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Tunable High Performance 16-Channel Demultiplexer on 2D Photonic Crystal Ring Resonator Operating at Telecom Wavelengths

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Here, we proposed a high performance 16-channel optical demultiplexer using two-dimensional photonic crystal ring resonator for telecommunication systems. By plane wave expansion (PWE) method the photonic band gap (PBG) of proposed structure calculated. Then, with finite difference time domain (FDTD) method the performance parameters of designed two-dimensional photonic crystal demultiplexer are analyzed. It is found that the channel wavelength of wavelength-division multiplexing (WDM) is truly tuned by changing the structure parameters of the demultiplexer and position of rod. Output peaks located in the optical communication C-band and L-band with the transmission efficiency of 99 %. The demultiplexer exhibits high-quality factor of 5176, and spectral width of 0.3. Very low crosstalk values are between −19 dB and −90 dB where, device only occupies an area of 1708.65 µm
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S. Naghizade and S. M. Sattari-Esfahlan*
Tunable High Performance 16-Channel
Demultiplexer on 2D Photonic Crystal Ring
Resonator Operating at Telecom Wavelengths
https://doi.org/10.1515/joc-2017-0199
Received November 12, 2017; accepted January 4, 2018
Abstract: Here, we proposed a high performance
16-channel optical demultiplexer using two-dimensional
photonic crystal ring resonator for telecommunication sys-
tems. By plane wave expansion (PWE) method the photo-
nic band gap (PBG) of proposed structure calculated.
Then, with finite difference time domain (FDTD) method
the performance parameters of designed two-dimensional
photonic crystal demultiplexer are analyzed. It is found
that the channel wavelength of wavelength-division multi-
plexing (WDM) is truly tuned by changing the structure
parameters of the demultiplexer and position of rod.
Output peaks located in the optical communication
C-band and L-band with the transmission efficiency of
99 %. The demultiplexer exhibits high-quality factor of
5176, and spectral width of 0.3. Very low crosstalk values
are between 19dB and 90 dB where, device only occu-
pies an area of 1708.65 µm
2
. The proposed compact
16-channel demultiplexer can find more applications for
the ultra-compact WDM systems in highly integrated tele-
communication circuits.
Keywords: high performance demultiplexer, 16-channel
optical demultiplexer, high-quality factor, telecommuni-
cation wavelengths
1 Introduction
Silicon-based ring resonators have been a skeleton element
of silicon photonics with potential applications to switch
[17], decoders [812], gates [1316], filters [1737] and
demultiplexers [11, 3847]. In order to rapid the growing
networks, multi-channel format conversion is desired,
because it will reduce the complexity, power consumption,
and the cost of the optical networks. So far, several methods
have been proposed based on PCs structures to separate the
channels from input signal [41, 4856]. Optical demulti-
plexer using ring resonator drop filter has desirable flex-
ibility in design and performance. In order to compact
integration and low power consumption, ring resonator-
based demultiplexers and compact switches are required
for transporting high data flow between computer chips,
optical networks and routing multiwavelength data. Ring
resonator-based demultiplexers have been investigated by
various authors [42, 49, 50, 57]. A type of heterostructure 3-
channel demultiplexer by PCs ring resonator is proposed by
Rakhshani etal. [58]. The mean value of crosstalk they
reported is 24.44 dB and they could achieve transmission
efficiency around 95 %. To separate the channels, they
utilized three ring resonators in which each one has a
different dielectric constant. A compact wavelength-
division multiplexing (WDM) demultiplexer for seven
channels in PCs is proposed by Boumami etal. [59]. They
suggest a T-branch WDM demultiplexer. The channel spa-
cing they have reported is around 50 nm which is not
suitable at all. Also the transmission ratio they achieved is
lower than 25 % in some channels. The best power trans-
mission coupling efficiency they reported is around 56 %
which is not suitable for detecting. Venkatachalam et al.
[60] proposed eight channels modified wavelength-division
demultiplexer. The average transmission efficiency, Q fac-
tor, and line spacing of their demultiplexer are 90%, 1960
and 1.8 nm, respectively. Fallahi et al. [61] proposed Four-
channel optical demultiplexer based on hexagonal photo-
nic crystal ring resonators. The average transmission effi-
ciency, quality factor, channel spacing and crosstalk are
equal to 95.8%, 1943, 2 nm and 11.8 dB, respectively.
