JP2006322843A - Optical transmission loss measuring system, its measuring system, cap, and optical transmission loss measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the loss of an optical transmission path in a short time at low cost. <P>SOLUTION: A measuring system 1 is arranged on an one-sided end of the optical transmission path 2 of a measured object, and a cap 32 with a reflection mirror is mounted on the other end. When a signal light output from LD 11 of the measuring system 1 passes the optical transmission path 2 through an optical isolator 12 and a triangular prism 13, it is reflected by the reflection mirror 32 provided on the cap 32 with the reflection mirror, passes the optical transmission path 2 and reaches the measuring system 1. Coming return light is guided by the triangular prism 13 and the intensity is detected in PD 14. In a control unit 15, a loss amount of the optical transmission path 2 is calculated on the basis of the intensity of the emission light from LD 11, the intensity of detected return light and a loss value of each connection part, the loss amount being a calculated result is output to a display part 154. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical transmission loss measuring system for measuring the loss of an optical transmission line such as an optical fiber, a measuring device and a cap thereof, and an optical transmission loss measuring method.

  Conventionally, for measuring the loss of an optical transmission line, a transmitter is connected to one end of the optical transmission line, a receiver is connected to the other end, and power is sent from the transmitter to the receiver, and then sent from the transmitter. A direct measurement method has been used in which the amount of loss is calculated by comparing the received power with the power received by the receiver (see, for example, Patent Document 1).

JP-A-6-17848

  In the above conventional measurement method, it is necessary to place active devices (devices that require power) at both ends, so be sure to turn on the power at one end (often a transmitter) before measuring. Turn on the power at one end (in this case, the receiver) and measure the loss. At this time, since it is necessary to operate both apparatuses substantially simultaneously, two workers are required. Moreover, although it is possible to measure even one worker, in this case, each time measurement is performed, the devices attached to both ends must be operated, resulting in poor work efficiency and labor. In addition, when one person wants to measure a plurality of optical transmission line losses within a short time, a plurality of transmitters must be set at one end of the optical transmission line, resulting in an increase in the cost of the measurement system.

  Therefore, the present invention has been made paying attention to the above circumstances, and the object of the present invention is an optical transmission loss measuring system capable of measuring a loss of an optical transmission line in a short time at a low cost and its measurement. An object is to provide an apparatus, a cap, and an optical transmission loss measurement method.

  In order to achieve the above object, an optical transmission loss measuring system according to the present invention is installed at one end of an optical transmission path to be measured, and measures the loss of the optical transmission path, and the other end of the optical transmission path. And a cap having a reflection mirror on the inner surface thereof in contact with the end face of the optical transmission path. The measuring apparatus includes an emitted light generating means for generating light of a certain intensity for measuring the loss of the optical transmission line, and the emitted light is incident on one end of the optical transmission line, and the one end of the optical transmission line An optical device for deriving reflected light from the reflecting mirror emitted from the optical device, detecting the intensity of the reflected light derived from the optical device, and based on the intensity of the emitted light and reflected light, the optical transmission path The amount of loss is calculated.

  Further, a measuring apparatus according to the present invention is installed at one end of an optical transmission line to be measured, and is attached to the measuring apparatus for measuring the loss of the optical transmission line and the other end of the optical transmission line, and the optical transmission line A measuring device used in an optical transmission loss measuring system comprising a cap having a reflection mirror on the inner surface in contact with the end surface of the optical output device, wherein the emitted light generates light of a constant intensity for measuring the loss of the optical transmission line A generating unit; and an optical device that makes the emitted light incident on one end of the optical transmission path and derives the reflected light emitted from the one end of the optical transmission path. Then, the intensity of the reflected light derived by the optical device is detected, and the loss amount of the optical transmission path is calculated based on the intensity of the emitted light and the reflected light.

  The cap according to the present invention includes a measuring device that is installed at one end of the optical transmission line to be measured and measures the loss of the optical transmission line, and a cap that is attached to the other end of the optical transmission line. The cap used in the optical transmission loss measuring system is provided with a reflection mirror on the inner surface in contact with the end face of the optical transmission path.

