Lucent Technologies Inc.

Other

Mei Du

Andrew John Stentz

Karsten Rottwitt

Thomas Andrew Strasser

David Alan Ackerman

Alan Glen Solheim

Mark Stephen Wight

Torben N Nielsen

Liming Zhang

William Crossley Dautremont-Smith

Kenneth L Bacher

Andreas Franz Ludwig Sizmann

A device for measuring dispersion of a link between two switching nodes of an optical network comprises a phase measuring unit PMU for determining a first phase of a data signal traveling on a first wavelength &lgr; , and a second phase of the same data signal traveling on a second wavelength &lgr; , received consecutively over the link under measurement. A dispersion measurement controller controls operation of the phase measuring unit and characterizes the dispersion of the link at a wavelength of interest &lgr;&equals;(&lgr; )/2, based on the first and second phases. The PMU includes a frame detector for determining a first and a second rotation signal indicative of the digital offset between the first and second test clocks with a respective frame start, and a phase detector for measuring the phase of these test clocks with respect to a static reference. The static reference is provided by the same data signal transmitted continuously over a reference wavelength. The test and reference clocks are 1:n divided to extend the range of the measurement. A method for characterizing the dispersion of a link of an optical network is also provided.

Dispersion measurement in optical networks

The use of a co-propagating fiber Raman amplifier in an optical WDM transmission system has been found to be practical in the situation where the fiber amplifier is operated into depletion and the characteristics of the input signals are controlled to exhibit a reduced integrated relative intensity noise (RIN) over the fiber crosstalk bandwidth. In particular, the reduction in the integrated RIN can be achieved by increasing the number of input channels (by adding more messages or simply using dummy channels), encoding the data in a particular fashion to reduce the integrated RIN, or decorrelating the plurality of N input signals below a predetermined, relatively low frequency (for example, 2 MHz).

WDM optical communication system using co-propagating Raman amplification

A fiber Raman amplifier is configured to use a co-propagating Raman pump source, which may be beneficial in a variety of system configurations (for example, in bidirectional communication systems). By carefully configuring the pump source characteristics, sufficient optical gain can be achieved in the co-propagating arrangement, the characteristics including: (1) using an optical pump power of at least 50 mW, (2) having a relatively large spectral bandwidth within the pump (to suppress SBS); and (3) a frequency difference between all longitudinal pump modes of each pump laser being separated by at least the walk-off frequency between the pump laser frequency and the signal frequency, and all intense longitudinal modes between different pump lasers being separated by at least the electrical bandwidth of the communication system.

Optical communication system with co-propagating pump radiation for raman amplification

Growing community of inventors

Scotch Plains, NJ, United States of America

Mei Du