JPH06258554A - Optical function device - Google Patents

Abstract

PURPOSE:To provide the optical function device which is low in loss steel in the case where it is optically coupled to other optical parts or the optical parts are mounted on its own body, by forming the part of a V-groove for holding and fixing an optical fiber collimator, which corresponds to a graded index type optical fiber, broader than the part corresponding to a single mode optical fiber. CONSTITUTION:The part 2 of the V-groove for holding and fixing the optical fiber collimator 6, which corresponds to the graded index type optical fiber, is formed broader than the part 3 corresponding to the single mode optical fiber 5. The V-groove is preferably formed by anisotropic etching. More specifically, window parts for the V-grooves varying in length and width are formed on an Si substrate 1 of a {100} face in the face direction by using the lithography technique to be used for the process for forming ordinary semiconductor ICs and thereafter, the V-grooves are formed by using an anisotropic etching method, more particularly anisotropic wet etching method which hardly dissolve the {111} face of the Si.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical functional device having an optical fiber collimator, and more particularly to an optical fiber, a laser diode (LD), a photodiode (PD),
An optical functional device that has an optical fiber collimator that collimates the outgoing light of an optical fiber when connecting optical components such as a waveguide or inserting optical components such as a polarizer, an isolator, and a waveguide between optical fibers. Regarding

[0002]

2. Description of the Related Art An optical fiber collimator using a graded index (GI) type optical fiber as a minute lens is disclosed in Japanese Patent Laid-Open No. 4-21803 and "Hirai et al., 19".
92 Autumn Meeting of the Society of Japan, C-228 ”,
It is suitable for mass production because it can be downsized and integrated. Such optical fiber collimators can be arranged facing each other to form a parallel beam system, and a functional device can be manufactured by inserting an optical component or the like between them. At this time, if the outer diameter of the GI type fiber is made larger than the outer diameter of the single mode (SM) optical fiber, a large-diameter parallel beam can be obtained, and the allowable value for the optical axis shift can be increased. There is an advantage that the distance between the collimators can be increased.

[0003]

Normally, a V groove is used to hold an optical fiber, but the outer diameter of the GI type optical fiber constituting the optical fiber collimator is larger than the outer diameter of the SM optical fiber. And the SM optical fiber floats from the V groove. However, since the length of the optical fiber collimator GI type optical fiber is as short as about 1 mm, it is actually S
The rear part of the M optical fiber is in contact with the V groove, and the GI type optical fiber floats above the V groove. As a result, the GI optical fiber of the optical fiber connector is displaced from the optical axis at the design stage, which causes a problem of increased loss.

In view of such circumstances, an object of the present invention is to
An object is to provide an optical functional device having an optical fiber collimator and having low loss.

[0005]

The optical functional device of the present invention which has achieved the above object is held and fixed on a V groove formed on a substrate and has a single-mode optical fiber larger than the single-mode optical fiber at the tip thereof. An optical functional device having an optical fiber collimator to which a graded index type optical fiber having a predetermined diameter is attached, wherein a portion of a V groove for holding and fixing the optical fiber collimator corresponds to the graded index type optical fiber. Is wider than the portion corresponding to the single mode optical fiber.

In the optical functional device of the present invention, only one or a plurality of optical fiber collimators are mounted on the substrate, and the optical functional device may be used by being optically coupled with other optical components. Alternatively, another optical component may be mounted on the same substrate and optically coupled to the optical fiber collimator. Further, in the optical functional device in which the optical components are mounted on the same substrate, at least a pair of optical fiber collimators are provided so as to face each other, and the optical components are mounted between these optical fiber connectors. It may be optically coupled.

Generally, a V-groove is formed by cutting with a blade saw in terms of simplicity. However, when forming a single V groove, partially changing the depth midway as in the optical functional device of the present invention not only requires high precision of the stage, but also the diameter of the blade is small. There is a risk that the simplicity, which is an advantage of cutting, may be lost because it has to be special.

Therefore, in the optical functional device of the present invention, the V groove for holding the optical fiber collimator is preferably formed by anisotropic etching. This method can easily form V-grooves having different widths and lengths by using a generally used semiconductor process without requiring a special device, and also has a high accuracy and a high width and length. It has the advantage of not being restricted.

Specifically, Si having a plane orientation of {100} plane
Anisotropic etching method in which a {111} plane of Si is hardly dissolved after forming a window for a V groove having different lengths and widths on a substrate by using a lithography technique used in a general semiconductor IC manufacturing process. In particular, the V groove may be formed by using the anisotropic wet etching method.

