Polarization-maintaining Waveguide Research Articles

Terahertz polarization-maintaining subwavelength filters

Terahertz (THz) polarization-maintaining waveguides, which have been considered fundamental elements in polarization-sensitive THz systems, are promising platforms in developing functional THz devices. Here, we propose a THz grating based on a subwavelength rectangular polymer waveguide, which filters two polarization states simultaneously. The proposed gratings are characterized and discussed using numerical simulations. We observe two transmission dips with over a 20.9 dB extinction ratio (ER) and around a 21.1 GHz full-width half-maximum (FWHM), where the reflective frequencies of the two polarization waves and the separation between them can be harnessed with appropriate structure designs. Furthermore, we demonstrate that the grating can operate as a polarization-maintaining narrow bandpass filter (ER>12.3 dB and FWHM<1.7 GHz) by introducing a π-phase shift. This work has the potential to open a new avenue for steering polarized THz radiation using the waveguide-based filters, which could be integrated in THz polarization-sensitive imaging, sensing, and wireless communication systems.

Analysis of Polarization-Maintaining Waveguide Used in Resonance Integrated Optical Gyro

Resonance integrated optical gyroscope, Polarization-maintaining waveguide, Single-mode condition, Birefringence. Abstract. A polarization-maintaining (PM) waveguide used in Resonance Integrated Optical Gyro (RIOG) is theoretically proposed. Three essential factors determining the PM performance, which are the single-mode condition, birefringence and core index, are analyzed and optimized respectively. The single-mode rectangular waveguide is obtained by analyzing the propagation mode of the rectangular waveguide. A high birefringence waveguide design method is brought up according to the theory of geometrical birefringence, realized by changing the cross-sectional shape of the waveguide. The effect that the core index contributes to the birefringence is also discussed, and an optimal core index of the waveguide to reach maximal birefringence is determined in the condition of single-mode transmission. The high birefringence PM Waveguide with geometrical birefringence of 1.5×10-4 is obtained by theoretical analysis, the simulation results shows that the polarization cross-talk in RIOG is obviously improved.

Correlation between Incident and Emission Polarization in Nanowire Surface Plasmon Waveguides

Nanowire plasmons can be launched by illumination at one terminus of the nanowire and emission can be detected at the other end of the wire. Using polarization dependent dark-field scattering spectroscopy, we measure how the polarization of the emitted light depends on the polarization of the incident light. We observe that the shape of the nanowire termination plays an important role in determining this polarization change. Depending on termination shape, a nanowire can serve as either a polarization-maintaining waveguide, or as a polarization-rotating, nanoscale half-wave plate. The understanding of how plasmonic waveguiding influence the polarization of the guided light is important for optimizing the structure of integrated plasmonic devices.

Method for the rotational alignment of polarization-maintaining optical fibers and waveguides

A novel method has been developed for measuring the rota- tional angle of a fiber's or a waveguide's polarization axis with respect to a reference angle. The reference angle is the polarization axis of the measuring device. The method also gives the true polarization extinction ratio of the measured fiber or waveguide. The method is suitable for the characterization and rotational alignment of polarization-maintaining waveguides and fibers. In particular, the method can be used to rotation- ally align the fiber-waveguide interconnections during waveguide char- acterization. The measuring device is either a linear polarizer or a polar- ization splitter that is accurately rotated with respect to the device under test. According to the experiments with a polarization-maintaining fiber, the method is very easy and inexpensive to implement, and the angular accuracy can be better than 0.2 deg. © 2003 Society of Photo-Optical Instrumen- tation Engineers. (DOI: 10.1117/1.1600730)

Two‐dimensional photonic‐crystal microwave waveguide

AbstractThis paper reports on the use of 2D photonic crystals to design microwave waveguides. The waveguide consists of a periodic arrangement of holes, with a square or rectangular cross section, that extends along the waveguide with a central defect defined by the absence of a hole. The theoretical analysis of such a structure is based on a biorthogonal‐basis method and provides a full‐vector description of the modes guided by the defect. Our results show that such a waveguide can be designed to support only one mode at any operating frequency. This mode is a polarization doublet whose dispersion is controlled by the geometrical parameters, thus permitting the design of a novel polarization‐maintaining waveguide. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 243–246, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11181