JPS6166138A - Method and apparatus for measuring characteristics of optical fiber - Google Patents

Abstract

PURPOSE:To perform readjustment positioning highly accurately, by repositioning a moving table on a carrier so that a positional error caused during the movement of the carrier is compensated by a measuring stage. CONSTITUTION:For example, when a moving table 26b is sent by a measuring stage 47a and a light shielding plate 27 comes to a position, where a specified amount of light is shielded with respect to a light sensor 53, the moving table 26b is stopped. The position of the moving table is precisely determined with respect to the light sensor 53. The light sensor 53 is arranged at the same position as the light sensor at a set stage, i.e., at the position, where the tip of an optical fiber to be measured is suitably aligned with an output end 57 and an input end 58 on the side of a measuring device. Therefore, the position deviation of the moving table 26, which is caused by the positional error between a carrier 25b and a guide rail 55, can be compensated. That error is caused during the movement of the carrier 25b from the set stage 46 to the measuring stage 47a.

Description

Detailed Description of the Invention (a) Technical field to which the invention pertains The present invention relates to a method and apparatus for measuring the characteristics of an optical fiber, and more particularly, to a method and an apparatus for measuring the characteristics of an optical fiber, and more specifically, to measuring the input end and the output end of the optical fiber whose characteristics are measured on a measurement stage. This invention relates to the alignment of the light emitting end and the light entering end of the measuring device and the device thereof.

(b) Prior art and its problems The basic principle of measuring the characteristics of an optical fiber is shown in FIG. 1o. Light is transmitted from a light generator 80 on the measuring device side to an output end 82 . Further, the light received from the input end 83 is transmitted to the measuring device 81. The optical fiber 91 to be measured is installed such that its both end tips, that is, the input end and the output end 90.90' are aligned with the output end 82 and the input end 83 on the measuring device side, respectively. In this way, the light from the light generator 80 passes through the optical fiber 91 to be measured and is transmitted to the measuring device 81, and the characteristics of the optical fiber to be measured are measured. During measurement, it is important to align the tip of the optical fiber to be measured with the light input/output end on the measuring device side in order to avoid connection loss. Regarding alignment, axial misalignment and axial positioning pose problems, but regarding axial misalignment, accurate alignment is possible by detecting the maximum received light power.

On the other hand, for axial positioning, the maximum power can be obtained during contact, but in order to prevent damage or contamination of the fiber end due to contact, the position of the end face of the optical fiber should be raised to avoid contact and provide an appropriate gap for measurement. Accuracy detection is required.

An example of a method for positioning the end face of an optical fiber in a conventional optical fiber characteristic measuring device is shown below. As shown in the side view in FIG. 5, both ends of the optical fiber 1 to be measured (the ends are aligned in the drawing) are held on a carrier 6 by a fiber guide 2 and a fiber holding block 4, respectively. .

In other words, the position of the optical fiber 1 to be measured in the axial direction is determined by the fiber guide 2 having an optical fiber guide groove with a 7-shaped cross section (not shown), and the axial position of the optical fiber 1 to be measured is It is determined by a fiber holding block 4 movable in the axial direction A. Here optical fiber 1
The axial direction of is perpendicular to the extending direction of a guide rail 11 (see FIG. 7), which will be described later, which is a moving path of carrier B. In order to smooth the axial movement of the optical fiber 1, the fiber holding block 4 can be integrated with a fiber retainer 6 placed on the fiber guide 2, as shown in FIG. Further, the fiber guide 2 can be positioned in a direction perpendicular to the axis of the fiber. In this way, the optical fiber can be moved in the axial direction while maintaining its position in the direction perpendicular to the axis, and therefore the relative position of the optical fiber end to the carrier B can be determined on the carrier 6. The position of the tip of the optical fiber 1 can be detected by an optical sensor as described below.

