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Fibers and Optical Communications
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Fiber lasers, fiber-optic amplifiers,
silicon photonics, lightwave system design, highly
nonlinear fibers
Prof. Govind Agrawal
Fiber lasers Fiber lasers use suitably
doped optical fibers as a gain medium. Most commonly
used dopants are erbium (Er) and ytterbium (Yb), although
almost any rare-earth element can be used for this
purpose. Erbium-fiber lasers operate near 1550 nm
and are useful for eye-safe applications. Ytterbium-fiber
lasers operate near 1050 nm and can provide high optical
powers as well as high-energy pulses. Prof. Agrawal's
group is currently focused on high-power applications.
Fiber-optic amplifiers use either
a suitably doped optical fiber or make use of nonlinear
such as stimulated Raman scattering and four-wave
mixing for providing gain. Erbium-doped fiber amplifiers
are used commercially in multichannel lightwave systems.
Prof. Agrawal's group is currently focused on fiber-optic
parametric amplifiers based on the four-wave mixing
inside an optical fiber.
Silicon photonics is an exciting
new research area in which silicon waveguides are
used for photonics applications. Several recent experiments
have used such waveguides for optical modulation,
Raman amplification, and four-wave. Prof. Agrawal's
group is currently focused on dispersion tailoring,
soliton propagation, and parametric amplification.
Lightwave system design: Optical
fibers exhibit many nonlinear effects, such as self-phase
modulation, cross-phase modulation, stimulated Raman
scattering, and four-wave mixing, all of which affect
the performance of a lightwave system. Prof. Agrawal's
group is involved in studying how the choice of modulation
format affects the impact of various nonlinear effects.
In particular, the group has studied the impact of
polarization mode dispersion on lightwave systems.
Highly nonlinear fibers are new types
of fibers in which the effective mode area is reduced
to enhance the nonlinear effects. This category includes
tapered fibers, photonic crystal fibers, and other
microstructured fibers in which a narrow silica core
is surrounded with a cladding containing multiple
air holes. Prof. Agrawal's group is studying new kinds
of nonlinear effects (such as supercontinuum generation)
inside such optical fibers.
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Slow-Light Techniques,
Stimulated Light Scattering, Soliton Propagation
Prof.
Robert Boyd
Prof. Boyd is interested in the use of slow-light techniques
to perform buffering and optical storage for use in
optical telecommunication systems. In addition, he is
interested in the study of fundamental physical processes
such as stimulated light scattering, soliton propagation,
and the nature of the nonlinear response of optical
fibers.
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Photonic crystal fibers
Prof.
Wayne Knox
Photonic crystal fibers are just one example of the
new kinds of optical fibers that have been made recently.
These fibers, together with holey fibers, and others
can have exotic properties such as very high nonlinearity,
engineerable dispersion, as well as custom doping to
produce new nonlinear optical devices. The Knox group
has developed a new way to manage the dispersion of
these devices on a sub-millimeter length scale, and
also novel ultrafast optics sources based on these novel
fibers.
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©2007 University of Rochester
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