JP3478460B2 - Optical line test system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical line test system used in the optical communication field. In particular, with regard to the optical line test method in an optical communication system using an optical fiber as a medium, the core of any optical fiber can be compared from a plurality of cores without affecting communication even when the communication line is in use. The system configuration. 2. Description of the Related Art As an optical line test system, for example, as shown in FIG. 2, a system has been proposed in which an optical fiber cable is tested and monitored in a state where a communication line is used. No. 63-186169 "Optical line test method"). In FIG. 2, two transmission devices 1 and 8 for performing optical communication using an optical fiber 5 as a medium, an optical coupler 4 for inserting a test light into the optical fiber 5, and a device immediately before the two transmission devices 1 and 8. An optical filter that transmits communication light and blocks test light,
7 are provided. The optical coupler 4 has four input / output ports a, b,
The optical fiber 5 for optical communication is connected to the ports a and c, and 1 × N is connected to the ports b and d.
Is connected to a movable side of the core wire selecting device 10, and a stabilizing light source 9 that outputs modulated light in a longer wavelength band than communication light as test light is connected to the movable side of the core wire selecting device 10. [0005] Here, when comparing the core of any optical fiber 5 in the optical fiber cable 6, the b
Core selection device 1 to be connected to a port and stabilized light source 9
Operate 0. In addition, when a core of any optical fiber 5 in the optical fiber cable 3 is checked, the core selecting device 10 is operated so as to connect the d port of the optical coupler 4 to the stabilized light source 9. [0006] By outputting modulated light in a longer wavelength band than the communication light from the stabilized light source 9, test light can be transmitted into the optical fiber 5. The worker can detect the test light transmitted from the cord by bending the optical fiber 5 at a constant radius that does not affect the optical communication (for example, see the 1983 IEICE Transactions, Method of improving coupling loss of optical fiber contrast device "). [0007] In this way, even if the communication line is in use, it is possible to compare the optical fibers of any of the plurality of optical fibers without affecting the communication. However, in the above-described optical line test method, the optical fiber 5 on the side of the optical fiber cable 3 is referenced with reference to the position of the optical coupler 4 before performing the optical fiber line comparison.
It is necessary to know in advance whether the control is the core control of the optical fiber or the core control of the optical fiber 5 on the optical fiber cable 6 side. Further, the core wire selecting device 10 needs to be connected to both the b port and the d port of the optical coupler 4. The present invention has been made in view of the above circumstances, and has as its object to reduce the size and cost of an optical line test system. In order to achieve the above object, according to the present invention, there are provided two transmission devices for performing optical communication using an optical fiber as a medium, an optical coupler for inserting test light into the optical fiber, Immediately before the two transmission devices, optical filters that transmit communication light and block test light are provided.
Two input / output ports are provided, two of which are connected to an optical fiber for optical communication, and one of the remaining ports is connected to a 1 × N core selection device, and the movable core selection device is movable. On the side, a stabilized light source that outputs modulated light in a longer wavelength band than the communication light is connected as the test light, and the other end of the optical coupler is connected.
One is the port to connect the optical filter which reflects only the test beam, ahead of the optical filter is characterized in that non-reflecting end to absorb both communication light, the test light is connected. According to the present invention, since it is not necessary to confirm which optical fiber cable side the optical fiber is based on the position of the optical coupler before performing optical fiber line contrast, the work efficiency is extremely high. Can be improved. Further, since only one port of the optical coupler needs to be connected to the core selection device, the size and economy of the core selection device can be reduced. Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is a block diagram showing an optical line test system according to a first embodiment of the present invention. In this embodiment,
Two transmission devices 1 and 8 for performing optical communication using an optical fiber 5 as a medium, and an optical coupler 4 for inserting test light into the optical fiber 5
And optical filters 2 and 7 that transmit communication light and block test light immediately before the two transmission devices 1 and 8, respectively. The optical coupler 4 has four input / output ports a, b, c, and d, of which the optical fibers 5 for performing optical communication are connected to the ports a and c, and 1 × N is connected to the port b. And a stabilizing light source 9 for outputting a modulated light in a longer wavelength band than the communication light as test light is connected to a movable side of the core wire selecting device 10, and a test light is connected to d port. An optical filter 11 that reflects only light is connected, and a non-reflection end 12 that absorbs both communication light and test light is connected to the end of the optical filter. As a procedure for performing the core wire comparison, first, the core wire selection device 10 operates so as to connect the stabilized light source 9 and the optical coupler 4. Next, the stabilizing light source 9 outputs a test light in response to an instruction from the operator. Then, the test light is transmitted to the cord selecting device 10.
