title: Efficient planar fiber-to-chip coupler based on two-stage adiabatic evolution.
abstract: A new, efficient adiabatic in-plane fiber-to-chip coupler design is proposed. In this design, the light from the fiber is coupled into a low-index waveguide with matching mode size. The mode is first adiabatically reduced in size with a rib taper, and then transferred into a high-index (e.g. silicon) waveguide with an inverse taper. The two-stage design allows to reduce the coupler length multiple times in comparison with pure inverse taper-based couplers of similar efficiency. The magnitude of length reduction increases with the refractive index of the low-index waveguide and the fiber mode size.
authors: Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. anatoly@mit.edu
authors: Anatol
authors: A
authors: Khilo
authors: Milos A
authors: MA
authors: Popović
authors: Mohammad
authors: M
authors: Araghchini
authors: Franz X
authors: FX
authors: Kärtner