications systems and the construction of high-energy fibre lasers. However, relatively little work has explored nonlinear pulse propagation in multimode fibres. Here, we consider highly nonlinear ultrashort pulse propagation in the anomalous-dispersion regime of a graded-index multimode...

Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a pr...

Multimode fibres (MMFs) are attracting interest for complex spatiotemporal dynamics, and for ultrafast fibre sources, imaging and telecommunications. This new interest is based on three key properties: their high spatiotemporal complexity (information capacity), the important role of disorder, and complex intermodal interactions. To date, phenomena...

We experimentally isolate and directly observe multimode solitons in few-mode graded-index fiber. By varying the input energy and modal composition of the launched pulse, we observe a continuous variation of multimode solitons with different spatiotemporal properties. They exhibit an energy-volume relation that is distinct from those of single-mode...

Optical imaging is commonly used for both scientific and technological applications across industry and academia. In image sensing, a measurement, such as of an object's position, is performed by computational analysis of a digitized image. An emerging image-sensing paradigm breaks this delineation between data collection and analysis by designing...

Nonlinear multimode optical systems support a host of intriguing effects that are impossible in single-mode settings. Although nonlinearity can provide a rich environment where the chaotic power exchange among thousands of modes can lead to novel behaviours, understanding and harnessing these processes to our advantage is challenging. Over the year...

Recent years have witnessed a resurgence of interest in nonlinear multimode optical systems where a host of intriguing effects have been observed that are impossible in single-mode settings. While nonlinearity can provide a rich environment where the chaotic power exchange among thousands of modes can lead to novel behaviors, at the same time, it p...

Deep-learning models have become pervasive tools in science and engineering. However, their energy requirements now increasingly limit their scalability ¹ . Deep-learning accelerators 2–9 aim to perform deep learning energy-efficiently, usually targeting the inference phase and often by exploiting physical substrates beyond conventional electronics...

Deep learning has become a widespread tool in both science and industry. However, continued progress is hampered by the rapid growth in energy costs of ever-larger deep neural networks. Optical neural networks provide a potential means to solve the energy-cost problem faced by deep learning. Here, we experimentally demonstrate an optical neural net...

We study the emergence of non-Gaussian quantum features in pulsed squeezed light generation with a mesoscopic number (i.e., dozens to hundreds) of pump photons. Due to the strong optical nonlinearities necessarily involved in this regime, squeezing occurs alongside significant pump depletion, compromising the predictions made by conventional semicl...

Ultra-short pulses propagating in nonlinear nanophotonic waveguides can simultaneously leverage both temporal and spatial field confinement, promising a route towards single-photon nonlinearities in an all-photonic platform. In this multimode quantum regime, however, faithful numerical simulations of pulse dynamics naively require a representation...

Deep learning has rapidly become a widespread tool in both scientific and commercial endeavors. Milestones of deep learning exceeding human performance have been achieved for a growing number of tasks over the past several years, across areas as diverse as game-playing, natural-language translation, and medical-image analysis. However, continued pr...

Deep neural networks have become a pervasive tool in science and engineering. However, modern deep neural networks' growing energy requirements now increasingly limit their scaling and broader use. We propose a radical alternative for implementing deep neural network models: Physical Neural Networks. We introduce a hybrid physical-digital algorithm...

Ultra-short pulses propagating in nonlinear nanophotonic waveguides can simultaneously leverage both temporal and spatial field confinement, promising a route towards single-photon nonlinearities in an all-photonic platform. In this multimode quantum regime, however, faithful numerical simulations of pulse dynamics naïvely require a representation...

We report an experimental demonstration of an optical neural network performing image classification with high accuracy using less than a single photon per scalar multiplication, validating theoretical predictions about quantum-limited performance of ONNs.

We experimentally demonstrate an optical neural network whose fundamental building blocks are controllable ultrafast quadratic nonlinear pulse-propagation processes. The network is trained in situ by a new backpropagation algorithm that generalizes to arbitrary physical systems.

Unexpected multimode solitary waves can be formed spontaneously in hollow-core fibres, hinting at a vast world of exciting nonlinear optics, with applications for generating few-cycle, ultra-intense pulses.

We propose a deterministic, measurement-free implementation of a cubic phase gate for continuous- variable quantum information processing. In our scheme, the applications of displacement and squeezing operations allow us to engineer the effective evolution of the quantum state propagating through an optical Kerr nonlinearity. Under appropriate cond...

Mode-locking is a process in which different modes of an optical resonator establish stable synchronization through non-linear interactions. This self-organization underlies light sources that enable many modern scientific applications, such as ultrafast and high-field optics and frequency combs. Despite this, mode-locking has almost exclusively re...

We propose a measurement-free construction of a cubic phase gate based on a Kerr nonlinearity and Gaussian transformations. Experimental feasibility is discussed for pulsed nanophotonic waveguides where quantum states are encoded into quantum solitons.

