JP4656871B2 - Optical fiber communication system - Google Patents

Description

  The present invention relates to an optical fiber communication system using a remote pumping light amplification technique.

  In an optical fiber communication system using an optical fiber, a repeater system that performs communication by arranging an optical amplifying repeater in a transmission line constituted by an optical fiber, and a non-repeating system that does not arrange an optical amplifier in the transmission line; There is. In recent years, in a repeaterless system, the transmission distance has been increased by remote pumping light amplification technology. With remote pumping light amplification technology, the optical fiber for signal light amplification is arranged at a predetermined position on the transmission line connecting the both end stations, and the pumping light having a wavelength different from the signal light wavelength is incident from the terminal station, In this technique, signal light is optically amplified with an optical fiber for signal light amplification to increase the transmission distance. An optical fiber communication system that has been actually developed includes an optical fiber for signal light amplification of EDF (erbium doped optical fiber), a signal light wavelength of 1550 nm, and a pumping light wavelength of 1480 nm (for example, patents). Reference 1).

  In remote pumping light amplification, it is necessary to supply pumping light with sufficient power to the optical fiber for signal light amplification in order to perform optical amplification. In order to achieve this object, there have been, for example, a method for transmitting the excitation light on another line, a method for Raman amplification of the excitation light, etc., in addition to the method for increasing the output of the excitation light (for example, non-patent literature) 1).

  FIG. 24 is a diagram showing an example of a system for supplying the pumping light having sufficient power to the optical fiber for signal light amplification. One terminal station, the A station 10, combines an optical transmitter 11 that transmits signal light, an excitation light source 15 that transmits excitation light for exciting the signal light, and a combination of the signal light and the excitation light. Means 14. The other terminal station, B station 20, is an optical receiver 21 that receives signal light, an excitation light source 25 that transmits excitation light for exciting the signal light, and a multiplexing that combines the signal light and the excitation light. Means 24. The transmission path between the A station 10 and the B station 20 includes an optical amplifying device 60 composed of a signal light amplifying optical fiber 61 and an optical amplifying device 60 ′ composed of a signal light amplifying optical fiber 61 ′.

  In this system, excitation light with sufficient power transmitted from the excitation light source 15 and signal light transmitted from the optical transmission device 11 are combined by the combining means 14 and passed through a transmission path (optical fiber). The signal light is amplified by a signal light amplification optical fiber 61 and the transmission distance of the signal light is extended. Similarly, also in the optical amplifying device 60 ′, the signal light is amplified by pumping light with sufficient power from the pumping light source 25, and the transmission distance is extended.

  FIG. 25 is a diagram illustrating an example of a system to which the method for transmitting the excitation light by another line is applied. Here, the excitation light source 15 ′ included in the A station 10, the excitation light source 45 included in the D station 40 that is separate from the A station 10 and the B station 20, and the C station that is separate from the A station 10 and the B station 20 The pumping light source 35 included in the station 30 and the pumping light source 25 ′ included in the station B 20 are connected to the remotely installed optical amplifying devices 60, 60 ′, 60 ″ by separate lines. In this way, the signal light is amplified to increase the transmission distance.

FIG. 26 is a diagram showing an example of a system to which a method for Raman amplification of the excitation light (which occurs in the wavelength 1450 nm band) is applied. Here, the A station 10 Raman-amplifies the excitation light transmitted from the excitation light source 15 (for excitation light Raman amplification) and Raman-amplifies the excitation light transmitted from the excitation light source 15 ′ (excitation light). Similarly, the B station 20 includes a pump light source 26 for Raman-amplifying pump light transmitted from the pump light source 25 (for pump light Raman amplification) and a pump light source 25 ′. And pumping light source 26 'for Raman amplification of pumping light to be transmitted (for pumping light Raman amplification), and C station 30 performs Raman amplification of pumping light transmitted from pumping light source 35 (for pumping light Raman amplification). The D station 40 includes a light source 36, and includes a pump light source 46 that Raman-amplifies pump light transmitted from the pump light source 45 (for pump light Raman amplification). The excitation light for Raman amplification is combined with the excitation light and transmitted through a transmission line (optical fiber), whereby the excitation light is Raman-amplified in the transmission line, and the optical amplifiers 60, 60 ′ installed remotely. , 60 ″, it is possible to input high-output pump light, and by increasing the gain of optical amplification, the transmission distance can be extended.
Patent No. 2714611 (FIG. 3 etc.) H. Maeda, G. Funatsu, and A. Naka “Design considerations of long span 10 Gbit / s WDM unrepeated transmission systems” suboptic2004, We8.4.

  However, in order to further extend the repeaterless transmission distance by the remote pumping light amplification technique, it is necessary to supply more optical power to the optical fiber for signal light amplification.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical fiber communication system capable of supplying more optical power to an optical fiber for signal light amplification. It is in.

In order to achieve the above object, the present invention provides an optical fiber communication system that performs communication between two end stations installed at both ends of an optical fiber that transmits signal light. Excitation light output means for signal light amplification to be output, excitation light output means for excitation light amplification to output the excitation light for excitation light amplification to the optical fiber, and excitation light for signal light amplification installed in the middle of the optical fiber When the light and the signal light are superimposed and input, at least one signal light amplifying means for amplifying the signal light, and installed in the middle of the optical fiber, the pumping light for pumping light amplification and the pumping for signal light amplification When the light is input to overlap, and characterized in that it comprises at least one of the signal light amplification pumping light amplifying means thulium of doped optical fiber for amplifying the signal light amplification pumping light To have. As a result, more optical power can be supplied by the signal light amplification means and the signal light amplification excitation light amplification means.

  It is possible to further extend the repeaterless transmission distance by the remote pumping light amplification technique.

  1 to 23 show an embodiment of the present invention. Embodiments of the present invention will be described with reference to the drawings. Hereinafter, a preferred embodiment in which the wavelength of the signal light transmitted from the optical transmitter is 1550 nm, the wavelength of the primary pumping light for signal light amplification is 1480 nm, and the wavelength of the secondary pumping light for pumping light amplification is 1400 nm. Indicates. However, it is not limited to these values.

