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International Journal of Digital Communication and Networks (IJDCN)
Volume 2, Issue 3, March 2015
Tristate and Gate Using Photonic Crystal
T.Arjun, P.Nandhakumar, M.Rajendran

Abstract - All optical logical gates based on Photonic crystal
waveguides is a promising technique in future high speed
all-optical signal processing. In this paper, Tristate AND gate is
proposed using photonic crystal. To realize this, the photonic
crystal is considered with a square lattice of dielectric rods
which are surrounded by air. The circuit design carried out by
using photonic suit AND gate. Tristate AND gate is designed by
introducing defects in the photonic crystal and changing
parameter values such as rod radius, lattice constant, dielectric
constant. In this paper, the structure operates efficiently on the
free space wavelength of 2.5nm with cross section of dielectric
rods of 0.2nm. The refractive index of the square lattice
dielectric rod is 2 and the 3 Kerr type non-linear rods have the
same parameter values except refractive index have the value of
20.
Keywords – All optical devices; Logical AND gate; Photonics
Crystal; Waveguide and Kerr effect.
I. INTRODUCTION
Now a day’s photonics is a new research field and
innovative domain till now most of the people don’t have the
awareness about the emerging field. Photonics is the science
of generating and harnessing light and other forms of radiant
energy whose quantum unit is photon[1]. The science that
includes the generation, emission, transmission, modulation,
signal processing, switching, amplification, detection and
sensing of light by lasers and other light sources. Whereas
enabling technology of the 20th century was undoubtedly
electronics, the 21st century is predicted to become the century
of photonics[6]. Photonics greatly benefits from the
advancement in electronics. In photonics, the logic gates are
very important because each and every components and
devices are designed based on the logical gates and where as
in electronics, the digital circuits are designed based on logic
gates. Logic gates are the basic building block of photonics.
All optical logic gates are key elements in optical signal
processing such as addressing, switching, header recognition,
data encoding and encryption [2]. All optical logic Gates
provide high performance in signal processing, computer
networks and optical networks [3]. The Main objective of the
project is to design and implement Tristate AND gate.
II. PHOTONICS
Photonics is the science that involves generation,
emission, transmission, modulation, signal processing,
switching, amplification and detection/sensing of light by
lasers and other light sources whose goal was to use light to
perform function [1]. The word photonics was born in a
similar way that the word electronics derived from electron.
Photonics describes components and systems that operate
Manuscript received March, 2015
T.Arjun, Department of Electronics and Communication
University College of Engineering Ariyalur – India. Email
[email protected]
P.Nandhakumar Department of Electronics and Communication
University College of Engineering Ariyalur – India. Email Id :
[email protected]
M.Rajendran Department of Electronics and Communication
University College of Engineering Ariyalur – India. Email Id :
[email protected]
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Id :
with photons particle of light in the same way that the word
electronics describes components and systems that operate
with electrons. Though covering all light technical application
over the whole spectrum, most photonic application are in the
range of visible and near infra-red light. It was the
development of the laser in which was invented in 1960’s and
the low lose optical fiber that placed in optical domain as the
next technological revolution and opened the new door in
optics in the name of “photonics”.
The word photonics derived from the Greek word
“photos” which means light. it was appeared in the late
1960’s. Other developments followed, the laser diode in the
1970’s, optical fiber for transmitting information and erbium
doped fiber amplifier. These inventions formed the basis for
the telecommunications revolution of the late 20th century and
provided infrastructure for the internet.
Though coined earlier, the term photonics came into common
use in the 1980s as fiber optic data transmission was adopted
by telecommunications network operators. Photonics as a
field focused largely on optical telecommunications.
However Photonics covers a huge range of science and
technology applications, including laser manufacturing,
biological and chemical sensing, medical diagnostics and
therapy, display technology and optical computing. Further
growth of photonics is likely if current silicon photonics
developments are successful [4].
I. OPERATION PRINCIPLE AN STRUCTURAL
ANLAYSIS
The basic logic gate AND operation is whenever all the
inputs are high which produces high output. Otherwise the output
is low. To realize, we considered two dimensional square lattice
phonic crystals composed of cylindrical silicon rod shown in
figure 1.b.
Figure 1.a :): Band diagram of two dimensional square lattice
photonic crystals.
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All Rights Reserved © 2014 IJDCN
International Journal of Digital Communication and Networks (IJDCN)
Volume 2, Issue 3, March 2015
the output port. so we get low output. This is AND gate
operation shown in figure 2.
In a Tristate AND gate, give another input to the AND
gate design. Using this third waveguide give the control
input to the circuit. When both inputs and control inputs are
high then only get a high output, because no standing waves
are produced. In any one of the input is low and the control
signal is low/high the standing waves are produced by the
Kerr type non-linear rods. This standing waves block the
output port, so the output is low.