Quantum neural networks (QNN) are a promising application of near-term quantum computers. We present an information theory of QNN’s expressive power, which we apply to an example optical QNN based on a Gaussian Boson Sampler.

We propose a deterministic, measurement-free implementation of a cubic phase gate for continuous-variable quantum information processing. In our scheme, the applications of displacement and squeezing operations allow us to engineer the effective evolution of the quantum state propagating through an optical Kerr nonlinearity. Under appropriate condi...

Mode-locking is a process in which different modes of an optical resonator establish, through nonlinear interactions, stable synchronization. This self-organization underlies light sources that enable many modern scientific applications, such as ultrafast and high-field optics and frequency combs. Despite this, mode-locking has almost exclusively r...

A key open question in quantum computation is what advantages quantum neural networks (QNNs) may have over classical neural networks (NNs), and in what situations these advantages may transpire. Here we address this question by studying the memory capacity $C$ of QNNs, which is a metric of the expressive power of a QNN that we have adapted from cla...

We outline a theoretical framework to understand the multitude of new mode-locked states possible in multi-transverse mode resonators. Full-3D measurements of mode-locked states comprising roughly 30 million modes agree with theoretical expectations.

We demonstrate a fiber oscillator that achieves 3 MW peak power, is easily started and is environmentally stable. The Mamyshev oscillator delivers 190-nJ pulses that can be compressed externally to 35 fs duration. Accurate numerical modeling of the gain medium provides insight into the behavior and performance of the device.

Ultrafast fiber lasers have the potential to make applications of ultrashort pulses widespread -techniques not only for scientists, but also for doctors, manufacturing engineers, and more. Today, this potential is only realized in refractive surgery and some femtosecond micromachining. The existing market for ultrafast lasers remains dominated by s...

We find adiabatic four-wave mixing in optical fibers allows efficient, near-octave-spanning near-infrared to mid-infrared conversion. Simulations indicate several possible fiber platforms, extending one-to-one broadband frequency conversion both to high-repetition-rate and high-energy applications.

We demonstrate an environmentally stable, self-seeded fiber oscillator based on spectral reshaping and reamplification. The oscillator delivers 140 nJ, linearly chirped pulses with 110 nm spectral bandwidth that can be compressed externally to 65 fs.

We demonstrate use of spatial light modulators to control modal excitation and make mode-resolved measurements of nonlinear pulse propagation in multimode fiber, and present a representative experiment wherein we observe discrete Raman beam clean-up.

We describe, through multiple theoretical and experimental realizations, spatiotemporal mode-locking (STML), the most general form of self-organization in optical oscillators. We discuss qualitatively new kinds of mode-locking, and routes to ultrahigh power, compact lasers.

We demonstrate a fiber oscillator that is environmentally stable and self-seeded. The oscillator generates 190 nJ, linearly chirped pulses that can be compressed to 35 fs resulting in 3 MW peak power.

Using spatial light modulators, we demonstrate control of modal excitation and mode-resolved measurement of nonlinear pulse propagation in multimode fiber, and present a representative experiment in which we observe discrete Raman beam clean-up.

We describe, in general terms, what spatiotemporal mode-locking is and how it happens. Then we describe several recent new developments, including qualitatively distinct kinds of 3D pulses and mode-locking physics.

Building on the scientific understanding and technological infrastructure of single-mode fibers, multimode fibers are being explored as a means of adding new degrees of freedom to optical technologies such as telecommunications, fiber lasers, imaging, and measurement. Here, starting from a baseline of single-mode nonlinear fiber optics, we introduc...

We demonstrate a fiber system which amplifies and compresses pulses from a gain-switched diode. A Mamyshev regenerator shortens the pulses and improves their coherence, enabling subsequent amplification by parabolic pre-shaping. As a result, we are able to control nonlinear effects and generate nearly transform-limited, 140-fs pulses with 13-MW pea...

A laser is based on the electromagnetic modes of its resonator, which provides the feedback required for oscillation. Enormous progress has been made in controlling the interactions of longitudinal modes in lasers with a single transverse mode. For example, the field of ultrafast science has been built on lasers that lock many longitudinal modes to...

We demonstrate that the pump’s spatial input profile can provide additional degrees of freedom in tailoring at will the nonlinear dynamics and the ensuing spectral content of supercontinuum generation in highly multimoded optical fibers. Experiments and simulations carried out at 1550 nm indicate that the modal composition of the input beam can sub...

We demonstrate a fiber source with the best performance from an ultrafast fiber oscillator to date. The ring-cavity Mamyshev oscillator produces 50-nJ and 40-fs pulses. The peak power is an order of magnitude higher than that of previous lasers with similar fiber mode area. This performance is achieved by designing the oscillator to support parabol...

We observe the self-organization of light into its most spatiotemporally-unstable state through propagation in graded-index multimode fiber. We understand this effect in terms of mode-coupling caused by dissipation, disorder, and nonlinearity.

