Nokia Networks Oy

Nokia Corporation

Alcatel N.v.

Jaakko Aarnio

Simo Kaarlo Tammela

Ari Juhani Tervonen

Peter Kersten

Johannes Koppenborg

The invention relates to an optical telecommunications network comprising several nodes (Nto N) connected to one another by optical transmission paths that form several working rings (Rto R), 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 (Nto N) including N nodes, a group of working rings (Rto R) including N rings, and a group of wavelengths (&#x3bb;to &#x3bb;) 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. Each node has an individual wavelength specific to the node, the said wavelength being one of wavelengths in the said group of wavelengths, and a reception ring specific to the node, from which the other nodes in the group of nodes do not receive.

Optical telecommunications network

The invention relates to an optical telecommunications network comprising several nodes (N . . . N ) interconnected by optical transmission paths that form several working rings (R . . . R ), each of which passes via every node (N . . . N ). 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 (N . . . N ), N/2 working rings (R . . . R ), and N wavelengths (I to I ) 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.

Optical telecommunications networks

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). To reduce crosstalk, the signals at different wavelengths and the signals to be multiplexed are demultiplexed and applied, respectively, to alternate second side (B) ports so that the second side ports alternately have a port belonging to the first group and a port belonging to the second group.

Optical multiplexing and demultiplexing

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.

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Espoo, Finland

Jaakko Aarnio