CN-118784066-B - Remote gain unit, attenuation detection method and remote pump transmission system

CN118784066BCN 118784066 BCN118784066 BCN 118784066BCN-118784066-B

Abstract

The invention relates to the technical field of optical communication, in particular to a remote gain unit, a decay detection method and a remote pump transmission system, which separate measurement light from signal light through corresponding optical path design, thereby realizing that the measurement light skips an amplifying optical fiber for transmission, avoiding the absorption of the amplifying optical fiber to the measurement light, being applicable to the direct measurement of the optical cable span loss in the remote pump transmission system, being applicable to the measurement light with any wavelength, thoroughly solving the problem that the direct measurement of the span loss in the remote pump transmission system is not possible, and providing great help for the operation and maintenance of the remote pump transmission system.

Inventors

WU JIANJUN
Duan Mingxiong
LIU SHICHEN
WANG WENZHONG
XU JIAN
YU JIEKUI
TAN MAN

Assignees

武汉光迅科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20240617

Claims (10)

1. The remote gain unit is suitable for a remote pump transmission system and comprises a first circulator (1), a first wavelength division multiplexer (2), an amplifying optical fiber (3), a second circulator (4) and a second wavelength division multiplexer (5); A first port of the first circulator (1) is connected with an input end of the remote gain unit, a second port of the first circulator (1) is connected with a transmission end of the first wavelength division multiplexer (2), and a third port of the first circulator (1) is connected with a transmission end of the second wavelength division multiplexer (5); The first port of the second circulator (4) is connected with the other end of the amplifying optical fiber (3), the second port of the second circulator (4) is connected with the output end of the remote gain unit, and the third port of the second circulator (4) is connected with the common end of the second wavelength division multiplexer (5); The second wavelength division multiplexer (5) is used for transmitting the pump light from the output end of the remote gain unit to the first wavelength division multiplexer (2), and is also used for transmitting the measuring light from the output end of the remote gain unit to the first circulator (1) so that the measuring light bypasses the amplifying optical fiber (3).
2. The remote gain unit according to claim 1, further comprising a mirror (6), wherein the mirror (6) is arranged between the other end of the amplifying fiber (3) and the first port of the second circulator (4), and wherein the mirror (6) is configured to reflect the pump light from the amplifying fiber (3) to increase the utilization efficiency of the pump light.
3. Remote gain unit according to claim 2, characterized in that the centre wavelength of the mirror (6) is in the range 1450nm-1650nm.
4. A remote gain unit according to claim 1, characterized in that the first circulator (1) is replaced by a third wavelength division multiplexer (7) when the wavelengths of signal light and the measuring light are not changeable and the wavelength difference between the signal light and the measuring light is greater than 40 nm; The transmission end of the third wavelength division multiplexer (7) is connected with the input end of the remote gain unit, the public end of the third wavelength division multiplexer (7) is connected with the transmission end of the first wavelength division multiplexer (2), and the reflection end of the third wavelength division multiplexer (7) is connected with the transmission end of the second wavelength division multiplexer (5); the third wavelength division multiplexer (7) is used for receiving signal light from the outside and transmitting the signal light to the first wavelength division multiplexer (2); The third wavelength division multiplexer (7) is further configured to transmit the measurement light to an input end of the remote gain unit, so as to measure an optical fiber attenuation in the remote pump transmission system according to the measurement light.
5. A remote gain unit according to any of claims 1-4, characterized in that the amplifying fiber (3) is an erbium doped fiber, a praseodymium doped fiber or a rubidium doped fiber.
6. The remote gain unit according to any of claims 1-4, wherein the wavelength range of the transmission end of the first wavelength division multiplexer (2) and the second wavelength division multiplexer (5) is 1525nm to 1560nm, and the wavelength range of the reflection end of the first wavelength division multiplexer (2) and the second wavelength division multiplexer (5) is 1450nm to 1500nm.
7. A remote gain unit according to any of claims 1-4, characterized in that the isolation between the ports on the first circulator (1) and the second circulator (4) is greater than or equal to 50dB, and the insertion loss between the ports is less than or equal to 0.5dB.
8. A method of attenuation detection suitable for use in a remote gain unit as claimed in any one of claims 1 to 7, the method comprising: When pump light is input from the output end of the remote gain unit, the first circulator (1) receives signal light from the outside and transmits the signal light to the first wavelength division multiplexer (2); The second circulator (4) receives pump light and measurement light from an output end of the remote gain unit and transmits the pump light and the measurement light to the second wavelength division multiplexer (5), the second wavelength division multiplexer (5) transmits the pump light to the first wavelength division multiplexer (2), and the second wavelength division multiplexer (5) transmits the measurement light to the first circulator (1); when the pump light is input from the input end of the remote gain unit, the first circulator (1) receives the signal light and the pump light and transmits the signal light and the pump light to the first wavelength division multiplexer (2); the first wavelength division multiplexer (2) transmits the signal light and the pump light into the amplifying optical fiber (3) to amplify the signal light, and the second circulator (4) transmits the amplified signal light to the output end of the remote gain unit; The first circulator (1) transmits the measurement light to an input end of the remote gain unit to measure the fiber attenuation in the remote pump transmission system according to the measurement light.
9. A remote pump transmission system, characterized by comprising a remote gain unit, a detection unit and a pumping unit according to any one of claims 1-7, wherein the pumping unit is connected to the input end or the output end of the remote gain unit; When the pumping unit is connected with the output end of the remote gain unit, the pumping unit is used for emitting the pumping light, and the pumping light sequentially passes through the second circulator (4), the second wavelength division multiplexer (5) and the first wavelength division multiplexer (2) and then is transmitted into the amplifying optical fiber (3) together with the signal light so as to amplify the signal light; The detection unit is used for receiving the measuring light from the input end of the remote gain unit and obtaining the optical fiber attenuation in the remote pump transmission system according to the measuring light.
10. A remote pump transmission system according to claim 9, characterized in that when the pump unit is connected to the input of the remote gain unit, the pump unit is configured to emit the pump light, the pump light and the signal light are input to the input of the remote gain unit simultaneously, and the pump light and the signal light are input to the amplifying optical fiber (3) together after sequentially passing through the first circulator (1) and the first wavelength division multiplexer (2) to amplify the signal light.

