JPH07230019A - Optical component and optical coupler - Google Patents

Abstract

PURPOSE:To eliminate the need to positioning of the optical axes of optical components and secure low-loss optical coupling. CONSTITUTION:A 1st optical waveguide element 31 has a V groove 35 formed in an Si substrate 36 and also has clad projection parts 38A, 38B, and 38C formed projecting from a clad part 37 to a core part 38 by utilizing a difference in etching rate. An optical fiber 33 is mounted in the V groove 35 and its end surface is joined with the end surface of the clad projection part 38A. Other clad projection parts 38B and 38C are fitted in spaces 46 and 47 of core parts 43 and 44 formed by utilizing the difference in etching rate of a 2nd optical waveguide element 32 reversely as well. Consequently, the need to position the optical axes of optical components is eliminated at either coupling part and the low-loss optical coupling is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component such as an optical fiber or an optical waveguide element and an optical coupler for coupling these optical components to each other. In particular, the optical component and the optical coupling capable of surely performing the optical coupling. Regarding vessels.

[0002]

2. Description of the Related Art In a communication device related to optical communication or an optical information processing device handling an optical signal, it is necessary to couple optical components such as an optical fiber and an optical waveguide element with low loss. Therefore, for example, when coupling an optical fiber and another optical component, it is necessary to optically couple the optical fibers with their optical axes aligned.

FIG. 3 shows how the optical axis is adjusted in a conventionally used optical coupler. Here, the optical waveguide device 11 is connected to the first and second optical fibers 12, 13
It shows the case of optical coupling by. Optical waveguide element 1
1 is fixed on the element fixing jig 14 in order to fix it positionally at a predetermined height.

One end of the first optical fiber 12 is inserted into a front end portion of a first manipulator 15 having an emission port facing an end portion on the right side of the optical waveguide element 11 in the drawing, and an optical signal is transmitted from there. It is designed to irradiate. One end of the second optical fiber 12 is inserted into the tip of a first manipulator 15 having an emission port facing the end on the right side of the optical waveguide device 11 in the drawing, and an optical signal is emitted from this end. It is like this. The same end of the second optical fiber 12 is
The optical waveguide device 11 is inserted through the tip of a second manipulator 16 having an entrance facing the left end of the optical waveguide device in the figure, so that the optical signal emitted from the optical waveguide device 11 is incident from here. Has become.

In the conventional optical coupler shown in this figure, in order to adjust the optical axis, for example, a light source 17 is connected to the other end of the first optical fiber 12 and the other end of the second optical fiber 13 is connected. The power meter 18 is connected. Then, the light reception level of the power meter 18 as a result of the light output from one end of the first optical fiber 12 entering the one end of the second optical fiber 13 through the optical waveguide element 11 is monitored, and both manipulators 15 are monitored. , 16 adjusts the optical axis so that the level becomes maximum.

However, if the optical axis adjustment of the optical coupler is performed in this way, even if the optical axis portion as shown in the example is a single body, it is shown in FIG.
There was a problem that it was necessary to make adjustments in one direction and it took a considerable amount of time to complete the adjustments. Recently, the array of optical components is progressing due to the miniaturization of optical devices.
When there are a plurality of optical axes to be adjusted, the adjustment of the optical axes becomes complicated accordingly, and the time required for the adjustment becomes longer.

Therefore, for example, JP-A-56-146107
In Japanese Patent Laid-Open Publication No. 2004-242242, a proposal is made in which a rectangular groove is formed in advance in an optical component to be coupled with an optical fiber. By installing an optical fiber in this rectangular groove, it is not necessary to adjust the optical axis. However, this proposal has a problem that an error occurs in the alignment of the optical axis by a subtle error in the diameter of the rectangular groove and the diameter of the optical fiber. Therefore, a proposal has been made to form a V groove instead of the rectangular groove.

FIG. 4 shows the principle structure of the latter optical coupler using the V groove. The Si substrate 22 of the optical waveguide device 21 is provided with a V groove 24 for positioning the optical fiber 23. Since the V groove 24 is processed by crystal anisotropic etching, the surface 25 having the crystal plane orientation (111) is also formed at the same time. In this proposal, since the optical fiber 23 is positioned by the V groove 24, optical axis alignment becomes unnecessary.