Considering the above mentioned demultiplexers, in this
paper our goal go to improve the performance parameters
of proposed structures, such as increasing the number of
output channels, decreasing the optical bandwidth, cross-
talk and improving the transmission efficiency and quality
factor. So we proposed a new shape defective resonant
cavity structure to realize the proposed demultiplexer.
Simulation results show that the proposed design provides
better WDM characteristics. The rest of the article is
*Corresponding author: S. M. Sattari-Esfahlan, Young Researchers
and Elite Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran,
E-mail: smsattarie@gmail.com
S. Naghizade, Young Researchers and Elite Club, Tabriz Branch,
Islamic Azad University, Tabriz, Iran
J. Opt. Commun. 2018; aop
Authenticated | smsattarie@gmail.com author's copy
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organized as follows: In Section 2, the analysis of photonic
band gap (PBG) structure is described. Section 3 focuses on
the design of proposed demultiplexer. In Section 4, simula-
tion and results are presented and discussed. Finally, the
conclusions are presented in Section 5.
2 Analysis of PBG structure
To design the proposed optical demultiplexer a hexa-
gonal lattice of dielectric rods with circular cross sec-
tion immersed in air background and xz plane is used.
To determine the physical structural parameters of our
proposed demultiplexer, in first step we must calculate
the gap map diagrams of the structure. In fact, for an
excellent design, it is better to use the gap map dia-
grams. The photonic band gap is extracted using plane
wave expansion (PWE) method calculations [62]. To
obtain the gap map diagrams, we calculated the band
structure at various values of the photonic crystal para-
meters, such as refractive index, the rod radius, and
the lattice constant. As shown in Figure 1(a), by
increasing the refractive index, the photonic band gap
shifted toward lower frequencies. Furthermore, as can
be seen in Figure 1(b), by decreasing the R/a ratio, the
photonic band gap shifted towards higher frequencies.
By considering the gap map diagrams, appropriate
parameters for designing the proposed structure can
be obtained. Thus, for our structure, the refractive
index, the dielectric rod radius, and the lattice constant
are taken to be, n=4.46, R= 111.6 nm, and a=620 nm,
respectively. Based on the above values, the photonic
band gap is obtained, as shown in Figure 2. According
to Figure 2, there are two PBGs in TM mode (blue color
areas). The first PBG in TM mode, which is between
0.29 < a/λ< 0.44, has the appropriate frequency range
for our goals. By choosing the lattice constant of
a=620nm,thePBGwillbeat1409nmλ<2137 nm,
which completely covers the wavelength range of the
third optical telecommunication window.
3 Design of proposed
demultiplexer
The proposed demulitplexer consists of 16-ring resona-
tors, bus waveguide, and eight Lbend waveguides. The
ring resonator is used to select the desired channel,
whereas the Lbend waveguide is employed for drop-
ping the selected channel. The general schematic of the
ring resonators used in the structure is shown in Figure
3. To improve the wavelength selection task, we have
introduced four scattering rods for each ring resonator,
whicharehighlightedwithbluecolorinFigure3.We
Figure 1: Gap map diagrams for TE and TM polarization: variation of
PBG versus a refractive index of dielectric rods and b R/a ratio.
Figure 2: The band diagram of proposed fundamental PC structure.
