Home

Group picnic 2015

Corning

Fiber green

Supercontinuum

Group bowling

Imaging - Gland

Our Research

Our group’s research deals with the science and applications of nonlinear fiber optics and wave propagation.
See below for our most recent publications.

Self-similar pulse evolution in a fiber laser with a comb-like dispersion-decreasing fiber

Self-similar pulse evolution in a fiber laser with a comb-like dispersion-decreasing fiber

Yuxing Tang, Zhanwei Liu, Walter Fu, and Frank W. Wise. “Self-similar pulse evolution in a fiber laser with a comb-like dispersion-decreasing fiber” Optics Letters, Vol. 41, Issue 10, pp. 2290-2293 (2016).

We demonstrate an erbium fiber laser with self-similar pulse evolution inside a comb-like dispersion-decreasing fiber (DDF), which has the potential of generating nJ-level few-cycle pulses directly from a fiber oscillator. A passive DDF is formally equivalent to a fiber with constant gain, and can thus support self-similar pulse evolution but without any bandwidth limitation. Considering the challenges to fabrication of DDF, we try to imitate an ideal DDF with a comb-like DDF based on segments of ordinary fibers, which offers major practical advantages. The laser generates 1.3 nJ pulses with parabolic shapes and linear chirps, which can be dechirped to 37 fs. This constitutes a 4-fold increase in pulse energy compared to previous reports of this pulse duration.

1

Generation of 8  nJ pulses from a normal-dispersion thulium fiber laser

Generation of 8  nJ pulses from a normal-dispersion thulium fiber laser

Yuxing Tang, Andy Chong, and Frank W. Wise. “Generation of 8  nJ pulses from a normal-dispersion thulium fiber laser” Optics Letters, Vol. 40, Issue 10, pp. 2361-2364 (2015).

There is great interest in development of better short-pulse lasers in the 2-5 μm region. We show the first thulium-doped fiber laser at 2 μm to reap the performance benefits of pulse propagation at normal dispersion. Ultra-high numerical-aperture fibers provide normal dispersion and are employed to shift the cavity dispersion to the normal regime. A laser that exhibits elements of self-similar pulse evolution generates 8-nJ and 130-fs pulses, which corresponds to 4 times the highest peak power achieved previously by a Tm fiber laser.

3

Spatiotemporal dynamics of multimode optical solitons

Spatiotemporal dynamics of multimode optical solitons

L. G. Wright, W. H. Renninger, D. N. Christodoulides, and F. W. Wise. “Spatiotemporal dynamics of multimode optical solitons”. Opt. Express 22, 3492-3506 (2015).

We launch pulses into multimode fiber, exciting multiple spatial modes. We show how nonlinear interactions between the modes give rise to a multimode soliton. A multimode soliton is a non-dispersing wavepacket that contains several distinct spatial mode components, and propagates through the fiber without changing its shape due to a balance between nonlinear and linear effects. We observe spatiotemporal soliton fission – the disintegration of an optical pulse into distinct multimode soliton components with different spatiotemporal properties. Lastly, we observe the effect of stimulated Raman scattering on multimode solitons. This causes them to shift to longer wavelengths, while maintaining their multimode soliton characteristics.

ststmms
Multimode fiber acts as an intermediate-dimensional system. As the size of the fiber becomes infinite, optical dynamics are (3+1)-D (space+time). Meanwhile, as the fiber becomes small it becomes single mode, so that optical dynamics can be described using only (1+1) dimensions. Analytically, stable spatiotemporal solitons are expected for some region (blue) between 1 and 3 spatial dimensions. It is in this regime that multimode solitons are expected.

Ultrafast fiber lasers based on self-similar pulse evolution: a review of current progress

Ultrafast fiber lasers based on self-similar pulse evolution: a review of current progress

A. Chong, L. G. Wright and F. W. Wise “Ultrafast fiber lasers based on self-similar pulse evolution: a review of current progress ” Rep. Prog. Phys. 78, 113901 (2015).

We summarize the state of research on lasers based on self-similar pulse evolutions, including passive similariton, amplifier similariton, and others. Self-similar fiber lasers are conceptually different from other kinds of short-pulse lasers. This distinction allows for exciting new laser design options.

selfsimilarrev
Characteristic steady-state round trip evolutions of the pulse chirp for different mode-locking regimes. Solid lines indicate the chirp of the pulse, while dashed lines indicate the local dispersion of the cavity. In the highlighted plot, the lines show the difference of the pulse from a parabolic pulse.

Ultrabroadband Dispersive Radiation by Spatiotemporal Oscillation of Multimode Waves

Ultrabroadband Dispersive Radiation by Spatiotemporal Oscillation of Multimode Waves

L. G. Wright, S. Wabnitz, D. N. Christodoulides, F. W. Wise “Ultrabroadband Dispersive Radiation by Spatiotemporal Oscillation of Multimode Waves ” Phys. Rev. Lett. 115, 223902 (2015).

We show that intense pulses in multimode fiber oscillate in space and time, and that this creates resonant radiation across the electromagnetic spectrum. This work provides a route to tunable sources of ultrashort pulses from IR to ultraviolet and beyond. Dreaming, this work could lead to a fiber-format alternative to the free-electron laser.

summary figure 1

The resonant dispersive radiation is diffracted off a grating onto a piece of white paper.

 

Divided Pulse Lasers

Divided Pulse Lasers
 
 
We show that divided-pulse amplification can be used within a laser cavity to increase the pulse energy of a soliton fiber laser. In divided-pulse amplification, pulses are split up N times prior to amplification. After amplification, they are recombined into a single pulse. By reducing the peak intensity within the gain fiber, each split copy can be amplified to the single-pulse limit, and therefore the final recombined pulse can have N times higher energy. This work was featured in Spotlight on Optics.

dpl schematic
Diagram of a general divided pulse laser. Pulses are divided before ampification in the gain fiber, then recombined before being output. A saturable absorber mirror (SAM) is used for mode-locking, while a dispersive delay (DD) can provide dispersion.

Recent News:

11/03/2016 – Prof Wise gave the Lester Wolfe lecture at the  Wellman Center for Photomedicine, Harvard Medical School.

wise-lester-wolfe-talk

10/18/2016 – Wise group is at FiO 2016! Work will be presented by Zhanwei Liu, Walter Fu and Zimu Zhu.

09/14/2016 – Special AEP seminar presented by Xiang Liu, Wise group alumni!

xiang-liu

07/18/2016 – Logan gives Summer Graduate Student STEM Colloquium talk:

IMG_5091