Multiple-zero multiple-pole optical filter transfer functions may be implemented more efficiently in an integrated optics architecture if higher order N × M optical couplers are utilized. For example, a coherent ring resonator made from two 3×3 couplers offers some advantages over the three mirror Fabry-Perot etalon, which is its analog. To this end we develop the formalism for obtaining the transfer functions and scattering matrices of ring resonators made from two N × M couplers. We then present a methodology for analyzing serial and parallel systems of N × M optical coupler ring resonators. 相似文献
Directional couplers in image guide technique for millimeter-wave circuits are discussed, and steps to improve their properties are demonstrated. The simple two-line-9 dB coupler with periodical coupling is compared to a design with an intermediate dielectric coupling element to reduce the frequency dependence. Radiation from the waveguide bends can be reduced significantly by inserting absorber materials at critical points. Experimental results for a-3 dB coupler are also given. 相似文献
We present numerical simulations of a directional coupler based on three-dimensional waveguides made of a nematic liquid crystal, acting as the waveguide core, infiltrated in polydimethysiloxane channels. Modeling is based on the combination of minimization of Oseen-Frank energy of the liquid crystal molecules with a beam propagation algorithm. Design of the coupler waveguides is optimized to minimize coupling lengths and maximise efficiencies. Such components can be made at low cost on flexible plastic substrates and can be also integrated with optofluidic devices for biomedical applications. 相似文献
A single mode 3 dB fused coupler, to be used as a redundant laser combiner in the submerged repeater of an undersea optical fibre transmission system, is described. The fabrication and package design of the component for this high reliability application is discussed, and the results of a wide range of environmental tests are given. 相似文献
Crosstalks of two-waveguide and three-waveguide directional couplers are analyzed mathematically based on the relationship between the coupled mode and the normal mode. Numerical techniques such as the finite-difference method and the beam propagation method are employed to confirm the validity of the derived expressions. The calculation results show that two-waveguide directional coupler is superior to any type of three-waveguide couplers from the practical viewpoint of the crosstalk and the coupling length. 相似文献
The advantages of supported metal strip gratings with respect to free-standing metal meshes are pointed out for applications as laser output couplers. A new, simple formula for the power transmission through the strip grating on a dielectric plate is derived from a line equivalent-circuit model. This formula is in good agreement with measurements performed on several samples, at different submillimeter wavelengths. An application to output couplers of far-infrared gas discharge lasers allows to improve the reliability of such lasers.x Unité associée au CNRS. U.A. 836. 相似文献
We studied electromagnetic beam reflection from layered
structures that include materials with negative refraction. Excitation of
leaky surface waves leads to the formation of anomalous lateral shifts in the reflected beams
with single or double peak structures. The presence of reasonable losses
within material with negative refraction, besides significant influence on
manifestation of the giant lateral shifts, can lead to their total
suppression and anomalously high absorption of the incident radiation. If,
in addition to the resonant excitation of leaky surface waves, radiation
inflow exactly compensates their irreversible damping, total absorption of the incoming
radiation can be achieved for moderately wide beams. 相似文献
Entangled photon pairs must often be spatially separated for their subsequent manipulation in integrated quantum circuits. Separation that is both deterministic and universal can in principle be achieved through anti‐coalescent two‐photon quantum interference. However, such interference‐facilitated pair separation (IFPS) has not been extensively studied in the integrated setting, which has important implications on performance. This work provides a detailed review of IFPS and examines how integrated device dependencies such as dispersion impact separation fidelity and interference visibility. The analysis applies equally to both on‐chip and in‐fiber implementations. When coupler dispersion is present, the separation performance can depend on photon bandwidth, spectral entanglement and the dispersion. By design, reduction in the separation fidelity due to loss of non‐classical interference can be perfectly compensated for by classical wavelength demultiplexing effects. This work informs the design of devices for universal photon pair separation of states with tunable arbitrary properties.