  In the optical transmission loss measuring method according to the present invention, a reflection mirror is attached to one end of an optical transmission line to be measured, and light having a certain intensity for measuring the loss of the optical transmission path is sent to the other end of the measurement target. The light reflected from the reflection mirror is taken out from the same end, the intensity of the reflected light is detected, and the loss amount of the optical transmission path is calculated based on the intensity of the emitted light and the reflected light. Is.

  According to the optical transmission loss measurement system, the measurement device and the cap thereof, and the optical transmission loss measurement method of the above invention, by attaching a reflection mirror to one end of the optical transmission path, the emitted light emitted from the measurement device is It passes through the optical transmission line from one end, is reflected by the reflection mirror, and passes again through the optical transmission line. Then, in the measuring device, the transmission loss of the optical transmission line can be measured by detecting the intensity of the return light. By configuring in this way, it is not necessary to install and operate both the transmission side and the reception side devices as in the conventional case, so that it is possible to efficiently measure the transmission loss of the optical transmission line at low cost. Become.

Further, the cap is characterized by having the following various configurations.
In the first configuration, when the optical transmission line is an optical fiber cable, and an end portion of the optical fiber cable is in a bare wire state, an insertion hole into which the bare wire portion is inserted is formed. A jig formed by fixing the reflection mirror at the end in the hole, and the core end of the optical fiber cable fixed to the jig with the bare wire portion inserted into the insertion hole. And a stopper.

  By configuring in this way, transmission loss can be measured even when the optical fiber cable to be measured is not terminated. In addition, since the end portion of the optical fiber cable is fixed by the stopper, the optical fiber cable core wire does not come out of the insertion hole, and measurement can be performed with higher accuracy. Further, if a matching agent is previously loaded in the insertion hole, the end face of the optical fiber cable and the reflection mirror are more closely attached, and the occurrence of irregular reflection or the like can be suppressed.

In the second configuration, when the optical transmission line is an optical fiber cable, and a female connector is attached to the end of the optical fiber cable, a male connector-shaped jig provided with a convex portion to be inserted into the female connector. The reflection mirror is attached to the tip of the convex portion so as to be joined to the end face of the optical fiber cable.
With this configuration, even when a female connector is attached to the end of the optical fiber cable to be measured, it is simple and efficient to simply insert a convex portion having a reflection mirror at the tip into the female connector. Transmission loss can be measured.

  Therefore, according to the present invention, it is possible to provide an optical transmission loss measuring system, its measuring device and cap, and an optical transmission loss measuring method capable of measuring the optical transmission line loss in a short time at a low cost. .

FIG. 1 is a block diagram showing an embodiment of an optical transmission loss measuring system according to the present invention. This system has an optical transmission line 2 such as an optical fiber or a waveguide as a measurement target, and includes a measurement device 1 and a cap 3 with a reflection mirror.
A measuring device 1 that generates measurement light is disposed at one end of the optical transmission line 2, and a cap 3 with a reflecting mirror is attached to the opposite end. The cap 3 with a reflection mirror is formed so that the light transmission path 2 is in close contact with the inside, and has a reflection mirror 32 having a high reflectance on the inner surface in contact with the end face of the light transmission path 2. The signal light emitted from the measuring device 1 to the optical transmission path 2 is reflected by the reflection mirror 32 and passes through the optical transmission path 2 again.

  The measuring apparatus 1 includes a light source (LD) 11 that generates signal light for measurement, an optical isolator 12 that blocks return light, a triangular prism 13 that demultiplexes outgoing light and return light, and return light. It includes a light intensity detector (PD: Photo Diode) 14 that detects the intensity, and further includes a control unit 15 that calculates the loss amount of the optical transmission path 2 and displays the calculation result.

  The control unit 15 includes a central processing unit (CPU) 151 such as a microprocessor, and a memory 152, a calculation unit 153, and a display unit 154 are connected to the CPU 151. The memory 152 stores known parameters including the intensity of emitted light and the loss value of each connection portion. The display unit 154 is configured with a liquid crystal display or the like, and displays the calculation result output from the calculation unit 153. Further, the calculation unit 153 compares the intensity of the reflected light detected by the PD 14 with the intensity of the emitted light output from the LD 11 and calculates the loss amount of the optical transmission line 2. Here, a calculation method of the loss amount performed by the calculation unit 153 will be described.

