JP2002328204A - Microlens and optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microlens which is easily handled compared with conventional lenses. SOLUTION: The lens is provided with a handling part 18 in one side of the edge of the lens face 16 in such a manner that the part 18 is linearly extended on the plane parallel to the lens face and over the lens face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens suitable for application to optical communication equipment and an optical module including the same, and more particularly, to a microlens such as a CGH element. The present invention relates to a microlens and an optical module.

[0002]

2. Description of the Related Art A microlens optically coupled to an optical element such as a laser diode or an optical fiber used in optical communication is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-199006.
And JP-A-11-295561. According to the former, it is proposed to use a spherical ball lens as the micro lens, and according to the latter,
It has been proposed to provide an annular portion at the edge of the circular lens surface of the microlens. These microlenses are arranged in grooves formed on a semiconductor substrate on which the above-described optical element is mounted, so that the optical elements are aligned with each other and optically properly coupled to each other. And so on.

[0003]

The diameter of a conventional microlens such as the above-mentioned ball lens or a microlens provided with an annular portion has a diameter of 10 mm.
It is only about 0 μm to 200 μm, and it is not easy to handle a micro lens for arranging such an extremely small lens at a predetermined position. In a microlens provided with an annular portion, a flat surface is defined on the annular surface surrounding the lens surface, but since the peripheral surface of the lens is a circular curved surface, negative pressure from the side of the lens is used. Not suitable for holding by suction.

Therefore, an object of the present invention is to provide a microlens which is easier to handle than conventional ones. Another object of the present invention is to provide a microlens that can easily hold by suction using negative pressure. Still another object of the present invention is to provide an optical module including a microlens that is easy to handle.

[0005]

The present invention employs the following structure to achieve the above object. <Structure> The present invention relates to a microlens comprising an optical substrate having a lens surface formed thereon, and on one side of an edge of the lens surface, a straight line extending beyond the lens surface on a plane parallel to the lens surface. An overhanging handling section is formed.

The handling portion according to the present invention projects linearly beyond the lens surface. Therefore, by holding the handling portion using a holding means or a negative pressure suction means, it is possible to handle the micro lens when handling the micro lens. Since the holding at the handling portion is enabled, the microlens can be handled more easily than before, without damaging the lens surface or contaminating the lens surface during handling.

The handling portion can be integrated with the edge at an intermediate portion between both ends. Further, the handling portion can be formed in a cantilever shape.

It is preferable that a flat surface is formed in the handling portion so as to facilitate suction and holding by a suction means from the side of the lens surface.

[0009] The flat surface of the handling portion may be constituted by an upper flat surface which is perpendicular to the lens surface and extends along the direction in which the handling portion extends.

[0010] The handling portion may be formed to be asymmetrical left and right with respect to an imaginary plane that includes the optical axis of the lens surface and specifies the one of the two surfaces of the optical substrate and crosses the handling portion. Further, a mark for specifying one of the two surfaces of the optical plate can be provided on the handling portion. When a lens surface is formed on one of the surfaces of the optical substrate by making the handling portion asymmetrical or by marking the handling portion, it is easy to determine which surface this lens surface is. In the case where lens surfaces having different optical characteristics are formed on both surfaces of the optical substrate, it is easy to determine which one of the lens surfaces exhibits the other optical characteristic.

[0011] A plurality of lens surfaces can be formed in alignment on the optical substrate, and in this case, the handling portion can be extended along the alignment direction of the lens surfaces.

A crystal substrate such as a silicon crystal substrate can be used as the optical substrate. A diffractive optical element utilizing a diffraction phenomenon can be formed on the lens surface.

