JP2001091771A - Optical waveguide component and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] At present, in an optical module using an optical waveguide, wavelength separation is performed by inserting a wavelength filter into a groove crossing the optical waveguide. For this reason, mass production is difficult, and there are performance problems such as an increase in optical loss and a change in isolation. SOLUTION: A groove-shaped optical waveguide pattern 1 is formed by molding.
After attaching the first optical member 14 formed with 2 to the base substrate 16 provided with the fiber fixing groove 17, and forming the wavelength filter 110 directly on the end face of the optical waveguide of the first optical member 14 by vapor deposition or the like Then, the second optical member 15 is attached to the base substrate 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide component mainly used for optical communication and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in public communications and computer networks, optical communications having broadband characteristics and added functions of wavelength multiplexing transmission and bidirectional transmission have been used for the purpose of speeding up and enhancing functions. Communication systems are permeating.

At present, the optical communication system is being expanded from a trunk system to a subscriber system for general homes and offices. In each home and office, the optical subscriber unit (ON
U, an optical network unit) is required, but the ONU converts an optical signal sent from the station into an electric signal and receives it, or converts an electric signal transmitted from the subscriber into an optical signal and converts it into an optical signal. An optical module having a function of sending out to an optical fiber is essential. It is indispensable to reduce the cost of optical modules in order to spread optical fibers to subscriber systems in the future.

A wavelength multiplexing method (WDM, wavele
ngth division multiplexing) is promising. This allows optical signals of multiple wavelengths to be transmitted over a single optical fiber,
The amount of information is increased in proportion to the number of wavelengths used.
At that time, the optical module in each home needs a function of performing wavelength separation.

FIG. 6 shows a general optical module configuration for WDM. Optical waveguide formed on Si substrate, interference film filter (wavelength filter), transmission laser diode
The main components are a photodiode (PD), a photodiode for reception, and a photodiode (PD) for monitoring an LD optical power.

[0006] The optical waveguide has a structure in which a core having a relatively higher refractive index than the periphery is embedded in a clad. Light propagates while being confined in a core having a high refractive index. As shown in the figure, the functions of branching and combining light can be realized by patterning the core into a circuit.

In FIG. 6, light having a wavelength of 1.3 .mu.m and light having a wavelength of 1.55 .mu.m are multiplexed and transmitted from the station side, and input from a common port 67 to an optical module. Here, light having a wavelength of 1.3 μm is used for two-way communication between a station and a subscriber,
The light of m is treated as a signal of only the subscriber from the station.
The light having a wavelength of 1.55 μm is reflected by the interference film filter 62 through the optical waveguide and is reflected from the port 2 (68). The light having a wavelength of 1.3 μm passes through the filter 62 and is branched and partially separated. Is received by the receiving PD 64 and converted into an electric signal.

On the other hand, for transmission, the LD 63 is modulated and driven, and an optical signal is sent from the common port 67 to the station.

Conventionally, such a module has been assembled by combining a large number of components such as lenses and prisms, and by assembling with high accuracy. However, the use of an optical waveguide as shown in FIG. Reduce points,
The miniaturization by integration became possible.

[0010]

However, the module shown in FIG. 6 has the following problems in terms of cost and productivity.

One is that the optical waveguide is expensive. FIG. 7 shows a general procedure for manufacturing an optical waveguide.

(A) A lower cladding film 72 is formed on a silicon substrate 71 (having a thickness of 20 μm or more). Further, a core film 73 is formed thereon (about 10 μm).

(B) The core film is patterned into a predetermined pattern by using photolithography and dry etching.

(C) Finally, an upper cladding layer 74 is formed (film thickness 20 μm or more).

Thus, the lower cladding on the substrate 71
A thin film is deposited in the order of the core and the upper clad. As a thin film forming process, there are mainly a flame deposition method, a CVD method, a vacuum deposition method and the like. However, since an optical waveguide requires a total film thickness of about 50 μm as a total film thickness of each layer, and the specification for the film thickness accuracy is strict. In addition, any process requires a long tact time and poor productivity.

Further, patterning is required after the formation of the core film, which uses a semiconductor process such as photolithography and dry etching, and is performed through expensive equipment and a long tact time. Therefore,
The current process has a problem that it is not suitable for mass production and it is difficult to reduce the cost.

Another problem is that a step of incorporating an interference filter is required. As shown in FIG. 6, the interference film filter 62 has an important function of separating wavelengths. Generally, it is common to use an interference film filter composed of a multi-layer dielectric oxide film on polyimide, dice a groove on the substrate in advance, insert the film-coated polyimide into this, and bond and fix it. Is being done.

Although an interference film filter originally has a high wavelength selectivity (isolation ratio), performance variations occur due to various factors when assembled in a groove. For example, FIG. 8 is a diagram when the polyimide substrate 81 inserted into the groove 83 is viewed from above, and the incident angle to the filter and the position of the reflected light due to the warp or inclination of the polyimide substrate 81 inside the groove 83. And the like vary subtly, and as a result, the wavelength separation performance and the transmission loss fluctuate. Further, the optical power after passing through the filter greatly varies depending on the positional accuracy at the time of groove processing. 82 is an optical waveguide, 84
Is an adhesive.