Description

Remote gain unit, attenuation detection method and remote pump transmission system Technical Field The present invention relates to the field of optical communications technologies, and in particular, to a remote gain unit, a method for detecting attenuation, and a remote pump transmission system. Background With the development of technology level and communication technology, the ultra-long-distance unrepeatered transmission system is increasingly applied to ocean communication, island communication and power communication, and the remote pump transmission technology is the most common optical amplification technology in the unrepeatered communication system, and as the remote pump transmission technology can greatly improve the unrepeatered transmission distance, the remote pump transmission technology is greatly applied to the ultra-long-distance unrepeatered transmission system. The remote pump system is composed of a remote pump unit and a remote gain unit, wherein the remote gain unit contains an erbium-doped fiber, and the erbium-doped fiber has great loss under the condition of no pumping light excitation, so that an optical signal cannot penetrate the remote gain unit under the condition of no pumping. Therefore, the loss of the optical cable is measured in two sections in the remote pump transmission system, and the front section and the rear section of the remote gain unit are measured, but in the practical application scene, the loss of the optical cable transmitted by the whole system cannot be accurately measured in the existing remote pump transmission system because the remote gain unit is placed in the middle of a line and is already in butt joint with the optical cable by adopting a method of measuring in two sections. In view of this, overcoming the drawbacks of the prior art is a problem to be solved in the art. Disclosure of Invention The invention aims to solve the technical problem that the span loss measurement of the full-link optical cable cannot be carried out after the operation of the conventional remote pump transmission system. The invention adopts the following technical scheme: in a first aspect, there is provided a remote gain unit adapted for use in a remote pump transmission system, comprising a first circulator 1, a first wavelength division multiplexer 2, an amplifying optical fiber 3, a second circulator 4 and a second wavelength division multiplexer 5; A first port of the first circulator 1 is connected with an input end of the remote gain unit, a second port of the first circulator 1 is connected with a transmission end of the first wavelength division multiplexer 2, and a third port of the first circulator 1 is connected with a transmission end of the second wavelength division multiplexer 5; The first port of the second circulator 4 is connected with the other end of the amplifying optical fiber 3, the second port of the second circulator 4 is connected with the output end of the remote gain unit, and the third port of the second circulator 4 is connected with the common end of the second wavelength division multiplexer 5; The second wavelength division multiplexer 5 is used for transmitting the pump light from the output end of the remote gain unit to the first wavelength division multiplexer 2, and is also used for transmitting the measuring light from the output end of the remote gain unit to the first circulator 1 so that the measuring light bypasses the amplifying optical fiber 3. Preferably, the remote gain unit further comprises a reflecting mirror 6, wherein the reflecting mirror 6 is arranged between the other end of the amplifying optical fiber 3 and the first port of the second circulator 4, and the reflecting mirror 6 is used for reflecting the pump light from the amplifying optical fiber 3 so as to improve the utilization efficiency of the pump light. Preferably, the center wavelength of the reflecting mirror 6 is in the range of 1450nm to 1650nm. Preferably, when the wavelengths of the signal light and the measurement light are not changeable and the wavelength difference between the signal light and the measurement light is greater than 40nm, the first circulator 1 is replaced by a third wavelength division multiplexer 7; The transmission end of the third wavelength division multiplexer 7 is connected with the input end of the remote gain unit, the public end of the third wavelength division multiplexer 7 is connected with the transmission end of the first wavelength division multiplexer 2, and the reflection end of the third wavelength division multiplexer 7 is connected with the transmission end of the second wavelength division multiplexer 5; The third wavelength division multiplexer 7 is configured to receive signal light from the outside and transmit the signal light to the first wavelength division multiplexer 2; the third wavelength division multiplexer 7 is further configured to transmit the measurement light to an input terminal of the remo