JP3133474B2 - Manufacturing method of optical waveguide with guide groove - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical waveguide having a guide groove used for connection with an optical fiber.

[0002]

2. Description of the Related Art To connect an optical waveguide and an optical fiber,
Conventionally, after aligning the optical waveguide so that the core of the optical fiber coincides with the core of the optical fiber, the optical fiber is fixed to the optical waveguide with an adhesive. However, since the adhesive shrinks during curing, the positions of the optical waveguide and the optical fiber are displaced at the time of fixing, and it has been difficult to accurately connect the optical waveguide and the optical fiber. In addition, since it is necessary to perform alignment by fine adjustment and fixation with an adhesive, it takes a long time to perform a connection operation, and since the optical fiber cannot be removed from the optical waveguide, the use of the optical waveguide is significantly limited. there were.

[0003] In order to solve the above problem, there has been proposed an optical waveguide in which an optical fiber can be connected without using a connecting agent and the optical fiber can be attached and detached. This optical waveguide comprises a connector base A, a waveguide substrate B, and two guide pins C as shown in FIG. To assemble the optical waveguide, the waveguide substrate B is bonded and fixed to the connector base A, and then the guide pins C are inserted into the waveguide substrate 51, and the guide pins C are connected to the core of the waveguide substrate B as designed. The guide pins C are adhered and fixed to the connector base A after the alignment is performed so that the above positional relationship is established.

Next, the core of the optical waveguide and the optical fiber D
Is connected to the connector E to which the optical fiber D is fixed.
By inserting a guide pin C into the fitting hole Q. However, this method also requires alignment of the guide pins C, so that it takes time to assemble the connector base A, the waveguide board B, and the guide pins C.

Conventionally, an optical waveguide shown in FIG. 4 has been proposed in addition to the optical waveguide shown in FIG. 3 (Japanese Patent Laid-Open No. 1-291204). This is obtained by superposing a superposed substrate J on which a trapezoidal superposed groove I is formed on a waveguide substrate H having V-shaped guide grooves G formed on both sides of a core F. Then, the guide pin N of the optical connector M, into which the optical fiber L is inserted and fixed, is fitted into a fitting hole K formed by the guide groove G and the overlap groove I. F is optically connected. This optical waveguide has an advantage that it does not require alignment for assembling parts and is easy to assemble.

[0006]

The waveguide substrate H shown in FIG. 4 forms a core F by depositing quartz glass on a silicon (Si) substrate by a normal flame deposition method, and machining both sides of the core F. To form a guide groove G. In this case, the accuracy of the relative position between the guide groove G and the core F must be improved. It is difficult for the position to be as designed. Further, since the manufacture of the guide pin N is also performed separately from the manufacture of the core F and the guide groove G, the assembling work is deteriorated and the assembling accuracy is reduced. There has been a problem that the position of the optical fiber F and the optical fiber N of the optical connector M are displaced and the connection loss increases.

An object of the present invention is to provide a method of manufacturing an optical waveguide having a guide groove, which can manufacture an optical waveguide which does not require a centering operation and has a high precision in the relative position between the guide groove and the core.

[0008]

According to the present invention, in order to achieve the above object, a core and a guide groove are formed in the same step by using a single photomask. That is, as shown in FIG. 1A, a buffer layer 2 of an optical waveguide is formed on the surface of a silicon substrate 1, a core layer 3 is formed thereon , and a resist agent is applied to the surface of the core layer 3. Overlay a photomask on which a core pattern and guide groove pattern are formed, and apply the resist agent to photolithography.
By further exposing and developing, a resist film 4 having the same pattern as the core pattern and the guide groove pattern formed in the photomask is formed on the core layer 3 as shown in FIG. 1C, a portion which is not masked by the resist film 4 is etched, and a guide groove edge 5 and a core 6 are formed as shown in FIG. As shown in FIG. 1E, the cladding layer 8 is formed around the core 6 by masking with the groove edge mask material 7 and the groove edge mask material 7 is removed .
The guide groove 9 is formed inside the adjacent guide groove edge 5 in the silicon substrate 1 by silicon anisotropic etching as described above.

[0009]

According to the method of manufacturing an optical waveguide with a guide groove of the present invention, since the relative position between the core 6 and the guide groove 9 is determined by one photomask, the accuracy of the relative position between the core 6 and the guide groove 9 is improved. I do. Since the depth of the guide groove 9 is determined by the interval between the adjacent guide groove edges 5, the depth of the guide groove 9 can be arbitrarily selected by controlling the interval on a photomask. .

[0010]

FIG. 1 shows an embodiment of a method of manufacturing an optical waveguide having a guide groove according to the present invention. The production is the following (1)-(5)
Perform in order.

(1) As the Si substrate 1 shown in FIG.
Using a crystal having a (00) plane crystal, quartz glass is deposited on the surface of the Si substrate 1 by flame deposition to form a buffer layer 2 below and a core layer 3 thereon.

