Accession Number : ADP008127

Title :   Investigations of Fabrication Tolerances of Narrow Bandwidth Directional Coupler Filters in InP,

Corporate Author : DEUTSCHE BUNDESPOST TELEKOM DARMSTADT (GERMANY)

Personal Author(s) : Zengerle, Remigius ; Leminger, Ottokar

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : Wavelength filters of narrow bandwidth are essential components of future photonic integrated circuits to be used, for example, in dense WDM systems. Based on the principle of asymmetrical directional couplers, there exist several studies and demonstrations in the InGaAsP/InP system. In order to achieve the desired wavelength selectivity in the nanometer range, filters with a length of several millimeters will be needed. The epitaxial layers for these structures are fabricated preferably by metal organic vapor phase epitaxy (MOVPE) to obtain a good homogeneity of the optical waveguide parameters. However, even with this technological process (and using a rotating susceptor) there exist parameter fluctuations across the substrate surface with possibly significant influence on the transmission characteristic of the filter itself. For example, the thickness of the individual layers varies across the wafer. On the other hand, the material composition of the quaternary epitaxial layers changes, too, resulting in a spatial variation of their refractive indices.

Descriptors :   *OPTICAL FILTERS, *INDIUM PHOSPHIDES, *SYMPOSIA, BANDWIDTH, CIRCUITS, COUPLERS, OPTICAL CIRCUITS, GERMANY, HOMOGENEITY, INTEGRATED CIRCUITS, EPITAXIAL GROWTH, REFRACTIVE INDEX, OPTICAL WAVEGUIDES, PHOTONICS, STRUCTURES, SUBSTRATES, SURFACES, THICKNESS, VAPOR PHASES, WAFERS.

Subject Categories : Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE