Photonic Crystal Channel Drop Filter Research Articles

Exploring the performance of 2-D square lattice photonic crystal channel drop filters with varying horizontal cavity dimensions

Exploring the performance of 2-D square lattice photonic crystal channel drop filters with varying horizontal cavity dimensions

An integrated 2-bit all optical analog to digital converter based on photonic crystal semiconductor optical amplifier

In this paper, by integrating InP/InGaAsP/InP Photonic crystal semiconductor optical amplifier (PhC-SOA) with photonic crystal channel drop filters (PhC-CDF), we present a novel fully integrated ultra-small low-power all-optical analog to digital converter (AO-ADC). The self-phase modulation in the PhC-SOA can shift the frequency of the Gaussian input pulse. The two output PhC-CDFs are designed in a way that appropriately codes the frequency-shifted pulse by the PhC-SOA, which consequently converts them to four desired digital output levels. The numerical results indicated that the center wavelength of an amplitude modulated Gaussian pulse with a center wavelength of 1551.228 nm, temporal pulse-width of 10.6 ps, and energy of 74.4 fJ can be shifted by 1.652 nm. This shift is accommodated by utilizing a PhC-SOA with a length of 9 µm and an injection current of 6.5 mA. The shifted pulse is then quantized and coded to the four digital levels of (00, 01, 10, 11) by two point-defect PhC-CDFs. The PhC-CDFs minimize the AO-ADC integral and differential nonlinearity (INL/DNL) errors by compensating for the effect of the nonlinear frequency shift induced by PhC-SOA. The proposed design offers a footprint of 142 µm2 AO-ADC working at 10 Gs/s.

Low Dimensional Channel Drop Filter for CWDM Optical Communication Networks

This work presents salient features of an optical wavelength channel drop filter based on two-dimensional photonic crystal technology. The photonic band gap of two-dimensional Photonic Crystal (2-DPC) channel drop filter has been obtained by using plane wave expansion (PWE) method. The parameters of the channel drop filter have been optimized for telecommunication wavelengths 1611 nm and 1631 nm with a refractive index contrast of 3.79 and 3.96 using Gallium Antimonide (GaSb) dielectric material. The number of dielectric rods in X and Z directions were taken as 21, and 20, respectively with a spacing of 540 nm of having elliptical rod radius 0.15µm & 0.1 µm. The proposed design gives around 98% dropping efficiency with a good quality factor about 352. This ultra-compact structure is proposed which can be used for Coarse Wavelength Division Multiplexing (CWDM) applications and photonic integrated circuits.

Compact photonic crystal multichannel drop filter for CWDM systems

A novel photonic crystal channel drop filter (PCCDF) is proposed to drop four coarse wavelength division multiplexing (CWDM) channels at 1490 nm, 1510 nm, 1530 nm and 1550 nm. A special coupled dual-loop design was used for multichannel forward/backward dropping for the first time. Due to the reduced number of the dropping resonators with this design, the proposed multichannel PCCDF has a very compact size (338 μ m2). High transmission efficiencies at the four ITU wavelengths (87.87%, 93.99%, 85.40% and 84.24%) can be obtained simultaneously. Furthermore, the same dimension parameters (lattice constant and rod radius) of the dual-loop resonators are helpful for easy fabrication. The proposed device could be used in future photonic integrated circuit-based CWDM communication systems.

Trapezoid 2D photonic crystal nanoring resonator-based channel drop filter for WDM systems

In the present work, a nanostructure of trapezoid photonic crystal ring resonator-based channel drop filter is designed for wavelength division multiplexing systems (WDM) to drop a channel at a center peak wavelength of 1543 nm. The proposed channel drop filter is composed of bus waveguide, drop waveguide, trapezoid nanoring resonator and reflector in a two-dimensional (2D) hexagonal lattice with circular rods arranged in air host. The trapezoid nanoring resonator is playing a very important role in WDM systems for dropping a single channel over a wide wavelength range. The photonic band gaps of perfect lattice structure and non-perfect lattice structure are absolutely calculated by plane wave expansion method. The functional properties of the designed filter are evaluated by finite difference time domain method (FDTD). The functional properties are center peak wavelength, dropping efficiency, passband width and quality factor. The FDTD method results show dropping efficiency is 100%, and quality factor is about 514.33 which are highly suitable for WDM systems. Further, lattice constant, inner and outer rod radius and refractive index difference of the structure are varied to tune the filter center peak wavelength and its corresponding functional parameters effects are investigated. The proposed nanoring resonator-based optical filter is ultra-compact size around $$14\, \upmu \hbox {m} \times 8.4\, \upmu \hbox {m}$$ ; hence, it is extremely suitable for WDM-based photonic communication systems and photonic integrated circuits.