In the actual measurement, as shown in Figure 7, an overview of the measurement system is shown in the top view. An optical fiber is installed on a carrier on a set stage, and then the carrier is sequentially moved along a guide rail via multiple measurement stages. In many cases, the characteristics of the optical fiber are measured sequentially at each measurement stage. To explain in detail below, first, both ends of the optical fiber 1a to be measured are placed on the set stage 13a manually or by an automatic device (not shown) via the fiber guide 2 a r 2 a' and the fiber holding blocks 4 a, 4 a'. Set it on carrier roller a. Next, at the set stage 161], the optical sensors 16 and 16' are used to position both ends of the optical fiber 1b in the axial direction.

The optical sensors 16 and 16' are located at positions that have a predetermined correspondence with the output end and the input end of the measurement light on the measurement stage (for example, indicated by 17 and 18, respectively, on the measurement stage 14a). .16' When the carrier carrying the optical fibers positioned by It is provided in such a position that it can be positioned coaxially with the FIG. 8 is a conceptual diagram of the optical sensor. In FIG. 8, reference numeral 39 denotes a light input/output end, which is supported by a support member. 40
is a unit that includes a light emitting element, a light receiving element, a photoelectric conversion element that converts optical power into electrical power, and a circuit that performs switching depending on whether the electrical power exceeds or falls below a certain amount. The input/output end 39 and the unit 40 are connected by an optical fiber 40. FIG. 9 shows details of the input and output ends of the optical sensor. 41 is a light transmission medium, 42 is a medium holder, and 46 is a supporting structure. 27 is a light shielding body. Light emitted from one of the light transmission media enters the other transmission medium, but if the light shield 27 exists between the input and output ends, passage of the light is blocked. An optical fiber is used as the transmission medium 41, and the fiber core diameter is about 40 μm, making it sensitive to light shielding. This makes it possible to deal with small light-shielding materials such as the tip of an optical fiber having a diameter of about 1 (about 10 μm).

Further, regarding the above-mentioned switching circuit, a stable non-contact type switching circuit is provided to enable a sharp response. With the above configuration, the optical sensor has an outer diameter of 125 μm.
A position detection accuracy of 1 μm was obtained in the axial direction of the optical fiber end.

Returning to FIG. 7, after the tip ends 9b and 9b' of the optical fiber to be measured 1b are positioned and adjusted on the set stage 13b, the carrier 31) on which the optical fiber to be measured is placed is moved along the guide rail. It is moved to the measurement stage (shown as 14a-14d in Figure 7). In the measurement stage, an output end and an input end (indicated by 17 and 18, respectively, in the measurement stage 14a), which are coupling ends connected to a light emitter and a measuring instrument (not shown) of the measurement device, are connected to the guide rail 11. The guide rails are arranged parallel to each other and at a constant distance from each other so as to be at a constant position with respect to each other, and facing at right angles to the guide rail. Since the end of the optical fiber to be measured has already been appropriately positioned by the action of the optical sensors 16 and 16' on the set stage 13b in accordance with the input and output end positions of the measurement stage, the carrier is placed on the measurement stage 1.
4a, the tips of both ends of the optical fiber to be measured 1ε, that is, the input end and the output end 9C19C', are arranged approximately coaxially with the output end 17 and the input end 18 on the measuring device side and in a predetermined positional relationship in the axial direction. It turns out. In this manner, the characteristics of the optical fiber 1c to be measured can be measured by operating the light emitting device and the measuring device of the measuring device on the measuring stage 14a. Next, the carrier can be moved again and the characteristics of the optical fiber to be measured can be similarly measured on each of the plurality of measurement stages. After completing the measurements on the plurality of measurement stages 14a to 14d, the optical fiber 1f to be measured is removed from the carrier 3f by a method not shown, and the carrier 3f is removed.
It is also possible to use the apparatus cyclically by moving the set stage 13a again.

