scholarly journals Diffraction mechanism of five-port transmission gratings

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Chenhao Gao ◽  
Bo Wang ◽  
Kunhua Wen ◽  
Ziming Meng ◽  
Qu Wang ◽  
...  
Keyword(s):  
Beam Splitter ◽  
Diffraction Order ◽  
Normal Incidence ◽  
Propagation Mechanism ◽  
Beam Splitting ◽  
Transmission Grating ◽  
Process Tolerance ◽  
Wide Range ◽  
Rigorous Coupled Wave ◽  
Modal Method

This paper designs a five-port transmission grating under normal incidence. Rigorous coupled-wave approach is used to optimize the grating parameters. The energy of the grating is mainly dispersed to the 0th, ±1st and ±2nd orders. The efficiency of each diffraction order under both polarizations is close to 20%. The modal method is used to describe the propagation mechanism of the two polarized lights in the grating, and the diffraction behavior of the grating is analyzed. In addition, the grating has a wide range of incident characteristics and a large process tolerance. Therefore, this five-port beam splitter with a connecting layer will be a good polarization-independent beam splitting device.

Encapsulated grating for three-port beam splitter in reflection

2016 ◽  
Vol 30 (06) ◽  
pp. 1650070 ◽  
Author(s):  
Wenhao Shu ◽  
Bo Wang ◽  
Hongtao Li ◽  
Liang Lei ◽  
Li Chen ◽  
...  
Keyword(s):  
Beam Splitter ◽  
High Efficiency ◽  
Normal Incidence ◽  
Grating Period ◽  
Practical Application ◽  
Wave Analysis ◽  
Incident Wavelength ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Independent Property

An encapsulated grating with a metal slab is designed as a reflection three-port beam splitter at the wavelength of 1550 nm under normal incidence. Such a new grating is aimed to separate energies into the ±1st and the 0th orders for both TE and TM polarizations. The grating parameters such as grating period, duty cycle and grating depth are optimized by using rigorous coupled-wave analysis. Based on optimized grating parameters, efficiencies can reach more than 32% with the polarization-independent property. It indicates that reflection three-port beam splitter with high efficiency can be obtained by the encapsulated grating. Moreover, the presented reflection three-port grating has advantages of wide incident wavelength range and angular bandwidth, which would be useful in practical application.

Beam generator of 4-channel with zeroth order suppressed by reflective T-type grating

2021 ◽  
pp. 2150218
Author(s):  
Chen Fu ◽  
Bo Wang ◽  
Zefan Lin ◽  
Zhisen Huang ◽  
Kunhua Wen ◽  
...  
Keyword(s):  
Beam Splitter ◽  
Propagation Mechanism ◽  
Total Efficiency ◽  
The Finite Element Method ◽  
Zeroth Order ◽  
Beam Splitting ◽  
Manufacturing Tolerance ◽  
Dielectric Grating ◽  
Good Uniformity ◽  
Better Than

Four-port beam splitter with good uniformity was proposed by T-type double-layer with different dielectric grating. The total efficiency of the beam splitter is over 90% with beam splitting uniformity better than 3%. At the same time, the simplified modal analysis is added to calculate the grating mode and effective refractive index of the grating area, which clearly describes the physical propagation mechanism inside the grating. The finite element method is used to investigate the normalized field of the grating, which more intuitively reflects the way of energy transfer inside the grating. Finally, the incident characteristics and manufacturing tolerance of the grating are analyzed. Properties of the T-type grating were analyzed in three methods, which more fully illustrates the applicability and stability of the grating in this paper.

Formation of 1 × 3 splitting by embedded double-layer reflective grating under second Bragg illumination

2019 ◽  
Vol 33 (33) ◽  
pp. 1950420 ◽  
Author(s):  
Chenhao Gao ◽  
Bo Wang ◽  
Kunhua Wen ◽  
Ziming Meng ◽  
Zhaogang Nie ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Double Layer ◽  
High Performance ◽  
Beam Splitter ◽  
Wave Method ◽  
Covering Layer ◽  
Process Tolerance ◽  
Large Period ◽  
Rigorous Coupled Wave ◽  
Splitting Effect

In order to obtain a [Formula: see text] grating with high performance, we designed a double-layer reflective grating beam splitter with a covering layer at a wavelength of 1550 nm. We obtain a better grating structure by modal analysis and rigorous coupled-wave method. The reflectivity of the three diffraction orders for the grating is close to 33.3%. The optimized data show that the grating beam splitter has a large period process tolerance for TE polarization. The grating performance has high incident performance and uniform splitting effect.

scholarly journals Compact Photonic Crystal Polarization Beam Splitter Based on the Self-Collimation Effect

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 198
Author(s):  
Geyu Tang ◽  
Huamao Huang ◽  
Yuqi Liu ◽  
Hong Wang
Keyword(s):  
Optical Communications ◽  
Beam Splitter ◽  
Extinction Ratio ◽  
Polarized Light ◽  
The Self ◽  
Polarization Beam Splitter ◽  
Optical Interconnection ◽  
Beam Splitting ◽  
Beam Splitters ◽  
Polarization Extinction Ratio

We propose a new compact polarization beam splitter based on the self-collimation effect of two-dimensional photonic crystals and photonic bandgap characteristics. The device is composed of a rectangular air holes-based polarization beam splitting structure and circular air holes-based self-collimating structure. By inserting the polarization beam splitting structure into the self-collimating structure, the TE and TM polarized lights are orthogonally separated at their junction. When the number of rows in the hypotenuse of the inserted rectangular holes is 5, the transmittance of TE polarized light at 1550 nm is 95.4% and the corresponding polarization extinction ratio is 23 dB; on the other hand, the transmittance of TM polarized light is 88.5% and the corresponding polarization extinction ratio is 37 dB. For TE and TM polarized lights covering a 100 nm bandwidth, the TE and TM polarization extinction ratios are higher than 18 dB and 30 dB, respectively. Compared with the previous polarization beam splitters, our structure is simple, the size is small, and the extinction ratio is high, which meets the needs of modern optical communications, optical interconnection, and optical integrated systems.

Rigorous Coupled Wave Analysis of Surface Plasmon Resonance Sensor Based on Metallic Grating

2011 ◽  
Vol 211-212 ◽  
pp. 465-468
Author(s):  
De Wei Chen
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Diffraction Order ◽  
Wave Analysis ◽  
Metallic Grating ◽  
Rigorous Coupled Wave Analysis ◽  
Resonance Sensor ◽  
Rigorous Coupled Wave ◽  
Coupled Wave

Since the development almost a decade ago of the first biosensor based on surface plasmon resonance (SPR), the use of this technique has increased steadily. In this study, we theoretically investigated the sensing character of SPR sensor with reflection type metallic with Rigorous Coupled Wave Analysis (RCWA) method, and the mechanism is analyzed by the field distribution. It is found that the sensitivity of negative diffraction order, which goes higher quickly as the resonant angle increases, is much greater than that of positive diffraction order.

scholarly journals Design and Fabrication of Moth-Eye Subwavelength Structure with a Waist on Silicon for Broadband and Wide-Angle Anti-Reflection Property

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 360 ◽  
Author(s):  
He Lin ◽  
Mingzhao Ouyang ◽  
Bingxu Chen ◽  
Qifan Zhu ◽  
Jinshuang Wu ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Incidence Angle ◽  
Structural Parameters ◽  
Diffraction Order ◽  
Wide Angle ◽  
Subwavelength Structure ◽  
Inductively Coupled ◽  
Beam Laser ◽  
Interferometric Lithography ◽  
Rigorous Coupled Wave

Reflection loss on the optical component surface is detrimental to performance. Several researchers have discovered that the eyes of moths are covered with micro- and nanostructured films that reduce broadband and wide-angle light reflection. This research proposes a new type of moth-eye subwavelength structure with a waist, which is equivalent to a gradient refractive index film layer with high–low–high hyperbolic-type fill factor distribution. The diffraction order characteristics of a moth-eye subwavelength structure are first analyzed using a rigorous coupled wave analysis. The moth-eye structural parameters are optimized within the spectral range of 2–5 μm using the finite-difference time-domain method. The experimental fabrication of the moth-eye structure with a waist array upon a silicon substrate is demonstrated by using three-beam laser interferometric lithography and an inductively coupled plasma process. The experimental and simulation results show good agreement. The experimental results show that the reflectivity of the moth-eye structure with a waist is less than 1.3% when the incidence angle is less than 30°, and less than 4% when the incidence angle is less than 60°. This research can guide the development of AR broadband optical components and wide-angle applications.

scholarly journals Multifunctional Gratings for Multiband Spatial Filtering, Retroreflection, Splitting and Demultiplexing Based on C2 Symmetric Photonic Crystals

2021 ◽  
Author(s):  
Andriy E. Serebryannikov ◽  
Diana C. Skigin ◽  
Guy A. E. Vandenbosch ◽  
Ekmel Ozbay
Keyword(s):  
Photonic Crystals ◽  
Specular Reflection ◽  
Diffraction Order ◽  
Spatial Filtering ◽  
Frequency Variation ◽  
Angle Of Incidence ◽  
Reflection Mode ◽  
Negative Order ◽  
Wide Range ◽  
Incident Wave Energy

