At the optical table (breadboard) where much of my experimental work from 2015 through 2018 was performed.

I am a postdoctoral research scientist in NTT's Physics and Informatics Laboratory and a visiting scientist in the group of Peter McMahon in Cornell's Applied Physics department.

Some items of potential interest:

- A complete list of my academic publications can be viewed here, via Google Scholar.
- NTT's Physics and Informatics Laboratory
- The research group of Peter McMahon
- The research group of Hideo Mabuchi
- The research group of Frank Wise
- I can be contacted through email: LGW32[at]cornell.edu

The rainbow of radiation emitted by multimode optical solitons as they undergo oscillations in spacetime, dispersed using a diffraction grating onto a piece of white paper. These are described this paper, after initially being reported as a curious mystery in this one.

## Research topic: nonlinear optics in multimode fibers

During my PhD, my research focused on nonlinear optics in multimode fibers and high peak power ultrashort-pulsed fiber lasers. More evocatively and intuitively, albeit slightly less rigorously, nonlinear optics in multimode fibers could be described as *nonlinear optics in interdimensional spacetime*, since the physics are essentially 4-dimensional light propagation (3 space + 1 time) where two of the spatial dimensions are incomplete - they are constrained by the fiber. This is also practically a great place to do physics, since we can make use of many developed technologies (the optical fibers themselves, for example, typically cost ~1 USD per meter) to study and control very complex, nonlinear dynamical processes across a range of different regimes by varying features of the fiber, by varying length scales, input conditions, or by adding in highly-dissipative processes such as laser gain.

**The "world of multimode fiber**": by varying easily-accessible parameters of the fiber (the number of modes, the amount of dissipation, and the amount of disorder, e.g.), we can study complex nonlinear dynamical processes in the lab that are hard to efficiently simulate on a computer, across a range of distinct regimes and scales. Here, free space corresponds to the infinite-mode limit where the multimode fiber is infinitely large, while single-mode fiber (SMF) is the 1-D limit.

In this sense multimode fibers are an excellent experimental model system for *complex nonlinear dynamics*. By *complex nonlinear dynamics* here, I mean that processes or systems that:

- involve many distinct degrees of freedom and/or allowable states (e.g., the spatial modes of the fiber, as well as the many frequencies within short optical pulses),
- involve many distinct processes through which those degrees of freedom interact, some of which are nonlinear (e.g., Kerr and Raman nonlinearities, dispersion, intrinsic disorder in the waveguide, gain competition and relaxation within a multimode laser), and
- are in general not at equilibrium.

The inherent information density of multimode fibers also makes them popular for next-generation optical telecommunications, for studies of complex linear systems, and for applications in optical information processing.

**Several relevant publications:**

- L.G. Wright, Z.M. Ziegler, P.M. Lushnikov, Z. Zhu, M.A. Eftekhar, D.N. Christodoulides, and F.W. Wise (2018) “Multimode Nonlinear Fiber Optics: Massively Parallel Numerical Solver, Tutorial and Outlook,”
*IEEE Journal of Selected Topics in Quantum Electronics***24**(3), 1-16. - L.G. Wright, Z. Liu, D.A. Nolan, M.-J. Li, D.N. Christodoulides, and F.W. Wise (2016) “Self-organized instability in graded-index multimode fibres,”
*Nature Photonics***10**, 771–776. - L.G. Wright, S. Wabnitz, D.N. Christodoulides, and F.W. Wise (2015) “Ultrabroadband Dispersive Radiation by Spatiotemporal Oscillation of Multimode Waves,”
*Physical Review Letters***115**(22), 223902. - L.G. Wright, D.N. Christodoulides, and F.W. Wise (2015) “Controllable spatiotemporal nonlinear effects in multimode fibres,”
*Nature Photonics***9**(5), 306-310. - L.G. Wright, W.H. Renninger, D.N. Christodoulides, and F.W. Wise (2015) “Spatiotemporal dynamics of multimode optical solitons,”
*Optics Express***23**(3), 3492-3506. - L.G. Wright, D.N. Christodoulides, and F.W. Wise (2017) “Spatiotemporal mode-locking in multimode fiber lasers,”
*Science***358**(6359), 94-97.