(2) A resist agent ( not shown ) is applied to the surface of the core layer 3, and a photomask on which a guide groove pattern (not shown) and a core pattern are displayed is placed thereon, and light is irradiated from above to guide the guide. The guide groove pattern and the core pattern are transferred onto the core layer 3 by exposing the groove pattern and the core pattern, and a resist film 4 having the same shape as the pattern is formed as shown in FIG. At this time, the alignment is performed based on, for example, the orientation flat of the Si substrate 1 so that the guide groove pattern is parallel to the (110) plane of the Si substrate 1. In addition, pre-etching is performed to improve the accuracy of the alignment, and the alignment is performed based on the pre-etching.

(3) Reactive ion etching with a fluorine-based etching gas is performed to etch only the portions of the buffer layer 2 and the core layer 3 that are not masked by the resist film 4 as shown in FIG. A guide groove edge 5 having the same shape as the guide groove pattern and a core 6 having the same shape as the core pattern are formed in the remaining portions. The etching is performed until the Si substrate 1 is completely exposed. After the end of etching,
The resist film 4 is removed using a remover.

(4) Again using the fire accumulation method, FIG.
The clad layer 8 is formed around the core 6 as shown in FIG. At this time, a plate-like groove edge mask plate 7 is placed on the guide groove edge 5 and temporarily fixed so as not to be buried, so that the cladding layer 8 does not deposit on the guide groove edge 5. The groove edge mask plate 7 is removed after forming the cladding layer 8.

(5) The Si substrate 1 is anisotropically etched using the guide groove edge 5 of FIG. 1E as a mask. in this case,
If the Si substrate 1 shown in FIG. 1C is immersed in an alkaline etchant such as ethylenediamine pyrocatechol, only the portion of the Si substrate 1 where the surface is exposed is etched, and as shown in FIG. A V-shaped guide groove 9 is formed between the corresponding guide groove edges 5.

In the method of manufacturing an optical waveguide with a guide groove according to the present invention, the order of the step of forming the cladding layer 8 in FIG. 1D and the step of forming the guide groove 9 in FIG. Is also good.

FIG. 2 shows how to connect an optical waveguide manufactured by the method of manufacturing an optical waveguide with a guide groove according to the present invention to an optical connector to which an optical fiber is fixed. First, a superimposed substrate 21 is superimposed on the optical waveguide 20 and bonded and fixed.
A fitting hole 23 is formed by the zero guide groove 9 and the overlapping groove 22 formed on the overlapping substrate 21 by etching, machining, or the like. In this case, the polymer substrate 21 is made of silicon having the same thermal expansion coefficient as the Si substrate 1 or a borosilicate having substantially the same
Use a glass.

Next, the optical connector 24 is inserted into the fitting hole 23 shown in FIG.
A guide pin 25 projecting from the optical connector 24 is fitted into the joint end face 27 of the optical fiber 26 inserted into the optical connector 24.
Is optically bonded to the core 6 of the optical waveguide 20.

[0019]

(1) According to the method for manufacturing an optical waveguide with a guide groove of the present invention, the following effects can be obtained. An optical waveguide with high accuracy in the relative position between the core 6 and the guide groove 9 can be manufactured. (2) Since the accuracy of the relative position between the core 6 and the guide groove 9 is high, the light between the core 6 of the optical waveguide 20 and the optical connector 24 can be obtained simply by fitting the guide pin 25 of the optical connector 24 into the guide groove 9 of the optical waveguide. Since the optical axes of the fibers 25 coincide with each other and no aligning operation is required, the joining operation is facilitated. (3) The depth of the guide groove 9 can be easily adjusted, and the accuracy of the depth can be increased.

[Brief description of the drawings]

FIGS. 1A to 1E are process explanatory views of a method for manufacturing an optical waveguide with a guide groove according to the present invention.

FIG. 2 is an explanatory diagram of an optical fiber connection method using an optical waveguide with a guide groove manufactured by the manufacturing method of the present invention.

FIG. 3 is an explanatory diagram of a conventional connection method between an optical waveguide and an optical fiber.

FIG. 4 is an explanatory view of another conventional connection method between an optical waveguide and an optical fiber.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Buffer layer 3 Core layer 4 Resist film 5 Guide groove edge 6 Core 7 Mask material for groove edge 8 Cladding layer 9 Guide groove

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 6/12-6/14 G02B 6/30

Claims (1)

(57) [Claims] 1. A forming a buffer layer 2 of the optical waveguide on the surface of the silicon substrate 1, the core layer 3 is formed thereon, a resist agent is coated on the surface of the core layer 3, and the core pattern thereon superimposing a photomask guide groove pattern is formed, exposed and current resist agent by photolithography
By imaging, the core formed on the photomask
Register with the same pattern as the
A test film 4 is formed on the surface of the core layer 3 and the silicon substrate 1
Of the portion not masked by the etching with the resist film 4 to form a guide groove edge 5 in a portion which is not etched and the core 6, and the groove edge mask material 7 hoax disk for over the same guide groove edge 5 core 6 A cladding layer 8 is formed around
A method of manufacturing an optical waveguide with a guide groove, comprising forming a guide groove 9 inside the adjacent guide groove edge 5 of the silicon substrate 1 by silicon anisotropic etching after removing the groove edge mask material 7 .