[0009]

However, according to this proposal, it is inevitable that a considerable gap 26 is formed between the optical waveguide device 21 and the end face of the optical fiber 23, and low-loss optical coupling can be performed. There was a problem that I could not. This is because the tip of the optical fiber 23 placed in the V groove 24 hits the surface 25 as shown by the broken line in the figure, and the gap 26 with a predetermined interval is generated.

In order to solve such a problem, Japanese Unexamined Patent Publication No. 1-262604 proposes to cut the portion of the optical fiber 23 which hits the surface 25 at the same inclination angle as the surface 25. . This allows the optical fiber 2
The tip of 3 can be in contact with the optical waveguide element 21 without a gap. However, for this purpose, it is necessary to accurately process the end surface of the optical fiber 23 on the optical waveguide element 21 side so that the end surface has a predetermined inclination angle, and further, this obliquely processed surface is completely parallel to the surface 25. Optical fiber 23
It was necessary to rotate the axis of.

Therefore, a first object of the present invention is to use V-grooves to eliminate the need for optical axis adjustment, and to perform optical coupling with other optical components with low loss without special processing of the optical fiber. An object of the present invention is to provide an optical coupler that can be used.

A second object of the present invention is to provide an optical component capable of easily performing optical coupling.

[0013]

The invention according to claim 1 is
The present invention relates to an optical component having a core part that allows light to pass therethrough and a clad part surrounding the core part. The clad portion of this optical component is made of a material having a higher etching rate than the core portion, and the core portion is projected by a predetermined length from the end surface of the clad portion subjected to the etching. The protruding clad portion can be brought into contact with another optical component or fitted into a recess of another optical component to achieve low-loss optical coupling.

A second aspect of the present invention relates to an optical component having a core portion for transmitting light and a clad portion surrounding the core portion. The clad part of this optical component is made of a material whose etching speed is slower than that of the core part.
It is characterized in that the core portion is recessed by a predetermined length from the end face of the etched cladding portion. By fitting the recessed clad portion into the convex portion of another optical component, low-loss optical coupling can be performed.

According to a third aspect of the present invention, there is provided (a) a core portion for transmitting light and a clad portion surrounding the core portion,
The clad part is made of a material having a higher etching rate than the core part, and the first optical component in which the core part projects by a predetermined length from the end surface of the clad part subjected to the etching, and (b) It has a core part to pass through and a clad part surrounding it, and the clad part is made of a material whose etching speed is slower than that of the core part. The optical coupler is composed of a second optical component in which the protruding core portion of the first optical component is fitted in this portion. By thus fitting the convex portions and the concave portions of the first optical component and the second optical component, it is possible to obtain an optical coupler that has low loss and does not require positioning.

The invention according to claim 4 has (a) a core part for transmitting light and a clad part surrounding the core part,
The clad portion is made of a material that has a faster etching rate than the core portion, and the core portion protrudes from the end surface of the clad portion that has been etched for a predetermined length. The third optical component, which has a pedestal in which a V groove is engraved parallel to this, and (b) itself has a cylindrical shape and is mounted on the V groove with its axial direction aligned with the length direction of the V groove. The optical coupler is composed of a fourth optical component whose end face faces the end face of the core portion when placed.
By arranging the fourth optical component in the V groove of the third optical component in this way, the core portion of the third optical component can be brought sufficiently close to the end face of the fourth optical component, or both can be brought into contact with each other. Therefore, it is possible to obtain an optical coupler that has low loss and does not require positioning.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows the structure of an optical coupler according to an embodiment of the present invention. This optical coupler is composed of a first optical waveguide element 31, a second optical waveguide element 32 and an optical fiber 33 which are optically coupled to the first optical waveguide element 31. Here, the first optical waveguide device 31 includes a Si (silicon) substrate 36 in which the V groove 35 is arranged, a rectangular parallelepiped clad portion 37, and two end faces 37A of the clad portion 37 which are parallel to each other. , 37B, and a Y-shaped core portion 38 partially protruding from each of the core portions 37, 37B. The clad portion 37 is arranged on the right half surface of the Si substrate 36 in the figure.

The end face 37A on the side facing the optical fiber 33
The clad protrusion 38 </ b> A protruding from the V groove 35 is arranged in parallel with the V groove 35 at a predetermined distance. V groove 3
5 is set at a position such that an imaginary plane lowered perpendicularly to the plane of the Si substrate 36 including the central axis of the clad protrusion 38A intersects the intersecting line of two planes forming the V groove 35. There is. Two clad protrusions 38B and 38C protrude from the end surface 37B on the side facing the second optical waveguide element 32.