FIG. 2 is a diagram illustrating a calculation model of the loss amount of the optical transmission line 2.
The insertion loss of the optical isolator 12 is Li (dB), the absorption loss generated in the optical demultiplexing circuit 13 is Lp (dB), the loss that occurs when the optical transmission line 2 and the main unit 1 are coupled is Lc (dB), The transmission loss of the transmission line 2 is Lx (dB), the loss that occurs when the reflection mirror 32 reflects light is Lm (dB), and the loss that occurs when the direction of the returning light is changed by the optical demultiplexing circuit 13 Let Lh (dB).

  Further, the power of light generated by the light source 11 is Ps (dBm), the power after passing through the optical isolator 12 is P1 (dBm), the power after passing through the optical demultiplexing circuit 13 is P2 (dBm), and optical transmission is performed. The power after coupling with the path 2 is P3 (dBm), the power when reaching the opposite side of the optical transmission path 2 is P4 (dBm), and the power of the light reflected by the reflection mirror 32 and returned is P5. (DBm), where P6 (dBm) is the power when the direction is changed by the optical demultiplexing circuit and enters the PD 14, the following equation is established.

P1 = Ps-Li
P2 = P1-Lp
P3 = P2-Lc
P4 = P3-Lx
P5 = P4-Lm
P6 = P5-Lx-Lc-Lp-Lh
Lx = Ps-Li-Lp-Lc-Lx-Lm-Lc-Lp-Lh-P6
Therefore, the transmission line loss Lx is obtained as follows.

2Lx = Ps-Li-Lp-Lc-Lm-Lc-Lp-Lh-P6
Lx = (Ps-Li-Lp-Lc-Lm-Lc-Lp-Lh-P6) / 2
Here, Ps is the output value of the light source 11, P6 is the light reception value of the photodiode 14, and all other loss values are known fixed values, so Lx can be obtained from the above equation.

By the way, in this measuring apparatus 1, since the signal light output from the LD 11 and the reflected light from the reflecting mirror 32 pass through the same end face, it is necessary to guide the reflected light to the PD 14 using a half mirror or the like. . FIG. 3 shows an example of the structure of a triangular prism using a half mirror.
In the figure, the signal light incident surface 131 of the triangular prism 13 is provided with an AR (Anti-Reflective) coating so that the signal light incident from the LD 11 is not reflected outside the prism. Further, since the signal light incident surface 131 also functions to reflect the return light from the optical transmission path 2 to the PD 14, a reflection film is also provided at the same time.

  On the other hand, the return light incident surface 132 has an AR coating on the outside of the prism so that the reflected light returning from the light transmission path 2 is not reflected out of the triangular prism 13. With such a structure, the light returning from the reflection mirror 32 can be redirected and incident on the PD 14 to measure the intensity of the return light.

The structure of the cap 3 with a reflecting mirror will be described with reference to FIGS.
FIG. 4 is an example of a structure when the optical transmission line 2 is terminated. For example, when the optical fiber is terminated by a connecting optical connector (ferrule), the reflection mirror 32 is installed in the back of the insertion portion having an inner diameter matching the diameter of the ferrule 21 on the cap 3A with the reflection mirror. The reflecting mirror 32 is fixed so as to be parallel to the end face of the ferrule 21 so that the reflecting mirror 32 is in close contact with the end face of the ferrule 21.

  On the other hand, FIG. 5 is an example of the structure of the cap 3 with a reflecting mirror when the optical transmission line 2 is not terminated. In this case, it is necessary to slightly peel off the coating of the fiber core wire (coated core wire) 22. Then, the end surface of the fiber core wire (bare wire) 23 with the coating removed is trimmed with a fiber cutter or the like. And it inserts in the cap 3B with a reflecting mirror as shown in FIG. The cap 3B with the reflection mirror is provided with an insertion hole 31 having a taper so that the bare wire 23 can be easily inserted, and the reflection mirror 32 is installed in the back thereof. As in FIG. 4, the surface of the reflection mirror 32 is fixed at a position parallel to the cut surface so as to be in close contact with the cut surface of the bare wire 23. Further, since the end face of the bare wire 23 is unpolished, an alignment agent 33 is previously loaded in the insertion hole 31 for accommodating the bare wire 23 so as to be more closely attached to the reflecting mirror 32, and irregular reflection or the like occurs. To prevent. Furthermore, a stopper 34 for fixing the coated core wire 22 is provided so that the coated core wire 22 does not come out of the insertion hole 31.

