Paired interference 3-dB coupler based on SOI rib waveguides with anisotropic chemical wet etching

A 3-dB paired interference (PI) optical coupler in silicon-on-insulator (SOI) based on rib waveguides with trapezoidal cross section was designed with simulation by a modified finite-difference beam propagation method (FD-BPM) and fabricated by potassium hydroxide (KOH) anisotropic chemical wet etching.The- oretically,tolerances of width,length,and port distance are more than 1,100,and 1μm,respectively. Smooth interface was obtained with the propagation loss of 1.1 dB/cm at the wavelength of 1.55μm.The coupler has a good uniformity of 0.2 dB and low excess loss of less than 2 dB.     

Multimode Interference 3-dB Coupler in Silicon-on-Insulator Based on Silicon Rib Waveguides with Trapezoidal Cross Section

A 3-dB multimode interference optical coupler based on rib waveguides with trapezoidal cross section was designed and fabricated on silicon-on-insulator wafer. Potassium hydroxide (KOH) anisotropic chemical etching of silicon was used to fabricate the waveguides to obtain smooth interface. A modified finite-difference beam propagation method was used to simulate the multimode rib waveguide with slope interfaces. The rms roughness of etching interface is as small as 1.49nm. The propagation loss of the waveguide is 1.3dB/cm at wavelength of 1.55μm. The fabricated 3-dB coupler has a good uniformity of 0.2 dB.     

Single-Mode Behaviour Judgment of Optical Waveguides by Imaginary-Distance Beam Propagation Method Under Perfectly Matched Layer Boundary Condition

Imaginary-distance beam propagation method under the perfectly matched layer boundary condition is applied to judge single-mode behaviour of optical waveguides, for the first time to our knowledge. A new kind of silicon-on-insulator-based rib structures with half-circle cross-section is presented. The single-mode behaviour of this kind of waveguide with radius 2μm is investigated by this method. It is single-mode when the slab height is not smaller than the radius.     

一种新的基于最小平方逼近的广角光束传播方法

用最小平方逼近展开传播算子，实现了一种新的半矢量显式高阶有限差分光束传播方法-这种方法中不需要选择参考折射率，并在整个传播常数（包括辐射模的传播常数）分布区域进行逼近，解决了在泰勒展开和庞德逼近中存在的参考折射率选择和远离展开点误差增大等问题-用这种方法对几种典型波导结构进行了数值模拟，模拟结果验证了算法的正确性和可靠性- 关键词： 光束传播方法 有限差分 集成光学 数值方法