Simulation of Pulse Propagation in ZBLAN Fiber
by Ali Cox
supervisor: Brian Washburn, Associate Professor of Physics
Kansas State University Physics Department REU Program
This program is funded by the National Science Foundation through grant number PHYS-1461251. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
Below, I describe the Project Overview, my Research Description, my Research Progress, and will eventually post my Final Presentation . Scroll all the way down to learn more About Me. Finally, I've included some Useful Links.
This research is motivated by the demand for
a source of coherent light in the mid-infrared range (~3 microns wavelength).
Light at this wavelength has many applications including medical treatment and
sensitive particle detection, but it is difficult to produce. Femtosecond fiber
lasers show a drastic decrease in power beyond 2 microns due to the absorptive
properties of silica.
One solution to this problem is to use
nonlinear fiber optics to downshift the frequency of an abundant source of
coherent light whose wavelength is not far from 3 microns. However, this method
is fruitless if done using silica fiber for the same reason that silica fiber
lasers themselves fail to produce 3 micron light – silica absorbs all light in
the mid-infrared range. We thus look into a more exotic type of optical fiber
called ZBLAN fiber. The letters in its name represent the various heavy
metal-fluorine compounds it is doped with to make it transparent to
mid-infrared light.
My research focuses on understanding the
non-linear properties of this fiber and implementing them in code to be able to
numerically simulate pulse-propagation through ZBLAN fiber.
The primary
nonlinear optical effect I am concerned with in down-shifting the frequency of
light is Stimulated Raman Scattering. Every fiber medium has a unique Raman
gain signature that describes the rate at which energy is transferred from one
frequency to every frequency below it. In order to be able to simulate pulse
propagation in ZBLAN fiber, I must reconstruct the Raman response function by
extracting information from the experimental ZBLAN Raman gain spectrum. Once I
obtain the Raman response, my goal is to implement it in code and determine the
pulse parameters required to see a shift toward 3 microns in the spectrum of an
initial pulse pumped into ZBLAN fiber.
Final Presentation: Click here to download my presentation in powerpoint format, and here for pdf.
I am a sophomore physics major at Reed
College. Some of my favorite things to do are sailing, building things and
seeing them work the way I planned, and just thinking about stuff.
If I had to choose one concrete aspect of
this REU program that has helped me grow the most, it would be the bi-weekly
responsibility to present on our research progress. I feel like these
presentations have made me a better communicator and listener. But generally
speaking, I think the time I spent with the people I met here and the
connections I have made has been an overall maturating experience. I definitely
recommend giving this program a shot to anyone who is considering it.
American Physical Society Statements on Ethics