Open AccessMicron scale directional coupler as a transducer for biochemical sensing
Author(s) -
Ken Uchiyamada,
Kyohei Okubo,
Miwa Yokokawa,
Edwin T. Carlen,
Kiyoshi Asakawa,
Hiroaki Suzuki
Publication year - 2015
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.23.017156
Subject(s) - cladding (metalworking) , optics , transducer , refractive index , materials science , signal (programming language) , power dividers and directional couplers , optoelectronics , light intensity , physics , acoustics , computer science , metallurgy , programming language
A microfabricated directional coupler (DC) was used for the detection of DNA conjugated with quantum dots. Output optical signals from DCs of a wide range of device lengths correspond well to theoretical and simulation results. Even 20 µm-long DC devices could detect changes in the output optical intensity by monitoring the near-field pattern using a CCD camera. The signal was enhanced 60 × using a 1500 µm-long DC device. For large cladding refractive-index changes between air and water, the normalized signal changed cyclically several times between 0 and 1. The results suggest that the DC can be the basis for miniaturized two-dimensionally integrated biochemical sensors.