Figure1.b :) schematic diagram of 2D photonic crystal lattice
The Rod has the refractive index of 0.2nm. Free space
wavelength of the Rod is 2.5nm and alpha and delta values are
2754. The structure consists of Kerr type nonlinear rods and
T-branch waveguide. The rod Refractive index of the 3 Kerr
type nonlinear rods is 20. The main structure of the device is
the line defect .The structure consists of a bent waveguide
with three embedded Kerr-effect nonlinear rods and a
T-branch waveguide. The Kerr effect is a nonlinear
interaction of light in a medium with an instantaneous
response, related to the nonlinear electronic polarization
[1].The Kerr effect is a nonlinear optical effect occurring
when intense light propagates in crystals and glasses, but also
in other media such as gases. Its physical origin is a nonlinear
polarization generated in the medium, which itself modifies
the propagation properties of the light. In particular, the
refractive index for the high intensity light beam itself is
modified according to
∆n=n2I
(1)
With the non-linear index n2 and optical intensity I.
The n2 value of a medium can be measured e.g. with
the z-scan technique. Note that in addition to the Kerr effect,
electrostriction can significantly contribute to the value of the
nonlinear index [3&4]. The electric field of light causes
density variations (acoustic waves) which themselves
influence the refractive index via the photo elastic effect. That
mechanism, however, occurs on a much longer time scale and
is thus relevant only for relatively slow power modulations,
but not for Ultra short pulses.
Fused silica, as used e.g. for silica fibers, has a nonlinear
index of ≈ 3 × 10−16 cm2/W. For soft glasses and particularly
for semiconductors, it can be much higher, because it depends
strongly on the band gap energy. The nonlinearity is also often
negative for photon energies above roughly 70% of the band
gap energy (self-defocusing nonlinearity).
The time and frequency dependent refractive index
change leads to self-phase modulation and Kerr lensing, for
different overlapping light beams also to cross-phase
modulation. Note that the effective refractive index increase
caused by some intense beam for other beams is twice as large
as that according to the equation shown above, assuming that
both beams are in the same polarization state[4].
The waveguides are formed by the removal of some of
the rods from a photonic crystal by introducing line defects,
which consists of a square lattice of infinite circular rods
made of linear dielectric material embedded in air. The three
red rods creating the bend are considered to be of Kerr-type
nonlinear material with a relative dielectric constant of 20
and the same radius as the linear rods. When both inputs are
high, then only we get high output. Because no standing
waves are produced .in other cases standing waves are
produced by the Kerr type nonlinear rods, this waves block
Figure 2 :) Schematic diagram of photonic Tri-state AND gate
II. SIMULATION RESULT
The simulation result of Tri-state AND gate depicts that
when all the three input ports are high, the output is high due
to Kerr effect which shown in figure 3.a and result is verified
from graph.
Figure 3.a :)Output of Tri-state AND gate when two inputs
and control input high
Figure 3.a.1 ) Graph result of Tri-state AND gate which
consists of three inputs are high
The simulation results which shown in figure 3. b & 3. c
indicate that when any one of the input is low, the output is
low.
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All Rights Reserved © 2014 IJDCN
International Journal of Digital Communication and Networks (IJDCN)
Volume 2, Issue 3, March 2015
[6] H.J.Caulfield and S.Dolev, “Why future supercomputing
requires optics”, Nano photonics 4(5), 261- 263(2010).
[7] R. H. Stolen and A. Ashkin, “Optical Kerr effect in glass
waveguide”, Appl. Phys. Lett. 22, 294 (1973).
[8] M. Sheik-Bahae et al., “Dispersion and band-gap scaling of the
electronic Kerr effect in solids associated with two-photon
absorption”, Phys. Rev. Lett. 65 (1), 96 (1990).
[9] E. L. Buckland and R. W. Boyd, “Electrostrictive contribution to
the intensity-dependent refractive index of optical fibers”, Opt. Lett.
21 (15), 1117 (1996).
[10] E. L. Buckland and R. W. Boyd, “Measurement of the
frequency response of the electrostrictive nonlinearity in optical
fibers”, Opt. Lett. 22 (10), 676 (1997).
Figure 3..b:)output of Tri-state AND gate when two inputs are
high and one input is low
Figure 2.c:)output of Tri-state AND gate when two inputs are
high and one input is low
V. CONCLUSION
The performance of a novel architecture for a Tri-state
AND gate based on a photonic crystal interference bent
waveguide with three embedded Kerr-type nonlinear rods and
a T-branch waveguide has been proposed and demonstrated.
The mechanism explained in this paper may be easily
extrapolated to other Photonic crystal configurations made of
holes with some of them filled with a nonlinear Material,
which is more feasible in an experimental device. As the use
of photonic crystal Technology facilitates further large-scale
optical integration. The proposed Tri-state logic gate is very
useful and requires low power consumption. Hence, it is
useful for ultrafast optical logical operations and future
optical computing components.
REFERENCES
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logic gate”, InfSci 176(22), 3379-3392(2006).
[3] Y.Zhang and B.Li “Optical switches and logic gates based on
self-collimated beams in two dimensional photonics crystal” Opt
express 15(15), 9287-9292(2007).
[4] B.E.A.Saleh and M.C.Teich: Fundamentals 0f Photonics, A
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