Numerical analysis of traveling-wave photodetectors´ bandwidth using the finite-difference time-domain method

Author

Kong, Soon-Cheol ; Lee, Seung-Jin ; Lee, Jung-Hoon ; Choi, Young-Wan

Author_Institution

Optoelectronics & Opt. Commun. Lab., Chungang Univ., Seoul, South Korea

Volume

50

Issue

11

fYear

2002

fDate

11/1/2002 12:00:00 AM

Firstpage

2589

Lastpage

2597

Abstract

We present full-wave analysis of traveling-wave photodetectors (TWPDs) using the finite-difference time-domain (FDTD) method. Impulse response in the frequency domain is obtained after time-domain data are calculated by the FDTD method. The impulse response includes the optical field profile, carrier transit time, microwave loss, microwave dispersion, and velocity mismatch all together. Three-decibel bandwidth is analyzed with the thickness of an i-layer and waveguide width as the design parameters. It is shown how transit time and microwave characteristics affect the bandwidth according to the TWPD´s length. Three-decibel bandwidth is dominated by carrier transit time in case the device length is shorter than 300-500 μm under the conditions given in this paper. However, if the device length gets longer, microwave characteristics affect the bandwidth.

Keywords

Maxwell equations; computational electromagnetics; coplanar waveguides; finite difference time-domain analysis; microwave photonics; photodetectors; ridge waveguides; transient response; Maxwell´s equations; RF optic link; carrier transit time; finite-difference time-domain method; frequency domain; full-wave analysis; impulse response; microwave dispersion; microwave loss; millimeter-wave photonics; optical field profile; ridge-type CPW multilayered structure; three-decibel bandwidth; transit time; traveling-wave photodetectors; velocity mismatch; Bandwidth; Coplanar waveguides; Finite difference methods; High speed optical techniques; Microwave devices; Numerical analysis; Optical losses; Optical waveguides; Photodetectors; Time domain analysis;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2002.804508

Filename

1046034