JPH0548165Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fine movement collimator for an optical fiber that can accurately couple an optical fiber and a laser light source, for example.

[Prior Art] In order to efficiently make gas/solid-state laser light, semiconductor laser light, etc. enter an optical fiber, a collimator has been conventionally used to couple the laser light and the optical fiber.

What is required here is to fix the end face of the optical fiber precisely with respect to the narrow laser incident beam, that is, so that the optical axis and focal length coincide. Conventionally, for this adjustment, various types of adjustment devices have been used, in which a holding base on which the optical fiber is fixed is moved back and forth, left and right, and up and down using a cross-movement holder, a screw feed, etc., and a tilting device is also used.

However, these adjustment devices have problems such as having to operate a plurality of elements because there are many objects to be adjusted, making the adjustment complicated and difficult, and having a large number of parts, making them expensive and causing many failures.

[Purpose of the invention] The purpose of the invention is to easily align the focal length and optical axis of the imaging lens by moving the end face of the optical fiber on a spherical surface centered on the principal point of the imaging lens. An object of the present invention is to provide a fine movement collimator for optical fiber.

[Summary of the invention] The gist of the invention to achieve the above objectives is as follows:
A lens holding member having an imaging lens built into an opening and having a convex portion; and an optical fiber holding member having a concave portion slidably in close contact with the outer surface of the convex portion of the lens holding member and holding an optical fiber. , a fixing member that fixes the optical fiber holding member at an arbitrary position with respect to the lens holding member, and at least one of the outer surface of the convex portion of the lens holding member and the inner surface of the recessed portion of the optical fiber holding member. A fine movement collimator for an optical fiber, characterized in that the optical fiber has a substantially hemispherical surface whose center is the principal point of the imaging lens and whose radius is the focal length, and the end face of the optical fiber is located on the hemispherical surface. It is.

[Embodiments of the invention] The invention will be described in detail based on illustrated embodiments.

FIG. 1 is a longitudinal sectional view, FIG. 2 is a front view of the lens holding member, and FIG. 3 is a front view of the optical fiber holding member. This collimator is the lens holding member 1
and an optical fiber holding member 2. The disk-shaped lens holding member 1 is provided with a convex portion 3 having an approximately hemispherical outer surface at the center of one side. A hole 4 is provided so as to penetrate therethrough. A ring-shaped lens holder 5 is installed along the inner wall of this hole 4, and this lens holder 5
An imaging lens 6 is attached to. Note that the convex portion 3 of the lens holding member 1 is located at the principal point H of the imaging lens 6.
It is a spherical surface whose center is , and whose radius is the focal length r of the imaging lens 6 . In addition, the lens holding member 1
Four screw holes 7 are provided at symmetrical positions with respect to the center, and the lens holding member 1 is screwed to the laser emission surface of various laser oscillators.

A disk-shaped fiber holding member 2 having the same diameter as the lens holding member 1 has a recess 8 having a spherical inner surface with the same curvature r that is in close contact with the protrusion 3 of the lens holding member 1 and is provided with an opening 9 at the center. An optical fiber mounting base 10 is provided at the center of the opposite side to the recess 8, and the end face of the fiber F faces the opening 9 and is fixed to be located on the spherical surface of the recess 11. Here, the distance between the end face of the fiber F and the principal point H of the imaging lens 6 corresponds to the focal length r of the imaging lens 6. The fiber holding member 2 is provided with three through holes 11 at positions symmetrical with respect to the optical fiber F, and these through holes 11 are coaxial with three screw holes 12 provided in the lens holding member 1, and a tilt screw 13 is screwed into the screw hole 12 through the through hole 11.