  FIG. 1 shows a first embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the combining means 14 for combining the signal light, the primary pumping light, and the secondary pumping light, and the other end including the optical receiver 21 that receives the signal light. A pumping light amplifying apparatus 50 including a pumping light amplification optical fiber 51 on the A station 10 side, and a signal light amplification on the B station 20 side, installed in the transmission path between the B station 20, the A station 10 and the B station 20 And a signal light amplifying device 60 including an optical fiber 61 for use. In other words, the secondary pumping light source is arranged in the same signal light transmitting station as the primary pumping light source, and the pumping light amplifying device and the signal light amplifying device independent of the transmission path are arranged.

  First, the signal light transmitted from the optical transmitter 11, the primary pump light transmitted from the primary pumping light source 12 for signal light amplification, and the second pump light transmitted from the secondary pumping light source 13 for pumping light amplification. The next excitation light is multiplexed by the multiplexing means 14. The combined signal light, primary pump light, and secondary pump light reach the pump light amplifying apparatus 50 through the transmission path. In the pumping light amplifying device 50, the primary pumping light is amplified by the secondary pumping light in the pumping light amplification optical fiber 51. Subsequently, in the signal light amplifying apparatus 60, the signal light is amplified by the amplified primary pump light in the signal light amplification optical fiber 61. Then, the signal light reaches the optical receiver 21 of the B station 20 through the transmission path. According to the first embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 2 shows a second embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the combining means 14 for combining the signal light, the primary pumping light, and the secondary pumping light, and the other end including the optical receiver 21 that receives the signal light. In the transmission path between the B station 20 and the A station 10 and the B station 20, the pumping light amplification optical fiber 71 is included on the A station 10 side, and the signal light amplification optical fiber 72 is included on the B station 20 side. The signal light and pumping light amplifying device 70 is configured. In other words, the secondary pumping light source is arranged in the same signal light transmission side station as the primary pumping light source, and an amplification device including the pumping light amplification device and the signal light amplification device is arranged in the transmission path.

  First, the signal light transmitted from the optical transmitter 11, the primary pump light transmitted from the primary pumping light source 12 for signal light amplification, and the second pump light transmitted from the secondary pumping light source 13 for pumping light amplification. The next excitation light is multiplexed by the multiplexing means 14. The combined signal light, primary pump light, and secondary pump light reach the signal light and pump light amplifying apparatus 70 through the transmission path. In the signal light and pumping light amplifying apparatus 70, the primary pumping light is amplified by the secondary pumping light in the pumping light amplification optical fiber 71. Subsequently, in the signal light amplification optical fiber 72, the signal light is amplified by the amplified primary pump light. Then, the signal light reaches the optical receiver 21 of the B station 20 through the transmission path. According to the second embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 72 for signal light amplification.

  FIG. 3 shows a third embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, The primary pumping light source 22 for signal light amplification, the secondary pumping light source 23 for pumping light amplification, the primary pumping light and the secondary pumping light are combined and input to the transmission line toward the A station 10 side. A signal light amplifying device 60 including a signal light amplifying optical fiber 61 installed on the transmission path between the B station 20 including the multiplexing means 24 and the A station 10 and the B station 20; A pumping light amplifying apparatus 50 including a pumping light amplification optical fiber 51 is formed on the station 20 side. In other words, the secondary pumping light source is arranged in the same station as the primary pumping light source in the signal light receiving side, and the pumping light amplifying device and the signal light amplifying device independent of the transmission path are arranged.

  First, the primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are multiplexed by the multiplexing means 24 and transmitted from the B station 20 through the transmission path. The excitation light amplification device 50 is reached. In the pumping light amplification optical fiber 51, the primary pumping light is amplified by the secondary pumping light. The amplified primary pump light reaches the signal light amplifier 60 through the transmission path. The primary pump light amplifies the signal light transmitted from the optical transmitter 11 and passing through the transmission path from the opposite side in the signal light amplification optical fiber 61. The amplified signal light reaches the optical receiver 21 of the B station 20 through the transmission path. According to the third embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 4 shows a fourth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, The primary pumping light source 22 for signal light amplification, the secondary pumping light source 23 for pumping light amplification, the primary pumping light and the secondary pumping light are combined and input to the transmission path toward the A station 10 side. Is installed in the transmission path between the B station 20 including the multiplexing means 24 and the A station 10 and the B station 20, includes the signal light amplification optical fiber 72 on the A station 10 side, and is excited on the B station 20 side. The signal light and pumping light amplifying device 70 includes an optical fiber 71 for optical amplification. That is, the secondary pumping light source is arranged in the same station as the primary pumping light source in the signal light receiving side, and the amplifier device including the pumping light amplifier device and the signal light amplifier device is arranged on the transmission line.

  First, the primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are multiplexed by the multiplexing means 24 and transmitted from the B station 20 through the transmission path. The signal light and pumping light amplifying device 70 is reached. Then, in the excitation light amplification optical fiber 71 on the B station 20 side, the primary excitation light is amplified by the secondary excitation light. The amplified primary pump light amplifies the signal light transmitted from the optical transmitter 11 and passing through the transmission path from the opposite side in the signal light amplification optical fiber 72. The amplified signal light reaches the optical receiver 21 of the B station 20 through the transmission path. According to the fourth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 72.

  FIG. 5 shows a fifth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pump light source 12 for signal light amplification, and a pump light amplifier. A secondary pumping light source 13, A station 10 including multiplexing means 14 for multiplexing signal light, primary pumping light, and secondary pumping light, an optical receiver 21 for receiving signal light, and for signal light amplification Primary pumping light source 22, secondary pumping light source 23 for amplifying pumping light, primary pumping light, secondary pumping light and signal light are combined and input to the transmission path toward the A station 10 side. The B station 20 including the multiplexing means 24, the pumping light amplifying device 50 including the pumping light amplification optical fiber 51 installed on the A station 10 side, and the pumping light amplification optical fiber 51 installed on the B station 20 side. Is installed between the pumping light amplifying device 50 'and the pumping light amplifying device 50'. It is, and a signal optical amplifier 60 for containing the signal light amplification optical fiber 61. That is, the secondary pumping light source and the primary pumping light source are arranged in the signal transmitting station and the signal receiving station, and the transmitting pumping light amplifying device, the signal light amplifying device, and the receiving side are independent of the transmission path. This is a configuration in which an excitation light amplifying device is arranged.

