SU1765795A1 - Device for aligning optic fibers - Google Patents

Abstract

Use: when connecting optical fibers. SUMMARY OF THE INVENTION: To increase the accuracy of the alignment and expand the scope of use in the gap between the adjustable fibers, which are fixed in micropositioners with V-grooves, a rhombohedral prism with reflective edges is positioned. Two mirrors are installed between the prism and the microscope objective, the illuminator is located along the axis of the microscope under the prism, and the micropositioners are made with the possibility of rotation of the V-shaped grooves around their longitudinal axes. 2 Il.

Description

The invention relates to the technology of alignment of optical fibers, in particular the method of combining their optical axes, as well as the planes of polarization of anisotropic single-mode optical fibers (AOOV) and can be used in radio, electronic and instrument-making branches for the installation of cable products of fiber-optical transmission systems ( PLOT).

A device for adjusting optical fibers before the welding operation is known, which contains two light sources, a mirror system for translating the image onto the screen, screen, micropositioners with a V-shaped groove in which the ends of the optical fibers are fixed (see Device for splicing optical fibers using electric arc under field conditions, Electron Lett, 16, No. 5.1979, 152-153).

The disadvantage of the device is that the adjustment of the optical fibers is carried out along the outer casing projected onto the screen in a plane parallel to the optical axis; Since the cladding is not coaxial with the light guide part of the optical fiber due to eccentricity and technological tolerances, so that we cannot achieve the exact installation of the matching fibers. This is especially critical for single-mode optical fibers, where the alignment error in this way exceeds the diameter of the light guide part. For anisotropic single-mode optical fibers, the known alignment device is generally unacceptable, since it is impossible to isolate the plane of polarization of the light-guiding part of the optical fiber.

It is also known a device comprising a mirror system consisting of two small prisms arranged side by side. The mirror system is mounted on a carriage that can be moved between the ends of the optical fibers using a micrometer screw. The system may be in two positions, in which

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each face faces its own prism. In both positions, the beam deflects at an angle of 45 ° and is directed to a microscope consisting of objective and ocular parts, between which a beam splitter is placed, directing the light from the source to the objective part. The light reflected by one of the prisms is directed to the end of one of the optical fibers, reflected from the end and goes back through the lens, the splitter and further into the eye. There is a cross in the eye of the microscope, the center of which is on the optical axis. Optical fibers are fixed in V-shaped grooves of micro-positioners, which have the ability to move in three coordinates (see EPO patent No. 0091738, Cl. G 02 B 7/26, 1983).

The drawback of the device is that the adjustment is carried out using a movable carriage, which allows only alternately adjusting the optical fibers, aligning the center of the optical fiber core with the cross of the ocular part of the microscope, while the carriage must be moved to adjust the second fiber. in the precision mechanism it is carried out with tolerances, and this system has an optical lever; therefore, a small deviation of the carriage leads to a significant change in the position of the visible image ca optical fiber. At the same time, the true position of the optical axes does not correspond to that established by the cross of the ocular part of the microscope, which significantly reduces the alignment accuracy. Alignment of anisotropic optical fibers is generally impossible due to the lack of rotational movement of micropositioners.

The aim of the invention is to improve the alignment accuracy and the expansion of the field of application of the device.

The goal is achieved by the fact that in a known device for adjusting optical fibers containing a mirror-prism system located between the end surfaces of optical fibers, a microscope including an ocular and objective parts, a fixed illuminator and micropositioners installed with the ability to move in three coordinates, the mirror-prism system is made of a mirror rhombohedral prism and two fixed mirrors that are installed with the ability to reflect the end surfaces of optical fibers con is in the focal plane of the microscope, and micropositioners are installed with the possibility of rotational motion.

FIG. Figure 1 shows the optical layout of the device; in fig. 2 abc shows the results of the optical fiber alignment process.

