Circular Photonic Crystal Ring Resonator Research Articles

Characteristics of Add Drop Filter using single and dual PCRR in square lattice

A Photonic Crystal Ring Resonator (PCRR) based Add Drop Filter is designed using two dimensional (2D) square lattice PC silicon rods in air host. The normalized transmission spectra for a single-ring and dual-ring configurations have been investigated using 2D Finite Difference Time Domain (FDTD). The filter characteristics such as coupling efficiency, dropping efficiency, resonant wavelength and Q factor are numerically analyzed for single ring and dual ring PCRR. It is noted that the coupling efficiency, dropping efficiency and Q factor of single ring circular PCRR with scatterer rod are 100%, 100% and 186.75, respectively. The backward dropping is observed in single ring PCRR whereas forward dropping are noticed in dual ring PCRR based ADF. The Photonic Band Gap (PBG) with respect to structural parameters such as the radius of the rod, lattice constant and refractive index difference, and propagation modes in periodic and nonperiodic structure are calculated by Plane Wave Expansion (PWE) method.

Two dimensional Photonic Crystal Ring Resonator based Add Drop Filter for CWDM systems

In this paper, two-dimensional circular Photonic Crystal Ring Resonator (2D PCRR) based Add Drop Filter (ADF) using circular rods is designed for ITU-T G.694.2 eight channel Coarse Wavelength Division Multiplexing (CWDM) systems to add/drop a channel centered at a resonant wavelength of 1491nm. The Plane Wave Expansion (PWE) method and 2D Finite Difference Time Domain (FDTD) method are employed to obtain the Photonic Band Gap (PBG) range and output spectra of the ADF. Close to 100% of coupling and dropping efficiencies, 13nm of passband width and 114.69 of quality factor are observed for the designed filter at 1491nm which is highly sufficient and fulfill the requirement of ITU-T G.694.2 CWDM system. Further, the resonant wavelength tuning possibilities of ADF are theoretically studied to cover the lower channels of CWDM systems. The structural parameters such as refractive index, lattice constant and radius of the rod in the structure are considered for resonant wavelength tuning.

Coupled mode theory analysis for circular photonic crystal ring resonator-based add-drop filter

A two-dimensional circular photonic crystal ring resonator (PCRR)-based add-drop filter (ADF) is designed for ITU-T G.694.2 eight-channel coarse wavelength division multiplexing systems. The resonant wavelength and pass-band width of the ADF are 1491 and 13 nm, respectively. Close to 100% of coupling and dropping efficiencies and a 114.69 quality factor are observed through simulation. Then the coupled mode theory (CMT) analysis of circular PCRR-based ADF is attempted to compare obtained CMT response into simulated finite difference time domain method response. The overall size of the device is much smaller; that is, 11.4×11.4 μm, which is highly suitable for photonic integrated circuits and all optical photonic network applications.

Performance evaluation of PCRR based add drop filter with different rod shapes

Two Dimensional (2D) circular Photonic Crystal Ring Resonator (PCRR) based Add Drop Filter (ADF) is designed and the impacts of rod shape with its filling fraction is examined to evaluate the performance of the filter. The ADFs are devised separately using rods of circular, hexagonal and square shape in square lattice PC. For various values of rod’s cross sectional dimension and shape, the resonant wavelength, coupling efficiency, dropping efficiency, Q factor and passband width of the designed filters are investigated through simulation. The calculated filling fraction of a square, circular and hexagonal rods in the lattice structure is 11.9006 × 10-12 sq.m, 13.1134 × 10-12 sq.m and 15.16 × 10-12 sq.m and their respective resonant wavelength is 1494 nm, 1504 nm and 1520 nm. It is observed that there is 1 nm wavelength shift to longer wavelength while increasing the overall filling fraction by 0.1233 × 10-12 sq.m. From the simulated results, it is observed that the circular and hexagonal rods based ADF impart better performance than square rod based ADF.

