JP2001066438A - Optical fiber array element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high precision optical fiber alignment when optical fibers are arrayed on a substrate. SOLUTION: Front ends of plural optical fibers 3 are freed of their coatings and arranged at regular intervals in the alignment direction of the optical fibers by V-shaped grooves 1a formed in an optical fiber holding member (substrate) 1. A flat plate member 8 is put on the arranged front ends and an adhesive is filled and cured between the flat plate member 8 and the V-grooved substrate 1 to fix the optical fibers 3. In the resulting array structure, the eccentric direction of the core and clad of each of the optical fibers 3 is matched with the alignment direction of the optical fibers 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber array element used as a multi-beam light source for a laser beam printer or the like.

[0002]

2. Description of the Related Art An example of an optical fiber array element known as a prior art is disclosed in Japanese Patent Application Laid-Open No. Hei 5-224097.

The optical fiber array described in this patent uses optical fibers each having an independent coating, and a plurality of V-shaped grooves are formed at the tip of each optical fiber whose coating is removed and whose cladding is exposed. It is dropped into each groove of the formed substrate. As is well known, the structure of each of the optical fibers from which the coating has been removed includes a core portion and a clad portion which are light propagation regions. Then, a flat plate serving as a lid is applied to the portion dropped into the groove of the optical fiber from above, the optical fiber is sandwiched, and solidified by an adhesive. The light emitting end face of the optical fiber is polished.

In the above-described series of manufacturing processes, what is important as the performance of the optical fiber array is the arrangement accuracy of the individual optical fibers, and more specifically, the arrangement interval and the linearity between the cores of the optical fibers. is there. Speaking of the alignment accuracy of the optical fiber array section of this reference, the alignment accuracy is determined by the manufacturing accuracy of each optical fiber, that is, the variation in the outer diameter of the clad, the roundness of the clad, the center of the clad and the center of the core. There is no mention of the deviation (the amount of eccentricity), the manufacturing accuracy of the substrate on which the V-shaped groove is formed, and the flatness of the flat plate that holds the optical fiber from above.

[0005] Since these various factors accumulate and affect the final accuracy, if no special consideration is given to these factors, a higher precision such that only a submicron order alignment error can be tolerated. It has been difficult to realize an optical fiber array.

As another example, USP. 4,8
75,969.

The optical fiber array described in this patent uses optical fibers each having an independent coating, and light is incident from one end face of each optical fiber from a light source such as a semiconductor laser. On the other hand, the opposite ends of the optical fibers are aligned in a row on the substrate to form an optical fiber array. The coating is removed from the tip of each optical fiber forming the optical fiber array, and the optical fiber is exposed. Each end of the optical fiber whose tip is exposed is further etched in the radial direction of the optical fiber by a few centimeters of hydrofluoric acid, and the outer diameter of the cladding (125 microns at first) is reduced to several tens of microns.

Each of the optical fibers having been subjected to such a tip processing is arranged on a substrate having a groove formed on the surface as shown in FIG. This substrate is formed with U-shaped grooves at the ends corresponding to the number of optical fibers arrayed, and holds a portion covered with the optical fiber at this portion. On the other hand, a V-shaped groove is formed at the opposite end of the substrate, into which the tip of the optical fiber whose outer diameter has been reduced by etching is dropped. Next, a glass plate is applied from above the optical fiber, and the optical fiber is sandwiched between the glass plate and the substrate. Thereafter, the space between the glass plate and the substrate is filled with an adhesive such as an ultraviolet curable resin and then cured, and the light emitting end face of the optical fiber is polished.

In the optical fiber array of this reference, the accuracy of the finally completed optical fiber array is the same as that of the previous example in the manufacturing accuracy of each optical fiber, the manufacturing accuracy of the V-shaped groove, and the flat plate for holding the optical fiber from above. It still depends on multiple factors such as the flatness of. Since these various factors accumulate and affect the final accuracy, it is necessary to minimize the error of each element in order to improve the accuracy, but nothing is said about this . Further, even if the plurality of error factors described above are reduced, there is a physical limit, so that it has been difficult to realize a more accurate optical fiber arrangement.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical fiber array element capable of realizing a highly accurate optical fiber array in an optical fiber array.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of optical fibers for receiving and propagating light emitted from a light source, and an optical fiber array in which the tips of the plurality of optical fibers are arranged. An optical fiber holding member for disposing at equal intervals in the direction, a flat plate member to which the optical fiber is applied, and an optical fiber array element including an adhesive filled between the flat plate member and the optical fiber holding member,
The array structure was such that the eccentric direction of the core and the clad of the optical fiber matched the arrangement direction of the optical fiber.

