Ring Resonator Configuration Research Articles

Analysis and design of a compact CRLH inspired – Defected ground resonators for triple band antenna applications

In this work, a triple-band negative refraction index metamaterial antenna employing a new configuration of the complementary split ring resonator is presented. The antenna has been designed to operate at 2.4 GHz, 2.9 GHz, and 4.38 GHz. The complementary split ring resonator is etched in the ground plane of a microstrip patch with a new shape of defected ground structure for reducing the particle size. The configuration has the advantages of smaller size compared to conventional complementary split ring resonators presented in the literature. The proposed antenna has a patch size of 28 × 28 mm2. Compared to conventional single band microstrip patch radiator size; its size has been reduced by 30% at the lowest operating frequency. The antenna has reflection coefficient less than −10 dB at the three operating frequencies. The antenna has a reasonable gain at the three operating frequencies of 3.28 dB, −4.5 dB and −3.1 dB at 2.4 GHz, 2.9 GHz, and 4.38 GHz, respectively. Also, the antenna efficiency is 57.6%, 6.3%, and 12.3% at these frequencies, respectively.

Glucose Sensing Using Slot Waveguide-Based SOI Ring Resonator

An optical ring resonator based sensor is proposed for bio-sensing applications. It is applied to glucose level monitoring in blood samples in the range 10 to 200 mg/dl using minimal invasive technique. Two configurations of ring resonator are proposed that are based on ridge and slot waveguide. The average sensitivity of slot ring resonator is observed to be 360 nm/RIU, which is six times higher (60 nm/RIU) than that of ridge ring resonator. Both the sensor configurations are adept to respond to slight variation in glucose concentration, which affects the refractive index and ultimately the spectral shift of the resonator.

A novel photonic crystal ring resonator configuration for add/drop filtering

A novel compact photonic crystal ring resonator (PCRR) configuration is proposed to realize high-efficiency waveguided add-drop filtering. Its wavelength selection and dropping-direction exchange functions are demonstrated numerically. The working mechanism of this nested dual-loop resonant cavity structure is analyzed in detail.

Ultracompact graphene-assisted ring resonator optical router

Optical routers with compact footprint and low energy consumption are of high demand for optoelectronic integrations. We demonstrate a graphene-assisted optical router based upon silicon ring resonator configurations. The electrical tunability and the influence that graphene has upon the effective mode index are investigated, from monolayer to multiple graphene layers. The corresponding waveguide structure design is further discussed and optimized via numerical simulations. Meanwhile, the design recipes are also discussed and our proposal possesses broad free spectrum range reaching 3.64 THz, lenis crosstalk below −15 dB, low loss and low power consumption that is propitious to versatile wavelength division multiplexing systems and on-chip silicon optical interconnects.

Improved Planar Resonant RF Sensor for Retrieval of Permittivity and Permeability of Materials

In this paper, the improved planar resonant sensors based on the generalized split ring resonator (SRR) configuration are proposed for the permittivity and the permeability testing of magneto-dielectric samples. It is observed that the proposed inter-digital capacitor-based SRR and the meandered line-based SRR provide better sensitivity for dielectric and magnetic measurement, respectively, when compared with the standard SRR-based microwave sensors. Both the sensors are first modeled under unloaded condition, using the full wave electromagnetic solver, the CST Microwave Studio, in order to ensure their operating frequency range near 2.45 GHz of industrial, scientific and medical band. In the next step, the numerical simulation of these sensors is carried out by loading them with a number of reference materials in order to develop empirical model for the determination of permittivity and permeability of test samples. Additionally, the equivalent circuit models of these sensors are obtained using the Advanced Design System circuit simulator and results are compared with the numerical simulation. All the sensors are designed and fabricated on 1.27-mm-thick RT/Duroid 6006 substrate, and testing is carried out using the network analyzer. A number of standard dielectric and magneto-dielectric samples are tested using the proposed scheme in order to retrieve their permittivity and permeability values. The measured data of each sample are in good match with the corresponding reference values available in literature having a typical error of less than 6%.

Design and performance evaluation of hybrid optical sensor

An efficient and cost effective optical sensor is proposed using a hybrid configuration of ring resonator and Bragg grating. The proposed hybrid optical sensor (HOS) is based on transmission power, overlap integral, refractive index profile and wavelength shift by using finite difference time domain photonics simulation software. It has been found that the proposed HOS provides better electric field distribution (0.118v/m), Poynting vector (1.98e−10), transmittance power (1.75dB), overlap integral (1.009%), transmission power (0.024a.u.) and wavelength shift (1nm) as compared to conventional ring resonator. The proposed design with SiO2 grating obtained highest average sensitivity of 4.97nm/μe.

