JP2002131532A - Dielectric multilayered film filter and dielectric multilayered film filter module having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric multilayered film filter and a dielectric multilayered film filter module having the above filter such that the filter substrate as a holding body of the dielectric multilayered film is made thick and the dielectric multilayered film is held only by the substrate so as to allow only the dielectric multilayered film to be present, that the transmission loss of light is extremely little and that the filter can be easily manufactured and handled. SOLUTION: The dielectric multilayered film filter is obtained by preparing the filter substrate 4 having a pyramid-like through hole 41 composed of tapered guide parts 411 and a through hole 412, then forming a metal thin film 42 on the surface of the filter substrate 4 except for the through hole 412 region, and then forming a dielectric multilayered film 12 on the surface of the metal thin film 42 including the through-hole 412 region. The dielectric multilayered film filter module has the above filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric multilayer filter and a dielectric multilayer filter module having the same, and more particularly to a dielectric multilayer filter having a guide holding plate for guiding and holding an optical fiber and having the same. The present invention relates to a dielectric multilayer filter module.

[0002]

2. Description of the Related Art A conventional example will be described with reference to the drawings. Referring to FIG. 4, a conventional example of a dielectric multilayer filter will be described.
This dielectric multilayer filter 1 is formed by forming a dielectric multilayer film 12 on the surface of a thin glass plate 11. This dielectric multilayer filter 1 is formed by forming a dielectric multilayer filter on a thin glass plate having a thickness of about 100 μm and having a large area, and performing dicing to cut the filter into a size of several mm square.

Referring to FIG. 5, a conventional example of a dielectric multilayer filter module incorporating a dielectric multilayer filter will be described. A dielectric multilayer filter 1 is formed on the surface of a substrate 3 having a V-shaped cross section. It is inserted into the slit 32.
After the dielectric multilayer filter 1 is inserted into the slit 32 of the cross-sectional V-groove forming substrate 3, the slit 32 is filled with a transparent adhesive 33 and fixed to the cross-sectional V-groove forming substrate 3. Here, the input optical fiber 21 and the transmission / reception optical fiber 23 were positioned in the cross-sectional V-groove 31 formed in the cross-sectional V-groove forming substrate 3, and the fiber end faces were opposed to each other through the dielectric multilayer filter 1. In this state, it is bonded and fixed to the cross-sectional V-groove forming substrate 3.

Referring to FIG. 6, another conventional example of a dielectric multilayer filter module incorporating a dielectric multilayer filter will be described. The dielectric multilayer filter 1 is a dielectric filter having no thin glass plate 11. This is a conventional example composed of only the multilayer film 12. The dielectric multilayer filter 1 composed of only the dielectric multilayer film 12 is formed by forming a dielectric multilayer film on the surface of a chromium film deposited on the surface of a glass substrate, and then forming the required size. The dielectric multilayer film 12 can be formed by cutting and removing the chromium film by etching (for details, see JP-A-4-101106).
reference).

Referring to FIG. 7, the above dielectric multilayer filter module can transmit or reflect a specific wavelength from a plurality of lights having different wavelengths transmitted through an optical fiber. . That is, light having a wavelength of 1.55 μm transmitted through the transmission / reception optical fiber 23 passes through the dielectric multilayer filter 1, is sent to the photodiode 8 via the input optical fiber 21, and is transmitted via the input optical fiber 21. The light having a wavelength of 1.31 μm does not pass through the dielectric multilayer filter 1 but is reflected and sent out through the transmission / reception optical fiber 23.

[0006]

However, the conventional example in which a slit 32 is formed in the substrate 3 having a V-shaped groove and the dielectric multilayer filter 1 having an extremely small thickness is inserted into the slit 32 has various problems. are doing. That is, the slit 3 formed in the substrate 3 with the V-shaped cross-section formed by the dielectric multilayer filter 1
2 is not easy. Positioning of the insertion of the dielectric multilayer filter 1 into the slit 32 greatly affects the optical transmission characteristics of the dielectric multilayer filter module. The thickness of the dielectric multilayer filter 1 is extremely thin, about 15 μm. To insert this into the slit 32, the width of the slit 32 must be
And the width of the slit 32 must be 2
It is formed to about 0 μm. Therefore, the dielectric multilayer filter 1 has play in the slit 32, and its position is not strictly determined by the design position. In order to improve the positioning accuracy, the width of the slit 32 must be designed and formed to be narrow. However, the narrower the width, the more difficult it is to insert the dielectric / dielectric multilayer filter 1 and the easier it is to handle.