In the above-described structure, the lens holding member 1 is attached to various types of laser oscillators, such as gas and solid, with their optical axes aligned accurately. When the laser beam enters the imaging lens 6 from the right direction in FIG. 1, it is focused by the imaging lens 6 and has a focal length r
The light is focused on the spherical optical axis that is separated by the distance, and almost enters the optical fiber F arranged at this focal position. However, although the focal lengths r match as is, it is not guaranteed that the optical axes of the optical fiber F and the laser beam exactly match, so the end face of the optical fiber F must be adjusted to match the focal position exactly. It is necessary to do so. Therefore, the end face of the optical fiber F is slightly moved by individually adjusting the three tilting screws 13 that join the lens holding member 1 and the optical fiber holding member 2. As a result, the optical fiber holding member 2 is attached to the spherical convex portion 3 of the lens holding member 1.
Since the end face of the optical fiber F is centered on the principal point H of the imaging lens 6 and has a focal length r
Move within a sphere whose radius is . Therefore, by adjusting the three tilting screws 13 to align the optical axes, it is possible to match the focal positions. The optical axis is adjusted while measuring the amount of light emitted from the opposite end of the optical fiber F using, for example, a detector, and it can be determined that the optical axis is aligned when the amount of light is at its highest. In addition, the three tilting screws 13 can be used for a long period of time without loosening.

FIG. 4 shows a case where a semiconductor laser light source 14 is used as a light source, and a package 15 holding the semiconductor laser light source 14 is attached to the rear part of the lens holding member 1, and an optical fiber mounting base 10 is attached to the rear part of the lens holding member 1.
and the optical fiber F are omitted from illustration. In addition,
Reference numeral 16 denotes a collimator lens, which plays the role of converting the luminous flux emitted from the semiconductor laser light source 14 into parallel light. This embodiment also has the same effect as the first embodiment.

In the embodiment, the outer surface of the convex portion 3 and the inner surface of the recessed portion 8 are both spherical, but either one may be a spherical surface and the other may be an annular contact surface that closely contacts the spherical surface. For example, from a manufacturing standpoint, it is easy to make the convex part 3 spherical, but the concave part 8
Since it is difficult to make the inner surface of the convex part a spherical surface, the same effect can be obtained by making the inner surface of the convex part a tapered surface and making a line contact with the convex part 8.

Fig. 5 shows another example of the use of the optical fiber fine collimator.The optical fiber fine collimator not only takes light into the optical fiber F, but also converts the light emitted from the optical fiber F into parallel light and emits it. For example, by arranging two fine-motion collimators for optical fibers facing each other, the present invention can be applied to a sensor that detects a light-blocking object using parallel light.

[Effects of the invention] As explained above, the fine movement collimator for optical fiber according to the invention moves the end face of the optical fiber on a spherical surface centered on the principal point of the imaging lens and whose radius is the focal length. Adjustment is easy because there is no need to match the distance and only the optical axis needs to be adjusted, and the structure is simple and the number of parts is small, so failures are rare and it can be used for long periods without adjustment.

[Brief explanation of the drawing]

The drawings show an embodiment of the optical fiber fine collimator according to the present invention, in which Fig. 1 is a longitudinal sectional view, Fig. 2 is a front view of the lens holding member, Fig. 3 is a front view of the optical fiber holding member, and Fig. 4 is a front view of the optical fiber holding member. The figure is a longitudinal sectional view of another embodiment, and FIG. 5 is an explanatory diagram of another usage example. 1 is a lens holding member, 2 is an optical fiber holding member, 3 is a convex portion, 6 is an imaging lens, 8 is a concave portion,
10 is an optical fiber mounting base, 11 is a through hole, 12 is a screw hole, 13 is a tilting screw, 14 is a semiconductor laser light source, H is a lens principal point, and F is an optical fiber.

Claims (1)

[Scope of utility model registration request] A lens holding member having an imaging lens built into an opening and having a convex portion; and an optical fiber holding member having a concave portion slidably in close contact with the outer surface of the convex portion of the lens holding member and holding an optical fiber. , a fixing member that fixes the optical fiber holding member at an arbitrary position with respect to the lens holding member, and at least one of the outer surface of the convex portion of the lens holding member and the inner surface of the recessed portion of the optical fiber holding member. A fine movement collimator for an optical fiber, characterized in that the optical fiber has a substantially hemispherical surface whose center is the principal point of the imaging lens and whose radius is the focal length, and the end face of the optical fiber is located on the hemispherical surface. .