PC based optical salinity sensor for different temperatures

The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator (PCRR) is proposed and designed for monitoring the salinity of the seawater from 0% to 100% (0 g/L to 100 g/L) at 25 °C. The concentration of the salinity in the seawater changes the refractive index of the seawater. The change in the refractive index of the seawater brings the change in the output signal intensity of the sensor as the seawater flows inside the sensor. By detecting the output power and mapping the salinity level, the salinity can be evaluated. The proposed sensor is composed of periodic Si rods embedded in an air host with a circular PCRR placed between the inline quasi waveguides. Approximately, 2.69% of output power reduction is observed for every 5% (5 g/L) increase in the salinity as the seawater has a unique refractive index for each salt level. With this underlying principle, the performance of the sensor is analyzed for different temperatures.

Single and dual PCRR in square lattice for filtering applications

A Photonic Crystal Ring Resonator (PCRR) based Channel Drop Filter is designed using Two Dimensional (2D) square lattice PC silicon rods in air host. The normalized transmission spectra for single-ring and dual-ring configurations have been investigated by using the 2D Finite Difference Time Domain (FDTD). The filter characteristics such as dropping efficiency, resonant wavelength and Q factor are numerically analyzed for single ring and dual ring PCRR. It is noted that the dropping efficiency and Q factor of single ring circular PCRR with scatterer rod are 100% and 186.75, respectively. The backward dropping is observed in single ring PCRR whereas forward dropping are noticed in dual ring PCRR based CDF. The Photonic Band Gap (PBG) with respect to structural parameters such as radius of the rod, lattice constant and delta, and propagation modes in periodic structure are calculated by Plane Wave Expansion (PWE) Method.

Investigation on parameters affecting the performance of two dimensional photonic crystal based bandpass filter

A two dimensional Photonic Crystal based Bandpass Filter is designed by exploiting coupling between the quasi waveguides and the circular Photonic Crystal Ring Resonator (PCRR). The output efficiency, resonant wavelength and bandwidth of PCBPF are investigated by varying the dielectric constant of the structure. The normalized transmission spectra of circular PCRR are taken using 2D Finite Difference Time Domain method. The Photonic Band Gap is calculated by Plane Wave Expansion method. Close to 100% (Band II) output efficiency is observed over the wavelength range from 1,504 to 1,521 nm and 85% (Band I) is obtained at 1,420 nm through simulation. The full width half maximum bandwidth of these bands is 35 and 20 nm, respectively. Further, the parameters that affect the resonant wavelength, output efficiency and bandwidth of the filter such as size of the reflector, radius of the coupling rods, lattice constant, rod radius and number of rods in the structure are analyzed. The overall size of the proposed filter is 11.4 μm × 10.2 μm, which is smaller than the filters already reported in the literature and highly desirable for Photonic Integrated Circuits.

PCRR Based Bandpass Filter for C and L+U Bands of ITU-T G.694.2 CWDM Systems

A two Dimensional (2D) Photonic Crystal Ring Resonator (PCRR) based Bandpass Filter (BPF) is designed to cover C and L+U bands of Coarse Wavelength Division Multiplexing (CWDM) systems. It is devised with two quasi waveguides and a circular PCRR. The simulation results are obtained using 2D Finite Difference Time Domain (FDTD) method. The Photonic Band Gap (PBG) is calculated by Plane Wave Expansion (PWE) method. The BPFs allow the entire C-band (BPF1) and L+U bands (BPF2), which are extended from 1530 to 1565 nm (C band) and 1565 to 1675 nm (L+U bands). The computed bandwidth of BPF1 and BPF2 is 32 nm and 97 nm respectively. The size of the device is minimized from a scale of few tens of millimeters to the order of micrometers. The overall size of the BPF1 is around 12.8 µm × 11.4 µm and 11.4 µm × 11.4 µm for BPF2.