2S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer
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have called the radius of these scattering rods Rsc and
equal to 111.6 nm. Also, one bigger rod employed in
center of ring resonator and highlighted via dark red
color in Figure 3 where the radius of this rod is rc and
equal to 167.4 nm. In the around of bigger rod existing
16-fold defect rods which are highlighted via dark
greencolorsinFigure3andtheradiusofthesedefect
rods called rd and this size is different for each ring
and in fact the demultiplexing technique is based on
this discrepancy. The 12-fold defect rods arranged in
the area of assumed circle and the diameter of this
circle (see Figure 3) called 2Rr. The fourfold defect
rods exists in the inside of mentioned circle in the
both side of bigger rod and the distance of these rods
from each other called with P, W and Sparameters
where, P, W and Sequal to 2a,0.5aand a,respectively
(see Figure 3). Other important part in the proposed
ring resonator is the position of one rod of threefold
coupling rods as shown with dark cyan color in Figure
3. To improving the coupling of optical waves from bus
waveguide to ring resonator and Lbend waveguides
one of coupling rods shifted in Zdirection and the size
of this rods are equal to the size of other 16-fold defect
rods (Rd). We have called this shifting dand equal to
d= 250 nm. The Gaussian light source is launched at
the bottom end of the structure through a bus wave-
guide. The size of the bus waveguide is 1240 nm (2*a),
which is useful to propagate the light waves linearly
and distribute them to ring resonators through cou-
pling rods. The footprint of the proposed structure is
1708.65 μm
2
. The output ports which are taken a placed
in the above of bus waveguide of the PC structure are
used to select wavelengths (λ1toλ8). The ports in the
low of bus waveguide used to select wavelengths (λ9to
λ16), which results in producing channels with high
performance optical parameters such as transmission
efficiency, Qfactor and cross talk. The proposed 16-
channel demultiplexer is shown in Figure 3. The radii
of the 16-fold defect rods and sixfold coupling rods
equal to rd =0.4625R,0.4650R, 0.4675R,0.47R,
0.4725R,0.475R, 0.4775R,0.48R, 0.4825R,0.485R,
0.4875R, 0.49R,0.4925R, 0.4950R, 0.4975Rand 0.5R
nm for the 1th to 16th channel, respectively.
4 Simulation and results
To simulate and analysis of the proposed structure, we
used full wave toolbox of R soft software which simulates
Figure 3: Schematic of designed ring resonator (a) and final sketch of proposed 16- channel demultiplexer (b).
S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer 3
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the optical devices based on FDTD method [63]. For
accurate modeling of the demultiplexer we need 3D simu-
lation, but it requires great amount of run time and very
powerful computer. So we used effective index approx-
imation method of PCs for satisfying this requirement and
with this approximation we reduce the 3D simulations to
2D simulations [64]. Grid sizes (Δx and Δz) in FDTD para-
meters are chosen to be a/16 which equals 38.75 nm. Due
to the stability consideration of the simulation, the time
step should be satisfy the Δt1=cffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
1=Δx2+1=Δy2
p, where
cis the speed of light in free space. Therefore, time step
(Δt) and the PML width surrounding our structure for
simulating 0.023 and 500 nm assumed respectively.
After simulation, λ1 = 1546 nm, λ2 = 1549.5 nm, λ3 = 1553
nm, λ4 = 1555.5 nm, λ5 = 1558.5, λ6 = 1561, λ7 = 1564,
λ8 = 1566, λ9 = 1568.2, λ10 = 1571, λ11 = 1573.2,
λ12 = 1575.5, λ13 = 1578.5, λ14 = 1581, λ15 = 1582.5 and
λ16 = 1586, were obtained for first to sixteen output chan-
nels, respectively. Liner and dB scale of output spectra
for the demultiplexer are depicted in Figure 4. The chan-
nel spacing is between 1.5 and 3.5 nm, and the average
bandwidth is 0.3 nm. The most outstanding characteristic
of our structure is its high transmission efficiency, the
minimum transmission efficiency of the structure is 98 %,
and the average quality factor (Q=λ0/Δλ) is more than
5176. The complete specification of the demultiplexer is
listed in Table 1. Also the crosstalk values are listed in
Table 2, in which crosstalk values are named as Xij,(i,j
varies from 1 to 16) that shows the effect of ith channel in
jth channel at central wavelength of jth channel. In Table
2, iand jindices are shown in column and row respec-
tively. The lower (better) the crosstalk level results in
better resolutions for output channels. The crosstalk
level for our structure varies from 19 to 90 dB. In the
proposed structure, the wavelength selecting mechanism
is based on choosing different size for the radiuses of
dielectric rods in the core part of the resonant rings. For
good representation of WDM task, Figure 5 is presented.
One can see that the light propagates through channels 6
and 10 at the wavelengths of λ6 = 1561 nm and λ10 = 1571
nm, respectively.
The comparison of the device performance with some
recent works has given in Table 3. Comparisons con-
fessed for superior performance of our demultiplexer
and endorsed that our device have a promising potential
to be used in WDM applications.
