JPH0357936A - Apparatus for measuring optical fiber preform - Google Patents

Abstract

PURPOSE:To enable the measuring of a refractive index distribution with a preform at rest by a method wherein an optical system is arranged on a frame movable in a direction (x) on a xz surface from a light source to a photodetector and the incident side of the optical system is set on one side of the frame viewed from a notch provided on the front of the frame while the outgoing side the optical system on the other side thereof. CONSTITUTION:An optical system is arranged on a frame 36 movable in a direction (x) on an xz surface from a light source 20 to a photo detector 26. When the optical system is set, a notch 38 is provided on the front of the frame 36 and the incident side of the optical system is set on the one side 42 of the frame 36 viewed from the notch 38 while the outgoing thereof on the other side 44 thereof. When the size of the notch 38 is adjusted to be larger than the preform 12 properly, a refractive index can be measured at many points of the preform 12 by moving the optical system together with the frame 36.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for non-destructively measuring the refractive index splitting of an optical fiber preform. [Prior Art] In Fig. 4, 12 is an optical fiber/nine base material. The optical fiber to the material l2 is immersed in the y direction (vertically placed) in the matching oil l6 placed in the oil tank l4 (see arrow l3 for the xyz direction). A transparent glass window l8 is provided in the oil tank l4. Light in two directions emitted from the light source 20 enters the optical fiber/<ffl material l2 through the lens 22 and the window 1B, and the emitted light is received by the light receiver 26 via the lens 24, and the information contained in the emitted light is received. Analyze and measure the refractive index distribution. [Problem to be solved by the invention] Conventionally, in order to maintain the stability of the optical axis, the light receiving unit 2 from the light source 20
The refractive index distribution was measured by fixing the optical system leading to l26 and moving the base material l2 in the X direction. Furthermore, when measuring a different position in the y direction of the base material l2, the base material l2 was moved in the y direction. However, recently, as the base material 12 has become larger, the need for simultaneous multi-point measurement has become important. For example, in the case of simultaneous measurement of three points, the optical system is installed in three stages as shown in Figure 5, and measurements are taken at the same time. However, in that case, in the method of moving the base material 12, after moving the base material 12 by a minute length in the It is necessary to move l2 by a minute length in the X direction. The time it takes for the signal to stabilize differs depending on the optical system at each stage, so we had to adjust to the slowest optical system at the sweetfish station, which was a waste of time. This invention enables the optical systems at each stage to perform measurements independently (without waiting for other measurement systems to stabilize) even in the case of simultaneous multi-point measurement as described above. [F stage to solve the problem] As shown in Figures 1a and lb, (1) On the xz plane, on the pedestal 36 movable in the X direction,
Installing an optical system from the light source 20 to the light receiver 26. (2) When installing the optical system, a notch 38 is provided in the front of the pedestal 36, and the pedestal 3 when viewed from the notch 38
The incident side of the optical system is installed on one side 42 of the optical system 6, and the incident side is installed on the other side 44 of the optical system. [Function] In the above configuration, if the size of the notch 38 is appropriately larger than the base material l2, the refractive index fraction can be measured by fixing the base material l2 and moving the optical system together with the mount 36. You will be able to do this. [3] Example [11 Configuration of Apparatus In Figures 1a and 1b, 30 indicates the entire measuring apparatus. 3l is a substrate, for example, rectangular, and has a rectangular notch 32 extending inward from the front surface. 34. 34 is a rail, which is fixedly provided in the X direction on the board 3l. Reference numeral 36 denotes a frame, which is placed on the rail 34 and is connected to the motor 39.
(fixed on the board 3l) and can be moved in the X direction by the action of the screw 40. This pedestal 36 is also shaped like a square thick plate, for example, and has a large long sword-shaped notch 38 that enters inward from the front, making it U-shaped as a whole. The optical configuration of the light source 20 to the light receiver 26 is rearranged on the pedestal 36 as follows. That is, the light source 20 is placed on the bottom side 4l of the U-shaped pedestal 36.
Further, an incident side lens 22 is installed on one side 42, and an output side lens 24 and a light receiver 26 are installed on the other side 44, respectively. Furthermore, the optical path is bent at right angles by mirrors 21, 23, and 25. [2] How to use the device. (1) In the case of measuring only one point: Mainly, in Figures 1a and 52 (only the pedestal 36 and the optical system thereon are shown),
The light emitted in the direction is directed to the X direction by the mirror 2l, and
2, changes its direction in two directions again by the mirror 23, and enters the base material l2. The light emitted from the base material 12 passes through the mirror 25
The beam changes direction in the X direction and passes through 24 and enters the light receiver 26. The base material 12 is kept stationary and the pedestal 36 is moved forward.
Then, the light between the mirrors 23 to 25 scans the base material l2 in the X direction from end to end, so that the refractive index separation of the base material l2 is measured. Also, measurement equipment W! If either the base material 130 or the base material l2 is moved in the y direction, one measuring device fi30 can move the base material 1
It is possible to measure the refractive index distribution at many points in 2. (2) In the case of simultaneous multi-point measurement: For example, in the case of three-point 1'i71 II Ill measurement, as shown in Fig.
Use C. In this case, since the base material 12 is not moved, each measuring device i30A-C can perform measurements independently without being influenced by other measuring devices. [Other Embodiments] The optical path of the optical system from the light source 20 to the light receiver 26 may be kept straight without using a mirror. [Effect of the invention I: The optical system from the light source to the light receiver is installed on a mount that can be moved in the X direction on the XZ plane, and a notch is provided in the front of the mount, and Since the entrance side of the optical system is installed on one side of the mount and the output side is installed on the other side, (1) the refractive index distribution can be measured while the base material l2 remains stationary. (2) Especially in the case of multi-point rotational measurement, as mentioned above, each stage can be measured independently, and other measurements 'A2F
There is no need to wait for the received signal to stabilize, eliminating wasted time. 4. 1a to 3 are related to embodiments of the present invention, and are illustrated in FIGS.
Figure a is a plan view, Figure 1b is a side view, Figure 2 is an explanatory diagram of how to use it when measuring only one point, Figure 3 is an explanatory diagram of how to use it when measuring multiple points simultaneously, and Figure 4 is an explanatory diagram of how to use it when measuring multiple points simultaneously. The figure is an explanatory diagram of the conventional technique in the case of measuring only one point, and the trS5 diagram is an explanatory diagram of the conventional technique in the case of simultaneous measurement of multiple points. l2: Optical fiber base material l4: Oil tank l6: Matching oil 18: Window 20: Light source 21, 23, 25: 22, 24:
Lens 26: Light receiver 30: Measuring device 3l: Substrate 32. 38:! IQ missing 34: Rail 36: Frame 4l: Base 42, 44: Side mirror Patent Shipper Makkura Electric Cable Co., Ltd.

Claims (1)

[Claims] Light emitted from a light source is transmitted to an optical fiber base material placed in the y direction in the z direction.
In a measuring device for an optical fiber preform, the optical fiber preform receives light emitted from the optical fiber preform from a direction, and an optical system from the light source to the photoreceiver is mounted on a stand movable in the x direction on the xz plane. and a notch is provided in the front surface of the pedestal, and the entrance side of the optical system is installed on one side of the pedestal when viewed from the notch, and the output side of the optical system is placed on the other side. Fiber base material measuring device.