Abstract The concept of multifunctional reflection-mode gratings based on rod-type photonic crystals with C2 symmetry is introduced and examined. The specific modal properties lead to the vanishing dependence of the first-negative-order maximum on the angle of incidence within a wide range, and the nearly sinusoidal redistribution of the incident-wave energy between zero order (specular reflection) and first negative diffraction order (deflection) at frequency variation that are the key features enabling various functionalities in one structure and functionality merging. The elementary functionalities offered by the studied structures, of which multifunctional scenarios can be designed, include but are not restricted to multiband spatial filtering, multiband splitting, and demultiplexing. The proposed structures are shown to be capable in multifunctional operation in case of an obliquely incident polychromatic wave. The generalized demultiplexing is demonstrated for the case when several polychromatic wavesare incident at different angles. The same deflection properties yield multiband splitting, and merging demultiplexing and splitting functionalties in one functionality, which may contribute to various multifunctional scenarios. The proposed gratings arealso studied in transmissive configuration.

SURFACE-RELIEF THREE-PORT OUTPUT WITH A CONNECTING LAYER GRATING UNDER THE SECOND BRAGG CONDITION

2019 ◽  
Vol 26 (02) ◽  
pp. 1850140 ◽  
Author(s):  
BO WANG ◽  
WENHUA ZHU ◽  
HONGTAO LI ◽  
SUFANG YIN ◽  
CHENGYUE SU ◽  
...  
Keyword(s):  
Surface Relief ◽  
Polarized Light ◽  
Grating Period ◽  
Fused Silica ◽  
The Novel ◽  
Bragg Condition ◽  
Rigorous Coupled Wave Analysis ◽  
Different Depths ◽  
Rigorous Coupled Wave ◽  
Modal Method

A three-port surface-relief grating with a connecting layer under the second Bragg condition is put forward and designed for the free space application in this paper. Such grating can function as a beam splitter, which can split the polarized light into the [Formula: see text]2nd order and the [Formula: see text]1st order and the 0th order based on the optimum grating profile parameters. By using rigorous coupled-wave analysis, a highly-efficient polarization-dependent connecting-layer-based grating can be obtained with the optimum different depths and thicknesses with the grating duty cycle of 0.65 and grating period of 1150[Formula: see text]nm. On the basis of the designed grating profile parameters, a modal method can explain the propagating process. Compared with the conventional surface-relief fused-silica grating, the diffraction efficiencies for TE polarization in three orders are improved. Therefore, the novel conception of the grating under the second Bragg condition is significant for further applications such as interferometer with improved efficiency for TE polarization.

High-Precision Polarizing Beam Splitting System Based on Polarizing Beam Splitter

2016 ◽  
Vol 43 (12) ◽  
pp. 1210001
Author(s):  
罗敬 Luo Jing ◽  
刘东 Liu Dong ◽  
徐沛拓 Xu Peituo ◽  
白剑 Bai Jian ◽  
刘崇 Liu Chong ◽  
...  
Keyword(s):  
High Precision ◽  
Beam Splitter ◽  
Beam Splitting ◽  
Polarizing Beam Splitter ◽  
Splitting System

scholarly journals A Comprehensive Review of Acoustic Methods for Locating Underground Pipelines

2020 ◽  
Vol 10 (3) ◽  
pp. 1031 ◽  
Author(s):  
Ying Liu ◽  
Daryoush Habibi ◽  
Douglas Chai ◽  
Xiuming Wang ◽  
Hao Chen ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Propagation Mechanism ◽  
Multiple Perspectives ◽  
Buried Pipelines ◽  
Buried Pipe ◽  
Comprehensive Review ◽  
Detection Techniques ◽  
Underground Pipelines ◽  
Wide Range ◽  
Acoustic Methods

Underground pipelines are vital means of transporting fluid resources like water, oil and gas. The process of locating buried pipelines of interest is an essential prerequisite for pipeline maintenance and repair. Acoustic pipe localization methods, as effective trenchless detection techniques, have been implemented in locating underground utilities and shown to be very promising in plastic pipeline localization. This paper presents a comprehensive review of current acoustic methods and recent advances in the localization of buried pipelines. Investigations are conducted from multiple perspectives including the wave propagation mechanism in buried pipe systems, the principles behind each method along with advantages and limitations, representative acoustic locators in commercial markets, the condition of buried pipes, as well as selection of preferred methods for locating pipelines based on the applicability of existing localization techniques. In addition, the key features of each method are summarized and suggestions for future work are proposed. Acoustic methods for locating underground pipelines have proven to be useful and effective supplements to existing localization techniques. It has been highlighted that the ability of acoustic methods to locate non-metallic objects should be of particular practical value. While this paper focuses on a specific application associated with pipeline localization, many acoustic methods are feasible across a wide range of underground infrastructures.

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