Siemens Aktiengesellschaft

Hans H Witte

Franz Auracher

Hubert Aulich

Steven Moustakas

Anton Sauer

A device and method for reducing level dynamics in an optical star bus transmission system is disclosed wherein variable electrical resistors are connected in series to the electro-optical transmission elements of the system transmitters and are selectively adjusted so that differences in the signal power levels at a selected system receiver are reduced to zero, and hence the differences in the signal power levels at the remaining system receivers are substantially reduced. Furthermore, variable electrical resistors are connected in series to the gain controlling resistors of the amplifier stages of the receivers of the system so that when any specific transmitter couples power into the system, differences in the output levels of the amplifier stages of the receivers are also substantially reduced. The invention may be practiced with trimming potentiometers.

Device and method for reducing level dynamics in an optical transmission

An optical star coupler, which includes a mixing element consisting of a planar waveguide having an input and output end for interconnecting two groups of light conducting fibers with a packing density of each group of fibers being as high as possible and the planar waveguide having a thickness approximately equal to the diameter of the fibers, characterized by each fiber which is to be connected to a fiber of a fiber optical system having a diameter approximately equal to the core diameter of this fiber of the fiber optical system and, preferably, the mixing element on the surfaces, which are not connected to the fibers, are in contact with a medium having an index of refraction less than the index of refraction of the mixing element. Preferably, this medium comprises a material having substantially the same coefficient of thermal expansion and is an optical adhesive.

Optical star coupler with a planar mixer element

A passive bus system for decentrally structured multi-computer systems, particularly multi-microcomputer systems, allows execution of a bit-serial information exchange between the individual computers of the system achieving the bandwidth required for high transmission speeds with simple and reliable means, capable of decentralized monitoring and control. Exclusively optical transmission means is employed for all data exchange operations in a communications level shared by all of the function units of the multi-computer system, exclusively decentralized control devices are individually allocated to the function units for control of the bus system seizure.

Passive bus system for decentrally organized multi-computer systems

An optical four-gate coupler, which is particularly useful when used in a bus system and has a pair of input fibers and a pair of output fibers which are arranged with the planar end faces of the four fibers abutting one another in an axial offset fashion characterized by one of the input fibers having a smaller cross-section than the remaining fibers.

Optical four-gate coupler

An optical unit having at least one longitudinal side coupling zone characterized by the unit comprising at least one glass fiber having a glass core with a glass cladding layer surrounding the core with a step in the index of refraction from a greater to a lower value occurring at the junction between the glass core and cladding layer, the cross section of the glass fiber remaining uniform along the entire length and the core having at least one constriction to form the longitudinal coupling zone. To form the optical unit, a device utilizing a double crucible with a nozzle opening of the inner crucible being arranged to discharge into the nozzle opening of the outer crucible and provided with a means for regulating the flow therethrough is utilized. If the unit includes a plurality of optical fibers, these fibers may be individually formed and held together by an adhesive, the cladding of the fiber may be fused together or the unit may be formed jointly by utilizing a crucible having a plurality of nozzle openings for the inner crucible so that a continuous cladding layer is disposed around a plurality of cores.

Optical unit having a longitudinal side coupling zone

An input/output coupler for multi-mode optical or light conducting fibers comprises a substrate, a first light conductor, which is disposed on the substrate and has an end face forming a coupling point or surface, a main light conducting fiber, which is disposed on the substrate with an end face at the coupling surface and a center of the end face offset by a distance a from the center of the coupling surface, and a strip waveguide, which is coupled to a branch light conducting fiber and is disposed on the substrate with an end face in contact with a portion of the coupling surface so that a portion of a light signal entering the coupler in the first light conductor is applied to both the main and branch light conducting fibers and signals entering the coupler in the branch and main light conducting fibers are applied to the first light conductor. The first light conductor may be either a light conducting fiber or an additional strip waveguide, which is coupled to a light conducting fiber. Preferably, the substrate has guide grooves formed in a layer of material for positioning the various light conducting fibers and the material of the layer is the same as the material used to form the strip waveguide.

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Munich, Germany

Hans H Witte