  First, in the A station 10, the signal light transmitted from the optical transmitter 11, the primary pump light transmitted from the primary pump light source 12, and the secondary pump light transmitted from the secondary pump light source 13. Are combined by the combining means 14 and reach the pumping light amplifier 50 through the transmission line. Here, in the excitation light amplification optical fiber 51, the primary excitation light is amplified by the secondary excitation light. Then, the primary excitation light and the signal light are directed to the signal light amplifying device 60. On the other hand, in the station B 20, the primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are combined by the combining unit 24. The pumping light amplifying device 50 ′ is reached through the transmission line. Here, in the excitation light amplification optical fiber 51 ′, the primary excitation light is amplified by the secondary excitation light. The amplified primary pump light travels to the signal light amplifier 60 through the transmission path. The primary pumping light amplified from both the input side and the output side arrives at the signal light amplifier 60. Thereby, the signal light is amplified in the signal light amplification optical fiber 61. The amplified signal light arrives at the optical receiver 21 in the B station 20 through the transmission path. According to the fifth embodiment, the primary pumping light is amplified by the secondary pumping light, and more power can be supplied to the signal light amplifying optical fiber 61 from both sides.

  FIG. 6 shows a sixth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. A secondary pumping light source 13, A station 10 including multiplexing means 14 for multiplexing signal light, primary pumping light, and secondary pumping light, an optical receiver 21 for receiving signal light, and for signal light amplification Primary pumping light source 22, secondary pumping light source 23 for amplifying pumping light, and combining means for combining the primary pumping light and the secondary pumping light and inputting them toward the A station 10 side to the transmission line B station 20 including 24, an excitation light amplification optical fiber 71 installed on the A station 10 side, an excitation light amplification optical fiber 71 ′ installed on the B station 20 side, and a signal light amplification optical fiber installed therebetween The signal light including the optical fiber 72 and the excitation light amplifying device 70 are configured. That is, the secondary pumping light source and the primary pumping light source are arranged in the signal transmission side station and the signal reception side station, and the transmission side pumping light amplifying device, the signal light amplifying device, and the receiving side pumping light are arranged on the transmission path. In this configuration, an amplifier including an amplifying device is arranged.

  First, in the A station 10, the signal light transmitted from the optical transmitter 11, the primary pump light transmitted from the primary pump light source 12, and the secondary pump light transmitted from the secondary pump light source 13. Are combined by the combining means 14 and reach the signal light and pumping light amplifying apparatus 70 through the transmission line. On the other hand, in the station B 20, the primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are combined by the combining unit 24. The signal light and the excitation light amplifying device 70 are reached through the transmission line. In the pumping light amplification optical fiber 71 on the A station 10 side of the signal light and pumping light amplification device 70, the primary pumping light is amplified by the secondary pumping light, and the signal light and pumping light amplification device 70 on the B station 20 side. Similarly, in the excitation light amplification optical fiber 71 ′, the primary excitation light is amplified by the secondary excitation light, and the amplified primary excitation light is a signal sandwiched between the excitation light amplification optical fibers. In the optical fiber 72 for optical amplification, the signal light is amplified. The amplified signal light arrives at the optical receiver 21 in the B station 20 through the transmission path. According to the sixth embodiment, the primary pumping light is amplified by the secondary pumping light, and more power can be supplied to the signal light amplifying optical fiber 71 from both sides.

  FIG. 7 shows a seventh embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the multiplexing means 14 for multiplexing the signal light and the primary pumping light, the B station 20 at the other end including the optical receiver 21 for receiving the signal light, A The pumping light amplification optical fiber 51 on the station 10 side and the secondary pumping light source 13 on the B station 20 side of the pumping light amplification optical fiber 51 are connected to the secondary pumping light source 13 and the secondary pumping light is directed to the A station 10 side. And a signal light amplifying device 60 including a signal light amplifying optical fiber 61 on the B station 20 side of the pumping light amplifying device 50. ing. In other words, the secondary pumping light source is placed in the same signal transmission side station as the primary pumping light, and both functions are provided as shown by the pumping light amplifying device independent of the transmission path and the signal light amplifying device or the dotted line in the figure. The secondary pumping light source is connected by a separate line so that the pumping light amplifying device is in the form of backward pumping.

  The signal light transmitted from the optical transmission device 11 and the primary pumping light transmitted from the primary pumping light source 12 are combined by the multiplexing means 14 and reach the pumping light amplifying device 50 through the transmission line, and the pumping light amplification light The light enters from the A station 10 side of the fiber 51. The secondary pumping light transmitted from the secondary pumping light source 13 is incident from the B station 20 side of the pumping light amplification optical fiber 51 via the multiplexing means 52 and is primary transmitted by the pumping light amplification optical fiber 51. Amplifies the excitation light. The signal light and the amplified primary pump light reach the signal light amplifier 60, and the signal light is amplified by the primary pump light in the signal light amplification optical fiber 61. The amplified signal light reaches the optical receiver 21 of the B station 20. According to the seventh embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 61.

  FIG. 8 shows an eighth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the multiplexing means 14 for multiplexing the signal light and the primary pumping light, the B station 20 at the other end including the optical receiver 21 for receiving the signal light, The pumping light amplification optical fiber 51 on the station 20 side and the secondary pumping light source 13 on the A station 10 side of the pumping light amplification optical fiber 51 are connected to the secondary pumping light, signal light, and primary pumping. A pumping light amplifying apparatus 50 including a multiplexing means 52 for multiplexing light, and a signal light amplifying apparatus 60 including a signal light amplifying optical fiber 61 on the B station 20 side of the pumping light amplifying apparatus 50. ing. In other words, the secondary pumping light source is placed in the same signal transmission side station as the primary pumping light source, and both functions are provided as shown by the pumping light amplifying device independent of the transmission path and the signal light amplifying device or the dotted line in the figure. The pumping light amplifying device has a configuration in which secondary pumping light sources are connected by separate lines so as to be in the form of forward pumping.

