Title :
Design of ultra-broad-band LiNbO3 optical modulators with ridge structure
Author :
Mitomi, Osamu ; Noguchi, Kazuto ; Miyazawa, Hiroshi
Author_Institution :
NTT Opto-Electron. Labs., Kanagawa, Japan
fDate :
9/1/1995 12:00:00 AM
Abstract :
This paper describes novel coplanar waveguide (CPW) electrode and asymmetric coplanar strip line (A-CPS) electrode structures, introducing ridged LiNbO3 substrates and thicker electrodes, for ultra-broad-band LiNbO3 optical modulators. The structures are designed here with quasistatic analysis using the finite-element method. Ridged-structures with CPW and A-CPS electrodes are shown to be able to reduce the driving-voltage below that of the conventional planar-type electrodes and are suitable for modulation of exceeding 100 GHz and driving voltage of far less than 4 V under an optical wavelength of 1.55 μm and 50 Ω characteristic-impedance system. The ridge-type CPW can provide a broader bandwidth characteristic with a relatively thinner buffer layer and thinner electrode than the ridge-type A-CPS and is easier to fabricate. The ridge-type LiNbO3 modulators are consequently candidate devices for future ultra-high-speed optical fiber transmission systems
Keywords :
coplanar waveguides; electro-optical modulation; finite element analysis; lithium compounds; optical communication equipment; optical fibre communication; optical fibres; ridge waveguides; strip line components; 1.55 micrometre; 50 ohm; LiNbO3; asymmetric coplanar strip line; bandwidth characteristic; coplanar waveguide; driving-voltage; finite-element method; quasistatic analysis; ridge structure; ultra-broadband optical modulators; ultra-high-speed optical fiber transmission systems; Bandwidth; Buffer layers; Coplanar waveguides; Electrodes; Finite element methods; Optical buffering; Optical modulation; Optical waveguides; Strips; Voltage;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