However, in the above method, once the optical fiber axial direction positions of the tip ends of both ends of the optical fiber to be measured are determined on the set stage, the positions are not adjusted thereafter until the measurement is completed. Therefore, in order for the tip ends of both ends of the optical fiber to be measured to be accurately aligned with the input and output ends on the measuring instrument side at each measurement stage, no positional deviation should occur during the movement of the carrier. Therefore, it is necessary to maintain the positional relationship between the guide rail 11 and the carrier 3 with extremely high precision. However, in reality, highly accurate positioning is difficult due to the accuracy of the parts and the effects of temperature, dust, etc. For this reason, even if the tip ends of both ends of the optical fiber to be measured are positioned on the set stage, some degree of positional deviation will occur while the carrier moves from the set stage to the measurement stage. Thus, in order to perform highly accurate measurements on the measurement stage, a means for compensating for this positional deviation is required. The most accurate method for this is to detect and reposition the tips of both ends of the optical fiber to be measured using optical sensors on each measurement stage, as was done on the set stage, but this method is not suitable for the following reasons. It is difficult to implement. That is, since the location where the optical sensor should be installed is approximately the same position as the input/output end on the measuring device side, the sensitivity of the optical sensor is affected by the presence of the input/output end. Furthermore, matching oil is applied to the tips of both ends of the optical fiber to be measured to prevent end face reflections during measurement after being set on the set stage. This is because detection is significantly hindered. Compensation for positional deviations that occur during the movement of the carrier to the measurement stage must therefore be achieved by other methods.

(C) Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to directly adjust the position of the input and output ends of the optical fiber to be measured on the measurement stage. The object of the present invention is to provide a method and apparatus that can be performed easily and with high precision without having to use manual methods.

(b) Structure of the Invention For this purpose, the present invention provides a set stage and a measurement stage having input and output ends of an optical measurement system along a guide, and measures optical fibers to be measured which are arranged approximately parallel to each other on the set stage. An input/output end is placed on a carrier movable on the guide, and when the carrier is moved to the measurement stage, the input/output end is coaxial with the optical measurement system input/output end and is spaced at a predetermined distance in the axial direction (13)'. In the method and apparatus for measuring the characteristics of an optical fiber to be measured, the carrier is positioned at a desired position and then moved to the measurement stage for optical measurement, wherein the input and output ends of the optical fiber to be measured are measured on the set stage. When the carrier is moved to the measurement stage on a moving stage that can be moved and positioned on the carrier in a direction perpendicular to the guide, the carrier is coaxial with the input/output end of the optical measurement system and at a predetermined interval in the axial direction. The present invention is characterized in that the position of the movable stage on the carrier is repositioned to compensate for a positional deviation that occurs during movement of the carrier on the measurement stage.

As a result, a method and apparatus are provided that allow readjustment and positioning of the input and output ends of the optical fiber to be measured on the measurement stage with high precision and ease without directly adjusting the positions of the input and output ends of the optical fiber to be measured. .

1) Embodiment of the Invention As shown in the side view in FIG. 1, a movable stage 26 is disposed on the carrier 25, and both ends of the optical fiber to be measured, that is, the input and output ends are placed on this movable stage 26 along its axis. A pair of fiber guides 28 that are positioned and guided in the perpendicular direction and a pair of fiber holding blocks 29 that hold the fiber to be measured movably in the axial direction are mounted. That is, a fiber guide 28 and a fiber holding block 29 for holding the optical fiber to be measured are placed on the carrier 25 via the moving table 26. Here, the fiber guide 28 and the fiber holding block 29 have the same structure and function as the fiber guide 2 and the fiber holding block 4 described in the prior art.

In the present invention, the movable table 26 is movable only in the axial direction of the optical fiber, that is, in the uniaxial direction perpendicular to a moving path of the carrier 25, which will be described later, or a guide rail 55 serving as a guide. When the moving table 26 is fed in the direction of the arrow, the moving table 26 moves with the optical fiber 1' placed thereon.The moving table 26 is provided with a light shielding plate 27. As shown in FIG. 2, the light shielding plate 27 protrudes from the guide rail 55 toward the light emission end and light incidence end positions of the measurement stage, and cooperates with the light sensor to move the moving stage 26 as will be described later. The role is to determine the position of the The optical sensor for positioning the moving table has the same configuration as described above.

