Patent ID: 6061484
Filing Date: 2000-05-09
Classification: G02B,H04J

Abstract:
An add/drop multiplexer for use in optical wavelength division multiplexing, the add/drop multiplexer having a first trunk input port (1) for receiving traffic signals from a first part of a first trunk fibre, a second trunk input port (2) for receiving traffic signals from a first part of a second trunk fibre, a first trunk output port (11) for outputting traffic signals to a second part of the first trunk fibre, a second trunk output port (12) for outputting traffic signals to a second part of the second trunk fibre, and a branch input port (3) for receiving traffic signals from a branch input fibre, and/or a branch output port (13) for outputting traffic signals to a branch output fibre;the add/drop multiplexer comprising:means (21, 22) for routing from the first trunk input (1) to the branch output (13) a first set of traffic signals (.lambda..sub.4, .lambda..sub.7, .lambda..sub.10.) at carrier wavelengths predetermined for transmission of signals from the first trunk fibre to a branch station (40) and for routing from the second trunk input (2) to the branch output (13) a second set of traffic signals (.lambda..sub.2, .lambda..sub.5, .lambda..sub.12) at carrier wavelengths predetermined for transmission of signals from the second trunk fibre to the branch station (40), and means (33) for combining said first and second sets of traffic signals for output at the branch output; and/ormeans (23) for separating traffic signals (.lambda..sub.1, .lambda..sub.8, .lambda..sub.11) received at the branch input (3) into a third set of traffic signals (.lambda..sub.1, .lambda..sub.8, .lambda..sub.11) at carrier wavelengths predetermined for transmission of signals from the branch station (40) to the first trunk fibre and a fourth set of traffic signals (.lambda..sub.1, .lambda..sub.8, .lambda..sub.11) at carrier wavelengths predetermined for transmission of signals from the branch station to the second trunk fibre, and means (31) for routing the third set of traffic signals (.lambda..sub.1, .lambda..sub.8, .lambda..sub.11) to the first trunk output (11) and the fourth set of traffic signals (.lambda..sub.1, .lambda..sub.8, .lambda..sub.11) to the second trunk output (12) respectively.