Patent ID: 8971704
Filing Date: 2015-03-03
Classification: H04B,H04J

Abstract:
1. An optical network comprising: a first optical network element, a second optical network element, a transmission path between said first optical network element and said second optical network element, said first optical network element comprising a first optical transmitter arranged to generate and transmit a first optical signal, a first controller arranged to control said first optical transmitter to generate and transmit said first optical signal at a wavelength selected from a predetermined plurality of wavelengths, a first optical receiver apparatus arranged to detect a backscatter portion of said first optical signal returned to said first optical network element along said transmission path by scattering, and a second optical receiver apparatus arranged, to detect a second optical signal; said second optical network element comprising a second optical transmitter arranged to generate and transmit said second optical signal, a second controller arranged to control said second optical transmitter to generate and transmit said second optical signal, and third optical receiver apparatus arranged to detect an optical signal having a wavelength within a receiving wavelength band, said first optical receiver apparatus being arranged to detect a predetermined criterion of said returned backscatter portion of said first optical signal at said selected wavelength and to detect a characteristic of said predetermined criterion said characteristic indicative of the backscatter optical power of said returned backscatter portion of said first optical signal at said selected wavelength and said first optical receiver apparatus being arranged to compare said characteristic with a threshold value, said first controller being arranged to iteratively generate and transmit said first optical signal at different wavelengths of said predetermined plurality of wavelengths, said first controller being arranged to identify a wavelength for which said characteristic is above said threshold value and being further arranged to control said first optical transmitter to subsequently maintain generation and transmission of said first optical signal at said wavelength, and said third optical receiver apparatus being arranged to detect said first optical signal having said wavelength within a receiving band.