The present invention relates to a lensed fiber and the method of making the same, particularly to a conical-wedge-shaped lensed fiber and the method of making the same.
For optimal performance in fiber-optic communication system, efficient coupling between diode laser and fiber is essential. In order to enhance the coupling efficiency between diode laser and fiber, various types of lensed fibers are provided as follows.
Referring to
Referring to
Referring to
Referring to
Consequently, there is a need for improved lensed fiber and the method of making the same to solve the above-mentioned problem.
The primary objective of the present invention is to provide a method for making a conical-wedge-shaped lensed fiber, which has simplified fabricating process and needs not to set up any particular angle of rotation of the fiber. Therefore, the fabricating time and cost are reduced, and the coupling efficiency of the lensed fiber is up to 90%.
Another objective of the present invention is to provide a method for making a conical-wedge-shaped lensed fiber. In comparison to other fabrication techniques of lensed fiber used in high-power diode lasers, the advantages of the present invention are the ability to control over two axial curvatures and the small fiber offset in grinding and polishing processes, resulting in producing a good elliptical microlens in the fusing process.
To achieve the above objectives, the present invention provides a method for making a conical-wedge-shaped lensed fiber, comprising the following steps:
a is a perspective view of a conical-wedge-shaped fiber according to the preferred embodiment of the present invention;
b is a top view of the conical-wedge-shaped fiber of
c is a side view of the conical-wedge-shaped fiber of
d is a front view of the conical-wedge-shaped fiber of
a is a perspective view of a conical-wedge-shaped lensed fiber according to the preferred embodiment of the present invention;
b is a top view of the conical-wedge-shaped lensed fiber of
c is a side view of the conical-wedge-shaped lensed fiber of
d is a front view of the conical-wedge-shaped lensed fiber of
Referring to
The optical fiber 51 has a central axis 56 and an end, wherein the central axis 56 extends in the longitudinal direction of the optical fiber 51. The tapered region 52 is at the end of the optical fiber 51. The sides of the tapered region 52 are a first surface 52a, a second surface 52b, a third surface 52c and a fourth surface 52d in sequence. The top of the tapered region 52 is an intersecting line 52e. Preferably, the intersecting line 52e is a straight line and its length is 10 to 40 μm, most preferably, 30 μm. The first surface 52a and the third surface 52c are flat planes and intersect at the intersecting line 52e. The second surface 52b and the fourth surface 52d are curved surfaces and they do not intersect.
Referring to
Referring to
Referring to
Referring to
The optical fiber 61 has a central axis 66 and an end, wherein the central axis 66 extends in the longitudinal direction of the optical fiber 61. The tapered region 62 is at the end of the optical fiber 61. The sides of the tapered region 62 are a first surface 62a, a second surface 62b, a third surface 62c and a fourth surface 62d in sequence. The top of the tapered region 62 is the lens 63. Preferably, the lens 63 is semi-ellipsoidal. The first surface 62a and the third surface 62c are flat planes and the extensions of the first surface 62a and the third surface 62c intersect at an intersecting line (not shown) that is perpendicular to the central axis 66. The second surface 62b and the fourth surface 62d are curved surfaces and they do not intersect.
Referring to
Referring to
Referring to
The lens 63 is at the top of the tapered region 62, and the geometric center of the lens 63 is on the central axis 66. The appearance of the lens 63 can be semi-ellipsoidal or hemispherical.
The present invention also relates to a method for making a conical-wedge-shaped lensed fiber, comprising:
(a) providing an optical fiber having a central axis and an end;
(b) machining (for example, cutting) the end of the optical fiber to form a flat end face;
(c) machining (for example, lapping, polishing or grinding) the end of the optical fiber to form a conical region;
(d) machining (for example, lapping, polishing or grinding) one side of the conical region to form a flat first surface;
(e) machining (for example, lapping, polishing or grinding) another side of the conical region to form a flat third surface, wherein the first surface and the third surface intersect at a intersecting line that is perpendicular to the central axis, and the appearance of the optical fiber is like the above-mentioned conical-wedge-shaped fiber 50; and
(f) fusing the intersecting line to form a lens, wherein the appearance of the lensed fiber is like the above-mentioned conical-wedge-shaped lensed fiber 60.
Referring to
(c1) fixing the optical fiber 51 in a fixture 72 above a machining plate 73 (for example, lapping plate, grinding plate or polishing plate);
(c2) adjusting the inclination angle between the fixture 72 and the machining plate 73 to form a first angle θ between the optical fiber 51 and the surface of the machining plate 73, and then positioning the end of the optical fiber 51 at the surface of the machining plate 73; and
(c3) rotating the optical fiber 51 along the central axis 56, feeding the optical fiber 51 to the machining plate 73, and preferably rotating the machining plate 73 simultaneously so as to form a conical region at the end of the optical fiber 51.
Then, in the embodiment, the above-mentioned step (d) comprises the following steps:
(d1) stopping the optical fiber 51 from rotating;
(d2) rotating the machining plate 73, and feeding the optical fiber 51 to the machining plate 73 so as to form the first surface 52a.
Then, in the embodiment, the above-mentioned step (e) comprises the following steps:
(e1) elevating the optical fiber 51 with respect to machining plate 73;
(e2) rotating the optical fiber 51 along the central axis 56 with 180 degrees; and
(e3) feeding the optical fiber 51 downward to the machining plate 73 to form the third surface 52c, and forming the intersecting line 52e. So far, the appearance of the optical fiber 51 is like the above-mentioned conical-wedge-shaped fiber 50.
Finally, in the embodiment, the above-mentioned step (f) is fusing the neighborhood area of the intersecting line 52e by electric arcs so that the neighborhood area of the intersecting line 52e is melted to become liquid state and then forms a lens 63 (
Preferably, after the step (e), the embodiment further comprises a step of chemically etching the intersecting line 52e to form a concave shape. The chemically etching step can improve the radius of curvature of the lens 63 and raise the coupling efficiency of the quadrangular-pyramid-shaped lensed fiber 60
The advantage of the present invention is simplified fabricating process and that it need not to set up any particular angle of rotation of the optical fiber 51. That is, after the conical region is formed in step (c), the optical fiber 51 is fed to the machining plate 73 directly to formed the first surface 52a, and need not to set up any particular angle of rotation of the optical fiber 51. Then, in step (e), the optical fiber 51 is rotated with 180 degrees and machined to form the third surface 52c. Therefore, the fabricating time and cost are reduced, and the coupling efficiency of the lensed fiber is up to 90%.
An example is described below. In the example, a 980-nm high-power diode laser with a typical far-field divergence of 7° (horizontal)×30° (vertical) is used, and the fiber used in this example is a 980-nm step-index single-mode fiber (produced by Prime Optical Fiber Corporation) with the mold field radius of 5.7 μm, while the refractive index of the core is 1.416.
Then, the relative position between the laser and the fiber is defined. As shown in
While several embodiments of this invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of this invention are therefore described in an illustrative but not restrictive sense. It is intended that this invention may not be limited to the particular forms as illustrated, and that all modifications that maintain the spirit and scope of this invention are within the scope as defined in the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
094101850 | Jan 2005 | TW | national |
Number | Date | Country | |
---|---|---|---|
Parent | 11183406 | Jul 2005 | US |
Child | 11820212 | Jun 2007 | US |