Si anisotropic wet etching utilizes the characteristic that the etching rate for {111} planes with high atomic density is much slower than the etching rate for other {100} and {110} planes. V-grooves having an angle determined by can be formed. Therefore, V grooves having different depths can be formed by changing the etching width.
That is, using a photomask capable of forming a pattern on the order of microns, this pattern is transferred onto a substrate by a lithography technique having excellent dimensional and positional accuracy, and then Si anisotropic etching is performed. At this time, if patterns having windows of various widths are formed on the photomask in advance, the Vs for a plurality of optical fiber collimators are collectively formed.
Grooves can be formed.

[0011]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 is an exploded perspective view showing an optical functional device according to the first embodiment. As shown in FIG. 1, a GI fiber V-groove 2 having an opening width of 385 μm and an SM fiber V-groove 3 having an opening width of 240 μm are formed in a Si substrate 1, and on these V grooves 2 and 3, An optical fiber collimator 6 including a GI optical fiber 4 and an SM optical fiber 5 is mounted and held. Here, as the GI type optical fiber 4, one having a relative refractive index difference Δ = 1%, an outer diameter of 200 μm and a length of 1.0 mm is used, and as the SM optical fiber 5,
An outer diameter of 125 μm is used, and the optical fiber collimator 6 can be held on the V grooves 2 and 3 while keeping the optical axis thereof straight. The optical fiber collimator 6 may be fixed to the V grooves 2 and 3 with an adhesive, or may be fixed from above by using a clamp (not shown), for example.

The process of forming the V-grooves 2 and 3 of the optical functional device of FIG. 1 will be described with reference to FIG.

First, the Si substrate 1 having a plane orientation of {100} plane
A silicon nitride film 7 is vapor-deposited thereon to a thickness of 0.5 μm (step (a)). Next, the photosensitive resin 8 is applied on the silicon nitride film, and the window portion 8a corresponding to the portions to be the V grooves 2 and 3 is patterned by lithography (step (b)).
At this time, the width of the portion of the window portion 8a corresponding to the GI fiber V groove 2 was 385 μm, and the width of the portion corresponding to the SI optical fiber V groove 3 was 240 μm. Next, photosensitive resin 8
Using the mask as a mask, the silicon nitride film 7 corresponding to the window 8a is removed to form the window 7a, and then the photosensitive resin 8 is removed (step (c)). The substrate 1 in this state is immersed in a 40% potassium hydroxide (KOH) aqueous solution kept at 50 ° C. for 5 hours to perform anisotropic wet etching to form V grooves 2 and 3 (step (d)). . Finally, the silicon nitride film 7 is removed.

Here, the width of the openings of the V-grooves 2 and 3 is
It defines the center position of the fiber, and V-grooves of various depths can be formed by changing this width. In addition,
The opening angle θ of the V grooves 2 and 3 of this embodiment is 70.53 °.

The anisotropic wet etching solution is K
The OH solution is not limited to hydrazine, E
PW (ethylenediamine-pyrocatechol-water), TM
AH (tetramethylammonium hydroxide) or the like can also be used. Further, the mask material is not limited to the silicon nitride film, and may be any material such as a silicon oxide film which has a characteristic of being hardly dissolved in each etching solution. Needless to say, the V groove may be formed by anisotropic dry etching.

FIG. 3 is an exploded perspective view showing an optical functional device according to the second embodiment. As shown in FIG. 3, the optical functional device comprises a V-groove 2 for GI fiber on a Si substrate 1.
A to 2D and V-grooves 3A to 3D for SM fiber, GI
Fiber V grooves 2A to 2D are formed so as to be adjacent to each other continuously, and optical fiber collimators 6A to 6D are mounted and held on these V grooves 2A to 2D and 3A to 3D. That is, this optical functional device becomes a collimator array with a space of 385 μm. Further, in such an optical functional device, when the V groove width is changed, the center position of the optical fiber is changed, but the array interval can be freely set.

FIG. 4 is an exploded perspective view of an optical functional device according to the third embodiment. The optical functional device of this embodiment has a V
The LD 9 is mounted on the Si substrate 1 in which the grooves 2 and 3 are formed, and the optical fiber connector 6 and the LD 9 held in the V grooves 2 and 3 are optically coupled with their optical axes aligned. It is supposed to be done.

In the case of actually manufacturing such an optical functional device, by using a photomask pattern designed so that a V groove that matches the optical axis of the LD can be formed,
The optical fiber collimator can be fixed on the V groove without alignment.
Although the LD 9 is shown as the optical component here, the PD
It may be a (photodiode) or a waveguide.

