JP3641502B2 - MT connector core misalignment measurement method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for measuring the displacement of an optical fiber position of an MT connector, and particularly improves the measurement accuracy.
[0002]
[Prior art]
An MT connector used as a multi-core connector for an SM type optical fiber is as shown in FIG. In this MT connector, a plurality of fiber strands 103 of the optical fiber tape 104 are fixed in an inserted state in the fiber hole of the connector ferrule 101, and the end surface of the fiber strand is arranged in the same plane as the front end surface of the ferrule 101. The optical fiber 103 is aligned by the guide pins 102 and connected.
[0003]
The end face of each optical fiber is in strong contact with the clip 105.
[0004]
The average connection loss is 0.35 dB, and this MT connector is effective for shortening the cable connection work time.
[0005]
However, generally, the connection loss of the multi-fiber connector is larger than the loss of the fusion splice. There remains a need to improve the connection loss of multi-fiber connectors.
[0006]
The factor that most affects the connection loss of this type of connector is the misalignment between the cores of the optical fibers to be connected. Against this background, it has been desired to develop a high-accuracy measurement technique for misalignment of the optical fiber core of a multi-fiber connector.
[0007]
Conventionally, the following two methods are known as methods for measuring the shift of the optical fiber core position of the MT connector.
[0008]
One is (1) two guide pin holes on both sides, and a light source is illuminated from the rear end face of the ferrule of the MT connector in which a large number of fiber holes are formed between them, and the objective lens on the front end face side This is a method in which an image pickup device is arranged through the front end face image of the ferrule. In this method, the illumination light from the light source passes through the guide pin hole and the fiber hole and enters the imaging device as transmitted illumination light. Since the image processing apparatus is provided with imaging data of transmitted illumination light from the front end face of the ferrule, the image processing apparatus can obtain the edge contours at the front end face of the guide pin hole and the fiber hole. Based on the result, the center positions of the guide pin hole and the fiber hole are obtained, and the deviation of the position of the fiber hole with respect to the center position of the guide pin hole is measured. -343 “Development of high-precision dimension measurement technology for multi-fiber connectors”).
[0009]
As another method, (2) Japanese Patent Laid-Open No. 6-201356 is known. As shown in FIG. 5, in this measurement method, dummy pins 91 having dummy optical fibers 92 are inserted into two guide pin holes 106 that determine the position when the MT connector is connected, and a plurality of optical fibers 103 are formed into a plurality of pieces. It is fixed in the fiber hole 107 in the inserted state, and the end faces of the optical fibers 92 and 103 are arranged on substantially the same plane at the front end face of the ferrule 101. Then, illumination light is incident from the optical fiber 92 of the dummy pin 91 and the rear end surface side of the optical fiber 103 inserted into the fiber hole 107, and the emitted illumination light of each of the optical fibers 92 and 103 is imaged on the front end surface side. The center positions of the guide pin hole 106 and the core of the optical fiber 103 are obtained. This is a method of measuring the deviation of the core center position of the optical fiber 103 from the design position based on the center position of the guide pin hole 106 and the design data.
[0010]
[Problems to be solved by the invention]
In the above method (1), the eccentricity of the fiber hole can be evaluated, but the eccentricity of the optical fiber itself inserted therein cannot be evaluated. In addition, there is a disadvantage that the center position cannot be accurately calculated because the influence of the end face of the guide pin hole is large due to optical measurement. In the above method (2), since the light emitted from the fiber core on the front end face of the fiber hole is imaged in a non-contact manner, the inclination of the optical fiber relative to the camera, the polishing angle of the end face of the optical fiber, the height of the end face of the optical fiber is increased. There are many causes of measurement errors, such as differences in focus points due to mismatch. For this reason, various measurement correction means are required.
[0011]
[Means for Solving the Problems]
In the MT connector core misalignment measuring method according to the present invention, a connector (reference connector) whose core position misalignment amount and direction are known in advance and a connector (measuring connector) for measuring the core misalignment are used as a guide pin. The optical fiber cores are connected to each other using guide pins having almost no clearance between the holes and the guide pins, and the amount of attenuation of the optical power incident on the optical fiber is measured to measure the connection loss of the connector. Next, replace the guide pin with a thin one, shift the connector end face in the connection shear direction of the connector, and obtain the shift amount and the shift direction with the smallest connection loss for each optical fiber to obtain the relative relative to the reference connector. The gist is to obtain a positional shift by a contact formula between optical fiber cores .