  The combining means 14 combines the signal light transmitted from the optical transmitter 11 and the primary pump light transmitted from the primary pump light source 12, and reaches the pump light amplifier 50 through the transmission path. The secondary pumping light transmitted from the secondary pumping light source 13 is combined with the signal light and the primary pumping light in the multiplexing means 52 of the pumping light amplifying apparatus 50, and in the pumping light amplification optical fiber 51, The primary excitation light is amplified by the secondary excitation light. The signal light and the amplified primary pump light reach the signal light amplifier 60, and the primary pump light amplifies the signal light in the signal light amplification optical fiber 61. The amplified signal light reaches the optical receiver 21 of the B station 20. According to the eighth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 9 shows a ninth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the multiplexing unit 14 that combines the primary pumping light and the secondary pumping light, the B station 20 including the optical receiver 21 that receives the signal light, and the signal light A pumping light amplifying apparatus 50 including a multiplexing unit 52 for combining the primary pumping light and the secondary pumping light, and a pumping light amplification optical fiber 51 closer to the B station 20 than the multiplexing unit 52; It is composed of a signal light amplification device 60 including a signal light amplification optical fiber 61 on the B station 20 side with respect to the light amplification device 50. In other words, the secondary pumping light source is placed in the same signal transmission side station as the primary pumping light source, and both functions are provided as shown by the pumping light amplifying device and the signal light amplifying device independent of the transmission path or the dotted line in the figure. The primary excitation light and the secondary excitation light are combined, and in the excitation light amplification device, the primary excitation light source and the secondary excitation light source are separated by separate lines so as to be in the form of forward excitation. Is a connected configuration.

  The signal light transmitted from the optical transmission device 11 reaches the pumping light amplification device 50 through the transmission path. On the other hand, the primary pumping light transmitted from the primary pumping light source 12 and the secondary pumping light transmitted from the secondary pumping light source 13 are combined by the combining means 14 and are transmitted through the transmission path. Reach 50. Here, the signal light, the primary pumping light, and the secondary pumping light are multiplexed by the multiplexing unit 52. Subsequently, in the excitation light amplification optical fiber 51, the secondary excitation light amplifies the primary excitation light. The amplified primary pumping light and signal light are sent to the signal light amplifying device 60 through the transmission line. In the signal light amplifying device 60, the primary excitation light amplifies the signal light in the signal light amplification optical fiber 61. The amplified signal light reaches the optical receiver 21 in the B station 20 through the transmission path. According to the ninth embodiment, since the primary pumping light is amplified by the secondary pumping light, further power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 10 shows a tenth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. Secondary excitation light source 13, combining means 14 for combining signal light, primary excitation light, and secondary excitation light, and further, primary excitation light source 12 ′, secondary excitation light source 13 ′, primary excitation light A station 10 composed of multiplexing means 14 ′ for multiplexing light and secondary pumping light, B station 20 including an optical receiver 21 for receiving signal light, and signal light and primary from the multiplexing means 14 Excitation light, secondary excitation light, and the primary excitation light and secondary excitation light from the multiplexing means 14 ', and the optical fiber for amplifying the excitation light on the B station 20 side. 51, and an optical fiber for signal light amplification on the B station 20 side of the pump light amplifier 50 from the pump light amplifier 50. And a signal optical amplifier 60 for containing the 61.

  First, the signal light transmitted from the optical transmitter 11, the primary pump light transmitted from the primary pump light source 12, and the secondary pump light transmitted from the secondary pump light source 13 are combined by the combining unit 14. Is combined. The primary pumping light transmitted from the primary pumping light source 12 'and the secondary pumping light transmitted from the secondary pumping light source 13' are combined by the multiplexing unit 14 '. The combined signal light and pumping light reach the multiplexing means 52 of the pumping light amplifying apparatus 50 through the transmission path and are combined. Subsequently, in the excitation light amplification optical fiber 51, the secondary excitation light amplifies the primary excitation light. The signal light and the amplified primary pump light reach the signal light amplifier 60 through the transmission line, and the signal light is amplified by the primary pump light in the signal light amplification optical fiber 61. The amplified signal light reaches the optical receiver 21 in the B station 20 through the transmission path. According to the tenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 11 shows an eleventh embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A B station 20 including a primary pumping light source 22 for signal light amplification, a secondary pumping light source 23 for pumping light amplification, a multiplexing unit 24 for multiplexing the primary pumping light and signal light, and the A station 10 side The signal light amplifying device 60 including the signal light amplifying optical fiber 61 and the pump light amplifying optical fiber 51 on the B station 20 side of the signal light amplifying device 60 and the secondary pump light on the transmission line B station And a pumping light amplifying apparatus 50 including a multiplexing means 52 for inputting toward the 20 side. In other words, the secondary pumping light source is placed in the same signal receiving station as the primary pumping light source, and both functions are provided as indicated by the pumping light amplifying device and the signal light amplifying device independent of the transmission path or the dotted line in the figure. And a secondary pumping light source connected by a separate line so that the pumping light amplifying device is in the form of forward pumping.

  The primary pumping light transmitted from the primary pumping light source 22 reaches the pumping light amplifying device 50 via the multiplexing means 24, and the secondary pumping light transmitted from the secondary pumping light source 23 is pumping light. The light enters the pumping light amplification optical fiber 51 from the side opposite to the primary pumping light via the multiplexing means 52 of the amplifying apparatus 50, and the primary pumping light is amplified by the secondary pumping light. The amplified primary pump light reaches the signal light amplifier 60 through the transmission path. From the opposite side, the signal light transmitted from the optical transmitter 11 reaches the signal light amplifier 60 through the transmission path. In the optical fiber 61 for signal light amplification of the signal light amplifier 60, the signal light is amplified by the primary signal light. The amplified signal light is received by the optical receiving device 21 via the pumping light amplifying device 50 and the multiplexing means 24 in the B station 20. According to the eleventh embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 12 shows a twelfth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A B station 20 including a primary pumping light source 22 for signal light amplification, a secondary pumping light source 23 for pumping light amplification, a multiplexing unit 24 for multiplexing the primary pumping light and signal light, and the A station 10 side Thus, the signal light amplifying device 60 including the signal light amplifying optical fiber 61, the pumping light amplifying optical fiber 51 on the A station 10 side on the B station 20 side of the signal light amplifying device 60, the signal light and the primary light The pumping light amplifying apparatus 50 includes a multiplexing unit 52 that combines the pumping light and the secondary pumping light. In other words, the secondary pumping light source is placed in the same signal receiving station as the primary pumping light source, and both functions are provided as indicated by the pumping light amplifying device and the signal light amplifying device independent of the transmission path or the dotted line in the figure. The pumping light amplifying device is configured such that a secondary pumping light source is connected by a separate line so as to be in the form of backward pumping.

