Dispersionless one-way slow wave with large delay bandwidth product at the edge of gyromagnetic photonic crystal

2020 ◽  
Vol 34 (10) ◽  
pp. 2050086
Author(s):  
Ye Liu ◽  
Chun Jiang
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Communication Systems ◽  
Slow Light ◽  
Weak Interactions ◽  
Group Velocity Dispersion ◽  
Edge State ◽  
Group Index ◽  
Light Waveguide ◽  
Modal Field

We theoretically, demonstrate a high delay bandwidth product (DBP) and zero group velocity dispersion (GVD) in a two-dimensional one-way slow light waveguide. The waveguide consists of gyromagnetic photonic crystal (GMPC) and a cladding formed by silicon photonic crystal. At the edge of the band, weak interactions (“semi-anticrossing”) between the chiral edge state (CES) mode and the mode localized at the surface of cladding are observed. The group velocity of CES wave can be tuned by adjusting the modal field distribution. As a result, an extraordinarily large value of normalized DBP of 0.63 with a group index of 10.32 and a bandwidth ranging from [Formula: see text] to [Formula: see text] is obtained. This result may contribute to one-way slow light applications in information communication systems.

scholarly journals Slow Light Tuning in Annular Slotted Photonic Crystal Waveguide with Incoming Polymer

2021 ◽  
Vol 2109 (1) ◽  
pp. 012008
Author(s):  
Konttao Zhu ◽  
Hongxue Yang ◽  
Hui Du
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Slow Light ◽  
Transmission Rate ◽  
Group Velocity Dispersion ◽  
Flat Band ◽  
Group Index ◽  
Photonic Crystal Waveguide ◽  
Processing Scheme ◽  
Operating Wavelength

Abstract An advanced post-processing scheme of reconfigurable dielectric infiltration into an annular slotted photonic crystal waveguide (ASPhCW) is proposed in this paper. Ionic liquids have had prominent effects in enhancing the optical properties of photonic crystals, especially in the aspect of tuning the transmission rate and velocity through optical materials. Using the two-dimensional plane wave expansion method, the flat band dispersion of the slow light is obtained and the tuning of the operating wavelength of the crystal could be realized by incoming polymer technology. The operating wavelength tuning range could be as large as 459.27nm and the group index could be tuned as high as 44.8 with a near zero group velocity dispersion. Using this method, a high group index equaling 45 with the bandwidth equaling 11.3nm and the normalized delay bandwidth product (NDBP) equaling 0.25 is realized. This incoming polymer technology provides an effective method of getting flat band of slow light flexibly and makes it possible to offer longer delay and low group velocity after fabrication.

Slow Light Waveguide with Low Group-Velocity Dispersion and Low Loss in 2-D Photonic Crystal

2011 ◽  
Vol 31 (1) ◽  
pp. 0113001
Author(s):  
张栋 Zhang DongZhao ◽  
赵建林 JianlinLü ◽  
吕淑媛 Shuyuan
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Slow Light ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Low Loss ◽  
Light Waveguide

SLOW LIGHT AND DISPERSION COMPENSATION BY CASCADING TWO PHOTONIC CRYSTAL WAVEGUIDES

2014 ◽  
Vol 28 (03) ◽  
pp. 1450025
Author(s):  
YE LIU ◽  
BO FANG ◽  
LILI WANG ◽  
CHUN JIANG
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Slow Light ◽  
Group Velocity Dispersion ◽  
Dispersion Compensation ◽  
Dispersion Relations ◽  
Maximum Point ◽  
Line Defect ◽  
Photonic Crystal Waveguides ◽  
Zero Group

In this paper, we propose a structure with cascaded two photonic crystal line-defect waveguides to reduce group velocity dispersion (GVD) of slow light. The width of the line-defect waveguides is tuned to obtain the two matched dispersion relations, where one of the dispersion relations has a maximum point with zero group velocity and large positive GVD; the other has a minimum point with zero group velocity and large negative GVD. The waveguides have ultra slow light with the group velocity 0.0012c. Finite-difference time-domain simulation demonstrates that the spreading of the slow light pulse in the first waveguide can be recovered by the dispersion compensation of the second waveguide with positive GVD.

ALL-DIELECTRIC PERIODIC MEDIA ENGINEERED FOR SLOW LIGHT STUDIES

2013 ◽  
Vol 27 (27) ◽  
pp. 1330020 ◽  
Author(s):  
H. KURT
Keyword(s):  
Group Velocity ◽  
Structural Changes ◽  
Slow Light ◽  
Spectral Characteristics ◽  
Group Index ◽  
Future Directions ◽  
Dispersion Engineering ◽  
Air Interface ◽  
Potential Applications ◽  
Light Waveguide

The paper presents various novel approaches to implementing slow light media by manipulating the group velocity via dispersion engineering of guided modes. Light is confined and then linked with a low group velocity inside a photonic crystal waveguide (PCW) and at the PC-air interface. We discuss both basic and engineered slow light waveguide structures. The structural changes in PCs greatly modify the spectral characteristics of the dispersion curves. The search for flat bands gives rise to various strategies for slowing the optical pulses. An appropriate and commonly adopted figure of merit (FOM) is accepted to quantify and characterize the performance of the designed slow light devices. The trade-off relationship between the group index and the bandwidth is highlighted. Efficient excitation of slow modes demands the design of additional interfaces as couplers between the input waveguide and slow mode guide structure. Other challenges of slow light studies, such as various loss sources, are mentioned. Finally, the potential applications of slow light are outlined, and remarks on future directions are presented.