The second optical waveguide element 32 is a Si substrate 41.
And a rectangular parallelepiped clad portion 42 arranged on this, and two core portions 4 embedded in the clad portion 42.
3 and 44. These core parts 4
3, 44 are clad protrusions 38B from the end face 42A of the clad part 42 facing the first optical waveguide device 31.
It is arranged in the clad portion 42 so as to be retracted by a length of 38C. As a result, the core portions 43 and 44 and the end surface 42
Spaces 46 and 47 each having a rectangular parallelepiped shape are arranged between A. These spaces 46 and 47 have such positions and sizes that the clad protrusions 38B and 38C of the first optical waveguide device 31 can be fitted therein.

The clad portion 37 of the first optical waveguide device 31
Is formed on the Si substrate 36 by CVD (Chemical Vapor Depos
ition) and other PSG (Phospho Silicate Glas)
s) layer, and the core part 38 is made of BPSG (Boro Phospho).
Silicate Glass) layer. The cladding portion 42 of the second optical waveguide element 32 is made of a BPSG layer, and the core portions 43 and 44 are both GPSG (Germo Phospho).
Silicate Glass) layer.

The V groove 35 on the Si substrate 36 of the first optical waveguide device 31 is formed by using an anisotropic etching technique. Therefore, when the V groove 35 is formed, the slope 49 having the crystal plane orientation (111) is also formed. Assuming that the clad protrusion 38A does not exist, the optical fiber 33 cannot fully approach the end face 37A due to the existence of the slope 49, as described above with the related art.

The three clad protrusions 38A, 38B and 38C of the first optical waveguide device 31 are formed by an etching process using buffered hydrofluoric acid. That is, B
Since the core part 38 made of the PSG layer has a slower etching rate for buffered hydrofluoric acid than the clad part 37 made of the PSG layer, the clad part 37 is faster than those parts having a simple rectangular parallelepiped shape before the etching process. Etched and clad protrusions 38A, 38B, 38
C is formed.

In the case of the second optical waveguide element 32, GP
The core portions 43 and 44 made of the SG layer have a faster etching rate for buffered hydrofluoric acid than the clad portion 42 made of the BPSG layer. As a result, the core parts 43, 4 are formed from these parts having a simple rectangular parallelepiped shape before the etching process.
4 is etched faster, forming spaces 46, 47.

In this embodiment, the core portions 38, 43, 44 of the first and second optical waveguide elements 31, 32 have a depth of 35.5 μm or more, and the diameter of the optical fiber 33 is 125.
μm. In the optical coupling of the optical coupler, the optical fiber 33 was moved in the direction of the first optical waveguide element 31 along the V groove 35, and its end face was brought into contact with the end face of the clad protrusion 38A. Further, the other clad protrusions 38B and 38C of the first optical waveguide element 31 are completely fitted into the spaces 46 and 47 of the second optical waveguide element 32, and the two clad protrusions 38 are formed.
The end faces of B and 38C were brought into contact with the end faces of both core portions 43 and 44. This made it possible to achieve optical coupling in which optical loss was neglected.

FIG. 2 shows the principle of the optical coupling between the optical fiber and the first optical waveguide element in the optical coupler of this embodiment. The radius of the optical fiber 33 is 62.5 μm, and the slope 4 of the Si substrate 36 of the first optical waveguide device 31 is
The angle formed by 9 with the axis of the optical fiber 33 is 54.7 °. Assuming that the thickness of the cladding portion 37 from the lower end of the core portion 38 to the upper surface of the Si substrate 36 is 12.5 μm, from the point where the end portion of the optical fiber 33 contacts the slope 49 to the surface where the Si substrate 36 contacts the cladding portion 37. Has a height of 50 μm.
Therefore, at this time, the distance d between the end face of the optical fiber 33 and the end face 37A facing the end face is “50” as a value “ta”.
It becomes the number divided by n 54.7 °, which is 35.4019.
μm. That is, in the present embodiment, if the depth of both core portions 38, 43, 44 of the first and second optical waveguide elements 31, 32 is 35.5 μm or more, the clad protrusion portion 3 is formed.
The end face of 8A comes into contact with the end face of the optical fiber 33.

