Vertical Optical Coupling Structure Based on Polymer for Small Size and High-Speed Photodetectors

• Published in: IEEE photonics technology letters Vol. 30; no. 21; pp. 1886 - 1889
• Main Authors: Viana, Carlos, Tegegne, Zerihun Gedeb, Nanni, Jacopo, Tartarini, Giovanni, Algani, Catherine, Marty, Frederic, Pavy, Nicolas, Polleux, Jean-Luc
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Alignment; Couplings; Electronics; Engineering Sciences; Optical communication; Optical couplers; Optical coupling; Optical device fabrication; Optical fibers; optical interconnections; passive alignment; Photodetectors; Photodiodes; Photometers; polymer; Polymers; Thin films; vertical optical couplers
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2018.2871268

This letter presents a new collective and passive thin-film 3D vertical optical coupling structure, which is fabricated based on SU-8 polymer. This technology compensates for the alignment errors of the present passive optical coupling solutions. The structure is collectively manufactured on a matrix of small-sized photodiodes on wafer level to vertically couple with a single-mode optical fiber. The proposed structure shows a coupling efficiency between the 10-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> active area diameter photodetector and single-mode fiber of 94% and a 1-dB alignment tolerance of <inline-formula> <tex-math notation="LaTeX">\pm 9~\mu \text{m} </tex-math></inline-formula> at 1550 nm. Its wafer-level mass-production capability and manufacturing process simplicity make this novel coupling approach a potential solution for short- and long-range optical communication applications.