The dynamics of a spontaneous downconversion process with the idler mode coupled to an auxiliary mode is analysed. Depending on the presence or absence of nonlinear phase mismatch, a Zeno or anti–Zeno effect is found. This behavior is understood by using the dressed modes picture of the device. A possibility to achieve a quasi–phase– matching by careful adjustment of coupling strength is pointe...

Ahtract -A computer-aided sjnthesis design procedure is given for nonuniform quadrature directional couplers in inhomogeneous media. A wiggly geometry is employed which effective11 slows the odd-mode phase veloci5 to match the even-mode phase velocity. The wiggly geometry results in improved isolation and increased effective dielectric constant. This technique provides a shorter coupler length ...

The dynamics of a spontaneous downconversion process with the idler mode coupled to an auxiliary mode is analysed. Depending on the presence or absence of nonlinear phase mismatch, a Zeno or anti–Zeno effect is found. This behavior is understood by using the dressed modes picture of the device. A possibility to achieve a quasi–phase– matching by careful adjustment of coupling strength is pointe...

This paper presents a novel design of compact contra-directional coupler with high directivity for high-power monitoring in frequency. Microstrip parallel coupled lines are widely used directional couplers; however, they show poor inherently. Their has been improved by many works. However, the suggested approaches often result other limitations, such as weak structure monitoring, or larger size...

A simple waveguide directional coupler is described which uses the split-block type of construction common in millimeter-wave components. The coupler uses an array of metal probes suspended on quartz stand-offs. Depending on the number of coupling elements, the coupling can be in the range 15-30 dB, with typically ± 2 dB variation across the waveguide band, and directivity > 10 dB. The coupler,...

USA TEL: (1) 631 231-1700 • INT’L TEL: (1) 631 231-1390 • FAX (1) 631 231-1711 E-MAIL: [email protected] • www.nardamicrowave.com In today’s microwave practice, the directional coupler has become a virtually indispensable measurement tool. It provides a simple, convenient, accurate means for sampling microwave energy without moving parts and without the need for adjustments. Unlike other met...

We study the propagation and switching of slow-light pulses in nonlinear directional couplers composed of two parallel waveguides, where each waveguide contains a Bragg grating. We show that by optimizing the phase shift between the Bragg gratings, one can obtain specific dispersion characteristics enabling all-optical pulse manipulation in space and in time. We demonstrate that the power-contr...