  FIG. 6 shows a dummy with a reflecting mirror that is used in a state where the optical transmission line 2 is terminated and accommodated in an optical outlet, an optical outlet, or an optical rosette, and a female connector-shaped ferrule connection optical adapter 4 is mounted. An example of the optical connector 3C will be described. The dummy optical connector 3 </ b> C with a reflecting mirror is a male connector having a ferrule-shaped convex portion that is inserted into the ferrule connection optical adapter 4. At this time, since the optical transmission line 21 to be measured has already been terminated using the ferrule 21, the reflection mirror 32 is pasted on the end face of the convex portion provided in the dummy optical connector 3C with the reflection mirror to connect the ferrule. By attaching to the optical adapter 4, the ferrule 21 to be measured and the reflection mirror 32 are in close contact with each other, and the loss of the optical transmission line 2 can be measured.

Next, the operation of the optical transmission loss measurement system configured as described above will be described. FIG. 7 is a flowchart showing the operation procedure and contents of the control unit 15 shown in FIG.
First, the signal light emitted from the LD 11 prior to this passes through the optical isolator 12 provided to block the reflected light, and further passes through the triangular prism 13 and then enters the optical transmission line 2. Since the cap 3 with the reflection mirror is attached to the end of the optical transmission path 2, the signal light that has arrived from the optical transmission path 2 is reflected by the reflection mirror 32, passes through the optical transmission path 2 again, and is measured. 1 arrives. The incoming signal light has its traveling direction changed by the half mirror and is received by the PD 14. The PD 14 detects the intensity of the received signal light and inputs it to the control unit 15.

  In response to this, the CPU 151 of the control unit 15 acquires the intensity of the reflected light detected by the PD 14 in step S7a. Then, in step S7b, known parameters such as the intensity of the emitted light and the loss value of each connection portion are read from the memory 152. Then, the process proceeds to step S7c, and the calculation unit 153 calculates the loss amount of the optical transmission line 2 based on the acquired reflected light intensity and the read-out known parameter. In step S7d, the control unit 151 causes the display unit 154 to display the calculated loss amount.

  As described above, in this embodiment, the measuring device 1 is arranged at one end of the optical transmission line 2 to be measured, and the cap 32 with the reflection mirror is attached to the other end. When the signal light output from the LD 11 of the measuring apparatus 1 passes through the optical transmission path 2 via the optical isolator 12 and the triangular prism 13, it is reflected by the reflection mirror 32 provided on the cap 32 with the reflection mirror and transmitted again. It passes through the path 2 and arrives at the measuring device 1. The incoming return light is guided by the triangular prism 13 and the intensity is detected at the PD 14. The control unit 15 calculates the loss amount of the optical transmission line 2 based on the intensity of the emitted light from the LD 11, the intensity of the detected return light, and the loss value of each connection portion, and the loss amount as a calculation result Is output to the display unit 154.

  Therefore, according to this embodiment, the cap 3 with a reflective mirror that can be manufactured at low cost is used for optical transmission such as an optical fiber when constructing an optical network such as an optical fiber or the like in a premises / home. By simply attaching to one end of the path 2, the loss of the optical transmission path can be measured easily and efficiently using the measuring device 1.

  If this invention is utilized, it becomes possible to perform the opening test after indoor optical wiring efficiently. For example, the present invention is particularly effective for a star wiring opening test such as an optical home network where optical cores from each room are finally concentrated on a home gateway. At the time of wiring, if a cap with a reflection mirror is attached to the optical fiber or ferrule of each room, and the measuring device of the present invention is used at the location where the wiring finally concentrates, the measurement can be performed in a short time and the workability is high.

  Also, as shown in FIGS. 4 to 6, only the cap 3 with a reflecting mirror corresponding to the wiring state of the optical transmission path 2 is attached regardless of whether termination processing is performed during optical wiring. The transmission loss of the optical transmission line 2 can be easily measured using the measuring device 1 of the present invention.