And is distributed by the optical coupler 4 via the port c and output from the port c and the port d. The test light output from the port c propagates through the optical fiber 5 toward the transmission device 8. The test light output from the d port is reflected by the optical filter 11 and returned to the optical coupler 4. Then, the test light returned from the optical filter 11 is distributed again by the optical coupler 4, a part is output from the port a, and propagates through the optical fiber 5 toward the transmission device 1. The test light propagating toward the transmission devices 1 and 8 is cut off by the optical filters 2 and 7, and thus does not affect optical communication. The worker bends the optical fiber 5 at a constant radius that does not affect optical communication, so that the test light transmitted from the cord can be detected. In this manner, even if the communication line is in use, the optical fiber can be compared with any optical fiber from among the plurality of optical fibers without affecting communication. As is apparent from the present embodiment, before performing the optical fiber alignment, the optical fiber 5 on the optical fiber cable 3 side or the optical fiber cable 6 side is determined based on the position of the optical coupler 4. Since it is not necessary to check whether the optical fiber 5 is the core line contrast, the work efficiency can be greatly improved. Also, since only the b port of the optical coupler 4 needs to be connected to the core selection device 10, the core selection device can be reduced in size and economical. Second Embodiment FIGS. 3 and 4 show an optical waveguide and an optical filter used in an optical line test system according to a second embodiment of the present invention. In this embodiment, as shown in FIG.
The functions of the optical coupler 4 and the non-reflective end 12 of the first embodiment are realized by arranging the optical waveguides 13 in an array at a small interval. As shown in FIG. 4, the optical filter 11 disposed at the d port of the optical waveguide 13 is formed by removing a part of a thin film-shaped optical filter having a wavelength selecting function. It is manufactured by forming a portion where the interference film exists and a portion where the interference film does not exist. As a method of giving wavelength selectivity to a specific optical waveguide of the optical waveguide 13, for example, a configuration can be adopted in which a multilayer film-removed portion that does not have a wavelength selecting function is disposed at a predetermined position of the optical waveguide (Japanese Patent Application No. 2002-214873). Hei 5-15
No. 6509, “Optical filter and manufacturing method thereof”). In the case of this embodiment, as shown in FIG. 3, the optical coupler 4, the optical filter 11, and the non-reflection end 12 of the four cores in the first embodiment can be mounted on one optical waveguide. Extremely small size and economy can be achieved. Embodiment 3 FIG. 5 shows an optical waveguide used in an optical line test system according to a third embodiment of the present invention.
In the present embodiment, similarly to the second embodiment, the functions of the optical coupler 4 and the non-reflection end 12 of the first embodiment are realized by arranging the arrayed optical waveguides 13 at a minute interval. . Further, as the optical filter 11 for adding a wavelength selecting function to the d port of the optical waveguide 13, a grating is formed by irradiating an excimer laser through a phase mask. In this embodiment, as shown in FIG. 5, the optical coupler 4, the optical filter 11, and the non-reflection end 12 for the four cores in the first embodiment can be mounted on one optical waveguide, so that it is extremely compact and economical. Can be achieved. Further, as compared with the second embodiment, since there is no work of inserting the optical filter 11, the manufacturing cost is reduced and the economy can be improved. As a method of manufacturing the grating on the optical waveguide 13, it is particularly preferable to subject the quartz-based waveguide film doped with germanium to high-pressure hydrogen gas treatment before irradiating the waveguide film with an excimer laser. . This allows
This has the effect of dramatically reducing the light reflection intensity in a specific wavelength region in the ultraviolet-visible reflection spectrum (1996).
Spring Meeting of IEICE General Conference, SB11-5 "Production and evaluation of quartz waveguide grating"). As described above, according to the present invention, it is not necessary to confirm which optical fiber cable side based on the position of the optical coupler before performing optical fiber line contrast. ,
Work efficiency can be extremely improved. Also, since only one port of the optical coupler needs to be connected to the core selection device, the core selection device can be reduced in size and economical.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an optical line test system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a conventional optical line test system. FIG. 3 is an explanatory diagram showing an optical waveguide used in an optical line test system according to a second embodiment of the present invention. FIG. 4 is an explanatory diagram showing an optical filter used in an optical line test system according to a second embodiment of the present invention. FIG. 5 is an explanatory diagram showing an optical waveguide used in an optical line test system according to a third embodiment of the present invention. [Description of Signs] 1,8 Transmission device 2,7 Optical filter 3,6 Optical fiber cable 4 Optical coupler 5 Optical fiber 9 Stabilized light source 10 1 × N core selection device 11 Optical filter 12 that reflects only test light 12 Communication Non-reflection end 13 that reflects both light and test light Arrayed optical waveguides arranged with a minute gap

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-1632 (JP, A) JP-A-7-83795 (JP, A) JP-A-7-12680 (JP, A) JP-A-8- 149075 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 10/00-10/28 G01M 11/00-11/08

Claims (1)

(57) [Claims] [Claim 1] Two transmission devices that perform optical communication using an optical fiber as a medium, an optical coupler that inserts test light into the optical fiber, and a communication device immediately before the two transmission devices. Optical filters are provided to transmit light and block test light.Optical couplers provide four input / output ports, two of which are connected to optical fibers for optical communication, and one of the remaining ports is connected to one port. Is connected to a 1 × N core selection device, and to the movable side of the core selection device, a stabilizing light source for outputting a modulated light in a longer wavelength band than the communication light is connected as a test light, and the remaining optical coupler is connected . An optical filter that reflects only test light is connected to one port,
An optical line test system, wherein a non-reflection end that absorbs both communication light and test light is connected to the end of the optical filter .