Accession Number : ADP008212

Title :   Geometry Dependence of the Field-Induced-Guide/Antiguide Modulator,

Corporate Author : CALIFORNIA UNIV SANTA BARBARA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s) : Huang, T. C. ; Yang, T. C. ; Chung, Y. ; Dagli, N. ; Coldren, L. A.

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : Using the field-induced-guide (FIG) concept, guide/antiguide modulator with on/off ratio larger than 22dB, and optical bandwidth larger than 0.55 micrometer has been reported . The device is formed with a central guide sandwich between two antiguides. For the on-state, a guide situation is created, and the input light will be confined and propagated in the central guide region. For the off-state, a antiguide situation is created, and the input light will be diffracted out of the central guide region. It is obvious that the performance of the guide/antiguide modulator depends upon the geometrical dimensions of the gap G between the guide and antiguide electrodes, the active region length L, and the central guide width W. In order to understand the geometric dependence of the modulator, devices of different dimensions have been investigated, and both calculated and experimental results arc reported here. The measured on/off ratios for devices with G=2 micrometer (top data) and G=5 micrometer (bottom data) wide gaps are shown in Table 1. The devices are measured at 1.15 micrometer wavelength under push-pull operation, and the applied biases are approx. -8V. From the data in the same column, it can be seen that the modulators with longer modulation active lengths have larger on/off ratios. This is to be expected, since the diffraction loss increases with distance. Also, the data in the same row show that the modulators with narrower central guides have larger on/off ratios.

Descriptors :   *LIGHT MODULATORS, *ELECTROOPTICS, DIFFRACTION, ELECTRODES, INPUT, MODULATION, GEOMETRY.

Subject Categories : Optics
      Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE