JPH1152207A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device capable of enhancing accuracy and reliability and reducing production costs by decreasing the number of alignments, that is, positionally adjusted places and simplifying alignment work. SOLUTION: In the optical device 10 including a lens base plate 11 in which a lens 13 is formed and an optical element 12 optically coupled to the lens 13, a receiving hole 14 for receiving the optical element 12, in a state where the optical axis 20 of the lens 13 formed in the lens base plate 11 is coincident with the optical axis 17 of the optical element 12, is formed in the lens base plate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical device suitable for use in optical communication.

[0002]

2. Description of the Related Art In optical communication, light from a photoelectric conversion element such as a laser diode is guided to an optical fiber via an optical lens system. Such an optical system includes, for example, a first collimator formed of, for example, a convex lens that parallelizes light from a light emitting surface of a light emitting element such as a laser diode,
The parallelized light is condensed on a light receiving surface of another optical element such as an optical fiber, and is constituted by a second collimator formed of, for example, a convex lens.

[0003]

By the way, in the above-mentioned conventional optical system assembly, a plurality of optical elements manufactured as individual independent parts are sequentially aligned with their respective optical axes. In addition, alignment, that is, position adjustment is necessary so that the lens focal point of the first collimator is aligned with the light emitting surface of the light emitting element and the second collimator lens is aligned with the light receiving surface of the light receiving element. . In the manufacture of an optical device, reducing the number of parts requiring an alignment operation and simplifying the alignment operation leads to an improvement in accuracy and reliability of the optical device, and a reduction in manufacturing cost.
Therefore, the appearance of an optical device capable of reducing and simplifying the alignment work has been desired.

[0004]

The present invention adopts the following constitution in order to solve the above points. <Structure> The present invention provides a lens substrate on which a lens is formed,
An optical device optically coupled to a lens, the lens device comprising: a lens substrate for receiving the optical element by aligning an optical axis of the optical element with an optical axis of a lens formed on the lens substrate. A receiving hole is formed.

<Operation> In the optical device according to the present invention, by inserting the optical element into a receiving hole provided in the lens substrate, a lens which is an optical element formed on the lens substrate, In the coaxial state where the optical axis and the optical element inserted into the receiving hole are mutually aligned,
Can be assembled. Accordingly, by positioning the optical element in the receiving hole in accordance with the focal length of the lens, the lens and the optical element are aligned with the two optical elements, that is, the position adjustment is completed.
It can be handled as one optical element unit.

[0006] Therefore, when this optical unit is incorporated into another optical element, the number of alignments, that is, the number of positions to be adjusted can be reduced as compared with the assembling operation of individual independent optical elements, and the alignment operation can be simplified. Therefore, the accuracy and reliability of the optical device can be improved, and the manufacturing cost can be reduced.

[0007] By setting the depth dimension of the receiving hole formed in the lens substrate to an appropriate value in advance so that the optical element corresponds to the focal position of the lens of the lens substrate, the optical element is simply obtained. Is properly inserted into the receiving hole, in addition to the axis alignment of the optical element and the lens of the lens substrate, the position of the optical device and the lens in the lens focal direction can be adjusted. Special alignment of the lenses and optical elements constituting the unit, that is, position adjustment work can be eliminated.

An optical fiber, a light emitting element, a light receiving element or the like can be adopted as an optical element inserted into the receiving hole of the lens substrate. In addition, as a lens formed on the lens substrate, in addition to a normal shaped lens formed by polishing, a computer generated hologram obtained by etching a lens material using a mask obtained by executing a CAD program by a computer as an etching mask, A graded-index lens formed by ion exchange or a lens formed by dropping a photoresist material that shows good translucency for the wavelength used on a lens substrate and heating and melting this , Various lenses can be employed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. Embodiment 1 FIG. 1 shows an optical device according to the present invention. As shown in FIG. 1, the optical device 10 according to the present invention includes a lens substrate 11 made of a lens material, and an optical element 12 coupled to the lens substrate. Lens substrate 11
Examples of the lens material include quartz, optical glass, and silicon that transmits light having a wavelength of 1 μm or more used for optical communication. In the illustrated example, a CGH (computer hologram) that is a circular lens is provided on the lens substrate 11.
An element 13 and a cylindrical receiving hole 14 for receiving the optical element 12 optically coupled to the CGH element are formed. In the illustrated example, the optical element 12 is a conventionally well-known optical fiber including a core portion 15 and a clad portion 16, has a uniform circular cross section in the longitudinal direction along the central axis 17, and has a light receiving surface 18. It functions to guide the received light from the lens substrate 11 to a desired place.