A method of aligning the end face during measurement of an optical fiber to be measured using a carrier having a moving stage according to the present invention will be described with reference to FIG. Along the guide rail 55, a set stage 46 and a plurality of measurement stages 47a~
47d is provided. 25a to 25e are carriers,
Reference numerals 263 to 26e are movable tables, and 1'a to I'e are optical fibers to be measured. The optical fiber to be measured is held by a pair of fiber guides and a fiber holding block as in the prior art, and these are mounted on the set stage 4, for example.
6 respectively 28a, 28a' and 29a, 2
9a'. Reference numeral 52 denotes a positioning optical sensor for the moving table, and 34 and 35 denote optical sensors for positioning the tip of the optical fiber to be measured. The optical sensor for positioning the optical fiber to be measured is arranged only on the Cerato stage 46, and the optical sensor for positioning the moving table is arranged on the set stage 46 and each of the measurement stages 47a to 47d.

The optical sensors 34 and 35 for positioning the optical fiber to be measured are located at positions that have a predetermined correspondence with the output ends and the input ends 57, 58 to 63, 64 of the measurement light on the measurement stage, as described in the prior art. The optical fiber 1'a to be measured, which has been positioned by the sensor 34.
Provided at a position such that when reaching point a, the input/output end of the optical fiber to be measured, the output end on the measuring device side, and the input end 57, 58 are positioned coaxially with an appropriate axial spacing. It is being And positioning optical sensors 52 to 5 for the moving table.
In the measurement stages 47a to 47d, reference numerals 6 and 6 are arranged in a predetermined positional relationship with the light output end and light input end (for example, 57 and 58 points respectively in the measurement stage 47a) of the respective measuring devices. It is placed in the same position as Ugero on the measurement stage. First, on the set stage 46, the moving table 26a is moved in the optical fiber axial direction. When the light shielding plate 27 of the movable table comes to a position where it blocks a certain amount of light from the optical sensor 52,
The optical sensor 52 is activated and stops the movement of the moving table 26a via the switching circuit. Next, fiber holding blocks 29a, 2 are placed on the moving table 26a as described in the prior art.
By moving the fiber guide 28a,
A feed is applied to each end of the optical knife 1'a along 28a'. When the optical fiber tip reaches a position that blocks a certain amount of light from the optical sensors 34 and 35, the optical sensors 34 and 35
operates, and the fiber holding block 29a is connected to the fiber holding block 29a through a switching circuit.

29a', that is, the movement of the optical fiber to be measured i/a is stopped. As a result, the tips of both ends of the optical fiber 1'a to be measured on the set stage 46, that is, the input end and the output end, correspond to the light output end and input end positions (57, 58 to 63.64) on the measurement stages 47a to 47d. position,
That is, when the carrier is moved to the measurement stage, it is set at a position where it should be coaxially aligned with the light output end and the light input end on the measurement device side with a predetermined distance therebetween. Next, the carrier 25a is moved along the guide rail 55 from the set stage 46 to the measurement stage 47a with the moving table 26a placed thereon. At the measurement stage, for example 47a, the moving table 26b is fed again. The light shielding plate 27 is the optical sensor 5
When the moving table 26b reaches a position where a certain amount of light is blocked relative to the light sensor 3, the moving table 26b is stopped in the same manner as described above, and the position of the moving table is precisely determined with respect to the optical sensor 53. The optical sensor 53 is placed at the same position as the optical sensor 52 on the set stage, that is, at an appropriate position to align the tip of the optical fiber to be measured with the light output end 57 and light input end 58 on the measurement device side. It is possible to compensate for a positional shift of the movable table 26b due to an error in the positional relationship between the carrier and the guide rail that occurs while the carrier 25b moves from the set stage 46 to the measurement stage 47a. Therefore, moving platform 2
Both ends of the optical fiber Z1'b, which is held by a pair of fiber guides 28b, 28b' and fiber holding blocks 29b, 29b' on 6b, that is, the input and output ends are connected to the light output end 57 and the input and output ends of the measurement stage 47a. Shooting end 58
Since the predetermined relative positional relationship is precisely maintained, the end face of the optical fiber can be accurately positioned. Thereafter, the optical fiber end face positioning is similarly performed accurately on each of the measurement stages 47b to 47d.