Ultra-thin narrow-band, complementary narrow-band, and dual-band metamaterial absorbers for applications in the THz regime

In this paper, ultra-thin narrow-band, complementary narrow-band, and dual-band metamaterial absorbers (MMAs), exploiting the same electric ring resonator configuration, are investigated at normal and oblique incidence for both transverse electric (TE) and transverse magnetic (TM) polarizations, and with different physical properties in the THz regime. In the analysis of the ultra-thin narrow-band MMA, the limit of applicability of the transmission line model has been overcome with the introduction of a capacitance which considers the z component of the electric field. These absorbing structures have shown a wide angular response and a polarization-insensitive behavior due to the introduction of a conducting ground plane and to the four-fold rotational symmetry of the resonant elements around the propagation axis. We have adopted a retrieval procedure to extract the effective electromagnetic parameters of the proposed MMAs and we have compared the simulated and analytical results through the interference theory.

Internally-loaded ring resonator configuration for optical filter applications

We study on-chip Wavelength Division Multiplexing (WDM) application of ring resonators on Silicon-on-Insulator (SOI) platform. Though WDM devices have been demonstrated earlier, there are certain challenges which are yet to be tackled. Large FSR and narrow line width requirement for a WDM device cannot be fulfilled in a conventional WDM device as the requirement for both the metrics demand opposing structural requirements from a ring resonator. A larger FSR demands for a smaller resonator length whereas smaller line width requires a large resonator length device. We overcome this using an embedded type ring resonator configuration. The structure is made of a racetrack type ring resonator with another ring embedded inside it (loading the external ring). Such structures are capable of showing coupled resonator induced transparency (CRIT) which can result in a very narrow line-width. We present initial experimental demonstration of CRIT in an internally loaded micro ring resonator fabricated on SOI material platform. The structures were optimized using 3D-FDTD analysis and coupling-matrix method.

An optical channel drop filter based on 2D photonic crystal ring resonator

In this paper, we investigate an optical channel drop filter based on a new configuration of photonic crystal ring resonator in a two-dimensional square lattice of silicon rods. The numerical simulation results by the finite difference time domain method show that close to 100% dropping efficiency with quality factor of 1011 is achievable at wavelength λ = 1.55 μm, which is an important wavelength for optical communication systems. Also, we investigate the effect of different parameters on the filtering behavior of the structure and show that changing the refractive index, the lattice constant, and the radius of the rods in the structure affect the resonant wavelength, the dropping efficiency, and the quality factor of the filter. The simplicity of the design, its high dropping efficiency, and its high quality factor are the most significant advantages of our filter.

Effect of Input Amplitude to Power Amplification in Various Orientation of Ring Resonator

<p>Photonic ring waveguide resonators have great potential applications in wavelength filtering, switching, modulation and multiplexing. The response of coupled ring resonators can be designed by using various coupling configurations. Particularly, ring resonators can be used as wavelength filter when the wavelength fits a whole multiple times in the circumference of the ring. In this paper, we investigate the effect of input amplitude to power amplification in four ring resonator configurations and vary the input amplitude on five different wavelengths. With OptiFDTD Photonics Simulation Software V8.0, the results show the intensity phenomenon of filtering in optical circuit.</p><p> </p>

Effect of Input Amplitude to Power Amplification in Various Orientation of Ring Resonator

<p>Photonic ring waveguide resonators have great potential applications in wavelength filtering, switching, modulation and multiplexing. The response of coupled ring resonators can be designed by using various coupling configurations. Particularly, ring resonators can be used as wavelength filter when the wavelength fits a whole multiple times in the circumference of the ring. In this paper, we investigate the effect of input amplitude to power amplification in four ring resonator configurations and vary the input amplitude on five different wavelengths. With OptiFDTD Photonics Simulation Software V8.0, the results show the intensity phenomenon of filtering in optical circuit.</p><p> </p>

Multimode waveguide based directional coupler

The Silicon-on-Insulator (SOI) based platform overcomes limitations of the previous copper and fiber based technologies. Due to its high index difference, SOI waveguide (WG) and directional couplers (DC) are widely used for high speed optical networks and hybrid Electro-Optical inter-connections; TE00–TE01, TE00–TE00 and TM00–TM00 SOI direction couplers are designed with symmetrical and asymmetrical configurations to couple with TE00, TE01 and TM00 in a multi-mode semi-triangular ring-resonator configuration which will be applicable for multi-analyte sensing. Couplers are designed with effective index method and their structural parameters are optimized with consideration to coupler length, wavelength and polarization dependence. Lastly, performance of the couplers are analyzed in terms of cross-talk, mode overlap factor, coupling length and coupling efficiency.

Mode-multiplexed waveguide sensor

Optical sensors enable quantification of analyte concentrations non-invasively without being affected from electromagnetic fields. The development of single-mode waveguides (WGs) is simple approach; however, limitations in the spatial distribution of the refractive index and the inability to sense multiple samples at the same time. Here, we demonstrate a multi-mode WG model and matrix inversion method (MIM) to improve spatial information in at least one dimension. This method is used to optimize and estimate three external stimulus properties in TE00, TE01 and TM00 multiplexed modes for a semi-triangular ring resonator configuration. The multi-mode WG and MIM may have applications in the development of biosensors for multi-analyte detection.

New ultrasensitive resonant photonic platform for label-free biosensing.

