Optical transmission system and optical transmission device

Patent metadata

Field	Value
Publication number	US-9698902-B2
Application number	US-201514736458-A
Country	US
Kind code	B2
Filing date	Jun 11, 2015
Priority date	Jun 30, 2014
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

An optical transmission system includes: a first optical transmission device configured to transmit measurement light to an optical transmission line on a first direction; and a second optical transmission device configured, when an optical transmission characteristic is measured, to loop-back the measurement light received from the first optical transmission device through an optical transmission line on the first direction and to transmit the measurement light to the first optical transmission device through an optical transmission line on a second direction, wherein, when the optical transmission characteristic is measured, the first optical transmission device receives the measurement light loop-backed by the second optical transmission device and measures the optical transmission characteristic between the first optical transmission device and the second optical transmission device.

First claim

What is claimed is:

1. An optical transmission system comprising:
a first optical transmission device including
a wavelength selective switch (WSS) having a plurality of input ports and an output port, wherein
the plurality of input ports include
input ports to receive channel lights, respectively, and
a respective input port to receive measurement light generated by the first optical transmission device,

the WSS is controllable to output the received measurement light from the output port, and
the first optical transmission device is configured to transmit light which includes at least the measurement light and is output from the output port of the WSS, to an optical transmission line that transmits the light which includes at least the measurement light in a first direction; and

a second optical transmission device comprising
a first device which is an optical splitter or a WSS, and includes
an input port to receive the light which includes at least the measurement light transmitted by the optical transmission line, and
a plurality of output ports, and

a second device which is an WSS including a plurality of input ports and an output port, wherein

the second optical transmission device provides a loop-back connection between a respective output port of the plurality of output ports of the first device and a respective input port of the plurality of input ports of the second device, so that the measurement light included in the light received by the input port of the first device
is provided from the respective output port of the plurality of output ports of the first optical device to the respective input port of the plurality of input ports of the second device,
then output from the output port of the second device, and
then transmitted by the second optical transmission device to the first optical transmission device through an optical transmission line that transmits light transmitted by the second optical transmission device in a second direction,
so that the measurement light is thereby looped-back by the second optical transmission device to the first optical transmission device, and

the first optical transmission device receives the measurement light loop-backed by the second optical transmission device and is configured to measure an optical transmission characteristic between the first optical transmission device and the second optical transmission device in accordance with the received measurement light, wherein the measuring the optical transmission characteristic comprises at least one of:
measuring an optical signal-to-noise ratio (OSNR) of the received measurement light, and measuring an OSNR between the first optical transmission device and the second optical transmission device in accordance with the measured OSNR of the received measurement light,
measuring optical power variations of the received measurement light, and measuring a polarization dependent loss (PDL) between the first optical transmission device and the second optical transmission device in accordance with the measured optical power variations of the received measurement light,
analyzing a polarized wave state of the received measurement light, and measuring a polarization mode dispersion (PMD) between the first optical transmission device and the second optical transmission device in accordance with the analyzed polarized wave state of the received measurement light, and
analyzing a wavelength dependence on a phase of the received measurement light, and measuring chromatic dispersion (CD) between the first optical transmission device and the second optical transmission device in accordance with the analyzed wavelength dependence on a phase of the received measurement light,

wherein the measurement light is at a wavelength in a wavelength band that is a measurement target of the optical transmission characteristic.

2. The optical transmission system according to claim 1 , wherein the first optical transmission device varies the wavelength of the measurement light in the wavelength band.

3. The optical transmission system according to claim 2 , wherein the first optical transmission device varies the wavelength of the measurement light over the entire wavelength band when the optical transmission system is initially started up.

4. The optical transmission system according to claim 2 , wherein the first optical transmission device controls the wavelength of the measurement light so as to use an unused wavelength in the wavelength band while the optical transmission system is in operation.

5. The optical transmission system according to claim 1 , further comprising:
a third optical transmission device arranged between the first optical transmission device and the second optical transmission device, the third optical transmission device comprising:
a first device which is an optical splitter or a WSS, and includes
an input port to receive the light which includes at least the measurement light transmitted by the optical transmission line that transmits light in the first direction, and
a plurality of output ports, and
a second device which is an WSS including a plurality of input ports and an output port, wherein

the third optical transmission device provides a loop-back connection between a respective output port of the plurality of output ports of the first device and a respective input port of the plurality of input ports of the second device, so that the measurement light included in the light received by the input port of the first device
is provided from the respective output port of the plurality of output ports of the first optical device to the respective input port of the plurality of input ports of the second device,
then output from the output port of the second device, and
then transmitted by the second optical transmission device to the first optical transmission device through the optical transmission line that transits-transmits light in the second direction, so that the measurement light is thereby looped-back by the second optical transmission device to the first optical transmission device, wherein

the third optical transmission device and the second optical transmission device consecutively loop back the measurement light to the first optical transmission device, and
the first optical transmission device receives the measurement light loop-backed by the third optical transmission device and measures the optical transmission characteristic in accordance with the received measurement light looped back by the third optical transmission device and the received measurement light looped back by the second optical transmission device.

6. An optical transmission device comprising:
a first device which is an optical splitter or a wavelength selective switch (WSS), and includes
an input port to receive light which includes at least measurement light transmitted through a first optical transmission line in a first direction, and
a plurality of output ports, and

a second device which is a WSS including a plurality of input ports and an output port, wherein
the optical transmission device provides a loop-back connection between a respective output port of the plurality of output ports of the first device and a respective input port of the plurality of input ports of the second device, so that the measurement light included in the light received by the input port of the first device is provided from the respective output port of the plurality of output ports of the first optical device to the respective input port of the plurality of input ports of the second device, then output from the output port of the second device, and then transmitted by the optical transmission device to a second optical transmission line that transmits light transmitted by the optical

Assignees

• Fujitsu Ltd

Inventors

• Nakamura Kentaro
• Okano Satoru
• Sugaya Yasushi

Classifications

• H04B10/0775 Primary

  Performance monitoring and measurement of transmission parameters · CPC title