Improved design for SOI based evanescently coupled multilayer spot-size converter

We report an improved version of a spot-size converter (SSC) consisting of a silicon nanowire evanescently coupled to a phase-matched Poly-Si multilayer structure. With wider transversal dimensions the multilayer structure expands the mode significantly thus increasing the coupling efficiency with the conventional single-mode fiber. Detailed optimization process of a 17-layer based SSC is discussed and its coupling efficiency with a high-NA fiber of radius 2 μm is obtained as 98% providing only 0.087 dB loss. Vertical alignment tolerance between the optimized SSC and a high-NA fiber of radius 2 μm is also shown. This novel design does not consist of a taper and can be fabricated by using CMOS compatible process. It has a short device length and more relaxed alignment tolerances with the fiber. Full-vectorial and computationally efficient finite element method and the least squares boundary residual method have been used for the analysis and optimization of the proposed structure

An overground robotic exoskeleton gait training in complete spinal cord injured patients

The use of robotic systems during the rehabilitation of spinal cord injured patients can contribute to achieve significant outcomes. The aim of this study is to investigate the effects of an overground robot-assisted gait training in complete spinal cord injured patients. Sixteen SCI patients (mean age: 35.3 ± 10.3 yrs) underwent 20 robot-assisted gait training sessions based on an overground robotic exoskeleton. The preliminary results of this study show that the robot-assisted gait training in complete SCI patients can improve patient-robot interaction