Table 1: Simulation results of the proposed demultiplexer.
#ch r
d
λ(nm) ΔλnmðÞ QF T.E(%)
*
.R .  
.R..  
.R .  
.R..  
.R..  
.R .  
.R .  
.R .  
.R..  
 .R .  
 .R..  
 .R..  
 .R..  
 .R .  
 .R..  
 .R .  
*Transmission efficiency.
Figure 4: Output spectra of the demultiplexer, linear (a) and dB
scale (b).
4S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer
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5 Conclusions
In summary, in this article a high performance 16-
channel all optical demultiplexer is proposed and
designed using symmetric ring resonator for optical
WDM telecommunication applications. By increasing
the radius of the inner rods, 16 different channels via
different outputs can be tuned. From the simulation, it
is observed that the average optical transmission effi-
ciency, Quality factor and spectral width of designed
demultiplexer are obtained 99 %, 5176 and 0.3 nm,
respectively. Also the optical channel spacing in our
proposed structure is less than 3 nm and crosstalk
Table 2: Crosstalk values of the proposed demultiplexer (dB).
x
ij

              
              
              
              
              
              
              
              
              
               
               
               
               
               
               
              
Figure 5: Electric field distribution of proposed demultiplexer for: a λ
6
=1561 nm and b λ
10
=1571 nm.
S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer 5
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value is between 19 dB and 90 dB. The size of the
proposed demultiplexer is 1708.65° μm
2
which is very
small hence it can be employed for integrated photo-
nics, CWDM and DWDM applications.
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Table 3: Comparison of the proposed demultiplexer with reported one.
works Spectral width Channel
spacing
Worst QF Worst crosstalk
(dB)
Worst TE No of channels
Ref[]..   
Ref[].    
Ref[].<   
Ref[].    
Ref[]. .   
Ref[] ––< 
Ref[].   
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6S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer
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S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer 7
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8S. Naghizade and S. M. Sattari-Esfahlan: Tunable High Performance 16-Channel Demultiplexer
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... Optical demultiplexing plays an important role in WDM and DWDM technologies for the separation of optical waves from different channels . Currently, several works on demultiplexers are being carried out to improve the quality factor, transmission efficiency and reduce the spacing between channels and crosstalk (Naghizade and Sattari-Esfahlan 2018;Mohammadi and Seifouri 2019a, b;Vahid Vallahi et al. 2017;Naghizade and Sattari-Esfahlan 2019;Kannaiyana et al. 2017;Talebzadeh et al. 2016;Fallahi 2019;Rakhshani 2020;Lenin Babu and Sreenivasulu 2021;Balaji et al. 2021Balaji et al. , 2020Mohammadi et al. 2021Mohammadi et al. , 2020Foroughifar et al. 2021;Zhuang et al. 2020;Rao et al. 2020;Naghizade and Mohammadi 2020;Larioui et al. 2020;Hammood et al. 2020;Radhouene et al. 2020). For example, in the article (Moungar et al. 2019), the authors design a 16-channel dual-band demultiplexer that operates around 1.33 µm and 1.55 µm, with a quality factor equal to 517.6 and 622 respectively and crosstalk between − 9 dB and − 41 dB. ...
... For example, in the article (Moungar et al. 2019), the authors design a 16-channel dual-band demultiplexer that operates around 1.33 µm and 1.55 µm, with a quality factor equal to 517.6 and 622 respectively and crosstalk between − 9 dB and − 41 dB. In article (Naghizade and Sattari-Esfahlan 2018), they developed a 16-channel demultiplexer that achieves a quality factor of 4417 and crosstalk is between − 19 dB and − 90 dB. In ) the authors obtained a high quality factor equal to 5443 and a crosstalk equal to − 14.9 dB. ...
... And in Mohammadi and Seifouri 2019a they made a demultiplexer with a quality factor between 4440 and 5170 and low crosstalk between − 18.6 dB and − 34.6 dB. The basis of demultiplexer design is the realization of resonators, and to have the separation of wavelengths several techniques are used, as in Moungar et al. (2019); Naghizade and Sattari-Esfahlan 2018;Mohammadi and Seifouri 2019a;Fallahi et al. 2017), they have changed the radius of the internal bars of the resonators. And in Naghizade and Sattari-Esfahlan 2019 Kannaiyana et al. 2017), the authors changed the refractive index of the resonator's inner rods, and in both cases the ring resonator is used as a filter to differentiate wavelengths. ...
