MODE ANALYSIS AND SYSTEMATICAL DESIGN OF WIDE-BANDWIDTH PHOTONIC CRYSTAL 60° WAVEGUIDE BENDS WITH HIGH TRANSMISSION

2012 ◽  
Vol 26 (26) ◽  
pp. 1250170 ◽  
Author(s):  
TAO CHEN ◽  
CAILONG ZHENG ◽  
JINXING LI
Keyword(s):  
Photonic Crystal ◽  
Expansion Method ◽  
Transmission Efficiency ◽  
Slab Waveguide ◽  
Mode Analysis ◽  
Two Dimensional ◽  
Photonic Crystal Slab ◽  
High Transmission ◽  
Index Approach ◽  
Waveguide Bend

We present a procedure to enhance the transmission efficiency of a photonic crystal slab waveguide bend by introducing an air hole with the same radius at the center of bend and optimizing the positions of three neighboring holes in the corner. The improvement relies only on the method of displacing holes which is technologically preferred to controlling variations in hole size or shape. We employ the effective refractive index approach and two-dimensional plane wave expansion method to analyze the guide modes of the straight waveguide and waveguide bend. The transmission character of bent waveguides is investigated using two-dimensional finite-difference time-domain method. Numerical studies demonstrate that the approximate method of mode analysis is unsuitable to our model. Alternatively, we systematically study the effect of different positions of the holes on the transmission. The optimized bends for the high transmission with broad bandwidth are proposed.

WIDEBAND OPERATION OF 2D PHOTONIC CRYSTAL DIRECTIONAL COUPLER WITH TOPOLOGY OPTIMIZED WAVEGUIDE BENDS

2010 ◽  
Vol 19 (04) ◽  
pp. 543-550 ◽  
Author(s):  
YOSHINORI WATANABE ◽  
NAOKI IKEDA ◽  
YOSHIAKI TAKATA ◽  
YOSHINORI KITAGAWA ◽  
NOBUHIKO OZAKI ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Directional Coupler ◽  
Extinction Ratio ◽  
Slab Waveguide ◽  
Optimized Design ◽  
Two Dimensional ◽  
Photonic Crystal Slab ◽  
Waveguide Bends ◽  
Two Dimensional Photonic Crystal ◽  
Straight Waveguide

A directional coupler in a two-dimensional photonic crystal slab waveguide was optimized to operate in wideband by applying topology optimized bends at input/output ports. We fabricated the sample based on the optimized design and demonstrated that the directional coupler performs properly in the transmittance and the bandwidth comparable to the straight waveguide. We experimentally confirmed the excellent extinction ratio (12 ~ 15dB) of bar and cross port.

Multimode-Interference-Based Waveguide Crossing in Two-Dimensional Cubic Photonic Crystal

2013 ◽  
Vol 284-287 ◽  
pp. 2876-2879
Author(s):  
Yih Bin Lin ◽  
Jen Hao Cheng ◽  
Rei Shin Chen ◽  
Ting Chung Yu ◽  
Ju Feng Liu ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Integrated Circuits ◽  
Expansion Method ◽  
Transmission Efficiency ◽  
Multimode Interference ◽  
Plane Wave Expansion Method ◽  
Modal Dispersion ◽  
Optical Integrated Circuits ◽  
Difference Time ◽  
Novel Design

A novel design of photonic crystal waveguide crossing based on multimode-interference (MMI) structure is proposed. Two structures of difference device lengths are simulated and studied. The proposed structures have high transmission efficiency for a wide bandwidth. The crosstalk is -26dB with device length of 12 lattice periods and -39dB with device length of 24 lattice periods. The plane wave expansion method and finite-difference time-domain method are used to calculate the modal dispersion curve and field propagation, respectively. The proposed MMI-based waveguide crossing has the potential to be practical in high-density optical integrated circuits.

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