The CGH element 13 is formed on one surface 19 of the lens substrate 11 and has a convex condensing lens function of condensing light on the optical axis 20 at a focal point O separated by a focal length f. Such a CGH13 element can be formed in the following order, as is well known in the art.

That is, an optical path difference function ρ (x, y) showing desired optical characteristics is obtained, and this optical path difference function ρ (x, y) is subjected to, for example, Taylor expansion to obtain an optical path difference coefficient Cn. By executing a CAD program using these optical path difference coefficients Cn, a plurality of masks for the CGH element 13 exhibiting desired optical characteristics are obtained. An etching mask is formed on the lens substrate 11 by photolithography using these masks.
By performing selective etching using this etching mask, the CGH element 13 having desired optical characteristics and having small aberrations is formed on the lens substrate 11.

The receiving hole 14 is provided on the surface 1 of the lens substrate 11.
It opens to the other surface 21 located on the side opposite to 9, extends toward the CGH element 13 from this open end, and closes in the lens substrate 11. The central axis 22 of the receiving hole 14 is CGH1
3 coincides with the optical axis 20. The inner diameter d of the receiving hole 14 is
It is approximately equal to the outer diameter of the optical fiber 12 so that the optical fiber 12 is received without radial play in the hole. The closing surface 23 of the receiving hole 14 is the CGH element 1
The depth dimension D of the receiving hole 14 is set to coincide with the position of the focal point O of No. 3.

Accordingly, in the illustrated example, the optical element 12 is
By inserting the light receiving surface 18 into the receiving hole 14 such that the light receiving surface 18 comes into contact with the closed surface 23 of the receiving hole 14, the light receiving surface 18 receiving the light of the optical element 12 is changed to the CGH element 13.
At the focal point O of Since the optical element 12 having a circular cross section is received in the receiving hole 14 without play in the radial direction, the central axis 17 serving as the optical axis of the optical element 12 is the central axis of the receiving hole 14. 22, the optical axis 2 of the CGH element 13
0 can be made to coincide with the optical axis of the optical element 12, that is, the central axis 17. Therefore, the optical element 12 and the CGH1
The optical element 12 and the CGH 13 can be easily positioned in this coupled state by fixing both the optical element 12 and the CGH 13 using, for example, a fixing adhesive.

As a result, the parallel light 24 incident on the CGH element 13 is converted into the CGH 1
Concentrate on 3 focus O. Light concentrated at the focal point is transmitted from the light receiving surface 18 of the optical element 12 located at the focal point O to the optical element 12.
And is guided to a desired location along the longitudinal direction of the optical element 12.

In such an optical device 10, by positioning the optical element 12 and the CGH 13 in advance so as to be optically properly coupled, both the optical element 12 and the CGH 13 can be unitized. Therefore, the unitized optical element 12 and CGH element 13 can be incorporated as an optical device 10 into an optical system. From this, the optical system 12 and the CGH device 13 are added to the optical system.
Are compared to incorporating both individually 12 and 13
Since the mutual alignment, that is, the position adjustment, becomes unnecessary, alignment work in the production of the optical device can be eliminated and simplified, and the accuracy and reliability of the optical device can be improved.

The receiving hole 1 of the optical device 10 according to the present invention.
4 can be formed deep beyond the focal point O of the CGH element 13. However, when the optical element 12 is inserted into the receiving hole 14, it is necessary to adjust the light receiving surface 18 of the optical element 12 so as to match the position of the focal point O of the CGH element 13. In order to achieve this, it is desirable to set the depth dimension D of the receiving hole 14 in correspondence with the focal point O of the CGH element 13 as shown in the figure.

FIG. 2 shows another optical device according to the present invention. In the optical device 30 according to the present invention, as shown in FIG. 2, a shape lens 31 formed of a convex lens is used as a lens formed on the lens substrate 11. As is well known in the art, the shape lens 31 is formed on one surface 19 of the lens substrate 11 by polishing, and converts light emitted from a focal point O having a focal length f on the optical axis 32 into parallel light. Has functions. Further, as an optical element optically coupled to the shape lens 31, the light emitting element 3
3 is used.