Two-dimensional photonic crystal ring resonator-based channel drop filter for CWDM application

In this paper, a channel drop filter based on two-dimensional photonic crystal ring resonator (PCRR) is proposed. The proposed structure consists of bus waveguide, dropping waveguide and a ring resonator. We have focused on improving the dropping efficiency and quality factor of the structure by applying different optimization techniques. Optimized channel drop filter using PCRR is designed, and it is extended to drop three different channels by changing the inner rods radius in each ring resonator that act as a demultiplexer. As designed structure drops three different channels such as 1524, 1544 and 1565 nm, the band gap for the structure is calculated and observed by plane-wave expansion method. The normalized transmission spectra and resonance wavelengths for different radius are obtained using two-dimensional finite-difference time-domain method. The proposed PCRR-based demultiplexer has the channel spacing of about 20 nm which fulfils the requirements of coarse wavelength-division multiplexing systems. The size of the demultiplexer is small; hence, it can be utilized for photonic integrated circuits.

Photonic crystal channel drop filters based on circular-shaped cavities

This paper presents a novel photonic crystal-based channel drop filter in a silicon-on-insulator platform. The proposed structure consists of two line-defect waveguides and a special circular cavity between them. The effects of structural parameters and fabrication errors on resonant wavelength and drop efficiency of output signal are analyzed. Band structure calculations and propagation of electromagnetic field through device are done by plane wave expansion and finite-difference time-domain methods, respectively. In our design, drop efficiency of more than 81% and quality factor of about 2246 are achievable. Simulation results show the effectiveness of the proposed filter for narrowband applications in photonic communication systems.

Photonic crystal channel drop filter based on ring-shaped defects for DWDM systems

This paper presents a novel configuration of channel drop filters based on two-dimensional photonic crystal slabs in silicon-on-insulator platforms. The structure is composed of two photonic crystal line-defect waveguides as input and output ports, along with an L3 cavity with ring-shaped border holes. The effects of structural parameters and fabrication errors on resonance frequency and drop efficiency are investigated. Band structure and propagation of electromagnetic field through device are calculated by plane wave expansion and finite-difference time-domain methods. The results show that the quality factor and line-width of output signal are ~5690 and 0.27nm, respectively, indicating that the proposed filter can be properly used in dense wavelength division multiplexing systems with 0.8nm channel spacing.

A high quality factor photonic crystal channel-drop filter with a linear gradient microcavity

We design a channel-drop filter (CDF) with a linear gradient microcavity in a two-dimensional (2D) photonic crystal (PC). The model of three-port CDF with reflector is used to achieve high quality factor (Q-factor) and 100% channel-drop efficiency. The research indicates that adjusting the distance between reference plane and reflector can simultaneously influence the Q-factor due to coupling to a bus waveguide and the phase retardation occurring in the round trip between a microcavity and a reflector. The calculation results of 2D finite-difference time-domain (FDTD) method show that the designed filter can achieve the drop efficiency of 96.7% and ultra-high Q-factor with an ultra-small modal volume.

Photonic crystal channel drop filters based on fractal structures

In this paper we introduce new configurations of channel drop filters based on two-dimensional photonic crystals. Structures consist of two photonic crystal waveguides and a fractal-shaped resonator between them. The effect of structural parameters on resonance frequency and drop efficiency is investigated. Calculations of band structure and propagation of electromagnetic field through devices are done by plane wave expansion (PWE) and finite difference time domain (FDTD) methods, respectively. In our designs more than 95% drop efficiency with quality factor of ~1150 is achievable at wavelength near 1540nm, which in comparison with other photonic crystal resonator structures is a very satisfactory and acceptable result.