The microlens is disposed in the groove so as to face an end face of the optical fiber so that the microlens is optically coupled to the optical fiber disposed in the groove formed in the support substrate. In this case, a matching portion having an outer diameter equal to the outer diameter of the optical fiber can be formed on the other side of the edge of the lens surface. An optical module can be constituted by the support substrate and an optical fiber on the support substrate and a microlens optically coupled to the optical fiber, and the microlens is formed in the groove on the support substrate. By adapting the adapting portion, the optical axis of the optical fiber arranged in the groove and the microlens adapted to the groove can be relatively easily and accurately adjusted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows an optical module including a microlens according to the present invention. Optical module 10 according to the present invention
A supporting substrate 11 such as a silicon crystal substrate;
A light source 12, such as a semiconductor laser, provided on the surface 11a of the support substrate; and an optical fiber 14, one end of which is positioned by a groove 13 formed on the surface 11a of the support substrate 11, to receive light from the light source. And a pair of microlenses 15a and 15b arranged at an interval between the optical fiber and the light source 12.

One micro lens 15a disposed near the light source 12 has a collimating function on its surface facing the light source 12, which receives the divergent light from the light source and converts the divergent light into a parallel light flux. A circular lens surface 16 comprises an optical substrate 17 formed on a surface facing the light source 12.
The one microlens 15a and the optical fiber 1
4 has a circular lens surface 16 for condensing the parallel light beam passing through the one micro lens 15a on the center of the end surface 14a of the optical fiber 14. Consists of an optical substrate 17 formed on the surface facing the end face 14a of the optical fiber.

Therefore, both micro lenses 15a and 15a
5b, in the illustrated example, a lens surface 16 exhibiting optically equivalent optical characteristics is formed on the outer surface of the optical members 15a and 15b on the opposite side to the surfaces facing each other. When the optical fiber 14 is formed of, for example, a single mode optical fiber, it has an outer diameter of about 125 μm, and the lens surface 16 of each of the microlenses 15a and 15b has a smaller value than the outer diameter of the optical fiber 14. It is formed with a diameter.

The concave groove 13 on the supporting substrate 11 is a V-shaped concave groove in the example shown in the figure, and the optical fiber 14 is partially received in the peripheral groove by the optical fiber 14. Is properly supported on the support substrate 11. Also,
The light source 12 is formed using a photolithography technique used in a semiconductor manufacturing technique so that an optical axis of a light emitting surface thereof coincides with an optical axis of an optical fiber 14 positioned by the concave groove 13. Well-known electrode 12 '
Is fixed on the surface 11a in the vicinity of the terminal end of the groove 13.

As described above, the pair of microlenses 15a and 15b disposed between the light source 12 and the optical fiber 14 are optically equivalent. However, the focal lengths of the two can be different from each other or can be the same depending on the application. Hereinafter, these microlenses 15a and 15b will be further described.

Each of the microlenses 15a and 15b is composed of the optical substrate 17 on which the circular lens surface 16 is formed as described above. As the optical substrate, the light source 12 described above is used.
When the light from the substrate is light having a wavelength of, for example, 1.3 μm or 1.5 μm, a crystal substrate such as a silicon crystal substrate can be used.

As described above, the lens surface 16 having a smaller diameter than the outer diameter of the optical fiber 14 is formed on one surface of the optical substrate 17 as described above. In order to form the lens surface 16, each of the microlenses 15 a and 15 b can be formed by a CGH element, which is one of the diffractive optical elements, using a photolithography / etching technique used in a semiconductor manufacturing technique.

In the CGH element, as is well known, a photomask pattern necessary for obtaining a desired optical characteristic is obtained from an optical path difference function of an optical element exhibiting a desired optical characteristic by using a computer. By performing an etching process on a desired portion of the optical substrate using the mask pattern, a diffractive optical element having desired optical characteristics is formed. Therefore, the lens surface 16 exhibiting the desired diffractive optical characteristics can be formed by etching the desired portion of the optical substrate 17 using the mask pattern described above.

The lens surface 16 is not limited to the above-described diffractive optical lens surface, but may be a refraction-type lens surface.
It can be formed in a desired planar shape.