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In this paper an 8-channel demultiplexer has been proposed and simulated based on 2D photonic crystals for WDM and DWDM applications. The obtained quality factors are the best according to litterator until now and are between 4430 and 10363.33. The average transmission efficiency and average bandwidth are 94.31% and 0.239 nm respectively. Crosstalk values are low and range from − 18 dB to − 65.5 dB. Ring resonators as the basic structure for the design of the final demultiplexer structure are used to separate the optical waves. The proposed demultiplexer is a square array of dielectric rods of gallium arsenic GaAs with a refractive index of 3.37, operates around 1.55 µm. The designed device has a lattice constant equal to 610 nm and a fill factor equal to 0.2. To simulate our structure, we used COMSOL Multiphysics based on the finite element method. The proposed demultiplexer has a narrow average spacing of 1 nm with a small footprint of 461.76 µm² that can be exploited in optical integrated circuits.
... In these PBGs possess unique optical resonances and their properties can be customized through proper design of the band gap and the introduced defects. Thanks to the bandgap (PBG), several optical devices can be realized such as: optical filters (Rostamizadeh et al. 2020;Delphi et al. 2019;Alipour-Banaei et al. 2014a;Farah et al. 2016;Badaoui et al. 2011;Chaker et al. 2020), demultiplexers (Naghizade and Sattari-Esfahlan 2020;Mehdizadeha et al. 2016), logic ports (Mokhtari et al. 2020;Sharifi et al. 2017;Yan et al. 2019), adders (Neisy et al. 2018;Rahmani and Mehdizadeh 2018), analog-to-digital converters (Mehdizadeh et al. 2017b, c), encoders (Moniem 2016;Gholamnejad and Zavvari 2017), decoders (Parandin et al. 2018;Alipour-Banaei et al. 2014b;Daghooghi et al. 2018b) and splitters (Fedaouche et al. 2018;Fedaouche 2016 ...
... The dielectric used to realize the final structure is gallium arsenic GaAs proposed by Moungar et al. (2019) and Skauli et al. (2003), such that the linear refractive index is 3.37 around 1.55 (Moungar et al. 2019). We also used chalcogenide glass for the design of the resonators, with a linear index and a high non-linear Kerr coefficient equal respectively to 3.1 and 9 × 10 -17 m 2 /w (Daghooghi et al. 2018a, b;Li 2010;Rostamizadeh et al. 2020;Delphi et al. 2019;Alipour-Banaei et al. 2014a, b;Farah et al. 2016;Badaoui et al. 2011;Chaker et al. 2020;Naghizade and Sattari-Esfahlan 2020;Mehdizadeha et al. 2016;Mokhtari et al. 2020;Sharifi et al. 2017;Yan et al. 2019;Neisy et al. 2018;Rahmani and Mehdizadeh 2018;Mehdizadeh et al. 2016Mehdizadeh et al. , 2017bMoniem 2016;Gholamnejad and Zavvari 2017;Parandin et al. 2018;Fedaouche et al. 2018;Fedaouche 2016;Jiang et al. 2012;Ye et al. 2004;Assefa et al. 2004;Singh et al. 2017;Pal et al. 2017Pal et al. , 2018. The final structure of our decoder was simulated using COMSOL Multiphysics simulation software which is based on the FEM finite element method. ...
Article
Full-text available
In this paper, we have presented an efficient original architecture of all-optical 2 × 4 photonic crystal decoder based on non-linear ring resonators. The fundamental structure is a square lattice of 2D GaAs rods, operating around the wavelength 1.55 µm. The proposed decoder is composed of a combiner with three input ports, where the port E is used for excitation and A1, A2 are the control ports, and an optical switch with four output ports, and it is a nonlinear DMEX. For the creation of a switch at the wavelength of 1.55 µm, we used nonlinear chalcogenide glass rods with a nonlinear Kerr coefficient equal to 9 × 10–17 m2/w. The switching intensity and structure size are 1 Kw/µm2, 27.12 µm × 17.96 µm, respectively. The contrast ratio is about 8.7. The maximum crosstalk and insertion losses are calculated to be about − 22.1 and − 4.5 dB. The maximum and minimum power levels for logic states 0 and 1 are 0.05 × P0 and 0.37 × P0 where P0 is the input power. The finite element method was used to perform the necessary calculations.