A multi-analyte biosensing platform with ultra-high resolution ( = 0.2 ng/mL),-which is appropriate for the detection in the human serum of a wide range of biomarkers, e.g. those allowing the lung cancer early diagnosis, has been designed. The platform is based on a new configuration of planar ring resonator. The very strong light-matter interaction enabled by the micro-cavity allows a record limit-of-detection of 0.06 pg/mm(2), five times better than the state-of-the-art. The device with footprint = 2,200 μm(2) for each ring, due to its features, has the potential to be integrated in lab-on-chip microsystems for large-scale screenings of people with high risk of developing cancer.

OPTICAL BISTABILITY IN ALL-PASS MOBIUS CONFIGURATION MICRORING RESONATOR

A novel design of microring resonator called all-pass Mobius ring resonator is used to study optical bistability effect and spectral transmission for all-optical switching application with clockwise hysteresis loop operation. The bright soliton pulse is applied as the input source of the system. The propagation of the pulses within the system is simulated using the transfer matrix analysis. The all-pass Mobius ring resonator is able to operate under high nonlinearity as it has longer propagation length per roundtrip. The all-pass Mobius provides low transmission peak power of 3.65 mW as compared to the conventional all-pass configuration. The output-to-input relation of both design shows that the Mobius configuration is able to generate a higher hysteresis loop width of the bistable signal from 15.79 mW to 18.10 mW input power. The switching power of the optical bistability in Mobius configuration is 3.67 mW for threshold power of 16.95mW. This work shows the Mobius configuration is more suitable to be used for all-optical switching application as compared to the conventional all-pass ring resonator configuration.

Optical resonators based on Bloch surface waves

A few recent works suggest the possibility of controlling light propagation at the interface of periodic multilayers supporting Bloch surface waves (BSWs), but optical resonators based on BSWs are yet to be demonstrated. Here we discuss the feasibility of exploiting guided BSWs in a ring resonator configuration. In particular, we investigate the main issues related to the design of these structures, and we discuss their limitations in terms of quality factors and dimensions. We believe these results might be useful for the development of a complete BSW-based platform for applications ranging from optical sensing to the study of the light–matter interaction in micro and nano structures.

Asymptotic theory of a large fiber-laser array passive phase locking.

Coherent laser beam combining is a potentially attractive way to increase the combined beam brightness beyond the technological limits to single-mode fiber lasers. Passive phase locking (PPL) does not need external management and leads to strong simplification of the system. A specific feature of fiber amplifiers and lasers is that they possess optical path differences of the magnitude of many wavelengths. The involved problem in the PPL approach is to specify an ultimate limit to the phase-locked laser-array size. Earlier studies confirm the stabilizing role of gain saturation on beam-combining efficiency. The purpose of our study is to decipher the desired effect of nonlinearity on the combining efficiency in two architectures of a globally coupled fiber-laser array: (I)an array of amplifiers in ring resonator configuration with spatially filtered feedback; (II)an array of lasers also with external feedback. The external-cavity feedback in both systems results in global coupling, i.e., each element is coherently coupled to all the others. A semi-analytical approach based on the probability theory is developed to calculate the probability density for the efficiency as a function of system parameters in both ensembles. Comparison between (I) and (II) arrays indicates that the II-type arrays demonstrate better characteristics while scaling the array size.

All-fiber wavelength swept ring laser based on Fabry-Perot filter for optical frequency domain imaging.

Innovations in laser engineering have yielded several novel configurations for high repetition rate, broad sweep range, and long coherence length wavelength swept lasers. Although these lasers have enabled high performance frequency-domain optical coherence tomography, they are typically complicated and costly and many require access to proprietary materials or devices. Here, we demonstrate a simplified ring resonator configuration that is straightforward to construct from readily available materials at a low total cost. It was enabled by an insight regarding the significance of isolation against bidirectional operation and by configuring the sweep range of the intracavity filter to exceed its free spectral range. The design can easily be optimized to meet a range of operating specifications while yielding robust and stable performance. As an example, we demonstrate 240 kHz operation with 125 nm sweep range and >70 mW of average output power and demonstrate high quality frequency domain OCT imaging. The complete component list and directions for assembly of the laser are posted on-line at www.octresearch.org.

Magnetic Field Generator Design for Magneto-Optic Switching Applications

In optical communications, magneto-optic switching technologies are emerging alternatives, as well as complimentary solutions to their electro-optic counterpart. Their main attractions include low-power and low-cost solutions for signal routing used in fiber-based and all-optical circuits needed in fast dynamic communications systems. However, design of the magnetic field generator system required for these devices is a challenge that has limited their performance and integration onto silicon-based technologies. In this work, a novel approach to designing magnetic field generators for magneto-optic switching systems is provided. This practical field generation design method for magneto-optical interferometers highlights important trade-offs specific to different needs and applications. Example usage of this design process is provided in the application of a magneto-optic switch of ring resonator configuration. Optical and electrical results are also provided and discussed.

A fiber laser resonantly pumped 1617 nm bow-tie ring resonator Er:YAG laser

A fiber laser resonantly pumped 1617 nm Er:YAG laser is reported. A bow-tie ring resonator configuration was employed for the Er:YAG laser to operate at 1617 nm. The laser yields 2.38 W at 1617 nm output for an incident pump power of 12.11 W, with a slope efficiency of 30%.