Switching behavior engineerable, electro-optic directional couplers in aperiodic optical superlattice waveguides

Shih Yuan Yang, Hung Pin Chung, Sung Lin Yang, Tsai Yi Chien, Kuang Hsu Huang, Yen Hung Chen

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We report on the first study and a proof-of-principle demonstration of aperiodically alternating-Δβcouplers in LiNbO3 waveguides whose switching behavior can be engineered with a high degree of freedom. A high fabrication-tolerance and broad working-bandwidth electro-optic (EO) coupler is developed based on a unique Δβ scheme derived using a simulated annealing algorithm and realized in Ti-diffused aperiodically poled lithium niobate (APPLN) waveguides. The waveguide fabrication tolerance and the working bandwidth (149.2 nm) of the APPLN EO coupler are found to be increased by 2.7 and 2.4 times, respectively, over that of a conventional periodically alternating-Δβ (PPLN) coupler for ≥99% power transfer efficiency under a fixed switching voltage at the 1550 nm band. The results even hold for a domain poling-width error of ≤9%. An interesting APPLN EO coupler capable of working on a certain coupling state over a broad voltage operating range is also studied. The technology developed in this work should enable the production of coupler devices whose switching characteristics can be tailored and realized with much more relaxed fabrication and bandwidth control, which would be beneficial for the application in efficient and compact integrated-optic circuits/systems.

Original languageEnglish
Article number124800
JournalOptics Communications
StatePublished - 1 Mar 2020


  • Domain engineering
  • Electro-optic devices
  • Optical directional couplers
  • Optical waveguides
  • Simulated annealing


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