Slow light in silicon photonic crystal waveguides
T.F. Krauss, L. O’Faolain, D.M. Beggs, T.P. White and A. di Falco
School of Physics and Astronomy, University of St. Andrews, St. Andrews, KY16 9SS, UK
Corresponding author email: tfk@st-and.a.c.uk
The keen interest in slow light in nanostructured dielectrics is motivated by the fact that
slow light adds functionality to a material by structuring alone. Such nanostructuring is
wavelength-independent, i.e. it can be adjusted to any wavelength of interest within the
transparency window of the material. Furthermore, it enhances the weak light-matter
interaction in a material that may be of interest otherwise, such as silicon, and it adds
another degree of freedom to already highly electro-optic or nonlinear materials such as,
e.g. chalcogenide glasses [1]. Operating in the slow light regime enhances linear effects
such as gain, thermo-optic and electro-optic interactions, which scale as the slowdown
factor, whereas nonlinear effects may scale with its square [2]. In comparison to single
cavities, which are widely studied in the photonic crystal and nanophotonics community
and which also offer sizeable enhancement of these effects, slow light structures offer more
bandwidth, i.e. a broader wavelength range of operation. A corresponding figure of merit is
the mode order m, i.e. a cavity of mode order m offers m-times less bandwidth for the same
enhancement as a slow light waveguide. Therefore, devices based on slow light waveguides
are a platform that can address two key issues in
communications: Bandwidth and switching power. The
enhanced nonlinearity enables the design of low power alloptical switching and data processing devices, while
simulataneously accomodating the large bandwidth of
future ultrahigh-speed systems.
As an example for the slow light enhancement available in
these structures, we discuss an optical switch in directional
coupler geometry that is ≈40
times
shorter
than
a Figure 1 Slow light enhanced
optical switch. The photonic crystal
comparable switch requiring section is 8µm long, while the
the same refractive index switching section is only 5µm long.
change (fig. 1). Furthermore,
we will discuss the systematic tuning of the slow light
properties [4] and the fact that slow light can even be
achieved in slotted waveguides, thus enabling the possibility
of achieving substantial enhancements of the light-matter
Figure 2. Photonic crystal slotted interaction in other materials such as colloidal quantum dots
waveguide for dispersion control. and polymers (fig. 2).
[1] S. J. Madden, D-Y Choi, M. R.E. Lamont, V. G. Ta’eed, N. J. Baker, M. D. Pelusi, B. LutherDavies and B. J. Eggleton, Opt. Photon. News, 19, 18 (2008)
[2] T F Krauss, Journal of Physics D: Applied Physics, 40, 2666 (2007)
[3] D. M. Beggs, T. P. White, L. O'Faolain, and T. F. Krauss, Opt. Lett. 33, 147 (2008)
[4] J. Li, T.P. White, L. O’Faolain, A. Gomez-Iglesias andd T.F. Krauss, Opt. Exp. (accepted).
[5] A. di Falco, L. O’Faolain and T.F. Krauss, Appl. Phys. Lett. 92, 083501 (2008).
--------------------------------------------PRIMARY TOPIC: Q
SECONDARY TOPIC: P
THIRD TOPIC: M
PREFERRED FORMAT OF PRESENTATION (ORAL/POSTER): Invited
--------------------------------------------Corresponding author name: Thomas F Krauss
Corresponding author email: tfk@st-and.ac.uk
Please name this file: LastName_Topic1_Topic2
TOPICS
Please choose primary and secondary topics
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Optical properties of materials
A1
General
A2
Crystals
A3
Polycrystalline bulk and film
A4
Amorphous and organics
A5
Nanostructures, including photonic crystals
Preparation and Characterization of Quantum Dots, Quantum Wires and
Other Quantum Structures
Excitonic Processes
Luminescence, Phosphors, Scintillators and Applications
Photoinduced Effects and Applications
Photoconductivity and Photogeneration
Nonlinear Optical Effects and Applications
Electro-Optic Effects and Applications
Glasses for Optics, Optoelectronics and Photonics (including ZBLAN,
fluozirconate, oxyfluoride and other glasses)
Polymers for Optics, Optoelectronics and Photonics
Semiconductors for Optoelectronics
J1
Semiconductors for Optoelectronics: Wide Bandgap
J2
Semiconductors for Optoelectronics: Narrow Bandgap
J3
Semiconductors for Optoelectronics: Heterostructures
Light Emitting Devices (including organics)
Photonic and Optoelectronic Materials and Devices (including devices for
telecommunications, laser and detectors)
Optical Storage
Photovoltaics (materials and devices, and their properties)
Waveguides and Integrated Photonics
Silicon Photonics
Optical Fibers and Fiber Sensors
Experimental Techniques
Femtosecond Spectroscopy
Teraherz (THz) techniques, including materials, emitters and detectors
Defect Spectroscopy
Plasmons and Surface Plasmons
Selected Topics (e.g. Photocatalysts in Materials, Materials for Energy
Conversion etc)
Invited Abstract submission
Before: 1 February, 2008