  The primary pumping light transmitted from the primary pumping light source 22 reaches the pumping light amplifying device 50 through the multiplexing unit 24 and reaches the pumping light amplification optical fiber 51 through the multiplexing unit 52. Further, the secondary pumping light transmitted from the secondary pumping light source 23 enters the pumping light amplification optical fiber 51 via the multiplexing means 52 of the pumping light amplifying apparatus 50, and is generated by the secondary pumping light. The primary excitation light is amplified. The amplified primary pump light reaches the signal light amplifier 60 through the transmission path. From the opposite side, the signal light transmitted from the optical transmitter 11 reaches the signal light amplifier 60 through the transmission path. In the optical fiber 61 for signal light amplification of the signal light amplifier 60, the signal light is amplified by the primary signal light. The amplified signal light is received by the optical receiving device 21 via the pumping light amplifying device 50 and the multiplexing means 24 in the B station 20. According to the twelfth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 61.

  FIG. 13 shows a thirteenth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A B station 20 including a primary pumping light source 22 for signal light amplification, a secondary pumping light source 23 for pumping light amplification, a multiplexing unit 24 for multiplexing the primary pumping light and the secondary pumping light, and A A pumping light amplifying device 50 including a pumping light amplifying optical fiber 51 on the station 10 side, and a multiplexing means 52 for combining the primary pumping light, the secondary pumping light, and the signal light; The signal light amplifying apparatus 60 on the A station 10 side including the optical fiber 61 for signal light amplification is formed on the A station 10 side. In other words, the secondary pumping light source is placed in the same signal receiving station as the primary pumping light source, and both functions are provided as indicated by the pumping light amplifying device and the signal light amplifying device independent of the transmission path or the dotted line in the figure. The primary pumping light source and the secondary pumping light source are separated from each other so that the primary pumping light and the secondary pumping light are combined and the pumping light amplifying device is in the form of backward pumping. It is the structure connected by.

  The primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are multiplexed by the multiplexing means 24, and the pumping light amplification device 50 is transmitted through the transmission path. In the pumping light amplification optical fiber 51, the secondary pumping light amplifies the primary pumping light. The amplified primary excitation light reaches the signal light amplification optical fiber 61 of the signal light amplification device 60. On the other hand, when the signal light transmitted from the optical transmission device 11 reaches the signal light amplification optical fiber 61 of the signal light amplification device 60, the signal light is amplified by the primary pumping light. The amplified signal light is received by the optical receiving device 21 via the pumping light amplifying device 50. According to the thirteenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 14 shows a fourteenth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A primary pumping light source 22 for signal light amplification, a secondary pumping light source 23 for pumping light amplification, a multiplexing means 24 for multiplexing the primary pumping light and the secondary pumping light, and a primary pump for signal light amplification The B station 20 including the excitation light source 22 ′, the secondary excitation light source 23 ′ for amplifying the excitation light, and the combining means 24 ′ for combining the primary excitation light and the secondary excitation light, and the A station 10 side A pumping light amplifying device 50 including a pumping light amplifying optical fiber 51 and a multiplexing means 50 for combining the primary pumping light, the secondary pumping light, and the signal light, and the A station rather than the pumping light amplifying device 50. And a signal light amplifying device 60 including a signal light amplifying optical fiber 61. That.

  The primary pumping light transmitted from the primary pumping light source 22 and the secondary pumping light transmitted from the secondary pumping light source 23 are combined by the combining means 24 and combined by the pumping light amplifier 50 through the transmission path. The wave means 52 is reached. On the other hand, the primary pumping light transmitted from the primary pumping light source 22 ′ and the secondary pumping light transmitted from the secondary pumping light source 23 ′ are multiplexed by the multiplexing unit 24 ′, and the transmission path To the multiplexing means 52 of the pumping light amplifying apparatus 50. These excitation lights are amplified in the excitation light amplification optical fiber 51 by the secondary excitation light. The amplified primary pumping light reaches the signal light amplifying device 61 of the signal light amplifying device 60, and the signal light transmitted from the optical transmitting device 11 from the opposite side is the signal light amplifying light of the signal light amplifying device 60. The fiber 61 is reached. In the optical fiber 61 for signal light amplification, the signal light is amplified by the primary pumping light. The signal light is received by the optical receiving device 21 via the pumping light amplifying device 50 and the multiplexing means 24. According to the fourteenth embodiment, the primary pumping light is amplified by the secondary pumping light, and the power thereof is larger than that of the thirteenth embodiment. Therefore, the signal light amplifying optical fiber 61 is given more power. Can be supplied.

  FIG. 15 shows a fifteenth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, signal light and primary light. A station 10 including multiplexing means 14 for multiplexing excitation light, B station 20 including optical receiver 21 for receiving signal light, and C station 30 including secondary excitation light source 33 for amplifying excitation light A pumping light amplifying apparatus 50 including a pumping light amplifying optical fiber 51 on the A station 10 side, a multiplexing means 52 for combining the signal light, the primary pumping light, and the secondary pumping light, and pumping light amplification It is composed of a signal light amplifying device 60 including a signal light amplifying optical fiber 61 on the B station 20 side from the device. That is, the primary pumping light source is arranged in the station on the signal light transmitting side, the secondary pumping light source is arranged in a station other than the terminal station, and the pumping light amplifier and the signal light amplifier independent of the transmission path Alternatively, as shown by the dotted line in the figure, a device having both functions is arranged, and the pumping light amplifying device has a configuration in which a secondary pumping light source is connected so as to be in the form of backward pumping.

  The signal light transmitted from the optical transmitter 11 and the primary pumping light transmitted from the primary pumping light source 12 are multiplexed by the multiplexing unit 14 and reach the pumping light amplification optical fiber 51 of the pumping light amplifier 50. To do. On the other hand, the secondary pumping light is transmitted from the secondary pumping light source 33 of the C station 30 and reaches the pumping light amplification optical fiber 51 via the multiplexing means 52. In the pumping light amplification optical fiber 51, the primary pumping light is amplified by the secondary pumping light. The amplified primary pump light reaches the signal light amplification optical fiber 61 of the signal light amplifying apparatus 60 through the multiplexing means 52 together with the signal light, where the signal light is amplified by the primary pump light. The amplified signal light is received by the optical receiver 21. According to the fifteenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 16 shows a sixteenth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, signal light and primary light. A station 10 including multiplexing means 14 for multiplexing excitation light, B station 20 including optical receiver 21 for receiving signal light, and C station 30 including secondary excitation light source 33 for amplifying excitation light A pumping light amplifying apparatus 50 including a pumping light amplification optical fiber 51 on the B station 20 side, a multiplexing means 52 for multiplexing the signal light, the primary pumping light, and the secondary pumping light, and pumping light amplification It is composed of a signal light amplifying device 60 including a signal light amplifying optical fiber 61 on the B station 20 side from the device 50. That is, the primary pumping light source is arranged in the station on the signal light transmission side, the secondary pumping light is arranged in a station other than the terminal station, and the pumping light amplifier and the signal light amplifier independent of the transmission path Alternatively, as shown by the dotted line in the figure, a device having both functions is arranged, and the pumping light amplifying device has a configuration in which a secondary pumping light source is connected so as to be in the form of forward pumping.

