Power dividers and directional couplers

About: Power dividers and directional couplers is a research topic. Over the lifetime, 16955 publications have been published within this topic receiving 188760 citations.

Finite-element solution of integrated optical waveguides

Abstract: A vector H -field finite-element method has been used for the solution of optical waveguide problems. The permittivity of the guiding structures can be an arbitrarily tensor, only limited to being lossless. To extend the domain of the field representation, infinite elements have been introduced. To eliminate spurious solutions and to improve eigenvectors, a penalty function method has been introduced. To show the validity and usefulness of this formulation, computed results are illustrated for step channel waveguide, diffused channel waveguide, anisotropic channel waveguide, and channel waveguide directional couplers.

On-chip two-mode division multiplexing using tapered directional coupler-based mode multiplexer and demultiplexer

Abstract: We demonstrate a novel on-chip two-mode division multiplexing circuit using a tapered directional coupler-based TE(0)&TE(1) mode multiplexer and demultiplexer on the silicon-on-insulator platform. A low insertion loss (0.3 dB), low mode crosstalk (< -16 dB), wide bandwidth (~100 nm), and large fabrication tolerance (20 nm) are measured. An on-chip mode multiplexing experiment is carried out on the fabricated circuit with non return-to-zero (NRZ) on-off keying (OOK) signals at 40 Gbit/s. The experimental results show clear eye diagrams and moderate power penalty for both TE(0) and TE(1) modes.

Novel concept for ultracompact polarization splitter-rotator based on silicon nanowires

Abstract: A novel concept for an ultracompact polarization splitter-rotator is proposed by utilizing a structure combining an adiabatic taper and an asymmetrical directional coupler. The adiabatic taper structure is singlemode at the input end while it becomes multimode at the other end. When light propagates along the adiabatic taper structure, the TM fundamental mode launched at the narrow end is efficiently (close to 100%) converted to the first higher-order TE mode at the wide end because of the mode coupling between them. By using an asymmetrical directional coupler that has two adjacent waveguides with different core widths, the first higher-order TE mode is then coupled to the TE fundamental mode of the adjacent narrow waveguide. On the other hand, the input TE polarization does not change when it goes through the adiabatic taper structure. In the region of the asymmetrical directional coupler, the TE fundamental mode in the wide waveguide is not coupled to the adjacent narrow waveguide because of phase mismatch. In this way, TE- and TM- polarized light are separated while the TM fundamental mode is also converted into the TE fundamental mode. A design example of the proposed polarization splitter-rotator is given by using silicon-on-insulator nanowires and the total length of the device is less than 100μm. Furthermore, only a one-mask process is needed for the fabrication process, which is compatible with the standard fabrication for the regular photonic integrated circuits based on SOI nanowires.

Design of microwave filters, impedance-matching networks, and coupling structures. volume 2

Abstract: : Design techniques are presented for a wide variety of low-pass, band- pass, high-pass and band stop microwave filters; for multiplexers; and for certain kinds of directional couplers. Most of the design procedures described make use of either a lumped-element low-pass prototype filter or a step- transformer prototype as a basis for design. Prototype filter designs are tabulated, and data is given relevant to the use of prototype filters as a basis for the design of impedance-matching networks and time-delay net works. Design formulas and tables for step transformer prototypes are also given. The design of microwave filter structures to serve as impedance-matching networks is discussed. The design of microwave filters to achieve various time-delay (or slow-wave) properties is also discussed. Various equations, graphs, and tables are collected together relevant design of coaxial lines, strip-lines, waveguides, parallel coupled lines between common ground planes, arrays of lines between ground planes, coupling and junction discontinuities, and resonators. Techniques for measuring the Q's of resonators and the coupling coefficients between resonators are also discussed, along with procedures for tuning filters.

Third order nonlinear integrated optics

Abstract: The authors review progress in the application of nonlinear optical phenomena to integrated optics. Essentially all integrated optics devices such as directional couplers, Mach-Zehnder interferometers, prism couplers, etc., can be used for all-optical signal processing when at least one of the waveguiding media exhibits an intensity-dependent refractive index. Experimental and theoretical results on the operating characteristics and figures of merit of such devices, as well as a new class of phenomena based on large nonlinear changes in waveguide properties will be summarized. Also discussed are measurement techniques for evaluating waveguide nonlinearities. Progress in the implementation of other nonlinear third order interactions, such as degenerate four-wave mixing and nonlinear spectroscopy, will also be reviewed. >