**Other things that might be of interest: **

The evolution of a pulse's temporal profile, spectrum and spatial profile within a high power multimode mode-locked laser (simulated using a simplified, relatively speaking, spatiotemporal generalized nonlinear Schrödinger equation). Adapted from this paper, which has more details.

## Research topic: high power ultrashort-pulsed fiber lasers

The development of high power ultrafast fiber lasers meanwhile boils down to trying to make the shortest laser pulses (about 100 millionths of a billionths of a second, or 100 fs) with the highest power (>1 million watts), and at useful wavelengths, all by exploiting new laser physics in long pieces of glass (i.e., the optical fibers), typically containing dissolved rare-earth ions like Yb or Er. Despite their fantastic features, these lasers can be made quite small, quite cheap and quite tough (relative to other kinds of lasers). Increasingly, people like to use them for three-dimensional microscopy of biological samples and precision micromanufacturing.

The combination of the extremely high optical peak power, and the extremely tiny size of the fiber core, however, means that the light interacts with the medium nonlinearly: its huge electric fields change the medium's optical properties which in turn affects the light's propagation. This makes the design of ultrafast fiber lasers an intricate art and science of nonlinear optical waves, known as solitons, similaritons, and so on. The ultrafast fiber laser thus exemplifies the symbiotic superposition of applied physics: new nonlinear optical physics translating immediately into better fiber lasers, and with new fiber lasers serving as convenient little laboratories for studying fundamental physics of nonlinear waves and dynamics.

**Several relevant publications on this topic:**

- L.G. Wright, D.N. Christodoulides, and F.W. Wise (2017) “Spatiotemporal mode-locking in multimode fiber lasers,”
*Science***358**(6359), 94-97. - W. Fu, L.G. Wright, and F.W. Wise (2017) “High-power femtosecond pulses without a modelocked laser,”
*Optica***4**(7), 831-834. - Z. Liu, Z. Ziegler, L.G. Wright, and F.W. Wise (2017) “Megawatt peak power from a Mamyshev oscillator,”
*Optica***4**(6), 649-654. - Y. Tang, L.G. Wright, K. Charan, T. Wang, C. Xu, and F.W. Wise (2016) “Generation of intense 100 fs solitons tunable from 2 to 4.3 μm in fluoride fiber,”
*Optica***3**(9), 948-951.

## Earlier research

Previously, I was an undergraduate student at Queen's University in Kingston, Ontario, Canada, in the Engineering Physics program. During that time, I worked with James Fraser (on automated laser materials processing using coherent optical imaging), Simon Hesp (on asphalt binder chemistry), and Kevin Resch (on single-photon nonlinear optics). Before that I was an 'underundergraduate' in Weyburn, Saskatchewan, Canada. During this time I contributed to a couple anthology books on popular science, "1001 Inventions That Changed the World", and "Defining Moments in Science", and of course classically Canadian activities like playing outdoor ice hockey and visiting Moose Jaw.

**Several relevant publications on these topics:**

- P.J.L. Webster, L.G. Wright, Y. Ji, C.M. Galbraith, A.W. Kinross, C. Van Vlack, and J.M. Fraser (2014) “Automatic laser welding and milling with in situ inline coherent imaging,”
*Optics Letters***39**(21), 6217-6220. - P.J.L. Webster, L.G. Wright, K.D. Mortimer, B.Y.C. Leung, J.X.Z. Yu and J.M. Fraser (2011) “Automatic real-time guidance of laser machining with inline coherent imaging,”
*Journal of Laser Applications***23**, 022001. - J. Lavoie, J.M. Donohue, L.G. Wright, A. Fedrizzi, and K.J. Resch (2013) “Spectral compression of single photons,”
*Nature Photonics***7**(5), 363-366. - L.G. Wright, A. Kanabar, E. Moult, S. Rubab and S.A.M Hesp (2011) “Chemical Aging of Asphalt Cements from a Northern Ontario Pavement Trial,”
*International Journal of Pavement Research and Technology***4**, 259-268