Open AccessOn-chip second-order spatial derivative of an optical beam by a periodic ridge
Author(s) -
Seyed Saleh Mousavi Khaleghi,
Parisa Karimi,
Amin Khavasi
Publication year - 2020
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.399484
Subject(s) - optics , ridge , eigenmode expansion , beam (structure) , solver , physics , finite element method , reflection (computer programming) , transmission (telecommunications) , differentiator , normal mode , computer science , vibration , acoustics , telecommunications , paleontology , programming language , biology , thermodynamics , bandwidth (computing)
In this paper, a very simple periodic ridge on a symmetric slab waveguide is used for implementing an on-chip CMOS-compatible second-order spatial differentiator. The reflection and transmission coefficients of this structure show that the second derivative is performed in the transmission when the optical beam normally incidents on the periodic ridge. Simulations confirm that the reason behind the second-order spatial differentiation of the incoming beam is the excitation of the guided mode of the periodic ridge. A Maxwell's equation solver that utilizes the finite element method (FEM) is used to simulate this structure, and an eigenmode solver is utilized for the validation. The results of both methods have a very good agreement with each other.