An ultra-small heterostructure wavelength division multiplexer (WDM) with the ability to select two wavelengths from the s-band

In this article, a photonic crystal channel drop filter (CDF) based on \(2\times 3\) ring resonators is presented. At first, the effects of changing the radius of lattice rods and the lattice dielectric constant on the dropping efficiency of a 3-port CDF with one resonator are investigated. Then by developing this base structure, a new 4-port heterostructure CDF composed of two regions with rods made of silicone and germanium is presented, which can operate in the ‘S’ band of the communication window. The photonic crystal heterostructure CDF consists of a horizontal waveguide and two ring resonators that have been installed, in symmetry to the horizontal axis, in two regions with different refractive indices. These ring resonators act as energy couplers and capture at their resonant frequencies the electromagnetic energy which is propagated in the bus waveguide. For the analysis of transmission characteristics and the band structure of the filter, two methods have been employed: the two-dimensional Finite–difference time domain method and the Plane Wave Expansion method. In the final structure, dropping efficiencies of 97 and 89 % can be achieved at ports D and B, respectively, and also an acceptable quality factor can be obtained in the communication window. The overall size of this device is 174.14 \(\upmu \hbox {m}^{2}\). Due to its small size, this structure can be used in Wavelength Division Multiplexer applications in the Optical Integrated Circuits.

A New Two-Dimensional Photonic Crystal Channel Drop Filter Based on Two-Resonant Cavities

In this paper, a channel drop filter (CDF) is composed of two cubic lattice circular ring resonator cavities and point micro-cavities in a two-dimensional photonic crystal. The photonic band gap is calculated using the plane wave expansion (PWE) method and the optical characteristics of proposed structure are studying by the finite difference time domain (FDTD) method with perfectly matched layers (PMLs) acting as the boundary conditions . Two different wavelengths centered at 1773 nm and 1742 nm have been successful separation in this CDF. These demonstrate that our proposed structure is suitable for photonic integrated circuits (PICs) and coarse wavelength division multiplexing (WDM) optical communication systems.

Effect of fabrication tolerances on the performance of two-dimensional polymer photonic crystal channel drop filters: a theoretical investigation based on the finite element method

Guidelines for the design and fabrication of polymer photonic crystal channel drop filters for coarse wavelength division multiplexing are provided. A Fabry-Perot cavity consisting of a membrane-type slab photonic crystal, where a hole row perpendicular to the propagation direc- tion is removed, is considered. We selected nanoimprinting as the manu- facturing technique. The influence on the cavity performance of several key parameters, i.e., polymer core material, lattice geometry, defect length, and holes' radius, has been investigated in a device compliant with the requirement of the ITU-T G.694.2 standard. A detailed analysis of the fabrication tolerances has been carried out at 1551 nm. The maxi- mum acceptable drift of the geometrical parameters has been accurately evaluated by using the finite element method to prove that the fabrication tolerances do not significantly affect the performance of polymer filters for coarse wavelength division multiplexing, when manufactured by thermal nanoimprinting lithography. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. (DOI:

Optical single sideband modulation of 60-GHz radio over fiber (ROF) system using ultra compact photonic crystal ring-shaped channel drop filter

An ultra compact photonic crystal (PC) ring-shaped channel drop filter (RSCDF) is proposed to generate single side band (SSB) signal for 60GHz ROF system. This PC-RSCDF contains a bus waveguide, a resonant cavity, a ring-shaped waveguide (RSW) and a coupled cavity output waveguide. The notch depth and notch bandwidth of CDF can get 98% and 0.4nm respectively by inducing RSW and shifting the center defect rod of cavity and the rod around the cavity. Then, a method of fine tuning the resonant frequency of PC-RSCDF is proposed by adjusting the radius of insensitive rods which have weak coupling interaction with the light and the sensitivity of structure can be decreased, and the resonant frequency can be shifted to the sideband frequency of double side band (DSB) signal accurately. Finally, a 60GHz ROF SSB modulation system is demonstrated by using designed PC-RSCDF that can filter lower or upper sideband by changing its structure parameters. The extinction ratio (ER) of lower and upper sideband can get 20.9dB and 18.6dB respectively.