An adapter 34 having a circular cross section is employed for optically coupling the shape lens 31 and the light emitting element 33. The adapter 34 has a cylindrical base 35 that can contact the other surface 21 of the lens substrate 11.
And a cylindrical insertion portion 36 formed coaxially and integrally with the base portion and received in the receiving hole 14. The insertion section 36 is provided with a mounting section 37. A light emitting element 33 made of, for example, a light emitting diode is attached to a tip of the attachment portion.

In the illustrated example, the insertion portion 36 is inserted into the receiving hole 14 such that the base 35 of the adapter 34 contacts the other surface 21 of the lens substrate 11.
For example, the thickness dimension of the insertion section 36 and the length dimension of the attachment section are properly adjusted so that the light emitting element 33 attached to the attachment section 37 on the distal end surface of the insertion section 36 is located at the position of the focal point O of the shape lens 31. Is set.

Therefore, by inserting the insertion portion 36 into the hole of the receiving hole 14 so that the base portion 35 comes into contact with the other surface 21 of the lens substrate 11, the axis 38 passing through the light emitting point of the light emitting element 33, The optical axis and the optical axis 32 of the shape lens 31 can be matched, and the light emitting point of the light emitting element 33 can be located at the position of the focal point O of the shape lens 31. Therefore, optical coupling between the shape lens 31 and the light emitting element 33 can be easily performed. By fixing the adapter 34 to the lens substrate 11 in this coupled state, both the shaped lens 31 and the light emitting element 33 can be positioned relative to each other. Thereby, light from the light emitting element 33 located at the focal point O of the shape lens 31
, The light becomes parallel collimated light as is well known in the art.

In the optical device 30, similarly to the optical device 10, by positioning the shape lens 31 and the light emitting element 33 in advance so as to be optically coupled, both of them can be unitized.

Further, the collimated light obtained from the optical device 30 formed by using the unitized shape lens 31 and the light emitting element 33 is transmitted to the CGH element 1 of the optical device 10.
Both devices 30 and 10 can be combined to provide three incident lights. This makes it easier to assemble the optical system. Therefore, it is possible to eliminate and simplify the alignment work in assembling the optical system, and to improve the accuracy and reliability of the optical system.

As described above, the CGH element 1 having a light-condensing function is used as a lens formed on the lens substrate 11.
Although the example of the lens 3 and the shape lens 31 has been described, a concave lens or a prism lens having a deflecting function can be used instead.

[0024]

As described above, in the optical device according to the present invention, the optical element is placed in the receiving hole 14 of the lens substrate 11 according to the focal point O separating the focal length f of the lens formed on the lens substrate 11. By positioning, the lens formed on the lens substrate 11 and the optical element inserted into the receiving hole can be handled as one optical unit in which these two alignments, that is, the position adjustments are completed.

Therefore, according to the present invention, it is possible to reduce the number of alignments, that is, position adjustments, when incorporating this optical unit into another optical element, as compared with the work of assembling individual optical elements. As a result, the alignment operation can be simplified, so that the accuracy and reliability of the optical device can be improved, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an optical device according to the present invention.

FIG. 2 is a sectional view showing another optical device according to the present invention.

[Explanation of symbols]

 10, 30 Optical device 11 Lens substrate 12, 33 Optical element (optical fiber, light emitting element) 13, 31 Lens (CGH element, shaped lens) 14 Receiving hole 17, 38 Optical axis of optical element 20, 32 Optical axis of lens f Lens Focal length of O lens focus

Claims (4)

[Claims] A lens substrate having a lens formed thereon, and an optical element optically coupled to the lens, wherein the optical axis of the optical element coincides with the optical axis of the lens. An optical device, wherein a receiving hole for receiving the optical element is formed. 2. The optical device according to claim 1, wherein the optical element is unitized by being positioned at an appropriate position in the receiving hole in the lens substrate. 3. The optical device according to claim 1, wherein a depth dimension of the receiving hole is set to an appropriate value so that the optical element corresponds to a focal position of the lens. 4. The optical device according to claim 1, wherein the optical element is one of an optical fiber, a light emitting element, and a light receiving element.