OPTICAL TRANSMISSION SYSTEM AND OPTICAL TRANSMISSION DEVICE

• US 20150381272A1
• Filed: 06/11/2015
• Published: 12/31/2015
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: SUGAYA, Yasushi, NAKAMURA, Kentaro, OKANO, Satoru
• Granted Patent: US 9,698,902 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 10/0775 Performance monitoring and measurement of transmission parameters

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.

Claims

1. An optical transmission system comprising:

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.

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

3. The optical transmission system according to claim 1, further comprising:

one or more third optical transmission devices arranged between the first optical transmission device and the second optical transmission device, connected with optical transmission lines on the first direction and optical transmission lines on the second direction, and configured, when the 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 the second direction,

wherein, when the optical transmission characteristic is measured, each of the one or more third optical transmission devices and the second optical transmission device loop-backs the measurement light, consecutively.

4. 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.

5. 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.

6. The optical transmission system according to claim 1, wherein the optical transmission characteristic is any of an optical signal to noise ratio, polarization dependent loss, polarization mode dispersion, and chromatic dispersion.

7. An optical transmission device comprising:

an optical receiver configured to receive measurement light from an optical transmission line on a first direction; and

an optical transmitter configured, when an optical transmission characteristic is measured, to loop-back the measurement light received by the optical receiver and to transmit the measurement light to an optical transmission line on a second direction.

8. The optical transmission device according to claim 7,

wherein the optical receiver includes an optical device configured to receive light transmitted on the optical transmission line on the first direction and to output the light to any of a plurality of output ports,

wherein the optical transmitter includes a wavelength selective switch configured to select light to be inputted to a plurality of input ports in terms of a wavelength and to transmit the selected light to the optical transmission line on the second direction,

wherein any of the output ports of the optical device is connected to any of the input ports of the wavelength selective switch, and

wherein the wavelength selective switch selects the measurement light having a wavelength among light having wavelengths to be inputted and transmits the measurement light to the optical transmission line on the second direction.

9. An optical transmission device comprising:

an optical transmitter configured to transmit measurement light to an optical transmission line on a first direction; and

an optical receiver configured to receive the measurement light which is loop-backed to an optical transmission line on a second direction at another optical transmission device and to measure an optical transmission characteristic between the optical transmission device and the other optical transmission device.

10. The optical transmission device according to claim 9,

wherein the optical transmitter includes:

a wavelength selective switch configured to select light inputted to a plurality of input ports in terms of a wavelength and to transmit the selected light to the optical transmission line on the first direction; and

a measurement light transmitter connected to any of the input ports of the wavelength selective switch and configured to transmit, to the wavelength selective switch, measurement light having a wavelength selected by the wavelength selective switch, and

wherein the optical receiver includes;

an optical device to which light transmitted on the optical transmission line on the second direction is inputted and to output the light to a plurality of output ports; and

a measurement light receiver connected to any of the output ports of the optical device and configured to receive the measurement light loop-backed by the other optical transmission device and to measure the optical transmission characteristic.