In the above explanation, the fiber guide 28 having a V-groove optical fiber guide and the fiber holding block 29 were used, but as shown in FIG. Using a small second moving table 75, the optical fiber to be measured is appropriately positioned and held in the direction perpendicular to the axis by a method not shown on the second moving table 75, and the moving table 75 is movable in the direction of arrow E. The same optical fiber end face positioning as in the above embodiment can be performed. This will make the mechanism simpler. Regarding the light-shielding plate 27 of the movable table 26, it is recommended to use one with a knife-shaped tip as shown at 27' in FIG. This is convenient for accurate position detection using an optical sensor. In the above embodiment, an optical sensor is used for positioning the optical fiber to be measured, but instead of the optical sensor, a magnetic sensor, a contact type micrometer, or the like may be used. Further, in this embodiment, the moving path for transporting and positioning the carrier, ie, the guide rail, is referred to as a guide, but the guide may have a shape other than a rail.

The method and device of the present invention are suitable for multi-item measurement of multi-mode optical fibers that require a large number of inspection items (and high measurement accuracy), and can also use a plurality of carriers and automatically position the optical fiber end face. Taking advantage of this advantage, it can also be applied to cases in which workers can perform efficient measurements for a single measurement item simply by setting optical fibers on multiple carriers 6.7.c: t=ifflllffl- < f
-)(D*It'LM*Ttx < 1 ”:>(O
8.

It can also be applied when Furthermore, the method and apparatus of the present invention are applicable not only to measuring the characteristics of optical fibers but also to alignment of general optical fibers. 1. Effects of invention. 8, 8, 4, 4, 4, 8, 8, 4, 4, 8, 8, 4, 4, 5, 8, 8, 4, 5, 8, 1, 2, 3, 4, 5, 8, 8, 1, 2, 3, 4, 5, 8, 8, 8, 4, 4, 4, 5, 8, 8, 8, 8, 4, 4, 4, 4, 4, 7, 8, 8, 8, 8, 8, 4, 4, 4, 4, 5, 8, 8, 8, 8, 8, 8, 8, 4, and 5, respectively. positioning the input and output ends of the optical measurement system on a carrier movable on the guide at a position that is coaxial with the input and output ends of the optical measurement system and at a predetermined interval in the axial direction when the carrier is moved to the measurement stage; In the method and apparatus for measuring the characteristics of an optical fiber to be measured, the carrier is then moved to the measurement stage and optically measured. A position that should be coaxial with and at a predetermined distance in the axial direction from the input and output ends of the optical measurement system when the carrier is moved to the measurement stage on a moving stage that can be moved and positioned on the carrier in a direction perpendicular to the guide. and repositioning the movable table on the carrier in order to compensate for a positional deviation that occurred during movement of the carrier on the measurement stage.

As a result, the input and output ends of the optical fiber to be measured are placed on the carrier via a moving table that can be moved and positioned on the carrier. Once positioned, the position of the moving table itself is readjusted on the measurement stage, so that the input and output ends of the optical fiber under test can be readjusted and positioned indirectly, that is, directly at the input and output ends of the optical fiber under test. This can be done easily and with high precision without requiring manual position adjustment.

[Brief explanation of drawings]

FIG. 1 is a side view of a part of the optical fiber characteristic measuring device according to the present invention, showing a state in which both ends of the optical fiber to be measured are placed on a carrier, and FIG. 2 is a side view of the optical fiber according to the present invention. FIG. 3 is a schematic diagram showing an example of the shape of the light shielding plate and the relationship between the optical sensor. FIG. 5 and 6 are side views showing a conventional example corresponding to FIG. 1, and FIG. 7 is a top view showing a conventional example corresponding to FIG. 2. 8 is a diagram showing the concept of an optical sensor, FIG. 9 is a detailed sectional view of the light input/output end portion of the optical sensor, and FIG. 10 is a diagram showing the basic principle of optical fiber characteristic measurement. 1.1'-... Optical fiber to be measured 2.28...
...Fiber guide 3.25 ...Carrier 4.29 ...Fiber holding block 11.55
...Guide rails 13a, 13b, 46...Set stage 14
a to 14d, 47a to 47d--Measurement stage 16.16', 34.35... Optical fiber sensor 17.19.21, 23.57.59.61.63
...Output end 1B, 2Q, 22.24.5B, 60.62.64...
...Incidence end 26...Moving table 27...
Light shielding plates 52 to 56... Optical sensor for moving platform Fig. 7