The signal light transmitted from the optical transmitter 11 and the primary pumping light transmitted from the primary pumping light source 12 are multiplexed by the multiplexing unit 14 and reach the multiplexing unit 52 of the pumping light amplification device 50. On the other hand, secondary excitation light is transmitted from the secondary excitation light source 33 of the C station 30 and reaches the multiplexing means 52. The signal light, the primary pumping light, and the secondary pumping light are multiplexed by the multiplexing means 52, and then the primary pumping light is amplified by the secondary pumping light in the optical fiber 51 for amplifying pumping light. The amplified primary pump light reaches the signal light amplification optical fiber 61 of the signal light amplifier 60 together with the signal light, where the signal light is amplified by the primary pump light. The amplified signal light is received by the optical receiver 21. According to the sixteenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 61.

  FIG. 17 shows a seventeenth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light and an optical receiver 21 that receives the signal light. B station 20 including, a primary excitation light source 32 for signal light amplification, a secondary excitation light source 33 for amplification of excitation light, and a multiplexing means 34 for multiplexing the primary excitation light and the secondary excitation light. Pumping light amplifying apparatus 50 including pumping light amplification optical fiber 51 and multiplexing means 52 for combining primary pumping light, secondary pumping light, and signal light on the C station 30 and A station 10 side. And a signal light amplifying device 60 including a signal light amplifying optical fiber 61 on the B station 20 side with respect to the pumping light amplifying device 50. In other words, the secondary pump light and the primary pump light are placed in a station other than the terminal station, and both the pump light amplifier and signal light amplifier independent of the transmission path or the dotted line in the figure indicate And a pumping light amplifying apparatus in which the primary pumping light source and the secondary pumping light source are connected so as to be in the form of forward pumping.

  The signal light transmitted from the optical transmission device 11 reaches the multiplexing means 52 of the pumping light amplification device 50. On the other hand, the primary pumping light transmitted from the primary pumping light source 32 of the C station 30 and the secondary pumping light transmitted from the secondary pumping light source 33 are combined by the combining means 34 and transmitted through the transmission path. The multiplexing means 52 is reached. Subsequently, in the pumping light amplification optical fiber 51, the primary pumping light is amplified by the secondary pumping light, and in the signal light amplification optical fiber 61 of the signal light amplifier 60, the signal light is the primary pumping light. Is amplified by. The amplified signal light is received by the optical receiver 21 in the B station 20 through the transmission path. According to the seventeenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 18 shows an eighteenth embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. A secondary pumping light source 13, an A station 10 including multiplexing means 14 for combining the signal light, the primary pumping light, and the secondary pumping light, and a B station including an optical receiver 21 that receives the signal light A C station 30 including a primary pumping light source 32 for signal light amplification, a secondary pumping light source 33 for pumping light amplification, and multiplexing means 34 for multiplexing the primary pumping light and the secondary pumping light; A combining means 52 for combining the signal light, the primary pumping light and the secondary pumping light from the A station 10, and the primary pumping light and the secondary pumping light from the C station 30, and pumping light amplification light A pumping light amplifying apparatus 50 including a fiber 51, and an optical fiber for signal light amplification on the B station 20 side of the pumping light amplifying apparatus 50 And a signal optical amplifier 60 for containing one.

  The signal light transmitted from the optical transmitter 11 is combined by the multiplexing unit 14 together with the primary pump light transmitted from the primary pump light source 12 and the secondary pump light transmitted from the secondary pump light source 13. And reaches the multiplexing means 52 of the pumping light amplifying apparatus 50 through the transmission path. On the other hand, the primary pumping light source 32 in the C station 30 transmits primary pumping light, and the secondary pumping light source 33 transmits secondary pumping light, which is multiplexed by the multiplexing means 34 and transmitted through the transmission path. It reaches the multiplexing means 52 of the excitation light amplifying device 50. In the multiplexing means 52, the signal light, the primary pumping light, and the secondary pumping light are multiplexed, and then the primary pumping light is amplified by the secondary pumping light in the pumping light amplification optical fiber 51. The Then, the signal light is amplified by the primary excitation light in the signal light amplification optical fiber 61 in the signal light amplification apparatus 60 on the B station 20 side of the excitation light amplification apparatus 50. The amplified signal light is received by the optical receiver 21. According to the eighteenth embodiment, the primary pumping light is amplified by the secondary pumping light, and its power is larger than that of the seventeenth embodiment, so that the signal light amplifying optical fiber 61 is given more power. Can be supplied.

  FIG. 19 shows a nineteenth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A primary pumping light source 22 for signal light amplification, a B station 20 including multiplexing means 24 for combining the signal light and the primary pumping light, and a C station 30 including a secondary pumping light source 33 for pumping light amplification. A pumping light amplifying device 50 including a pumping light amplifying optical fiber 51 on the B station 20 side, a combining means 52 for multiplexing the signal light and the secondary pumping light, and the A station rather than the pumping light amplifying device 50. The signal light amplifying device 60 includes a signal light amplifying optical fiber 61 on the 10 side. In other words, the primary pumping light source is disposed in the station on the signal receiving side, the secondary pumping light source is disposed in a station other than the terminal station, and the pumping light amplifier and signal light amplifier independent of the transmission path or As shown by the dotted line in the figure, a device having both functions is arranged, and the pumping light amplifying device has a configuration in which a secondary pumping light source is connected by another line so as to be in the form of forward pumping.