... In these PBGs possess unique optical resonances and their properties can be customized through proper design of the band gap and the introduced defects. Thanks to the bandgap (PBG), several optical devices can be realized such as: optical filters (Rostamizadeh et al. 2020;Delphi et al. 2019;Alipour-Banaei et al. 2014a;Farah et al. 2016;Badaoui et al. 2011;Chaker et al. 2020), demultiplexers (Naghizade and Sattari-Esfahlan 2020;Mehdizadeha et al. 2016), logic ports (Mokhtari et al. 2020;Sharifi et al. 2017;Yan et al. 2019), adders (Neisy et al. 2018;Rahmani and Mehdizadeh 2018), analog-to-digital converters (Mehdizadeh et al. 2017b, c), encoders (Moniem 2016;Gholamnejad and Zavvari 2017), decoders (Parandin et al. 2018;Alipour-Banaei et al. 2014b;Daghooghi et al. 2018b) and splitters (Fedaouche et al. 2018;Fedaouche 2016 ...
... The dielectric used to realize the final structure is gallium arsenic GaAs proposed by Moungar et al. (2019) and Skauli et al. (2003), such that the linear refractive index is 3.37 around 1.55 (Moungar et al. 2019). We also used chalcogenide glass for the design of the resonators, with a linear index and a high non-linear Kerr coefficient equal respectively to 3.1 and 9 × 10 -17 m 2 /w (Daghooghi et al. 2018a, b;Li 2010;Rostamizadeh et al. 2020;Delphi et al. 2019;Alipour-Banaei et al. 2014a, b;Farah et al. 2016;Badaoui et al. 2011;Chaker et al. 2020;Naghizade and Sattari-Esfahlan 2020;Mehdizadeha et al. 2016;Mokhtari et al. 2020;Sharifi et al. 2017;Yan et al. 2019;Neisy et al. 2018;Rahmani and Mehdizadeh 2018;Mehdizadeh et al. 2016Mehdizadeh et al. , 2017bMoniem 2016;Gholamnejad and Zavvari 2017;Parandin et al. 2018;Fedaouche et al. 2018;Fedaouche 2016;Jiang et al. 2012;Ye et al. 2004;Assefa et al. 2004;Singh et al. 2017;Pal et al. 2017Pal et al. , 2018. The final structure of our decoder was simulated using COMSOL Multiphysics simulation software which is based on the FEM finite element method. ...
Preprint
In this paper, we have presented an efficient original architecture of all-optical 2×4 photonic crystal decoder based on non-linear ring resonators. The fundamental structure is a square lattice of 2D GaAs rods, operating around the wavelength 1.55 µm. The proposed decoder is composed of a combiner with three input ports, where the port E is used for excitation and A 1 , A 2 are the control ports, and an optical switch with four output ports, and it is a nonlinear DMEX. For the creation of a switch at the wavelength of 1.55 µm, we used nonlinear chalcogenide glass rods with a nonlinear Kerr coefficient equal to 9×10 ⁻¹⁷ m ² /w. The switching intensity and structure size are 1 Kw /µm ² , 27.12 µm × 17.96 µm, respectively. The contrast ratio is about 8.7. The maximum crosstalk and insertion losses are calculated to be about -22.1 and -4.5 dB. The maximum and minimum power levels for logic states 0 and 1 are 0.5P 0 and 0.37P 0 where P 0 is the input power. The finite element method was used to perform the necessary calculations.
... S. Naghizade et al. (2018) [27] proposed a high-performance 16-channel optical demultiplexer for telecommunication systems using a 2D PCRR. They used a 4.46 refractive index, a 111.6 nm radius of dielectric rods, and a 620-nm lattice constant. ...
