[Show abstract][Hide abstract] ABSTRACT: We present a CMOS compatible mass manufacturable, compact Si/SiO(2) multilayer GRIN lens mode size converter from standard single mode fiber to 300 nm-thick Si waveguide. The fiber-to-GRIN lens coupling loss is 2.6 ± 0.3 dB (coupling efficiency: 51~60%) with optimized focal length of 11.6~11.8 μm and Si/SiO(2) multilayer thickness of 7.4 μm.
[Show abstract][Hide abstract] ABSTRACT: We report on the fabrication and experimental demonstration of optical mode size transformation between standard single-mode fiber and 0.26 μm-thick Si-waveguide by 12 μm-thick Si/SiO(2) multilayer on-chip GRIN lens of lengths 16 μm or 24 μm butt-joint to 10 μm-wide terminated Si-waveguide. The overall coupling loss of the coupler was measured to be 3.45 dB in which the Fresnel reflection loss is estimated to be 2dB at the GRIN-lens/air interface. The on-chip integrated GRIN lens opens up the feasibility of a low cost passive aligned fiber-pigtailed electronic-photonics integrated circuits platform.
[Show abstract][Hide abstract] ABSTRACT: Vertical optical mode-size transformation from 260nm-thick Si-nanowaveguide to 10~12μm matching the single-mode-fibre-core has been demonstrated using compact multilayer Si/SiO2 asymmetric GRIN lens (length:~24μm). GRIN lens to single-mode-fibre practical coupling loss of -3.45 dB was achieved.