Although the clad portions 38, 43 and 44 have a rectangular cross section in the above-described embodiments, it is a matter of course that they may have a circular shape or another shape. In addition, although the size of each part is shown in the embodiment, it goes without saying that the size is not limited to this. Further, it goes without saying that the core portion and the clad portion only need to have a predetermined magnitude relationship in the etching rate as described above, and individual materials can be appropriately selected.

[0028]

As described above, according to the first aspect of the invention, the clad portion of the optical component is made of a material having a higher etching rate than the core portion, and the clad portion of the etched portion is The core portion projects from the end surface by a predetermined length. Therefore, the protruding clad portion can be brought into contact with another optical component or fitted into a recess of another optical component to achieve low-loss optical coupling. In addition, when they are fitted together, it is not necessary to align the optical axes.

Next, according to the second aspect of the present invention, the clad portion of the optical component is made of a material having an etching rate slower than that of the core portion. Is retracted for a certain length. For this reason, the recessed clad portion can not only perform low-loss optical coupling by being fitted to the convex portions of other optical components, but also can eliminate the need for alignment of the optical axis. is there.

According to the third aspect of the present invention, the first optical component is provided with a convex core portion due to the difference in etching rate, and the second optical component is provided with a concave portion at the tip thereof to be fitted therein. Since the core part is provided, it is possible not only to perform low-loss optical coupling by connecting them, but also to eliminate alignment of the optical axis. Moreover, since the protruding core portion of the first optical component is tapered by etching toward the tip, there is an advantage that it can be easily fitted into the concave portion of the second optical component. .

Further, according to the present invention, the core portion projects from the end surface of the clad portion that has been etched by a predetermined length and is parallel to the projecting core portion with a predetermined spacing. Since a third optical component having a pedestal in which a V groove is engraved is prepared, and a fourth optical component such as an optical fiber having a cylindrical shape is placed in the V groove, the fourth optical component is mounted. The end face of the fourth optical component can be brought close to or in contact with the projecting core without needing to bring the end face of the component sufficiently close to the end face of the clad portion of the third optical component, and low-loss optical coupling can be performed. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of an optical coupler according to an embodiment of the present invention.

FIG. 2 is a side view showing the principle of optical coupling on the optical fiber side of the optical coupler in the present embodiment.

FIG. 3 is an explanatory diagram showing a state of optical axis adjustment in a conventionally used optical coupler.

FIG. 4 is an explanatory diagram showing a principle configuration of an optical coupler using a conventional V groove.

[Explanation of symbols]

 31 1st optical waveguide element 32 2nd optical waveguide element 33 Optical fiber 35 V groove 36, 41 Si substrate 37, 42 Clad part 38, 43, 44 Core part 38A, 38B, 38C Clad protrusion part 46, 47 Space

Claims (4)

[Claims] 1. A core portion that allows light to pass therethrough and a clad portion surrounding the core portion. The clad portion is made of a material having an etching rate faster than that of the core portion. An optical component, wherein a core portion projects from an end face by a predetermined length. 2. A core portion that allows light to pass therethrough and a clad portion surrounding the core portion. The clad portion is made of a material having an etching rate slower than that of the core portion. An optical component in which the core portion is retracted from the end surface by a predetermined length. 3. A core portion that allows light to pass therethrough and a clad portion surrounding the core portion. The clad portion is made of a material having an etching rate faster than that of the core portion. It has a first optical component in which the core part protrudes from the end face by a predetermined length, a core part that allows light to pass through, and a clad part surrounding the core part. The clad part is made of a material having a slower etching rate than the core part. A second optical component in which the core portion is retracted from the end surface of the clad portion that has been etched by a predetermined length, and the protruding core portion of the first optical component is fitted in this portion. An optical coupler comprising: 4. A core portion that allows light to pass therethrough and a clad portion surrounding the core portion. The clad portion is made of a material having an etching rate faster than that of the core portion. A third part having a pedestal in which a core part projects from the end surface for a predetermined length and a V groove is formed in parallel with the projecting core part at a predetermined interval.
And the fourth optical component which itself has a cylindrical shape and has an end face facing the end face of the core portion when placed in the V groove with the axial direction aligned with the length direction of the V groove. An optical coupler comprising: a component.