Abstract: The invention relates to an optical telecommunications network comprising several nodes (N1 to N4) connected to one another by optical transmission paths that form several working rings (R1 to R4), each of which passes via each node. Information is transmitted in the network at several different wavelengths. To ensure that the network can be implemented as cost-effectively as possible, it comprises a group of nodes (N1 to N4) including N nodes, a group of working rings (R1 to R4) including N rings, and a group of wavelengths (?1 to ?4) including N wavelengths in such a way that each node in the group of nodes is configured to transmit signals at one wavelength in the group of wavelengths to all rings in the group of rings except to the ring from which it receives signals, and to receive signals at all wavelengths in the group of wavelengths except for its own transmitting wavelength from both directions in only one of the rings in the group of rings.

Abstract: The invention relates to an optical telecommunications network comprising several nodes (N1 . . . N8) interconnected by optical transmission paths that form several working rings (R1 . . . R5), each of which passes via every node (N1 . . . N8). Information is transmitted in the network at several different wavelengths. To ensure that the network can be implemented as cost-effectively as possible, it comprises N nodes (N1 . . . N8), N/2 working rings (R1 . . . R4), and N wavelengths (I1 to I4) in such a way that each node in the group of nodes is configured to receive signals at all the wavelengths in the group of wavelengths from only one of the rings in the group of rings as well as to transmit to at least all those rings in the group of rings from which the said node does not receive.

Abstract: The invention relates to the implementation of multiplexing and demultiplexing of optical signals. The multiplexing and demultiplexing are carried out by using the same waveguide phased array component (WGA). On the first side, the component comprises at least an input port and an output port (IG, OG), and on its second side a first group of ports that constitute the demultiplexer function output ports, and a second group of ports that constitute the multiplexer function input ports. An optical input signal is applied to the input port, such an input signal comprising a number of signals each at its own wavelength, the input signal is demultiplexed in the component and the demultiplexed signals are coupled to ports of the first group. The signals to be multiplexed are applied to ports of the second group and the multiplexed signal is coupled to the output port (OG).

Abstract: An optical mode filter, that is, an optical component in which the basic mode can propagate undamped as much as possible but which in higher modes are strongly damped. The optical mode filter, is an integrated optical wave guide formed by, a higher-refracting or an absorbent material disposed near a flat wave guide core. Two buffer layers are located opposite the wave guide core, and one is formed with a thinned region to function as a filter for higher modes being transmitted through the wave guide core.

Abstract: The invention relates to a method for thin needle biopsy in connection with mammography, wherein a stationary target is radiographed from two angles by means of a rotating picture head, the pictures are placed on a separate measurement table, and the x-, y-, and z-coordinates of the desired site in the target are calculated on the basis of the two pictures in a known manner.

Abstract: An apparatus for panoramic X-ray photography of the area of the dentition and the jaws, comprising a frame part, a bearing part linearly movable in relation to the frame part, and a support arm attached rotatably to the bearing part, the arm having at one end an X-ray film and at the opposite end an X-ray source. The movements of the bearing part, the support arm and the film are synchronized in such a way that an image of an area of desired shape, e.g. the patient's dental arch, is obtained on the film. The invention provides a possibility, without shifting the patient, of altering the enlargement and, additionally of tilting the X-ray beam a desired angle in relation to the horizontal, whereby e.g. teeth oblique in relation to the vertical can be photographed more sharply.

Abstract: An apparatus for panoramic X-ray photography of the area of the dentition and the jaws, comprising a frame part, a bearing part linearly movable in relation to the frame part, and a support arm attached rotatably to the bearing part, and having at one end an X-ray film and at the opposite end an X-ray source. The movements of the bearing part, the support arm and the film are synchronized in such a way that an image of an area of desired shape, e.g. the patient's dental arch, is obtained on the film. The invention provides the effect that the X-ray beam can be tilted to a desired angle in relation to the horizontal, whereby it is possible with greater sharpness to photograph, for example, teeth slanted in relation to the vertical. For this purpose, the support arm is tiltable about an axis perpendicular to its rotational axis so that, when this axis is vertical, the straight line connecting the source of radiation and the film is obligue to the horizontal.

Abstract: An apparatus is disclosed for delivering a controlled and metered amount of vapors of a vaporizable liquid in a carrier gas to a destination for use there (e.g., ether vapors to a mask for use in anesthesia during surgery). A feature of the apparatus is a metering device in which the height of a ball floating in the gas stream indicates the rate of flow.

Abstract: An apparatus is disclosed for delivering a controlled and metered amount of vapors of a vaporizable liquid in a carrier gas to a destination for use there (e.g., ether vapors to a mask for use in anesthesia during surgery). A feature of the apparatus is a metering device in which the height of a ball floating in the gas stream indicates the rate of flow.