Open AccessOn-chip orbital angular momentum modes generator and (de)multiplexer based on trench silicon waveguides
Author(s) -
Shuang Zheng,
Jian Wang
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.018492
Subject(s) - multiplexer , extinction ratio , optics , trench , angular momentum , polarizer , physics , waveguide , polarization (electrochemistry) , silicon , wavelength , multiplexing , optoelectronics , materials science , telecommunications , birefringence , chemistry , layer (electronics) , quantum mechanics , computer science , composite material
Based on an integrated silicon platform, we present an ultracompact structure to generate optical orbital angular momentum (OAM) modes, where only a waveguide with a specially designed trench is involved. Single-trench waveguide can support two orthogonal LP-like modes whose optical axes are rotated by around 45° with respect to the horizontal and vertical directions. By optimizing the structure parameters, OAM modes with topological charges of + 1 and -1 can be selectively generated by combining two orthogonal LP-like modes with different propagation constants. We study the structure parameters for both x- and y-polarizations over a wide wavelength range from 1.45 µm to 1.65 µm. The average mode purities are close to 90% for x- and y-polarizations. Moreover, we design an on-chip OAM modes (de)multiplexer (OAM 0 , OAM ± 1 ) for x-polarization based on trench silicon waveguides. It is shown that the mode extinction ratio can achieve approximately 20 dB from 1.52 µm to 1.58 µm.