Therefore, in order to reduce this, an extremely high-precision assembly process is required, and the tact time becomes longer,
An increase in equipment costs is inevitable. Therefore, at present, there is a problem that the interference film filter is not suitable for mass production and it is difficult to reduce the cost.

The present invention has been made in view of the above-mentioned problems.
An object of the present invention is to provide an optical waveguide component capable of easily realizing a small size and low cost of an optical module, and a manufacturing method for manufacturing the same.

[0021]

Means for solving the above problems will be described below.

According to the present invention (corresponding to claim 1), a plurality of optical members having an optical waveguide groove are provided on a substrate on which a fixing groove for fixing an optical fiber is formed. Is installed so as to be connected, an optical element is arranged between a plurality of optical members having the optical waveguide groove, the substrate, and a material having a higher refractive index than the optical member, the optical waveguide groove of the An optical waveguide component filled in a concave portion.

In this configuration, the substrate provided with the optical fiber fixing groove functions as a lower clad. The plurality of optical members having the optical waveguide groove function as an upper clad. The material filled in the groove functions as a core. If light is input from the end face of the groove, light that satisfies a specific condition is confined in the groove.

The optical waveguide component of this configuration does not require the conventional thin film deposition, so that the productivity can be increased. Further, the optical fiber and the optical waveguide can be easily coupled only by disposing the optical fiber in the fixing groove of the substrate also serving as the lower clad. Further, in this configuration, the optical waveguide grooves formed in the plurality of optical members are continuous, and an optical element can be provided at a boundary between the optical members. The optical element may be attached directly to the optical member on the substrate,
The end face of the optical member may be coated with a thin film.

In this configuration, a wavelength filter, an isolator,
It is possible to incorporate all kinds of optical elements such as a wave plate and various mirrors.

Further, a groove for inserting an optical element, which is conventionally required, is unnecessary. Therefore, the processing cost can be reduced, and the performance variation due to the incorporation error of the optical element can be extremely reduced.

As described above, the optical waveguide component of the present invention is advantageous in cost and productivity.

The present invention (corresponding to claim 4) provides a fixing groove for fixing an optical fiber on a substrate, and first, second,... N-th (n is an integer of 2 or more) optical members. Forming a first, second,..., N-th optical waveguide groove thereon, and applying a resin onto the first optical member or the substrate to form the first optical member. A second step of bonding a member to the substrate on the surface where the first optical waveguide groove is formed and curing the resin; and a second step of additionally forming another optical element on an end surface of the first optical member. Step 3, and applying a resin on the second optical member or the substrate,
A fourth step of curing the resin by bonding the second optical member to the substrate on the surface where the second optical waveguide groove is formed so that the first and second optical waveguide grooves are connected to each other; And the third through fourth steps are also performed for the third,..., N-th optical members, respectively.

In this manufacturing method, the optical fiber fixing groove and the optical waveguide groove of each optical member are formed by, for example, molding using a mold. By repeatedly molding with the same mold material, it is possible to mass-produce optical members having the same groove pattern.

Further, by applying a resin to the optical member or the substrate and attaching the optical member on the groove pattern surface and then curing the resin, the resin in the groove becomes an optical waveguide core, and the resin in the groove becomes Adhere to the substrate.

The positioning of each optical member and the substrate can be easily performed with an accuracy within ± 1 μm by using a positioning marker. The positioning marker can also be formed simultaneously by the molding method.

As described above, the optical waveguide component can be manufactured very easily. In this manufacturing method, an optical waveguide component is manufactured by combining a plurality of optical members on a base substrate having a fixing groove for an optical fiber, and a component having a wavelength separation function by directly forming a thin film on the interface of each member. Cheap,
Can be manufactured in large quantities.

The present invention (corresponding to claim 5) provides a fixing groove for fixing an optical fiber on a substrate, and first, second, and third fixing grooves.
.. The first, second,... N-th optical waveguide grooves formed on the n-th (n is an integer of 2 or more) optical member, respectively
A step of directly bonding the first optical member to the substrate on the surface where the first optical waveguide groove is formed, and a second step of filling the first optical waveguide groove with a core material. Step 3, a fourth step of additionally forming an optical element on the end face of the first optical member, and the second optical member
A fifth step of directly bonding the second optical waveguide groove to the substrate at a surface on which the second optical waveguide groove is formed so as to connect the second optical waveguide groove, and a step of filling the second optical waveguide groove with a core material. 6
Wherein the fourth through sixth steps are performed for the third,..., N-th optical members, respectively.

In the present manufacturing method, since the substrate and each optical member are directly bonded to each other, a component having excellent mechanical strength and high reliability can be easily manufactured.

[0035]

(Embodiment 1) A method for manufacturing an optical waveguide component according to Embodiment 1 of the present invention will be described with reference to FIG.

As shown in FIG. 1A, first, a groove-shaped optical waveguide pattern 12 is formed on the surface of an optical member 11 made of glass or transparent resin by molding using a mold (not shown).
Then, several positioning markers 13 are formed.

