2016/06/01 by Zhaolin Lu, Lu, Zhaolin, Peichuan Yin +3
Engineering · Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices #Semiconductor Lasers and Optical Devices
paper · pdf · doi:10.48550/arxiv.1606.00417
openalex publication_date 2016/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Efficient fiber-to-waveguide light coupling has been a key issue in integrated photonics for many years. The main challenge lies in the huge mode mismatch between an optical fiber and a single mode waveguide. Herein, we present a novel fiber-to-waveguide coupler, named "L-coupler", through which the light fed from the top of a chip can bend 90° with low reflection and is then efficiently coupled into an on-chip Si waveguide within a short propagation distance (<20μm). The key element is a bent metal-clad waveguide with a big matched input port. According to our finite-difference time-domain (FDTD) simulation, the coupling efficiency is over 80% within a broad range of working wavelengths in the near-infrared regime for a transverse electric input Gaussian wave. The coupler is polarization-dependent, with very low coupling efficiency (6%-9%) for transverse magnetic waves. The coupler can also be used for three-dimensional (3D) chip-to-chip optical interconnection by efficiently coupling light into an integrated photonic chip from a vertical-cavity surface-emitting laser (VCSEL), or Si waveguide on another chip. The work presented in this Arxiv article has been filed as a patent. Detailed description of this work may be published in future papers.