In this case, the optical fiber holding member is, for example, a V-groove substrate having a plurality of V-shaped groove structures formed at equal intervals on the surface, and the V-shaped groove structure of the V-groove substrate is It is manufactured by anisotropic etching of a Si wafer or by dicing any one of a Si wafer, a ceramic, and a glass material using a diamond blade saw.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic sectional view of an optical fiber array element according to an embodiment of the present invention, taken in a direction in which optical fibers are arranged. The distal ends of these optical fibers are formed on the substrate 1 constituting the optical fiber holding member, and are arranged at equal intervals in the optical fiber arrangement direction by V-shaped grooves 1a. In this arrangement, the flat plate member 8 is applied from above the substrate, and an adhesive is filled and hardened between the flat plate member 8 and the V-groove substrate 1 to fix the optical fiber 3. In the figure, white small points and black small points drawn in the optical fiber 3 indicate the amount of eccentricity between the core and the clad. In the present embodiment, the eccentric direction between the core and the clad is represented by the arrangement direction of the optical fiber 3. Has an array structure that matches the above.

Next, a manufacturing process of the optical fiber array element of the present embodiment will be described with reference to the process charts of FIGS.

An optical fiber holding member 1 shown in FIG.
Is a V-groove substrate having a plurality of V-shaped groove structures formed at equal intervals on the surface. The V-shaped groove structure of the V-groove substrate is anisotropic etching of a Si wafer or a diamond blade saw. It is manufactured by dicing of a Si wafer, ceramic, glass material, or the like using the above method.

The space between the V-grooves formed on the V-groove substrate 1 is usually several tens to several hundreds of microns. As shown in FIG. 2A, this V-groove substrate 1 is placed on a flat base 2 made of glass or ceramic so that the side edges of the base 2 and the direction of the V-groove are parallel. Pasted in.

Next, as shown in FIG. 2B, a plurality of independent optical fibers 3 (five in the figure) are prepared. The part 7 is exposed. Each of the optical fibers 3 whose tip portions are exposed is arranged so as to be adjacent to each other, and a part of the portion covered with the coating is fixed to the end of the base 2, while the tip portions of these optical fibers are One optical fiber is dropped into one V-groove arranged at equal intervals so as to be gathered substantially at the center on the V-groove substrate.

Thereafter, as shown in FIG. 2C, a flat plate member 8 is applied from above the optical fiber, and an adhesive is filled between the flat plate member 8 and the V-groove substrate. The optical fiber is sandwiched and cured while being pressed by the 8 and V-groove substrate 1.

FIG. 4 is an enlarged view of the end of the optical fiber 3, the V-groove substrate 1, and the flat plate member 8 showing the error i factor of each array element component, which causes an accuracy error of the optical fiber array element.

As shown in FIG. 4, the arrangement accuracy and the linearity between the cores of the optical fibers, which are the production accuracy of the optical fiber array, are determined by (1) the production accuracy of each optical fiber, that is, the outer diameter of the clad. , The circularity of the cladding, the deviation between the center of the cladding and the center of the core (the amount of eccentricity), and (2) the manufacturing accuracy of the substrate 1 on which the V-shaped groove 1a is formed, that is, the V-groove interval and the V-groove depth. It can be seen that the angle of the V-groove and (3) the flatness of the flat plate that presses the optical fiber from above.

Since these various factors accumulate and affect the final production accuracy of the optical fiber array, it is necessary to realize a more precise optical fiber arrangement that can tolerate only a submicron order arrangement error. ,
It is of utmost importance to reduce the number of the various factors mentioned above, which are error factors.

Here, consider the use of an optical fiber array for a multi-beam light source of a laser beam printer as a mode of use of the present invention.

FIG. 3 shows an optical system of a laser beam printer using a multi-beam generating optical fiber array as a light source.

In this optical system, a beam 10 emitted from an optical fiber array 9 of a light source irradiates a rotating polygon mirror 12 rotating at an equal angular velocity via an optical system 11. The light reflected by the rotary polygon mirror 12 is transmitted to the photosensitive drum 1 as an optical recording medium by an FΘ lens 13 disposed at the rear.
An image is formed as a plurality of minute light spot rows on the photosensitive drum 4 and the photosensitive drum is scanned at a constant speed. At this time, the semiconductor laser light source 15 at each of the optical fiber input ends of the optical fiber array 9 is connected to a character from an external controller (not shown).
By performing on-off according to the image data signal, character / image information is recorded on the photosensitive drum 14. The laser detector timing is determined by the photodetector 20.

At this time, since the minute light spot array on the photosensitive drum 14 merely forms an image on the drum by enlarging the end face of the optical fiber array 9 with a predetermined magnification, the light spot generally has a size corresponding to the size of the light spot. The arrangement interval of spots increases.
Therefore, in order to form a scanning line interval adjacent to each other on the photosensitive drum, scanning is performed by obliquely arranging the light spot rows.

However, at this time, if the optical fiber arrangement error of the original optical fiber array 9 is large, the interval between the scanning lines on the photosensitive drum also varies, thereby deteriorating the print quality.

Since the light spot array on the photosensitive drum is often set at an angle close to the horizontal, the scanning line spacing hardly affects the arrangement error in the optical fiber arrangement direction, but the scanning line interval is perpendicular to the arrangement direction. This has a sensitive effect on the placement error.

In order to solve this problem, in this embodiment, when the optical fiber is arranged on the V-groove as shown in FIG. 1, the optical fiber is rotated in the direction in which the optical fiber is arranged. And the eccentric directions of the core and the clad are matched.

By doing so, one of the error factors that determine the alignment accuracy of the optical fiber can be eliminated, and the linearity of the core can be improved with the current optical fiber and the V-groove substrate. This makes it possible to easily realize an optical fiber array with higher precision than a conventional optical fiber array.

When assembling the optical fiber array, in order to easily match the arrangement direction of the optical fiber with the eccentric direction of the core and the clad, it is necessary to mark the optical fiber in consideration of the assembling workability. good.

[0032]

As described above, according to the present invention, in the optical fiber array element, the alignment direction of the optical fiber and the eccentric direction of the core and the clad are easily matched to each other, so that the conventional optical fiber array can be improved. An optical fiber array with high accuracy can be easily realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross section of an optical fiber array element according to an embodiment of the present invention in an optical fiber arrangement direction.

FIG. 2 is an explanatory view showing a manufacturing process of the optical fiber array element of the embodiment.

FIG. 3 is a diagram showing an example in which the optical fiber array element of the embodiment is mounted on a laser printer as a multi-beam generating light source.

FIG. 4 is a diagram showing an error i-factor of each element part of the optical fiber array.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical fiber holding member, 3 ... Optical fiber, 6 ... Optical fiber coating part, 7 ... Optical fiber cladding part, 8 ... Flat plate member, 9 ... Optical fiber array, 10 ... Outgoing beam, 11
... Optical system, 12 ... Rotating polygon mirror, 13 ... FΘ lens, 14
... a photosensitive drum, 15 ... a semiconductor laser light source, 20 ... a photodetector.

Claims (3)

[Claims] A plurality of optical fibers for receiving and propagating light emitted from a light source; an optical fiber holding member for arranging distal ends of the plurality of optical fibers at regular intervals in an optical fiber arrangement direction; An optical fiber array device comprising: a flat plate member for holding down an optical fiber; and an adhesive filled between the flat plate member and the optical fiber holding member. An optical fiber array element having an array structure in which the fibers are arranged in the same direction. 2. The optical fiber holding member is a V-groove substrate having a plurality of V-shaped groove structures formed at regular intervals on the surface, and the V-shaped groove structure of the V-groove substrate is a Si wafer. 2. The optical fiber array element according to claim 1, wherein said optical fiber array element is produced by anisotropic etching. 3. The optical fiber holding member is a V-groove substrate having a plurality of V-shaped groove structures formed at regular intervals on the surface, and the V-shaped groove structure of the V-groove substrate is a dicing process. The optical fiber array element according to claim 1, wherein the optical fiber array element is manufactured by the following method.