Open AccessA Novel Vertical Directional Coupler Switch with Switching Operation‐Induced, Extinction Ratio‐Adjusted, and Extinction Ratio‐Enhanced Sections
Author(s) -
Cho SungChan,
Hong Hyun Ha,
Yang Choongreol,
Choi Jee Yon,
Kang Minho,
Hwang HyunYong,
Choi Youngwoo,
Kim Hae Geun,
Jung ByungMin,
Kim BooGyoun
Publication year - 2002
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.02.0402.0204
Subject(s) - extinction ratio , extinction (optical mineralogy) , refractive index , core (optical fiber) , optics , bar (unit) , asymmetry , materials science , physics , wavelength , meteorology , quantum mechanics
We propose a novel very short (< 300 μm) vertical directional coupler switch with high extinction ratios larger than 30 dB. The device consists of a switching operation induced section (SOIS), an extinction ratio adjusted section (ERAS), and an extinction ratio enhanced section (ERES). These are achieved by changing the refractive index of one core. The switching operation is induced by changing the refractive index of one core in the SOIS. The improvement of extinction ratios larger than 30 dB for both the cross and bar states is made by controlling the asymmetry of the refractive indices of both cores in the ERES. Through the ERAS, different extinction ratios between the cross and bar states at the end of the SOIS are changed to the same value. For this reason, the optimum asymmetry of the refractive indices of the cores for the maximum extinction ratios and the lengths of ERES are the same for cross and bar states. Design guidelines for high extinction ratios with large tolerances are presented.