[0012]
Further, instead of connecting the above-described reference connector and the connector to be measured, for example, a pair of connectors of the same production lot are connected, and the relative core position deviation of the pair of connectors is contacted between the optical fiber cores by the above-described method. The gist is to find it by a formula .
[0013]
[Action]
Since the connectors are directly connected to each other and the end face of the connector to be measured is shifted in the shearing direction of the connection surface to measure the optical power attenuation of the incident light of the optical fiber. That is, the connection loss is the lowest. Therefore, if the position where the connection loss is the smallest is obtained for each optical fiber, the core displacement of the connector under measurement can be known.
[0014]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of a measuring apparatus to which an optical fiber core misalignment measuring method for MT connectors is applied.
[0015]
A connector (hereinafter referred to as a reference connector) 100 whose optical fiber core position displacement amount and displacement direction are known is fixed to the apparatus main body and attached to a dedicated chuck 12 that does not move. The connector to be measured 101 is fixed to the X-axis and Y-axis stage 22 and is attached to a dedicated chuck 14 that moves with the stage.
[0016]
A light source 18 is provided on the rear end side of the reference connector 100 through the optical fiber 16, while a power meter 20 is provided on the rear end side of the measured connector 101 through the optical fiber 16. A linear scale is drawn on the side surface of the stage 22 that moves in parallel with the X and Y axes, and this movement is detected by the sensors 24 and 26, and a pulse corresponding to the amount of movement is output.
[0017]
Next, FIG. 2 is a block diagram showing a functional configuration of the measuring apparatus. As shown in FIG. 2, the X-axis stage 22 is movable by an X-axis drive mechanism 28, and the Y-axis stage 22 is movable by a Y-axis drive mechanism 30. These drive mechanisms 28, 30 are composed of a stepping motor or the like. Each is controlled by the stage driver 32. The output pulses of the sensors 24 and 26 are counted by the counter 34, and the movement amount is monitored and simultaneously input to the CPU 36.
[0018]
The output of the power meter 20 (optical power data) is sent to the CPU 36, the core position is calculated, and is appropriately displayed on the CRT 38. Note that the CPU 36 controls the stage driver 32.
[0019]
FIG. 3 shows the state of the MT connector ferrule 101 in the embodiment. Guide pins 105 are inserted into the guide pin holes of the ferrule of the reference connector through the guide pin holes 106 on both sides. Four optical fiber holes 107 are formed between the guide pin holes, and the optical fiber 16 is inserted. The optical fiber 16 is polished so as to be flush with the front end face of the ferrule 101, and the end face is exposed from the fiber hole 107.
[0020]
Next, an optical fiber core misalignment measuring method of the MT connector executed using the apparatus of FIG. 1 will be described. Measurement is performed sequentially in the following steps.
[0021]
1) The reference connector 100 and the connector to be measured 101 are connected by using a guide pin having almost no clearance between the guide pin hole and the guide pin, the optical power at this time is measured by the power meter 20, and the connection loss of the connector is measured. .
[0022]
2) With the above connectors connected, the reference connector 100 is fixed to the dedicated chuck 12 that is fixed to the apparatus main body and does not move, and the connector to be measured 101 is fixed to the dedicated chuck 14 fixed to the X-axis and Y-axis stages. . After fixing, check that the value of the power meter does not fluctuate with (1) above. Then, the X and Y coordinates of the stage at this time are set to (0, 0).
[0023]
3) Replace the guide pin with a thin one with each connector fixed to the chuck. At this time, it is confirmed that the coordinates of the stage are (0, 0) and that the value of the power meter is not changed.
[0024]
4) While monitoring the connection loss measurement value in the state (3), the stage 22 is shifted in the X-axis direction and the Y-axis direction to obtain the X and Y coordinates at which the connection loss is lowest.
[0025]
5) The positional deviation of the optical fiber core of the connector to be measured is obtained from the coordinates obtained in (4) above and the known positional deviation of the core of the reference connector 100.
