Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/100263
標題: Theoretical analysis of mode conversion by refractive-index perturbation based on a single tilted slot on a silicon waveguide
作者: Chia-Chih Huang 
Chia-Chien Huang 
摘要: 
We propose a compact mode converter operating at the mid-infrared wavelength of 3.4 µm, comprising an etched parallelogram slot filled with silicon nitride on a silicon-on-calcium fluoride platform. The tilted slot introduces transverse and longitudinal index perturbations on the waveguide eigenmodes, achieving mode conversion in the propagation direction. Differing from previous reports using massive parameter sweep, we provide analytical formulas to determine geometry parameters by considering the modified phase-matching condition and the profiles of coupling coefficient of coupled-mode theory. Rigorous 3D numerical examples demonstrate the transverse electric (TE)0-to-TE1, TE0-to-TE2, TE0-to-TE3, and TE0-to-TE4 converters to achieve conversion efficiencies (inter-modal crosstalk [CT] values) of >92.7% (<−27 dB), >91.7% (<−16 dB), >88.2% (<−13 dB), and >75.8% (<−10 dB), respectively, with a total transmitted power of >93%. Converter device lengths range from 16.84 to 24.61 µm for TE0-to-TE1 to TE0-to-TE4, respectively. Over a broadband wavelength of 100 nm, the conversion efficiency, power transmission, and maximum inter-modal CT are almost >80%, >90%, and <−10 dB, respectively. Also, the fabrication tolerance of the proposed structure is addressed. The proposed model can not only realize arbitrary mode-order conversion but extend to other wavelength bands. To validate the feasibility of our model, the numerical results of our device operating at the wavelength of 1.55 µm are also offered and compared with those of other reports. The proposed idea may pave a new approach to designing mode converters with arbitrary geometries.
URI: http://hdl.handle.net/11455/100263
Appears in Collections:奈米科學研究所

Files in This Item:
File Description SizeFormat
493.pdf1.7 MBAdobe PDFView/Open
Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.