... Recently, the best solutions for studying the optical properties of PC-based devices are considered to be numerical methods. The method of plane-wave expansion (PWE) [27] is an efficient and high-speed numerical method used to calculate the structure of the band and to extract the PC structures' photonic band gap (PBG) properties. This technique, however, is not ideal for studying the propagation of optical waves within PC-based devices and has some drawbacks. ...
Article
Full-text available
In this paper, a photonic crystal ring resonator (PCRR)-based optical demultiplexer is reported for Dense Wavelength Division Multiplexing (DWDM) applications. Diamond and silicon-dioxide are designed and simulated by an eight-channel PCRR. An average uniform spacing of 0.8 nm and 1.94 nm is obtained for the proposed demultiplexer, with silicon-dioxide and diamond, respectively. For the eight-channel PCRR structure, silicon-dioxide results in a maximum transmission efficiency of 91.48%. The quality factor is measured as 1613.336. Because of its light guiding mechanism, the ring resonator is found to be the most suitable and convenient for having dense wavelength division multiplexing amongst the different optical devices available based on photonic crystals.
... Splitters and wavelength division multiplexers are the most essential devices in optical integrated circuits and optical communication systems. To realize the proper functioning of wavelength splitters, we use resonant cavities that have a high-quality factor and can filter the desirable wavelengths with good bandwidth [14][15][16]. In addition to the multi-mode characteristic of ring resonators, their quality factor is limited by intrinsic input radiation losses. ...
Article
Full-text available
In this study, the design and simulation of an 18-channel demultiplexer based on resonant cavities in 2D photonic crystals is proposed. The lattice shape of silicon rods used in this structure is square. To have a reasonable percent transmittance from the input waveguide to resonant cavities, we have used point and linear defects, changing the radius of resonant cavities and adjusting the distance of the dielectric rods around the cavities. The main work of choosing the wavelength is performed by the resonant cavities. Due to a large number of output channels and long distances of the waveguides, the power reflector is used to compensate for the power losses in the waveguide path. The amount of the proposed structure’s percentage transmittance is between 90 and 100% and the quality factor is 5383 in the best case. The least bandwidth of the output signal spectra is 0.29 nm, and the amount of crosstalk between the output channels is from − 10 to − 62 dB. The overall dimensions of the proposed structure are 1069µm². One of the essential applications of the proposed demultiplexer structure is in WDM communication systems.
... A simple example of a PC is the Bragg reflector, which is a one-dimensional PC that can perfectly reflect incident light [20][21][22]. Owing to their outstanding reflection properties, PCs have been used in various optical devices such as resonators, waveguides, filters, absorbers, and polarization selectors [23][24][25][26][27][28]. Recently, the use of PC resonators in nanobeams has been studied and demonstrated experimentally, such as nanobeam lasers, programmable nanobeam resonators, and coupled nanobeam resonators [29][30][31]. ...
Article
Full-text available
We numerically demonstrated single-port coherent perfect loss (CPL) with a Fabry–Perot resonator in a photonic crystal (PC) nanobeam by using a perfect magnetic conductor (PMC)-like boundary. The CPL mode with even symmetry can be reduced to a single-port CPL when a PMC boundary is applied. The boundary which acts like a PMC boundary, here known as a PMC-like boundary, and can be realized by adjusting the phase shift of the reflection from the PC when the wavelength of the light is within the photonic bandgap wavelength range. We designed and optimized simple Fabry–Perot resonator and coupler in nanobeam to get the PMC-like boundary. To satisfy the loss condition in CPL, we controlled the coupling loss in the resonator by modifying the lattice constant of the PC used for coupling. By optimizing the coupling loss, we achieved zero reflection (CPL) in a single port with a PMC-like boundary.
... In particular, DWDM divides the optical spectra from a single mode fiber into a number of different wavelengths, with small channel spacing, to be distributed among multiple end users [10]. Though several advances have been reached like, for example, optical channel drop filters [11,12] and demultiplexers [13][14][15][16], these structures have a limited number of channels that can be used for communications. Moreover, the need of sophisticated fabrication techniques and precise electrical tuning of resonances, in order to avoid undesired interference, constitute the main limitations of these approaches. ...
