Showing papers on "Coupled mode theory published in 1976"
TL;DR: A planar optical 3-dB coupler is proposed that uses only a single region of mode conversion followed by a region of adiabatic modal evolution, provided by an overlay with fast and slow tapers, which makes the device synchronous at a single point.
Abstract: A planar optical 3-dB coupler is proposed that uses only a single region of mode conversion followed by a region of adiabatic modal evolution. These two regions are provided by an overlay with fast and slow tapers, which makes the device synchronous at a single point. Device length is noncritical. The device was fabricated with sputtered barium silicate and fused silica films and tested experimentally. Maximum power transfer of 40% was limited by a fabrication problem with the fast taper, but agreement with theory was obtained. An approximate coupled mode representation of the coupling between local normal modes is used to estimate power transfer at an abrupt transition and to provide design requirements for the fast and slow tapers. The theoretical concepts developed are applied to describe the operation of conventional directional 3-dB couplers and channel modal evolution 3-dB couplers which use branching waveguides.
35 citations
TL;DR: In this article, Raman amplification in weakly guiding optical fibers is investigated for the two cases of weak and strong mode coupling, in which the Stokes powers of different modes increase independently, and the gain of each mode depends on the initial poewrs of all laser modes.
Abstract: Raman amplification in weakly guiding optical fibers is investigated for the two cases of weak and strong mode coupling. Use is made of the statistical ensemble of similar fibers introduced by Marcuse for studying mode coupling in optical waveguides. In the weak‐coupling case, the Stokes powers of different modes increase independently, and the gain of each mode depends on the initial poewrs of all laser modes. In the strong‐coupling case, power equipartition between Stokes modes takes place throughout the fibers, and the common gain is the average of the individual mode gains.
20 citations
TL;DR: In this paper, the coupled-wave theory of the Bragg diffraction efficiency in acousto-optic and some crystalline holographic recording materials is presented, where the authors show that it can be strongly affected by multiple internal optical reflections.
10 citations
TL;DR: In this paper, a simple theory of coupled modes is developed for the study of double-beam microwave amplifiers under the optimum gain condition, and the dependence of the gain parameter on beam coupling is shown.
Abstract: A simple theory of coupled modes is developed for the study of double-beam microwave amplifiers under the optimum gain condition The dependence of the gain parameter on beam coupling is shown The values of the gain parameter and the optimum inhomogeneity factor are compared with that obtained by other methods