Abstract Based on a parabolically tapered multimode interference (MMI) coupler with a deep-etched SiO2/SiON rib waveguide, a compact wavelength demultiplexer operating at 1.30 and 1.55\mum wavelengths is proposed and analysed by using three-dimensional semi-vectorial finite-difference beam propagation method (3D-SV-FD-BPM). The results show that a MMI section of 330.0\mum in length, which is only 76% length of a straight MMI coupler, is achieved with the contrasts of 42.3 and 39.2dB in quasi-TE mode, and 38.4 and 37.8dB in quasi-TM mode at wavelengths 1.30 and 1.55\mum, respectively, and the insertion losses below 0.2dB at both wavelengths and in both polarization states. The alternating direction implicit algorithm with the Crank--Nicholson scheme is applied to the discretization of the 3D-SV-FD-BPM formulation along the longitudinal direction. Moreover, a modified FD scheme is constructed to approximate the resulting equations along the transverse directions, in which the discontinuities of the derivatives of magnetic field components Hy and Hx along the vertical and horizontal interfaces, respectively, are involved.
Received: 26 June 2006
Revised: 11 January 2007
Accepted manuscript online:
PACS:
42.79.Sz
(Optical communication systems, multiplexers, and demultiplexers?)
Fund: Project
supported by the Specialized Research Fund for the Doctoral
Program of Higher Education of China (Grant No 20060286042).
Cite this article:
Xiao Jin-Biao(肖金标), Liu Xu(刘旭), Cai Chun(蔡纯), and Sun Xiao-Han(孙小菡) Semi-vectorial analysis of a compact wavelength demultiplexer based on the tapered multimode interference coupler 2007 Chinese Physics 16 2015
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