Claims (11)

[Claims] (1) A set stage and a measurement stage having input and output ends of an optical measurement system are provided along a guide, and the input and output ends of the optical fibers to be measured, which are arranged approximately parallel to each other, are moved on the guide on the set stage. positioning the carrier at a position that is coaxial with the input/output end of the optical measurement system and at a predetermined interval in the axial direction when the carrier is moved to the measurement stage, and then moves the carrier to the measurement stage. In a method for measuring the characteristics of an optical fiber to be measured by moving it for optical measurement, the input and output ends of the optical fiber to be measured are moved on the set stage on the carrier at right angles to the moving direction of the carrier in the guide. When the carrier is moved to the measurement stage on a movable table that can be moved and positioned in the direction, the carrier is positioned coaxially with the input and output ends of the optical measurement system and at a predetermined interval in the axial direction, and the carrier is moved to the measurement stage. A method for measuring characteristics of an optical fiber, characterized in that the position of the movable table on the carrier is repositioned to compensate for a positional deviation that occurs during the movement of the carrier. (2) The method for measuring characteristics of an optical fiber according to claim 1, characterized in that one or more of the measurement stages are provided at predetermined intervals. (3) The first aspect of the present invention is characterized in that the positioning of the movable base is performed by a cooperative action of a light shielding plate provided on the movable base and optical sensors provided on the set stage and the measurement stage. Method for measuring optical fiber characteristics as described in Section 1. (4) The optical sensor on the measurement stage is provided in a predetermined relationship with the position of the input/output end of the optical measurement system on the measurement stage, and the optical sensor on the set stage is provided with the optical sensor on the measurement stage. 4. The method for measuring characteristics of an optical fiber according to claim 3, characterized in that the method is provided corresponding to the position of the sensor. (5) Claims 1 to 4 are characterized in that the input and output ends of the optical fiber to be measured are arranged on the carrier so as to extend in a direction perpendicular to the carrier movement direction in the guide. How to measure the characteristics of optical fiber. (6) A set stage and a measurement stage provided along a guide, and a carrier movable from the set stage to the measurement stage on the guide, and the carriers are arranged generally parallel to each other. Optical measurement in which means is mounted that allows the position of the input and output ends of the optical fiber to be adjusted in the direction perpendicular to its axis and in the axial direction, and the measurement stage is aligned coaxially with the input and output ends of the optical fiber to be measured and at a predetermined interval. In the optical fiber characteristic measuring device equipped with a system input and output end, means for holding the input and output ends of the optical fiber to be measured so as to be adjustable in a direction perpendicular to its axis and in an axial direction is provided on the carrier in a direction perpendicular to the guide. What is claimed is: 1. An optical fiber characteristic measuring apparatus, characterized in that the optical fiber characteristic measuring apparatus is provided on a movable table arranged movably, and means is provided on the set stage and the measurement stage for positioning the movable table in a direction perpendicular to the guide. (7) The optical fiber characteristic measuring device according to claim 6, wherein the measurement stage is composed of one or a plurality of measurement stages arranged at a predetermined interval from each other. (8) The means for positioning the movable base includes a light shielding plate provided on the movable base and a light provided on the set stage and the measurement stage for detecting the position of the light shielding plate and stopping the movement of the movable base. 7. The optical fiber characteristic measuring device according to claim 6, further comprising a sensor. (9) The optical fiber characteristic measuring device according to claim 8, wherein the light shielding plate of the movable table has a knife-edge shaped tip. (10) The optical sensor in the measurement stage is provided in a predetermined relationship with the position of the input/output end of the optical measurement system of the measurement stage, and the optical sensor in the set stage The optical fiber characteristic measuring device according to claim 6, characterized in that it is provided corresponding to the position of the optical sensor. (11) The optical fiber according to any one of claims 6 to 10, wherein the optical fiber to be measured is arranged on the carrier so that the input and output ends thereof extend in a direction perpendicular to the guide. Characteristic measuring device.