Article
We numerically demonstrate an all-dielectric approach for magnetically tunable add/drop of optical channels in dense wavelength division multiplexing applications. Our concept comprises a micro-ring resonator, with an inner magneto-optical disk, side-coupled to two waveguides. The simulation results, obtained within the ITU-T G.649.1 recommendation, indicate high performance add/drop of odd and even optical channels (along the entire C-band) by flipping the intrinsic magnetization of the disk. Since the simulations were performed with CMOS-compatible materials, it is hoped that the structure proposed here can be integrated into future ultrafast optical communication networks.
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The present study proposes a new type of wavelength division multiplexing as an optical demultiplexer with four, eight, and sixteen output channels. The proposed structure consists of a two-dimensional square array of dielectric rods. The wavelength selection is performed by two defect rods and one defect with a rectangular cross-section. The values of the parameters related to each defect are selected so that the resonant wavelength associated with each output channel is located in the third telecommunication window (1.55µm). It is observed that the proposed demultiplexers demonstrate a high transmission efficiency and low crosstalk. As it is wanted to see just one sharp wavelength at the output of each channel, the quality factor needs to be maximized. Based on the results, the maximum values for demultiplexers with four, eight, and sixteen channels are 19863.89, 14264.57, and 32304.46, respectively. Due to the device’s small size, it can be used for wavelength division multiplexing (WDM) systems in photonic integrated circuits.
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Crosstalk and insertion loss are the crucial determinants of ring resonated routers. A novel 2 × 2 optical switch is proposed through a combination of broadband waveguide crossing and X-shape photonic crystal ring resonators. The main goal of the proposed design is to demonstrate the switching wavelengths based on changing the refractive index and reduce the level of the crosstalk and insertion loss. The performance of the proposed structure is analyzed using two-dimensional finite difference time domain and plane-wave expansion methods. Results show that crosstalk noise and insertion loss can be significantly reduced by using optimized crossbar waveguide and novel structure with bending elimination, thereby allowing higher network scalability and better performance and utility for future many-core architectures. Maximum crosstalk and insertion loss of −37.41 and 0.3 dB are obtained at 1570.5 nm, respectively. The size of the proposed structure is 18.69 × 19.6 μm², which can be used for photonic integrated circuits design due to its compactness.
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We have proposed simple ring resonator 5-channel demultiplexer based on optical channel drop filter analysis that is applicable at third communication window (1550 nm) range. Our proposed base filter is the important part in designing the demultiplexer, inclusive one ring resonator contains one square dielectric rod at core. Demultiplexer structure introduced by arranging five filter with different ring core refractive index. Insomuch every ring core have individual refractive index, thus each ring have diverse resonant wavelength. Numerical results by the finite difference time domain (FDTD) method show quality factor (Q) and transmission efficiency of fundamental channel drop filter are 1038 and 93 %, respectively. It is found that transmission efficiency in designed demultiplexer is more than 90 % for each channel; channel spacing is less than 4.2 nm. The average crosstalk value, total footprint of demutiplexer is −17.85 dB, 689.61 μm
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Currently, the reversible logic circuit is a popular research topic in the field of information processing as it is a most effective approach to minimize power consumption, which can achieve the one-to-one mapping function to identify the input signals from its corresponding output signals. In this letter, we propose and experimentally demonstrate an optical Feynman gate for reversible logic operation using silicon micro-ring resonators (MRRs). Two electrical input signals (logic operands) are applied across the micro-heaters above MRRs to determine the switching states of MRRs, and the reversible logic operation results are directed to the output ports in the form of light, respectively. For proof of concept, the thermo-optic modulation scheme is used to achieve MRR’s optical switching function. At last, a Feynman gate for reversible logic operation with the speed of 10 kbps is demonstrated successfully.
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In this paper, we proposed optical filter based on two-dimensional photonic crystal elliptical channel for wavelength division multiplexing. We employed ring resonator with ellipse shaped core in proposed structure. The resonance wavelength of the ring resonators depends on two parameters: refractive index and radius of dielectric rods. We investigate the physical parameters governing the filter performance. Our results show that the transmission efficiency is 100 % due to nearly zero reflection and loss in channel. Band width of 4 nm and quality factor of 389 is obtained for filter. Also, the total footprint of proposed structure is 230.4 µm
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