Optical networks

Patent metadata

Field	Value
Publication number	US-9174191-B2
Application number	US-200913391453-A
Country	US
Kind code	B2
Filing date	Aug 19, 2009
Priority date	Aug 19, 2009
Publication date	Nov 3, 2015
Grant date	Nov 3, 2015

Abstract

An optical network ( 10 ) comprising an optical network element ( 12 ) comprising a first optical transmitter ( 14 ), a first controller ( 16 ), an optical receiver ( 18 ), a second optical transmitter ( 22 ), a second controller ( 24 ) and optical receiver apparatus ( 26 ). Said first controller is arranged to control said first optical transmitter to generate and transmit a first optical signal in response no second optical signal being detected. Said first controller is arranged to iteratively generate and transmit said first optical signal at different wavelengths of a plurality of wavelengths until said second optical signal is detected, and is further arranged to subsequently maintain generation and transmission of said first optical signal at said wavelength at which said second optical signal is detected. Said second controller is arranged to control said second optical transmitter to generate and transmit said second optical signal following detection of said first optical signal by said optical receiver apparatus.

First claim

The invention claimed is:

1. An optical network, comprising:
an optical network element;
a second optical transmitter;
a second controller; and
an optical receiver apparatus,
wherein said optical network element comprises:
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, and
an optical receiver arranged to detect a second optical signal;

wherein said second optical transmitter is arranged to generate and transmit said second optical signal,
wherein said second controller is arranged to control said second optical transmitter to generate and transmit said second optical signal,
wherein said optical receiver apparatus is arranged to detect an optical signal having a wavelength within a receiving wavelength band,
wherein said first controller is configured to
control said first optical transmitter to generate and transmit said first optical signal in response to said second optical signal not being detected,
control said first optical transmitter to iteratively generate and transmit said first optical signal at different wavelengths among said plurality of wavelengths while the optical receiver remains configured to detect the second optical signal at the same wavelength in each iteration, until said second optical signal is detected at the optical receiver with power greater than a threshold optical power, and
in response to a determination that the second optical signal is received at the optical receiver with power greater than the threshold optical power, subsequently maintain generation and transmission of said first optical signal at said wavelength at which said second optical signal is detected, and

wherein said second controller is arranged to control said second optical transmitter to generate and transmit said second optical signal following a detection of said first optical signal by said optical receiver apparatus.

2. The optical network as claimed in claim 1 , wherein said optical receiver does not detect optical signals having an optical power below the threshold optical power and is provided with a first loss of signal alarm arranged to generate a first loss of signal alarm ON signal when said second optical signal is not detected, said second optical signal not being detected when said second optical signal is received and has an optical power below said threshold optical power or when no second optical signal is received, and
wherein said first controller is arranged to receive said first loss of signal alarm ON signal and control said first optical transmitter to generate and transmit said first optical signal in response to receiving said first loss of signal alarm ON signal.

3. The optical network as claimed in claim 2 , wherein said first loss of signal alarm is further arranged to generate a first loss of signal alarm OFF signal when said second optical signal is detected, said second optical signal being detected when said second optical signal is received and has an optical power at or above said threshold optical power, and
wherein said first controller is arranged to
control said first optical transmitter to iteratively generate and transmit said first optical signal at said different wavelengths of said plurality of wavelengths until said first loss of signal alarm OFF signal is received, and
subsequently maintain generation and transmission of said first optical signal at said wavelength at which said first loss of signal alarm OFF signal is received.

4. The optical network as claimed in claim 1 ,
wherein said optical receiver apparatus does not detect optical signals having an optical power below said threshold optical power, and is provided with a second loss of signal alarm arranged to generate a second loss of signal alarm OFF signal when said first optical signal is detected, said first optical signal being detected when said first optical signal is received and has an optical power at or above said threshold optical power, and
wherein said second controller is arranged to receive said second loss of signal alarm OFF signal, and control said second optical transmitter to generate and transmit said second optical signal in response to receiving said second loss of signal alarm OFF signal.

5. The optical network as claimed in claim 1 , wherein said optical receiver apparatus comprises an optical detector coupled to an output port of a wavelength selective router.

6. The optical network as claimed in claim 5 , wherein said optical detector has a sensitivity threshold which is higher than a maximum adjacent crosstalk of said output port.

7. The optical network as claimed in claim 6 , wherein said first optical transmitter is arranged to generate and transmit said first optical signal having an optical power which is not greater than a difference between said sensitivity threshold and an attenuation experienced by said first optical signal on transmission across said network.

8. The optical network as claimed in claim 1 , wherein said first controller is arranged to control said first optical transmitter to initially transmit the first optical signal prior to said optical receiver performing any optical signal detection.

9. The optical network as claimed in claim 1 , wherein a wavelength of said second optical signal is not selected by said optical network element.

10. An optical network element, comprising:
an optical transmitter arranged to generate and transmit a first optical signal;
a controller arranged to control said optical transmitter to generate and transmit said first optical signal at a wavelength selected from a predetermined plurality of wavelengths; and
an optical receiver arranged to detect a second optical signal,
wherein said controller is arranged to
control said optical transmitter to generate and transmit said first optical signal in response said second optical signal not being detected,
control said optical transmitter to iteratively generate and transmit said first optical signal at different wavelengths among said plurality of wavelengths while the optical receiver remains configured to detect the second optical signal at the same wavelength in each iteration, until said second optical signal is detected at the optical receiver with power greater than a threshold optical power, and
in response to a determination that the second optical signal is received at the optical receiver with power greater than the threshold optical power, subsequently maintain generation and transmission of said first optical signal at said wavelength at which said second optical signal is detected.

11. The optical network as claimed in claim 10 , wherein said controller is arranged to control said optical transmitter to initially transmit the first optical signal prior to said optical receiver performing any optical signal detection.

12. The optical network element as claimed in claim 10 , wherein a wavelength of said second optical signal is not selected by said optical network element.

13. A method of configuring an optical transmitter in an optical network, the method comprising:
at a first network location remote from said optical transmitter, determining whether a first optical signal is present and has a wavelength within a receiving wavelength band, and when said first optical signal is present and has a wavelength within said receiving wavelength band, generating and transmitting a second optical signal; and
at a second network location, at which said optical tr

Assignees

• Cavaliere Fabio
• Giorgi Luca
• Grosso Renato
• Ericsson Telefon Ab L M

Inventors

• Cavaliere Fabio
• Giorgi Luca
• Grosso Renato

Classifications

• B01J6/002

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