Showing papers on "Mode scrambler published in 1992"

Wavelength multiplexed two dimensional image transmission through single mode optical fiber

Abstract: An apparatus and method are provided for transmitting two-dimensional images through a single mode optical fiber. Light from a broadband source is dispersed into component wavelengths, spatially modulated to contain an image, collected for multiplexing in a single mode optical transmission fiber, transmitted through the single mode fiber, and demultiplexed into its component wavelengths to reproduce the transmitted image. The two-dimensional dispersing and collecting elements may be realized using thin film channel waveguides having arrays of optical gratings. Because the dispersive element at the receiving (output) end of the transmission fiber must reproduce the dispersal pattern used at the source, the information transmitting device may be used for data encryption and decryption.

Widened output mode semiconductor optical component and method of fabricating it

Abstract: A widened output mode semiconductor optical component such as a laser includes superposed active and passive waveguides. The width of the active waveguide decreases in a rear part of a mode transition section to couple a "narrow" optical mode which is amplified and guided by the active waveguide to a "wide" mode which is guided by the passive waveguide and which has a mode size greater than that of the narrow mode. The width of the passive waveguide then decreases in a front part of this section to couple the wide mode to an even wider circular mode. The invention finds applications in the fabrication of optical heads for optical fiber telecommunication networks.

Mode transition matrix measuring system

Abstract: A mode transition matrix measuring system for nondestructively calculating mode-dependent losses and coupling of a multi-mode, graded-index, connectorized, passive fiber optic component, the mode transition matrix measuring system comprising mode selective launcher means having a plurality of optical paths with varying launch conditions, input-output optic means having at least one reference optical path and at least one optical path for the passive fiber optic component under test, mode selective detection means having a plurality of optical paths with a variety of mode filters, and means for data storage and matrix calculation, wherein the mode transition matrix and the modal power vector are calculated using measurements of the optical power propagated through optical courses comprising the optical paths

Measurement of mode splitting in asymmetric Y-junctions

Abstract: A measurement procedure is presented for the determination of mode splitting (or mode sorting) in asymmetric Y-junctions. This procedure avoids measurement errors introduced by bends, tapers, small damages in the waveguides outside the coupling region, variation in fiber-chip coupling, etc. It is based on the analysis of the normalized coupled power in an optical coupler in which a mode splitter is used. The method is illustrated with a mode splitter on lithium niobate. A value of 29.2+or-0.5 dB for the suppression of the unwanted mode is found, showing the applicability of the procedure. >

Transmission of two mode coded channels in one fibre using optical directional couplers as mode selective elements

Abstract: Mode multiplexing, a method for transmitting two signals along one fibre without time-or wavelength-multiplexing is presented with theoretical and experimental results. It is shown that two mode coded channels can be separated using optical directional couplers with enhanced mode selectivity combined with a simple signal processing unit.

Light propagation in thermally fused biconical taper single-mode optical fiber couplers

Abstract: Since the light propagation property of the currently produced single mode optical fiber couplers has not become clarified, there are various problems with their production method, namely in terms of their operability, stability, reproducibility and durability. The main purpose of this paper is to perform quantitative experiment on the major elements which is thought to influence light propagation of thermally fused biconical taper single mode optical fiber couplers. Furthermore, this paper aims to clarify light propagation property of single mode optical fiber couplers by calculating light output using mode coupled theory, in attempt to improving their production method.

Fiber and channel waveguide coupling improvement by mode pattern control

Abstract: In practical applications, the resultant channel waveguide of LiNbO3 substrate should be efficiently coupled to the single mode fiber. The core shape of single mode fiber is a circular distribution, but that of the conventional Ti:LiNbO3 channel waveguide is a semi-elliptical distribution. Optical mode patterns of channel waveguide and single mode fiber can not achieve the mode matching conditions. To improve coupling efficiency between channel waveguide and single mode fiber with arbitrary dimensions, the refractive index profiles and associated fundamental mode patterns of buried Ti/Mg:LiNbO3 channel waveguides are simulated and controlled from fabrication parameters. We have also investigated the dependences of coupling loss on radial and axial offsets.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.