The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 23, 2010
Filed:
Apr. 21, 2005
Steve Desbruslais, London, GB;
John Ellison, Essex, GB;
David Powell, Kent, GB;
Xtera Communications, Inc., Allen, TX (US);
Abstract
An optical transmission system comprises two optical fibers carrying optical signal traffic between two terminals, and a plurality of optical repeaters coupled to the two fibers each repeater having a permanently connected passive high loss loop back circuit between the two fibers. One terminal includes a transmitter, which launches a pulsed supervisory signal on a dedicated supervisory wavelength into one optical fiber, and a receiver, which detects a portion of the supervisory signal looped back from each repeater in order to identify the existence and location of faults in the transmission system. The pulsed supervisory signal is of sufficiently short duration such that portions of the signal returned from each repeater do not overlap with one another and interference with the counter-propagating traffic is avoided by utilizing a dedicated supervisory wavelength. Each return pulse is integrated sequentially by a single detector and processed by heterodyne reception and synchronous demodulation.