Contents I. Introduction
The design of passive polarization converters or rotators has attracted considerable attention in the last decade or so, motivated by the increasing need of miniaturization for integrated optics devices. Geometry of passive polarization converter. Based on this, several authors have reported efficient structures, each time smaller, capable to achieve almost full polarization conversion. Rotators several millimeters long and few decibel losses were presented in [1] and [2]. The fabrication process of such passive components was not simple, though it was less complex than the active ones. Van der Tol et al. [3] proposed a relatively simpler converter, based on a slant angle geometry. It had lower losses and was shorter and easier to fabricate than ones previously proposed [1], [2]. Tzolov and Fontaine [4] called attention to the possibility of efficient conversion being attained using a single-section polarization converter. Huang et al. [5] fabricated such single-section structure, obtaining 96% polarization conversion over a length of 720 . Finally, Rahman et al. [6], by means of finite-element simulations, showed that by varying the transverse geometry dimensions of the structure realized in [5], the efficiency could be improved to 99% with a drastic length reduction to 320 and 0.5-dB insertion losses.