In the illustrated example, a handling portion 18 having a length L of, for example, 250 to 300 μm is integrally formed on one side of the circular lens surface 16. Handling section 18
Is formed integrally with the edge so as to surround the upper half of the edge of the lens surface 16 at an intermediate portion between both ends thereof,
Moreover, the left and right sides are symmetrical with respect to a virtual plane P (see FIG. 2) passing through the optical axis of the lens surface 16, that is, a vertical plane.
Extends linearly in the lateral direction. The handling section 18 has a height H of 100 to 200 μm and a height H of 100 to 200 μm, for example.
It has an overall rectangular cross-sectional shape having a lateral dimension W of about 200 μm, and a rectangular flat surface 18a is defined on its upper surface.

Further, in the illustrated example, on the other side of the edge of the lens surface 16, a fitting portion 19 formed of an arc-shaped edge along the outer edge of the lens surface is integrally formed. The outer diameter of this arcuate edge, or conforming portion 19, is
Is set equal to that of Accordingly, each of the microlenses 15a and 15b has an optical axis 14 of the optical fiber 14 arranged on the concave groove 13 by positioning the arc-shaped edge 19 on the concave groove 13 with the lens surface 16 thereof oriented in a predetermined direction. Then, the optical axes can be matched.

At this time, the flat lower surface 18b excluding the arc-shaped edge 19 of the handling portion 18 is
Get on 1a. Therefore, the support substrate 11 is provided on the lower surface 18b.
Can be fixed.

In the optical module 10 according to the present invention, when each of the microlenses 15a and 15b is mounted on the support substrate 11, a handling portion 18 that protrudes from the lens surface 16 in both lateral directions along the lens surface is sandwiched. For example, a negative pressure holding means such as a negative pressure sucker for sucking and holding the holding portion or the handling portion 18 on the upper flat surface 18a can be used. In the handling at the handling portion 18, the lens surface 16 does not come into contact with the means for handling, so that the handling causes the lens surface 16 to be contaminated by the adhesion of oil and dust due to the contact. And there is no damage due to the aforementioned contact.

Therefore, by the handling in the handling section 18,
Since the microlenses 15a and 15b can be relatively easily arranged at appropriate positions in a predetermined posture, the assembling work of the optical module 10 is quick and easy.

<Examples 2 and 3> As shown in FIG. 2, the handling portion 18 is formed symmetrically with respect to a virtual plane P (see FIG. 2) passing through the optical axis of the lens surface 16, that is, a vertical plane. In this case, a mark 20 that clearly indicates which of the two surfaces of the optical substrate 17 has the lens surface 16 formed thereon can be attached to the handling portion 18.

In the example shown in FIG.
Is formed on one side of the flat surface 18a. In this example, when the microlenses 15a and 15b are viewed so that the mark 20 is located on the left hand, it can be easily known that the lens surface 16 is located in front of the microlenses 15a and 15b.

Further, the lens surface can be formed on the surface of the optical substrate 17 on the side opposite to the surface on which the lens surface 16 is provided.
Each lens surface can be easily identified.

Therefore, when the micro-lenses 15a and 15b are arranged at predetermined locations by holding the handling portion 18 or holding the flat surface 18a of the handling portion by suction, the lens surfaces 16 of the micro-lenses 15a and 15b can be easily identified. Therefore, the assembling work of the optical module 10 is further facilitated.

Instead of the mark 20, as shown by a virtual line in FIG. 2, a virtual plane P (see FIG. 2) passing through the optical axis of the lens surface 16 of the handling section 18, that is, one of the right and left half of the vertical plane. Is provided with an extension 18 ', the handling section 18 can be made asymmetrical in the left-right direction.
The asymmetry 8 allows the lens surface 16 of the optical substrate 17 to be easily identified.

Further, in the above description,
Although the example in which the handling portion 18 greatly extends in both lateral directions beyond the lens surface on the lens surface 16 has been described, by extending the handling portion 18 in only one lateral direction of the lens surface 16, It can be formed in a so-called cantilever shape.