Tunable Channel Drop Filter using Hexagonal Photonic Crystal Ring Resonators

In this paper, we have proposed a tunable two dimensional (2D) photonic crystal (PhC) channel drop filter (CDF) using ring resonators with suitable quality factor (Q) and transmission efficiency; we investigate parameters which have an effect on resonant wavelength in this CDF, such as dielectric constant of inner, coupling, adjacent and whole rods of the structure. Dropping efficiency at the resonance and quality factor of single ring are 90% and 1046, respectively. The footprint of the proposed structure is about 125.6μm 2 ; therefore this structure can be used in the future photonic integrated circuits. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.1788

Photonic crystal ring resonator channel drop filter

Photonic crystal channel drop filters (CDFs) with a ring resonator have been reported and have shown good optical properties to drop the light. Photonic crystal ring resonators (PCRRs) offer scalability in size and flexibility in mode design due to their multi-mode nature [1] compared to point-defect or line-defect photonic crystal (PhC) cavities. It is far smaller in size than other corresponding devices. In this paper, we proposed several channel drop filters combination of ring resonators and point defect micro-cavities. These ring resonators work as energy couplers. They capture the electromagnetic energy propagated in the input waveguide and send it to the output waveguide at its resonant frequencies. But ring resonators have too many resonant frequencies because of their multi-mode nature. So, point defect micro-cavities are used to further filter the original light wave. In our designed CDFs, close to 100% drop efficiency has been achieved at their center normalized frequencies, respectively.

Photonic crystal higher order three-port channel drop filter

We present a photonic crystal (PC) three-port channel drop filter (CDF) with flat-top response and high quality factor value of 8836.7, and it can be used in the dense wavelength division multiplexing (DWDM) system. The CDF is engineered based on the three-port system with the wavelength-selective reflection feedback, where both micro-cavities are the synthesized coupled-resonators. In this case, the conditions to achieve complete power transfer are same to that of the corresponding three-port system while both micro-cavities are the single-mode resonators. As two micro-cavities are single point-defect resonators or synthesized coupled-resonators respectively, it is confirmed that these CDFs exhibit different response characteristics by the simulation results calculated by using two dimensional finite-difference time-domain (2D-FDTD) method, and these filters will find applications in future wavelength division multiplexing (WDM) optical communication systems.

A compact in-plane photonic crystal channel drop filter

This paper presents a novel in-plane photonic crystal channel drop filter. The device is composed of a resonant cavity sandwiched by two parallel waveguides. The cavity has two resonant modes with opposite symmetries. Tuning these two modes into degeneracy causes destructive interference in bus waveguide, which results in high forward drop efficiency at the resonant wavelength. From the result of numerical analysis by using two-dimensional finite-difference time-domain method, the channel drop filter has a drop efficiency of 96% and a Q value of over 3000, which can be used in dense wavelength division multiplexing systems.

Proposal for postfabrication fine-tuning of three-port photonic crystal channel drop filters by means of optofluidic infiltration

We are proposing a procedure to reconfigure a three-port photonic crystal channel drop filter with two point-defect resonant cavities coupled to a bus and a drop W1-type waveguide, by means of selective optofluidic infiltration. Simulations show that, by selective infiltration of cavities and the air holes of the two parallel line defects that are partially surrounding the bus waveguide of the proposed channel drop filter (CDF), besides fine-tuning of the cavities resonant frequencies to the desired values, one can also fine-tune the CDF phase to an optimum condition for achieving optimum drop efficiency for any given resonant frequency. We have used the 2D finite difference time domain and plane wave method to perform the numerical simulations.

Tunable anisotropic photonic crystal channel-drop filter

In this numerical study, we present a tunable photonic crystal optical filter designcomposed of anisotropic material. Various tunable optical filters which are composed ofpoint and line defects in a square lattice of dielectric rods, with selective infiltration ofsome of the rods with anisotropic material, are presented. Our numerical simulations withthe finite-difference time-domain (FDTD) technique reveal that defect states originatingfrom the anisotropic material impurities can be effectively tuned. The tunable range of20 nm of the optical channel is obtained. Moreover, we suggest a new tunabletwo-port channel-drop photonic crystal filter based on a Y-splitter and show that, bytuning the characteristics of this structure, total transmission up to 94% and 84%in each output port is achievable. Also, we come to the fact that our proposedstructure, compared to conventional photonic crystal channel-drop filters, hasthe advantages in miniaturizing wavelength-selective filters for WDM systems.