The device contains a mirror-prism system, made in the form of a rhombohedral prism 1 with mirror edges 2-5 and two mirrors b, 7 of the microscope 8, including the objective part 9 and the ocular part 10, micropositioning devices 11, 12 with V-shaped grooves 13, 14 for fixing in them optical fibers 15, 16 with end surfaces 17, 18 perpendicular to their longitudinal axis, illuminator 19, Rhombohedral prism 1 is installed between micropositioner 11, 12, the longitudinal axes of V-shaped grooves 13, 14c can be returned but progressive translation displacements of the working area. Mirrors 6, 7 are fixedly fixed between the rhombohedral prism 1 and the microscope 8 in vertical, parallel planes perpendicular to the longitudinal axis of the V-shaped grooves. Micropositioners 11, 12 are mounted on a single axis symmetrically to a rhombohedral prism 1 with the possibility of moving along three coordinates x, y, z and axial rotation. The illuminator 19, rhombohedral prism 1, microscope 8 is installed on the same optical axis.

The operation of the device is as follows.

Optical fibers 15, 16c with a previously prepared end surface, perpendicular to their optical axis, are installed in V-shaped grooves 13,14 of micropositioning devices 11, 12 and fixed. From the illuminator 19, a beam of light is directed onto the mirror surfaces 3, 5 of the rhombohedral prism 1, which reflect part of the light onto the surfaces of the ends 17, 18 of the optical fibers 15, 16, which in turn reflect the light onto the mirror edges 2.4 of the rhombohedral prism 1, Reflected from faces 2, 4, the light is re-reflected by symmetrically mounted mirrors 6.7 into the optical system of the microscope 8, and an image of 20 ends of 17, 18 optical fibers is observed in the eyepiece. If the optical fibers 15, 16 are set so that their optical axes 21, 22 and the plane of polarization determined by the arrangement of the anisotropic elements 23, 24 coincide, then in the ocular part 10 of the microscope 8 one image of the ends of the optical fibers of double intensity is observed, which suggests that the optical fibers are adjusted (Fig. 2c).

After the rhombohedral prism is removed from the working area, it is possible to perform splicing of optical fibers. In the case of a mismatch between the optical axes and the plane of polarization determined by the anisotropic optical fiber elements 23, 24, two images of the ends of the optical fibers will be in the focal plane of the microscope (Fig. 2a). In order to combine images of the ends of optical fibers along the optical axis, micropositioner 11, 12 are moved in the x, z plane until the optical axes of the fibers completely coincide. In this case, an image is observed in the ocular part 10 of the microscope 8 (Fig. 2b). In this case, the polarization planes formed by anisotropic elements 23, 24 of optical fibers may not coincide. By rotating the micro-positioners around the longitudinal axis of the V-shaped grooves, complete image alignment is achieved. An image is observed in the ocular part of the microscope (Fig. 2c).

The image of FIG. 2a-c are for single-mode optical fibers with the butterfly polarization preserved; however, for any other optical fibers the alignment is carried out in the same way.

The proposed set of features in the invented device for aligning optical fibers provides it with the following advantages compared with the known devices:

improving the accuracy of the alignment of optical fibers by making the mirror system in the form of a rhombohedral prism, which makes it possible to simultaneously adjust the two ends of the optical fibers, which prevents the optical system from moving during the alignment process, which reduces the positioning accuracy;

expansion of the field of application (possibility of adjustment of anisotropic single-mode optical fibers).

Claims (1)

Claim device for adjusting optical fibers, containing micropositioners with V-shaped grooves, a microscope, an illuminator and a mirror-prism system installed with the ability to move into the working area between the V-shaped grooves, in order to improve the accuracy of the alignment and expansion areas of application, the mirror-prism system is made in the form of a rhombohedral prism and two mirrors installed between the prism and the lens of the microscope perpendicular to the axis of the V-shaped grooves and symmetrically Normally the relative axis of the microscope, the microscope illuminator is mounted on the axis at a rhombohedral prism, and made mikropozitsionery rotatably V-shaped grooves around their longitudinal axes. X 20 Lig 1 FIG. 2