The present invention is not limited to the above embodiment. The present invention can be applied to all network wirings using optical fibers, and can also be applied to loss measurement of optical transmission lines such as optical waveguides as well as optical fibers.
In addition, the configuration of the measuring device 1 and the cap 3 with the reflection mirror, the processing procedure in loss measurement and loss calculation, and the contents thereof can be variously modified without departing from the scope of the present invention.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

The block diagram which shows one Embodiment of the optical transmission loss measuring system concerning this invention. The figure which shows the calculation model of the loss amount of an optical transmission line. The figure which shows the structural example of the triangular prism shown in FIG. The figure which shows an example of a structure of a cap with a reflective mirror. The figure which shows the other structural example of a cap with a reflective mirror. The figure which shows an example of a structure of a connector with a reflective mirror. The flowchart which shows the operation | movement procedure of the control unit shown in FIG. 1, and its content.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Measuring apparatus, 2 ... Optical transmission line, 3, 3A, 3B ... Cap with a reflecting mirror, 11 ... Light source, 12 ... Optical isolator, 13 ... Triangular prism, 14 ... Light intensity detector, 15 ... Control unit, 151 ... CPU, 152 ... Memory, 153 ... Calculation part, 154 ... Display part, 32 ... Reflection mirror, 131 ... Signal light incident surface, 132 ... Return light incident surface, 21 ... Ferrule, 22 ... Fiber core wire (with covering), 23 DESCRIPTION OF SYMBOLS ... Fiber core wire (bare wire), 31 ... Insertion hole, 33 ... Matching agent, 34 ... Stopper, 3C ... Connector with a reflective mirror, 4 ... Optical adapter for ferrule connection.

Claims (6)

A measuring device installed at one end of the optical transmission line to be measured and measuring the loss of the optical transmission line;
A cap that is attached to the other end of the optical transmission path and has a reflection mirror on the inner surface that contacts the end face of the optical transmission path;
The measuring device is
Outgoing light generating means for generating light of constant intensity for measuring the loss of the optical transmission line;
An optical device that makes the emitted light incident on one end of the optical transmission path and derives the reflected light from the reflection mirror emitted from the one end of the optical transmission path;
Light intensity detecting means for detecting the intensity of reflected light derived by the optical device;
An optical transmission line loss measurement system comprising: transmission loss calculation means for calculating a loss amount of the optical transmission line based on the intensity of the emitted light and reflected light. A measuring device installed at one end of the optical transmission line to be measured and measuring the loss of the optical transmission line, and a reflection mirror mounted on the other end of the optical transmission line and in contact with the end face of the optical transmission line A measuring device used in an optical transmission loss measuring system comprising a cap,
Outgoing light generating means for generating light of constant intensity for measuring the loss of the optical transmission line;
An optical device that makes the emitted light incident on one end of the optical transmission path and derives the reflected light from the reflection mirror emitted from the one end of the optical transmission path;
Light intensity detecting means for detecting the intensity of reflected light derived by the optical device;
A measurement apparatus comprising: transmission loss calculation means for calculating a loss amount of the optical transmission line based on the intensity of the emitted light and reflected light. Installed at one end of the optical transmission line to be measured and used in an optical transmission loss measurement system comprising a measuring device for measuring the loss of the optical transmission line and a cap attached to the other end of the optical transmission line The cap,
A cap comprising a reflection mirror on an inner surface in contact with an end surface of the optical transmission line. When the optical transmission line is an optical fiber cable, and the core end of the optical fiber cable is in a bare wire state,
An insertion hole into which the bare wire portion is inserted is formed, and a jig formed by fixing the reflection mirror to an end portion in the insertion hole;
4. The cap according to claim 3, further comprising a stopper provided on the jig and fixing the end portion of the optical fiber cable in a state where the bare wire portion is inserted into the insertion hole. When the optical transmission line is an optical fiber cable and a female connector is attached to the end of the optical fiber cable,
A male connector-shaped jig having a convex portion to be inserted into the female connector, wherein the reflection mirror is attached to the end of the convex portion so as to be joined to the end face of the optical fiber cable. The cap according to claim 3.   A reflection mirror is attached to one end of the optical transmission path to be measured, and light of a certain intensity for loss measurement of the optical transmission path is incident from the other end of the measurement target, and the reflected light from the reflection mirror is the same end. And detecting the intensity of the reflected light, and calculating the loss amount of the optical transmission path based on the intensity of the emitted light and the reflected light.

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