We experimentally observe Raman shifted multimode solitons in few-mode graded-index fiber. They display spatiotemporal properties that depend on the specific launch conditions. Multimode solitons exhibit energy-volume relations distinct from both single-mode and spatiotemporal solitons.

We study extremely complex nonlinear pulse propagation in long disordered multimode fibers. Light self-organizes due to a spatial nonlinear attractor, then becomes spatiotemporally complex due to a spacetime instability.

We consider the propagation of strongly incoherent waves in optical fibers in the framework of the vector nonlinear Schrödinger equation (VNLSE) accounting for the Raman effect. On the basis of the wave turbulence theory, we derive a kinetic equation that greatly simplifies the VNLSE and provides deep physical insight into incoherent wave dynamics....

There is great interest in sources of coherent radiation in the mid-wave infrared (3–5 μm), and instruments based on fiber can offer major practical advantages. This range, and much broader, can be covered easily by supercontinuum generation in soft glass fibers, but with low power spectral density. For applications that require intense ultrashort...

We observe a nonlinear spatial self-cleaning process for femtosecond pulses in graded-index (GRIN) multimode fiber (MMF). Pulses with ∼80 fs duration at 1030 nm are launched into GRIN MMF with 62.5 μm core. The near-field beam profile at the output end of the fiber evolves from a speckled pattern to a centered, bell-shaped transverse structure with...

The dynamic evolution of the mode-locked regenerative amplifier based on single mode fiber, which is also called pulse-based start-up dissipative soliton mode-locked laser, is numerically simulated, and the evolutions of the pulse energy, pulse duration, and spectral bandwidth versus the cycling number of the incident pulse in the cavity are analyz...

We observe efficient supercontinuum generation that extends into the visible spectral range by pumping a low differential mode group delay graded index multimode fiber in the normal dispersion regime. For a 28.5 m long fiber, the generated spectrum spans more than two octaves, starting from below 450 nm and extending beyond 2400 nm. The main nonlin...

We theoretically demonstrate that the pump’s spatial profile can provide a degree of freedom in tailoring at will the nonlinear dynamics and the ensuing spectral content of supercontinuum generation in highly multimoded optical fibers.

We study supercontinuum in graded-index multimode fibers. Spatiotemporal oscillations of solitons produce radiation spanning from the mid-IR to ultraviolet. Applications to ultrafast fiber sources and connections to spatiotemporal modulation and conical wave instability are discussed.

We demonstrate generation of femtosecond pulses tunable from 2.6-3.6 μm through soliton self-frequency shift in a fluoride fiber. 8-nJ, 75-fs pulses at 3.6 μm are obtained, with 10 times higher peak power than prior results.

We demonstrate a fiber-based system delivering femtosecond pulses with 5 nJ energies, continuously tunable over 2-4.3 μm through soliton self-frequency shift in fluoride fibers. Pulses with 138-fs duration and 40-kW peak power are obtained at 4.3 μm.

We show that spatiotemporal oscillations of multimode solitons in graded-index fibers generate dispersive radiation spanning the mid-IR to UV. We discuss routes to compact sources of coherent ultrashort pulses across the electromagnetic spectrum.

We show that pulses launched into multimode fibers are attracted to the fundamental mode, which has maximum spatiotemporal instability. The self-organization and instability are caused by cooperation between disorder, nonlinearity and dissipation.

We study supercontinuum generation in step-index fibers with a varying number of modes. We observe new spatiotemporal effects, including evidence of multimode spectral incoherent solitons, and a universal transition to spatiotemporal complexity.

We experimentally isolate and measure multimode Raman solitons in few-mode graded-index fiber. We show that these waves are spatiotemporal solitary waves, and are qualitatively distinct from stationary solutions of the NLSE in integer-dimensions.

We observe a nonlinear spatial self-cleaning process in multimode fiber. Experiments and simulations show this effect is caused by Kerr nonlinear interactions between the modes. Several important applications will be discussed.

Self-similar fiber oscillators are a relatively new class of mode-locked lasers. In these lasers, the self-similar evolution of a chirped parabolic pulse in normally-dispersive passive, active, or dispersion-decreasing fiber (DDF) is critical. In active (gain) fiber and DDF, the novel role of local nonlinear attraction makes the oscillators fundame...

Despite the abundance and importance of three-dimensional systems, relatively little progress has been made on spatiotemporal nonlinear optical waves compared to time-only or space-only systems. Here we study radiation emitted by three-dimensionally evolving nonlinear optical waves in multimode fiber. Spatiotemporal oscillations of solitons in the...

We study nonlinear pulse propagation of high-energy ultrashort pulses in graded-index multimode fibers. By adjusting initial conditions, we observe and control a wide range of nonlinear effects including spatiotemporal effects resembling self-focusing and multiple filamentation.

Although new affordable high-power laser technologies enable many processing applications in science and industry, depth control remains a serious technical challenge. In this Letter we show that inline coherent imaging (ICI), with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration de...