  The primary pumping light transmitted from the primary pumping light source 22 reaches the pumping light amplification optical fiber 51 of the pumping light amplifying device 50 via the multiplexing means 24. On the other hand, when the secondary pumping light transmitted from the secondary pumping light source 33 of the C station 30 reaches the pumping light amplification optical fiber 51 through the multiplexing means 52 through the transmission path, the secondary pumping light is Amplifies the primary excitation light. The amplified primary pump light reaches the signal light amplification optical fiber 61 of the signal light amplification device 60 via the multiplexing means 52. From the opposite side, when the signal light transmitted from the optical transmission device 11 reaches the signal light amplification optical fiber 61 through the transmission line, the signal light is amplified by the primary pumping light, and the pumping light amplification device 50, the multiplexing The light is received by the optical receiver 21 via the means 24. According to the nineteenth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 61.

  FIG. 20 shows a twentieth embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A primary pumping light source 22 for signal light amplification, a B station 20 including multiplexing means 24 for inputting primary pumping light to the A station 10 side in the transmission path, and a secondary pumping light source 33 for pumping light amplification. A pumping light amplifying apparatus 50 including a pumping light amplifying optical fiber 51 on the A station 10 side, and multiplexing means 52 for inputting secondary pumping light toward the A station 10 side in the transmission path. And the signal light amplifying device 60 including the signal light amplifying optical fiber 61 on the A station 10 side of the pumping light amplifying device 50. In other words, the primary pumping light source is disposed in the station on the signal receiving side, the secondary pumping light source is disposed in a station other than the terminal station, and the pumping light amplifier and signal light amplifier independent of the transmission path or As shown by the dotted line in the figure, a device having both functions is arranged, and the pumping light amplifying device has a configuration in which a secondary pumping light source is connected by another line so as to be in the form of backward pumping.

  The primary pumping light transmitted from the primary pumping light source 22 reaches the pumping light amplification optical fiber 51 via the multiplexing unit 24 and the multiplexing unit 50 of the pumping light amplification device 50. On the other hand, when the secondary pumping light transmitted from the secondary pumping light source 33 of the C station 30 reaches the pumping light amplification optical fiber 51 through the multiplexing means 52 through the transmission path, the secondary pumping light is Amplifies the primary excitation light. The amplified primary excitation light reaches the signal light amplification optical fiber 61 of the signal light amplification device 60. From the opposite side, when the signal light transmitted from the optical transmission device 11 reaches the signal light amplification optical fiber 61 through the transmission line, the signal light is amplified by the primary pumping light, and the pumping light amplification device 50, the multiplexing means 24 is received by the optical receiving device 21 via 24. According to the twentieth embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the optical fiber 61 for signal light amplification.

  FIG. 21 shows a twenty-first embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, and an optical receiver 21 that receives signal light. B station 20 including, a primary excitation light source 32 for signal light amplification, a secondary excitation light source 33 for amplification of excitation light, and a multiplexing means 34 for multiplexing the primary excitation light and the secondary excitation light. A pumping light amplifying device 50 including a pumping light amplifying optical fiber 51 on the C station 30 and the A station 10 side, and a combining means 52 for inputting secondary pumping light toward the A station 10 side on the transmission line; It is composed of a signal light amplifying device 60 including a signal light amplifying optical fiber 61 on the A station 10 side with respect to the optical amplifying device 50. In other words, the primary pumping light source and the secondary pumping light source are arranged in a station other than the terminal station, and both the pumping light amplifying device and the signal light amplifying device independent of the transmission path or the dotted line in the figure indicate The pumping light amplifying device is connected by a separate line so that the pumping light amplifying device is in the form of backward pumping.

  The primary pumping light transmitted from the primary pumping light source 32 in the C station 30 and the secondary pumping light transmitted from the secondary pumping light source 33 are multiplexed by the multiplexing means 34 and pumped through the transmission path. When reaching the pumping light amplification optical fiber 51 on the A station 10 side via the multiplexing means 52 of the optical amplifying device 50, the secondary pumping light amplifies the primary pumping light. The amplified primary excitation light reaches the signal light amplification optical fiber 61 of the signal light amplification device 60. From the opposite side, the signal light transmitted from the optical transmitter 11 reaches the optical fiber 61 for signal light amplification 61 through the transmission path. Then, the primary pump light amplifies the signal light, and the amplified signal light is received by the optical receiver 21 of the B station 20 through the pump light amplifier 50. According to the twenty-first embodiment, since the primary pumping light is amplified by the secondary pumping light, more power can be supplied to the signal light amplifying optical fiber 61.

  FIG. 22 shows a twenty-second embodiment of the present invention. This optical fiber communication system includes an A station 10 including an optical transmitter 11 that transmits signal light, an optical receiver 21 that receives signal light, A primary pumping light source 22 for signal light amplification, a secondary pumping light source 23 for signal light amplification, and multiplexing means for inputting the primary pumping light and the secondary pumping light toward the A station 10 side on the transmission line. B station 20 including 24, a primary excitation light source 32 for signal light amplification, a secondary excitation light source 33 for amplification of excitation light, and a multiplexing means 34 for multiplexing the primary excitation light and the secondary excitation light. C station 30 including the pumping light amplification optical fiber 51 on the A station 10 side, and the primary pumping light and the secondary pumping light from the C station 30 are input to the A station 10 side on the transmission path. A pumping light amplifying apparatus 50 including a wave means 52, and a signal light amplifying light on the A station 10 side of the pumping light amplifying apparatus 50. And a signal optical amplifier 60 for containing Aiba 61.

  The primary pumping light transmitted from the primary pumping light source 22 in the B station 20 and the secondary pumping light transmitted from the secondary pumping light source 23 are combined by the combining unit 24 and excited through the transmission line. It reaches the multiplexing means 52 of the optical amplifying device 50. On the other hand, the multiplexing means 34 combines the primary pumping light transmitted from the primary pumping light source 32 and the secondary pumping light transmitted from the secondary pumping light source 33 in the C station 30, and the transmission path And reaches the multiplexing means 52 of the pumping light amplifying apparatus 50. The primary excitation light and the secondary excitation light are amplified in the excitation light amplification optical fiber 51 by the secondary excitation light. The amplified primary pump light travels to the signal light amplification optical fiber 61 of the signal light amplification device 60, and the signal light transmitted from the optical transmission device 11 of the A station 10 arrives from the opposite side. Then, the signal light is amplified to the primary pump light, and the amplified signal light is received by the optical receiver 21 in the B station 20 via the pump light amplifier 50. According to the twenty-second embodiment, the primary pumping light is amplified by the secondary pumping light and has a higher power than that of the twenty-first embodiment, so that the signal light amplifying optical fiber 61 is further improved. Power can be supplied.

