Two- and three-dimensional studies of a Silicon-based Chromatic
Dispersion Compensator
C. E. Png
a,*
, S. T. Lim
a
, E. P. Li
a
, A. J. Danner
b
, K. Ogawa
c
, Y. T. Tan
c
a
Computational Electronics and Photonics, Institute of High Performance Computing, A*STAR,
1 Fusionopolis Way, #16-16 Connexis Singapore 138632
b
Dept. of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore
117576
c
Optics and Electronics Laboratory, Fujikura Ltd, 1440 Mutsuzaki, Sakura, Chiba, 285-8550, Japan
ABSTRACT
In this work, we demonstrate two- and three-dimensional (3D) simulations of an active silicon-based photonic crystal
chromatic dispersion compensator utilizing the free carrier dispersion effect. The device has a low power consumption
of 114nW and its intrinsic device modulation speed is predicted to function at 40.5MHz. Due to the device architecture,
simulation must be carried out in 3D so as to fully encapsulate the effects of the photonic crystal contributions in the
active silicon. The novel device allows waveguiding and electrical transport to be individually tailored to a large extent.
Keywords: silicon photonics, silicon-on-insulator, chromatic dispersion compensator, free carrier dispersion effect,
photonic crystal, integrated optics, photonic circuits
1. INTRODUCTION
In high-speed optical-fiber communications, there is a key requirement to compensate chromatic dispersion as it plays a
significant role in the propagation of optical pulses in optical fibers [1]. Typical solutions developed to resolve
chromatic dispersive include optical components in the form of, for example Fiber Bragg Gratings, optical filters and
dispersion optical components [2-4]. Such devices are realized and installed as discrete elements in present optical fiber
communication systems. With the increasing proliferation of dense wavelength division multiplexing (DWDM), an
increase in component numbers will put pressure in the chip real estate and hence pose an issue in system construction.
This gives rise to the opportunity of demand for compact and integrated devices to reduce the device footprint along
with the lower power consumption which ultimately leads to lower costs. In passing, we note that a previous work
reported one of the first silicon-based chromatic dispersion compensator (CDC) using high field effects [5] and this
paper considers the design of carrier based comprising a p-i-n structure near to the optical core region.
We report modeling results on the power consumption and accuracy of a chromatic dispersion compensator (CDC) with
photonic crystals (PhC) patterned on a silicon (Si) substrate. The CDC reported here has one of the lowest power
consumption reported to date at 114 nW. The chromatic dispersion compensation is broadband, and produces constant
second order chromatic dispersion over a full optical communication band such as C-band. In this work, the device
operates at a wavelength of 1550nm.
2. SILICON CHROMATIC DISPERSION COMPENSATORS
In this section the design of the CDC is discussed. The device is based on a novel nanostructured electro-optic
waveguide consisting of low-loss Si3N4 rectangular core and two-dimensional (2D) Silicon/Silicon dioxide photonic-
crystal layer controlled by voltage bias. The importance of the electrical characteristics is underpinned by the fact that
the z-direction of the CDC is non-homogeneous. Hence, the traditional 2D study of carrier/charge movement is not
*pngce@ihpc.a-star.edu.sg ; phone +65 6419 1587; fax +65 6419 5176; www.ihpc.a-star.edu.sg
Passive Components and Fiber-based Devices VI, edited by Perry P. Shum,
Proc. of SPIE-OSA-IEEE Asia Communications and Photonics, SPIE Vol. 7630,
76301W · © 2009 SPIE-OSA-IEEE · CCC code: 0277-786X/09/$18 · doi: 10.1117/12.852149
Proc. of SPIE-OSA-IEEE/ Vol. 7630 76301W-1