Slow Light Properties of 2D Photonic Crystal Waveguide for Optical Storage in Optical Computers

2012 ◽  
Vol 452-453 ◽  
pp. 1210-1214
Author(s):  
Qi Liu ◽  
Qi Chao Liu
Keyword(s):  
Dielectric Constant ◽  
Photonic Crystal ◽  
Group Velocity ◽  
Slow Light ◽  
Group Velocity Dispersion ◽  
Expansion Method ◽  
Plane Wave Expansion Method ◽  
Central Frequency ◽  
Optical Computers ◽  
Guide Mode

Slow light properties of the photonic crystal line-defect waveguide are researched with the plane wave expansion method. The structure of the waveguide is adjusted with several methods mentioned above at the same time and the slow light properties get better. For the structure of dielectric rods, central frequency and the group velocity of the guided modes decrease with the increase of the radii of the defected rods as well as the dielectric constant. Effects on the slow light from the change of the defected rods’ position are also studied, through moving the rods up and down; we get the almost linear guide mode which has flat slow light curve and smaller group velocity. In a word, group velocity of the slow light is mainly affected by the radii and dielectric constant of the defected rods, and group velocity dispersion is decided by the change of the defected rods’ location.

scholarly journals Towards lab-on-chip ultrasensitive ethanol detection using photonic crystal waveguide operating in the mid infrared

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Rostamian ◽  
Ehsan Madadi-Kandjani ◽  
Hamed Dalir ◽  
Volker J. Sorger ◽  
Ray T. Chen
Keyword(s):  
Photonic Crystal ◽  
Slow Light ◽  
High Sensitivity ◽  
Guided Wave ◽  
Silicon On Insulator ◽  
Group Index ◽  
Photonic Crystal Waveguide ◽  
Mid Infrared ◽  
Lab On Chip ◽  
On Chip

Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to use such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of n g  = 73 and a strong localization of modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when combined with integrated with quantum cascade laser and detectors.

scholarly journals Slow light bimodal interferometry in one-dimensional photonic crystal waveguides

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Luis Torrijos-Morán ◽  
Amadeu Griol ◽  
Jaime García-Rupérez
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Communication Networks ◽  
Slow Light ◽  
Single Channel ◽  
Point Of Care ◽  
Semiconductor Industry ◽  
Optical Modulator ◽  
One Dimensional ◽  
Dimensional Photonic Crystal

AbstractStrongly influenced by the advances in the semiconductor industry, the miniaturization and integration of optical circuits into smaller devices has stimulated considerable research efforts in recent decades. Among other structures, integrated interferometers play a prominent role in the development of photonic devices for on-chip applications ranging from optical communication networks to point-of-care analysis instruments. However, it has been a long-standing challenge to design extremely short interferometer schemes, as long interaction lengths are typically required for a complete modulation transition. Several approaches, including novel materials or sophisticated configurations, have been proposed to overcome some of these size limitations but at the expense of increasing fabrication complexity and cost. Here, we demonstrate for the first time slow light bimodal interferometric behaviour in an integrated single-channel one-dimensional photonic crystal. The proposed structure supports two electromagnetic modes of the same polarization that exhibit a large group velocity difference. Specifically, an over 20-fold reduction in the higher-order-mode group velocity is experimentally shown on a straightforward all-dielectric bimodal structure, leading to a remarkable optical path reduction compared to other conventional interferometers. Moreover, we experimentally demonstrate the significant performance improvement provided by the proposed bimodal photonic crystal interferometer in the creation of an ultra-compact optical modulator and a highly sensitive photonic sensor.

scholarly journals Unidirectional Slow Light Transmission in Heterostructure Photonic Crystal Waveguide

2018 ◽  
Vol 8 (10) ◽  
pp. 1858 ◽  
Author(s):  
Qiuyue Zhang ◽  
Xun Li
Keyword(s):  
Photonic Crystal ◽  
Slow Light ◽  
Environmental Changes ◽  
Light Transmission ◽  
Square Lattice ◽  
Manufacturing Defects ◽  
Interfacial Defects ◽  
Waveguide Design ◽  
Light Waveguide ◽  
Backward Propagation

In conventional photonic crystal systems, extrinsic scattering resulting from random manufacturing defects or environmental changes is a major source of loss that causes performance degradation, and the backscattering loss is amplified as the group velocity slows down. In order to overcome the limitations in slow light systems, we propose a backscattering-immune slow light waveguide design. The waveguide is based on an interface between a square lattice of magneto-optical photonic crystal with precisely tailored rod radii of the first two rows and a titled 45 degrees square lattice of Alumina photonic crystal with an aligned band gap. High group indices of 77, 68, 64, and 60 with the normalized frequency bandwidths of 0.444%, 0.481%, 0.485%, and 0.491% are obtained, respectively. The corresponding normalized delay-bandwidth products remain around 0.32 for all cases, which are higher than previously reported works based on rod radius adjustment. The robustness for the edge modes against different types of interfacial defects is observed for the lack of backward propagation modes at the same frequencies as the unidirectional edge modes. Furthermore, the transmission direction can be controlled by the sign of the externally applied magnetic field normal to the plane.

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