A dielectric multilayer film 12 is formed on the surface of a glass thin plate 11.
In the case of the dielectric multilayer filter 1 formed by forming a film, the overall thickness is about 100 μm, and the thickness is made as thin as possible in order to suppress the loss of light due to the thin glass plate 11. As a result, the dielectric multilayer filter 1 having a small thickness is liable to be damaged at the time of dicing and assembling into a module, and has a drawback that it is difficult to handle. The present invention provides a dielectric multilayer filter which solves the above-mentioned problem by forming a dielectric multilayer film on a filter substrate having a pyramid-shaped through hole formed by performing anisotropic etching on a silicon substrate as a raw material. And a dielectric multilayer filter module having the same.

[0008]

A filter substrate having a tapered guide portion and a conical through-hole formed of a through-hole is formed on the surface of the filter substrate. A dielectric thin film filter was formed by removing the metal thin film 42 and forming the dielectric multilayer film 12 on the surface of the metal thin film 42 including the through hole 412 region. Claim 2: In the dielectric multilayer filter according to claim 1, the filter substrate 4 is formed of a silicon substrate, the conical through-hole 41 is a tapered guide 411 having a pyramidal guide, and A dielectric multilayer filter having a pyramid-shaped through hole having a square hole 41 was formed.

Further, claim 3: a pair of optical fibers 21,
A guide groove forming substrate on which a slit is formed on the surface of the guide groove, the slit being fitted to and fixed to the dielectric multilayer filter;
The dielectric multilayer filter 1 includes a filter substrate 4 that forms a conical through-hole 41 composed of a tapered guide 411 and a through-hole 412, and the through-hole 412 is formed on the surface of the filter substrate 4.
A metal thin film 42 is formed excluding the region, and the dielectric multilayer film 12 is formed on the surface of the metal thin film 42 including the through hole 412 region. A pair of optical fibers 21,
A dielectric multilayer film filter module 23 was positioned and fixed in the guide groove 31 of the guide groove forming substrate 3.

Further, in the dielectric multilayer filter module according to the present invention, the filter substrate 4 is formed of a silicon substrate, and the conical through-hole 41 is formed of a tapered guide portion 411 and a pyramid-shaped guide portion. Thus, a dielectric multilayer filter module which is a pyramidal through hole having the through hole 41 as a square hole was formed. Here, claim 5: A metal thin film 42 having a silicon thin film etchant resistance is formed on both front and back surfaces of the filter substrate 4 made of a silicon thin plate (step 1). The rectangular pattern 5 is formed on the metal thin film 42 on the back surface, the metal thin film 42 is removed by etching (step 2), and the filter substrate 4 made of a silicon thin plate is anisotropically etched to form a pyramidal through hole 41.
(Step 3), the dielectric multilayer film 12 is formed on the metal thin film 42 on the front surface (Step 4), the metal thin film 42 remaining on the back surface is removed by etching (Step 5), and dicing is performed. A method for manufacturing a dielectric multilayer film filter comprising cutting out to a predetermined size (step 6) was constructed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the embodiment shown in FIG. FIG. 1 is a diagram illustrating an embodiment of a dielectric multilayer filter. 1 is a dielectric multilayer filter, and 4 is a filter substrate. The thickness of the filter substrate 4 is designed to be about 500 μm. At the center of the filter substrate 4, a pyramidal through-hole 41, which is a pyramidal through-hole, is formed. The pyramid-shaped through hole 41 includes a tapered guide portion 411 and a square hole 412 that is a through hole. Reference numeral 42 denotes a metal thin film formed on the surface of the filter substrate 4, and a region corresponding to the square hole 412 is removed by penetration.
Reference numeral 12 denotes a dielectric multilayer film formed on the surface of the metal thin film. The metal thin film 42 is a film interposed between the filter substrate 4 and the dielectric multilayer film 12 to secure the metal thin film 42. After a metal thin film 42 is formed on the surface of the filter substrate 4 and a region corresponding to the square hole 412 is removed,
The dielectric multilayer film 12 is formed on the surface of the metal thin film 42 including the two regions.

