Patent ID: 8600239
Filing Date: 2013-12-03
Classification: H04J

Abstract:
1. A method of synchronizing a clock in an optical network including a first network element that is connected to a second network element, comprising: transmitting optical timing signals at a first wavelength and at a second wavelength from the first network element to the second network element; transmitting optical timing signals at the first wavelength and at the second wavelength from the second network element to the first network element; determining a ratio between velocities of light at the first wavelength and at the second wavelength based on timing information contained in the optical timing signals; and aligning the clock based on at least the ratio between the velocities of light and the timing information, wherein the optical timing signals transmitted from the first network element to the second network element are transmitted over one or more optical links which are distinct from one or more optical links over which the optical timing signals from the second network element to the first network element are transmitted.