<Embodiment 4> The example shown in FIG. 3 is a micro lens 1 in which a plurality of lens surfaces 16 are formed in a single handling section 18 at intervals in the extending direction of the handling section.
5c is shown. At the lower edge of each lens surface 16 is formed a fitting portion 19 (not shown) that fits into the concave groove 13 on the support substrate 11 that receives the optical fiber 14, as in the above-described example. Also in this example, the mark 20 as shown in FIG. 2 can be provided.

In the above description, the example in which the concave groove 13 is a V-shaped groove has been described, but the present invention is not limited to this.
4 can be provided with various cross-sectional shapes.

[0036]

According to the present invention, as described above, on one side of the edge of the lens surface, there is formed a handling portion which extends linearly beyond the lens surface on a plane parallel to the lens surface. This facilitates the handling operation at the handling portion that extends linearly beyond the lens surface. Further, the handling operation in the handling section makes it possible to handle the microlens without damaging the lens surface of the microlens and without contaminating the lens surface.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical module including a microlens (specific example 1) according to the present invention.

FIG. 2 is a perspective view showing specific examples 2 and 3 of the microlens according to the present invention.

FIG. 3 is a perspective view showing a specific example 4 of the microlens according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 optical module 11 support substrate 13 concave groove 14 optical fiber 15a, 15b, 15c micro lens 16 lens surface 17 optical substrate 18 handling unit 18a flat surface

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01S 5/022 H01S 5/022 (72) Inventor Takeshi Takamori 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industrial Co., Ltd. In-house (72) Inventor Hitori Maeno 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.F-term (reference) EE08 EE16 FF14 5F073 AB27 AB28 BA01 FA07 FA08 FA13

Claims (12)

[Claims] 1. An optical substrate on which a lens surface is formed, and a handling portion that protrudes linearly beyond the lens surface on a side parallel to the lens surface on one side of an edge of the lens surface. A microlens characterized by forming a microlens. 2. The microlens according to claim 1, wherein the handling portion is integrated with the edge at an intermediate portion between both ends. 3. The microlens according to claim 1, wherein the handling section has a flat surface for facilitating suction and holding by suction means from a side of the lens surface. 4. The microlens according to claim 3, wherein the flat surface of the handling portion is an upper flat surface that is perpendicular to the lens surface and extends in a direction in which the handling portion extends. 5. The optical system according to claim 1, wherein the lens surface is formed on one surface of the optical substrate, and the handling unit includes an optical axis of the lens surface to identify one of both surfaces of the optical substrate. 2. The microlens according to claim 1, wherein the microlens is formed asymmetrically with respect to an imaginary plane crossing the portion. 6. The lens surface is formed on one surface of the optical plate, and the handling portion is provided with a mark for identifying one of both surfaces of the optical plate. The microlens according to claim 1, wherein: 7. The microlens according to claim 1, wherein a plurality of lens surfaces are formed in alignment on the optical substrate, and the handling portion extends in the direction in which the lens surfaces are aligned. 8. The method according to claim 1, wherein the optical substrate is a crystal substrate. 9. The method according to claim 8, wherein the crystal substrate is a silicon crystal substrate. 10. The method according to claim 1, wherein the microlens is a diffractive optical element. 11. A microlens disposed in said groove so as to face an end face of said optical fiber so as to be optically coupled to an optical fiber disposed in a groove formed in a support substrate. 2. The microlens according to claim 1, wherein a fitting portion having an outer diameter equal to the outer diameter of the optical fiber is formed on the other side of the edge of the lens surface. 12. An optical fiber disposed in a groove formed in a support substrate, and a microlens disposed in the groove so as to be optically coupled to the optical fiber and opposed to an end face of the optical fiber. An optical module including: a handling portion that linearly extends beyond the lens surface on a surface parallel to the lens surface on one side of the edge of the lens surface of the microlens. An optical module, wherein a fitting portion having an outer diameter equal to the outer diameter of the optical fiber is formed on the other side of the edge.