  FIG. 23 shows a twenty-third embodiment of the present invention. This optical fiber communication system includes an optical transmitter 11 for transmitting signal light, a primary pumping light source 12 for signal light amplification, and a pumping light amplifier. The secondary pumping light source 13, the A station 10 including the multiplexing means 14 for multiplexing the primary pumping light, the secondary pumping light, and the signal light, the optical receiver 21 that receives the signal light, and the signal light amplification A primary pumping light source 22, a secondary pumping light source 23 for amplifying pumping light, a B station 20 including multiplexing means 24 for inputting primary pumping light to the transmission path toward the A station 10 side, and signal light amplification Primary excitation light source 32, secondary excitation light source 33 for amplifying excitation light, primary excitation light from primary excitation light source 32, and secondary excitation light from secondary excitation light source 33 are combined. The C station 30 including the multiplexing means 34, the primary excitation light source 42 for signal light amplification, and the excitation light amplification D station 40 including multiplexing means 44 for combining the next excitation light source 43, the primary excitation light from the primary excitation light source 42, and the secondary excitation light from the secondary excitation light source 43, and the A station On the 10th side, a pumping light amplifying device 50 'including a pumping light amplifying optical fiber 51' and a signal including a signal light amplifying optical fiber 71, a pumping light amplifying optical fiber 72, and a multiplexing means 73 on the B station 20 side. The light and pumping light amplifying device 70, and the pumping light amplifying device 50 'and the signal light and pumping light amplifying device 70 are arranged between the pumping light amplifying optical fiber 51 and the pumping light amplifying device 50 including the multiplexing means 52. Has been. In other words, the secondary excitation light source is arranged in the same signal transmission side station as the primary excitation light source, the secondary excitation light source and the primary excitation light source are arranged in two stations other than the terminal station, The next pumping light is placed in the same signal receiving station as the primary pumping light, and the pumping light amplifying device and the signal light amplifying device, which are independent of the transmission path, are provided with devices having both amplifying functions. In this configuration, two stations other than the station building and the signal light receiving station are connected by separate lines.

  In the A station 10, the signal light transmitted from the optical transmission device 11, the primary pump light transmitted from the primary pump light source 12, and the secondary pump light transmitted from the secondary pump light source 13 are: When combined with the combining means 14 and reaches the pumping light amplification device 50 ′ through the transmission line, the secondary pumping light amplifies the primary pumping light in the pumping light amplification optical fiber 51 ′. The amplified primary pumping light and signal light reach the multiplexing means 52 of the pumping light amplifier 50. On the other hand, in the C station 30, the primary pumping light transmitted from the primary pumping light source 32 and the secondary pumping light transmitted from the secondary pumping light source 33 are multiplexed by the multiplexing unit 34, and the transmission path The signal light from the A station 10, the primary excitation light, and the secondary excitation light are multiplexed. Subsequently, in the excitation light amplification optical fiber 51, the secondary excitation light amplifies the primary excitation light. In the station B, the primary pumping light is transmitted from the primary pumping light source 22 and reaches the multiplexing unit 73 of the signal light and pumping light amplifying device 72 via the multiplexing unit 24. The secondary excitation light source 23 reaches the multiplexing means 73 directly. In the D station 40, the primary pumping light transmitted from the primary pumping light source 42 and the secondary pumping light transmitted from the secondary pumping light source 43 are combined by the combining unit 44 and transmitted through the transmission path. The multiplexing means 73 is reached. Then, in the excitation light amplification optical fiber 72, the secondary excitation light amplifies the primary excitation light. In the signal light amplification optical fiber 71, the primary pumping light coming from both sides amplifies the signal light. The amplified signal light is received by the optical receiver 21. According to the twenty-second embodiment, the primary pumping light is amplified by the secondary pumping light, and considerable power can be supplied from both sides of the optical fiber 71 for signal light amplification.

  It is preferable that the pumping light amplification optical fiber 51 is doped with thulium, and the signal light amplification optical fiber 61 is doped with erbium.

1 is a block diagram of an optical fiber communication system showing a first embodiment of the present invention. It is a block diagram of the optical fiber communication system which shows the 2nd Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 3rd Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 4th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 5th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 6th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 7th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 8th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 9th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 10th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 11th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 12th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 13th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 14th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 15th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 16th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 17th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 18th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 19th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 20th Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 21st Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 22nd Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows the 23rd Embodiment of this invention. It is a block diagram of the optical fiber communication system which shows a prior art example. It is a block diagram of the optical fiber communication system which shows a prior art example. It is a block diagram of the optical fiber communication system which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Optical transmitter 12,12 ', 22,22', 32,42 Primary excitation light source 13,13 ', 23,23', 33,43 Secondary excitation light source 21 Optical receiver 51,51 ', 71, 71 ′ optical fiber for pumping light amplification 61, 72 optical fiber for signal light amplification

Claims (4)

In an optical fiber communication system that performs communication between two terminal stations installed at both ends of an optical fiber that transmits signal light having a wavelength of 1550 nm ,
Signal light amplification excitation light output means for outputting signal light amplification excitation light having a wavelength of 1480 nm to the optical fiber;
Excitation light amplification excitation light output means for outputting excitation light amplification light having a wavelength of 1400 nm to the optical fiber;
A signal light amplifying means comprising an optical fiber doped with at least one erbium that is installed in the middle of the optical fiber and amplifies the signal light when the signal light amplification excitation light and the signal light are superimposed and inputted. When,
Installed in the middle of the optical fiber, when the pumping light for pumping light amplification and the pumping light for signal light amplification are superimposed and input, at least one thulium is added to amplify the pumping light for signal light amplification. An optical fiber communication system comprising: a pumping light amplifying means for amplifying signal light comprising an optical fiber. An optical fiber connected from at least one of the pumping light output means for signal light amplification and the pumping light output means for pumping light amplification to the signal light amplification means or the pumping light amplification means for signal light amplification; The optical fiber communication system according to claim 1. At least one of the signal light amplification excitation light output means and the excitation light amplification excitation light output means is installed in a station other than the terminal station, and the signal light amplification means or the signal light amplification The optical fiber communication system according to claim 1, further comprising an optical fiber connected to the pumping light amplifying means. The optical fiber communication system according to any one of claims 1 to 3, wherein the signal light amplification means and the excitation light amplification means for signal light amplification are combined into one device.

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