FIG. 2 is a view for explaining an embodiment of the dielectric multilayer filter module. FIG. 2A is a diagram showing the dielectric multilayer filter module viewed from above, and FIG.
(B) is a figure which shows the cross section along line AA in Fig.1 (a). Reference numeral 3 denotes a cross-sectional V-groove forming substrate which is a guide groove forming substrate. A slit 32 for fitting and fixing the dielectric multilayer filter 1 is formed in the cross-section V-groove forming substrate 3. The dielectric multilayer filter 1 is fitted and fixed after applying the transparent adhesive 33 to the slit 32. Section V
The groove forming substrate 3 is further provided with a cross-sectional V-groove 31 having a slit 32.
Are formed in directions that intersect at an appropriate angle. The input optical fiber 21 is fitted and fixed on the side of the pyramidal through hole 41 of the dielectric multilayer film filter 1 and the transmission / reception optical fiber 23 is fitted and fixed on the side of the dielectric multilayer film 12. I have. Dielectric multilayer film 12 of cross-sectional V-groove forming substrate 3
On the side, if necessary, the output optical fiber 22 is provided at an appropriate angle with respect to the transparent adhesive 33 as shown in FIG.

Referring to FIG. 3, a process for manufacturing a dielectric multilayer filter having a filter substrate will be described. (Step 1) Metal thin film 4 resistant to silicon thin film etchant on both front and back surfaces of filter substrate 4 made of silicon thin plate
2 is formed. The material of the metal thin film 42 is chromium,
Alternatively, gold / chrome is employed. This gold / chromium is a two-layer film in which chromium for enhancing the adhesion of the filter substrate 4 to silicon is interposed. (Step 2) A quadrangular pattern 5 having the shape and dimension of the wide side of the pyramid-shaped through-hole 41 is formed on the metal thin film 42 on the rear surface by photolithography, and the metal thin film 42 is removed by etching. The etchant of the metal thin film 42 uses hydrochloric acid for chromium and aqua regia for gold / chromium.

(Step 3) The filter substrate 4 made of a silicon thin plate is anisotropically etched to form a pyramid-shaped through hole 41. Etchant of silicon thin plate is potassium hydroxide, tetramethylammonium hydroxide (T
MAH) is used. (Step 4) The dielectric multilayer film 12 is formed on the metal thin film 42 on the surface. (Step 5) The metal thin film 42 remaining on the back surface is removed by etching. (Step 6) Dicing is performed and cut out to a size of several mm square.

[0015]

As described above, according to the present invention, a filter substrate 4 having a pyramidal through-hole 41 formed by using a silicon substrate as a raw material and subjecting the silicon substrate to anisotropic etching.
Multilayer filter 1 in which dielectric multilayer 12 is formed
Was configured. As a result, the thickness of the filter substrate 4, which is a holder for the dielectric multilayer film 12, is increased as compared with the conventional example. Multi-layer filter 1 with very small light transmission loss in which only multi-layer dielectric 12 exists
Can be obtained. Then, the thickness of the filter substrate 4 itself can be designed to be as thick as about 500 μm as compared with about 100 μm including the glass thin plate of the conventional example.
It is possible to reduce the occurrence of breakage when dicing this into a square of several mm and when assembling the module.

