title: Implementation of discrete unitary transformations by multimode waveguide holograms.
abstract: Integration of holograms into multimode waveguides allows the implementation of arbitrary unitary mode transformations and unitary matrix-vector multiplication. Theoretical analysis is used to justify a design approach to implement specific functions in these devices. Based on this approach, a compact mode-order converter, a Hadamard transformer, and a spatial pattern generator-correlator are proposed and analyzed. Beam propagation simulations are used to verify the theoretical calculations and to address bandwidth, scalability, and fabrication criteria. Optical pattern generators were successfully fabricated using standard photolithographic techniques to demonstrate the feasibility of the devices.
authors.affiliation: Physical Sciences and Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA. sytseng@lps.umd.edu
authors.forename: Shuo-Yen
authors.initials: SY
authors.lastname: Tseng
authors.forename: Younggu
authors.initials: Y
authors.lastname: Kim
authors.forename: Christopher J K
authors.initials: CJ
authors.lastname: Richardson
authors.forename: Julius
authors.initials: J
authors.lastname: Goldhar