[0026]
Each of the above measurements is performed for each fiber strand.
[0027]
【The invention's effect】
According to the measurement method of the present invention, since the measurement is performed in the contact type between the optical fiber cores directly connected to the connector, the measurement error factor inherent in the conventional optical non-contact measurement is eliminated, and thus far It has become possible to measure the core position of the connector with a small core displacement (1 μm or less), which was difficult to measure.
[0028]
In addition, because it is excellent for measuring the core relative position deviation method between the pair of connectors, the measurement result is fed back to the connector production by obtaining the core relative displacement direction between the connectors manufactured under the same conditions. Has become more accurate, making it possible to manufacture highly accurate connectors.
[Brief description of the drawings]
FIG. 1 is a perspective view of an apparatus to which an MT connector core position deviation measuring method according to an embodiment is applied.
FIG. 2 is a block diagram of an apparatus to which the MT connector core misalignment measuring method of the embodiment is applied.
FIG. 3 is a partial cross-sectional perspective view of an MT connector ferrule according to an embodiment.
FIG. 4 is a perspective view showing a configuration of an MT connector.
FIG. 5 is a partial cross-sectional perspective view of a connector showing a conventional example.
[Explanation of symbols]
100 Reference Connector 101 Connector to be Measured 105 Guide Pin 106 Guide Pin Hole 107 Optical Fiber Wire Holes 12 and 14 Chuck 16 Optical Fiber 18 Light Source 20 Power Meter 22 X Axis and Y Axis Stages 24 and 26 Position Sensors 28 and 30 Stage Drive Mechanism

Claims (2)

At least two guide pin holes for determining a position at the time of connection are formed, and a plurality of optical fiber strands are respectively inserted into a plurality of fiber holes and fixed thereto, and a reference connector and a connector to be measured are connected to the guide pin holes. A first step of connecting the optical fiber cores by inserting a guide pin that fits into the optical fiber ;
Light enters from the rear end of the optical fiber inserted into the fiber hole of the reference connector, and the optical power of the incident light is measured at the rear end of the optical fiber inserted into the fiber hole of the connector to be measured. A second step to
A third step of fixing the reference connector to the stationary chuck, the connector to be measured to the chuck of the moving stage in the state of the first step, and replacing the guide pin with a guide pin thinner than the guide pin;
In the state of the third step, light is incident from the rear end side of the optical fiber inserted into the reference connector, and the incident light is incident on the rear end side of the optical fiber inserted into the connector to be measured. A fourth step of determining the X and Y coordinates at which the optical power is maximized by moving the X axis and Y axis stages when measuring the power;
The X and Y coordinates obtained in the fourth step, and a fifth step obtained by calculating the core position deviation of the measured connector from the previously measured and known core position deviation coordinates of the reference connector,
An MT connector core misalignment measuring method , comprising: measuring a misalignment of an optical fiber core inserted into a fiber hole of the connector to be measured by a contact method between optical fiber cores . At least two guide pin holes that determine the connection position are formed, and a pair of connectors in which a plurality of optical fiber strands are respectively inserted and fixed in a plurality of fiber holes are fitted into the guide pin holes. Inserting a guide pin to connect the optical fiber cores ; and
Light enters from the rear end of the optical fiber inserted into one fiber hole of the pair of connectors, and the optical power of the incident light at the rear end of the optical fiber inserted into the fiber hole of the other connector A second step of measuring
A third step of fixing one connector to the stationary chuck, the other connector to the chuck of the moving stage in the state of the first step, and replacing the guide pin with a guide pin thinner than the guide pin;
In the state of the third step, light is incident from the rear end side of the optical fiber inserted into one connector, and the optical power of the incident light is transmitted from the rear end of the optical fiber inserted into the other connector. Measuring the X and Y coordinates by moving the X-axis and Y-axis stages to obtain the maximum optical power,
A method for measuring a core misalignment of an MT connector , comprising: measuring a relative misalignment amount and a misalignment direction of a core misalignment of an optical fiber inserted into a fiber hole of the pair of connectors by a contact method between optical fiber cores. .

Images