FIG. 5 is an exploded perspective view of an optical functional device according to the fourth embodiment. The optical functional device of the present embodiment is 2
V-grooves 2A and 3A are formed by flame deposition on a Si substrate 1 in which two V-grooves 2A and 3A and 2B and 3B are arranged side by side.
The optical fiber connectors 6A and 6B held by A and 2B and 3B and the two waveguides 10a and 10b of the Y-branch quartz waveguide 10 are optically coupled with their optical axes aligned. . When actually manufacturing such an optical functional device, a plurality of optical fiber collimators are arranged on the V-groove without alignment by using a photomask pattern designed to form a V-groove that matches the optical axis of the waveguide. Can be fixed to. Although a waveguide is shown as an optical component here, it is not limited to this, and
It goes without saying that D or the like is also acceptable.

FIG. 6 is an exploded perspective view of an optical functional device according to the fifth embodiment. In the optical functional device of this embodiment, V grooves 2A and 3A and 2B and 3B for holding a pair of optical fiber connectors 6A and 6B facing each other are formed in a Si substrate 1, and a filter is provided between the V grooves 2A and 2B. A groove 12 for inserting and holding 11 is formed. Such V-grooves 2A and 3A and 2B and 3B
Pair of optical fiber collimators 6A and 6B held by
Since a parallel beam system is formed, an optical functional device having a filter function can be constructed by inserting and holding the filter 11 in the groove 12 in the middle thereof. Although the filter 11 is used as the optical component in this embodiment, an optical isolator or the like may be used instead.

FIG. 7 is an exploded perspective view of the optical functional device according to the sixth embodiment. The optical functional device of this embodiment has V grooves 2A and 3A to 2D and 3D for holding two pairs of optical fiber connectors 6A to 6D facing each other, and a groove 12 for inserting and holding a filter 11 in the middle thereof. Is formed. V-grooves 2A and 3A-2D and 3D
Since the optical fiber connectors 6A to 6D held at 1 form a parallel beam system, an optical functional device array having a filter action can be constructed by inserting and holding the filter 11 in the middle thereof. Although the filter 11 is used as the optical component in the present embodiment, it goes without saying that an optical isolator or the like may be used instead.

As described above, according to the present invention, the optical fiber collimator composed of the GI fiber and the SM fiber having different outer diameters can be held in a straight line along the V-groove, so that the optical fiber collimator and other optical parts can be kept in alignment with each other. Coupling or optical coupling with an optical component mounted on the same substrate can be realized easily and with low loss. Further, by forming the V-groove of the optical functional device of the present invention by using a commonly used semiconductor process and anisotropic etching of silicon, the V-groove for holding and fixing can be formed easily and highly accurately. However, there is an advantage that an optical functional device can be constructed with no alignment and combined with other optical components.

[0024]

As described above, according to the present invention,
It is possible to realize an optical functional device with low loss by optical coupling with another optical component, or when the optical component is mounted on itself.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an optical functional device according to a first embodiment of the present invention.

FIG. 2 is a process drawing showing a V-groove forming process.

FIG. 3 is an exploded perspective view showing an optical functional device according to a second embodiment of the present invention.

FIG. 4 is an exploded perspective view showing an optical functional device according to a third embodiment of the present invention.

FIG. 5 is an exploded perspective view showing an optical functional device according to a fourth embodiment of the present invention.

FIG. 6 is an exploded perspective view showing an optical functional device according to a fifth embodiment of the present invention.

FIG. 7 is an exploded perspective view showing an optical functional device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 1 Si substrate 2, 2A to 2D V groove for GI fiber 3, 3A to 3D V groove for SM fiber 4 GI type optical fiber 5 SM optical fiber 6, 6A to 6D optical fiber collimator 7 Silicon nitride film 8 Photosensitive resin 9 LD 10 Y-branch quartz waveguide 11 filter 12 groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Semura 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works

Claims (4)

[Claims] 1. A light which is held and fixed on a V-shaped groove formed on a substrate and has a graded index type optical fiber having a diameter larger than the single mode optical fiber and a predetermined length attached to the tip of the single mode optical fiber. An optical functional device having a fiber collimator, wherein a portion of the V groove for holding and fixing the optical fiber collimator corresponding to the graded index type optical fiber is wider than a portion corresponding to the single mode optical fiber. Characteristic optical functional device. 2. The optical functional device according to claim 1, wherein an optical component is mounted on the substrate, and the optical component and the optical fiber connector are optically coupled to each other. 3. The optical functional device according to claim 1, wherein the optical fiber connectors are provided on the substrate so as to face each other, and an optical component is mounted between the optical fiber connectors. An optical functional device characterized by being optically coupled to an optical fiber connector. 4. The optical functional device according to claim 1, 2 or 3, wherein the substrate is a silicon substrate, and the V groove is formed by anisotropic etching.