The filter substrate 4 has a tapered guide 4
When the dielectric multilayer filter 1 is incorporated into the cross-section V-groove forming substrate 3 to form the dielectric multilayer filter module, the dielectric multilayer filter 1 is formed by forming the pyramid-shaped through-hole 41 including the square hole 412 penetrating therethrough. Positioning of optical fiber end faces to be opposed to each other through the film 12 can be accurately performed. That is, in FIG. 2, the transmission / reception optical fiber 23 has its end face aligned with the side wall of the slit 32 of the cross-section V-groove forming substrate 3 and fitted and fixed in the cross-section V-groove 31.
Next, one surface of the dielectric multilayer film 12 corresponding to the square hole 412 of the dielectric multilayer filter 1 is
And the multilayer filter is joined and fixed to the slit 32. Here, the input optical fiber 21 is fitted into the cross-sectional V-groove 31 of the cross-sectional V-groove forming substrate 3, and the distal end of the optical fiber is engaged with and guided by the tapered guide portion 411 of the pyramidal through-hole 41. Push in the input optical fiber 21,
With the end face of the input optical fiber 21 being positioned on the other surface of the dielectric multilayer film 12 through the square hole 412, the input optical fiber 21 is fixedly joined to the V-shaped groove 31 in section. In this case, there is some mismatch between the square hole 412 of the pyramid-shaped through hole 41 of the filter substrate 4 previously positioned and fixed with respect to the sectional V-groove forming substrate 3 and the sectional V-groove 31 of the input optical fiber 21. However, the end face of the input optical fiber 21 is guided by the tapered guide portion 411 and can reliably reach the square hole 412. The end face of the input optical fiber 21 and the end face of the transmission / reception optical fiber 23 are formed by the dielectric multilayer film 12. The opposing axes can be aligned through the intermediary.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a dielectric multilayer filter.

FIG. 2 is a view for explaining an embodiment of a dielectric multilayer filter module.

FIG. 3 is a diagram illustrating a manufacturing process of the dielectric multilayer filter.

FIG. 4 is a diagram illustrating a conventional example of a dielectric multilayer filter.

FIG. 5 is a diagram illustrating a conventional example of a dielectric multilayer filter module.

FIG. 6 is a diagram illustrating another conventional example of a dielectric multilayer filter module.

FIG. 7 is a diagram illustrating the ingress and egress of transmitted light.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric multilayer film filter 11 Glass thin plate 12 Dielectric multilayer film 21 Input optical fiber 22 Output optical fiber 23 Transmitting and receiving optical fiber 3 Cross-section V-groove forming substrate 31 Cross-section V-groove 32 Slit 33 Transparent adhesive 4 Filter substrate 41 Pyramidal through hole 411 Tapered guide 412 Square hole 42 Metal thin film 5 Square pattern

Claims (5)

[Claims] 1. A filter substrate comprising a tapered guide portion and a conical through-hole comprising a through-hole, a metal thin film formed on the surface of the filter substrate except for a through-hole region, and a metal thin film penetrating through the surface of the metal thin film. A dielectric multilayer filter comprising a dielectric multilayer film including a hole region. 2. The dielectric multilayer filter according to claim 1, wherein the filter substrate is made of a silicon substrate, the conical through-hole is a pyramid-shaped guide with a tapered guide, and the through-hole is a square hole. A dielectric pyramid-shaped through-hole. 3. A guide groove having a guide groove in which a pair of optical fibers are fitted and fixed, and a guide groove forming substrate on the surface of which a slit intersecting the guide groove and in which a dielectric multilayer filter is fitted and fixed is formed. The dielectric multilayer filter includes a filter substrate that forms a conical through-hole including a tapered guide portion and a through-hole, and forms a metal thin film on the surface of the filter substrate except for a through-hole region. A pair of optical fibers is formed on the surface of the substrate with a guide groove formed by forming a dielectric multi-layer film including a through hole region on the surface, and aligning the end faces of the fibers with the opposing axes via the dielectric multi-layer film. A dielectric multilayer filter module characterized by being positioned and fixed at a position. 4. The dielectric multilayer filter module according to claim 3, wherein the filter substrate is made of a silicon substrate, the conical through hole has a tapered guide portion as a pyramid guide portion, and the through hole has a square hole. A dielectric pyramid-shaped filter module, characterized in that it is a pyramidal through-hole. 5. A thin metal film resistant to a silicon thin film etchant is formed on both front and back surfaces of a filter substrate made of a silicon thin plate (step 1). A metal thin film is formed by etching and removing the metal thin film (Step 2). A filter substrate made of a silicon thin plate is anisotropically etched to form a pyramid-shaped through hole (Step 3). A dielectric film comprising: forming a multilayer film (step 4); removing a thin metal film remaining on the back surface by etching (step 5); and performing dicing to cut out to a predetermined size (step 6). A method for manufacturing a multilayer filter.