Next, the optical member is cut so as to cross the optical waveguide pattern 12 as shown in FIG. Thus, the optical member is divided into a first optical member 14 and a second optical member 15. The cutting position is a position where an optical element such as a wavelength filter, a mirror or a wavelength plate is arranged.

On the other hand, in the same manner, the surface of the base substrate 16 made of glass or transparent resin
A groove 17, a flat stage 18 for installing an optical member, and several positioning markers 19 are formed. FIG. 2 shows the shape of the base substrate. This alignment marker corresponds to the above-described alignment marker of the optical member 13 with the concavo-convex reverse.

Next, as shown in (c), the first optical member 14
A UV resin is applied to the surface on which the groove-shaped optical waveguide pattern is formed, filled in the groove, and bonded on the base substrate 16 using the alignment markers 13 and 19. Thereafter, the base substrate 16 and the first optical member 14 are bonded and fixed by irradiating ultraviolet rays, and the UV resin in the grooves is cured. As a UV resin, the base substrate 16, the first and second optical members 14,
By using one having a refractive index higher than 15, the UV resin in the groove functions as an optical waveguide core.

Next, an optical thin film such as a thin film wavelength filter 110 or a reflection mirror is formed on the cut surface of the first optical member 14 by using a thin film forming process as shown in FIG. As the film material, a metal may be used, but it is preferable to form a dielectric material such as TiO ₂ or SiO ₂ in multiple layers because the transmission loss is small. In addition, as a thin film forming process, UV
It is desirable that the deposition be performed without damaging the resin. In particular, ion-assisted deposition capable of forming an optical thin film having excellent characteristics and reliability is desirable.

Finally, as shown in (e), the second optical member 1
5 is filled with UV resin in the optical waveguide groove in the same manner as the first optical member 14, and is adhered to the base substrate 15 to complete the optical waveguide component. The positioning of the second optical member 15 can be performed with high accuracy on the base substrate 16 by using the positioning marker formed by molding.

Thus, the optical waveguide groove pattern 12 formed on the first optical member 14 and the second optical member 15
The optical waveguide groove pattern 12 formed above can be arranged with almost no displacement. In addition, by setting the V-groove to a specific depth, the optical fiber and the optical waveguide that will be fixed to the V-groove later can be easily coupled.

Thus, the optical waveguide component shown in FIG. 3 is completed. FIG. 4 is a diagram showing an optical fiber connected to the V-groove of the optical waveguide component of FIG. 3 and viewed from above.

For example, in FIG.
3 has a specification of transmitting light having a wavelength of 1.3 μm and reflecting light having a wavelength of 1.55 μm. Input fiber 41
When light having a wavelength of 1.3 μm and light having a wavelength of 1.55 μm are input from outside, the light transmitted through the optical waveguide 42 is split by a thin-film wavelength filter 43, and the light having a wavelength of 1.55 μm is reflected by the filter. Thereafter, the light passes through the optical waveguide 44 and exits via the first output fiber 45. On the other hand, wavelength 1.
After passing through the thin-film wavelength filter 43, the light of 3 μm exits via the second output fiber 47. That is, the optical waveguide components shown in FIGS. 3 and 4 have a function of wavelength-separating light in an optical fiber.

The optical waveguide component of the present invention has a configuration capable of mass production, and is very useful in cost and productivity.

In this embodiment, the optical waveguide has been described by taking as an example an optical waveguide component having a two-branch pattern and having the function of wavelength separation. However, the present invention is not limited to this and is generally used. The present invention can be applied to all optical waveguide patterns.

In this embodiment, the optical member having the grooved optical waveguide pattern is cut and divided. However, as long as the individual optical waveguide patterns are continuously connected, each optical waveguide pattern is cut. The members may be molded separately.

The number of optical members provided on the base substrate is not limited as long as it is two or more.

The number of optical elements provided between the optical members is not limited as long as it is one or more.

In this embodiment, the optical thin film is directly coated. Since light cannot be confined like a waveguide inside the element, light leakage increases and loss increases when the element thickness is large.However, if an optical thin film is formed directly on the end face of the optical waveguide, the element thickness can be reduced, so that the performance can be reduced. Above is more advantageous. However, depending on the tolerance of the coupling loss, a plate-like element such as a wave plate or an isolator may be attached to the end face of the optical member instead of forming the thin film directly. In any case, it becomes possible to incorporate an optical element more easily than inserting an optical filter in a conventional groove.

In this embodiment, the UV resin is used as the core material of the optical waveguide. However, the present invention is not limited to this. For example, a thermosetting resin may be used.

In this embodiment, the V-groove for fixing the fiber formed on the base substrate is shown. However, the present invention is not limited to this. For example, a rectangular cross-sectional groove or a semicircular cross-sectional groove may be used.

It is desirable from the viewpoint of production that the marker for positioning the base substrate and each optical member be formed by molding as described in the present embodiment, but it is not limited to this. Alternatively, a marker may be formed by a metal film pattern or a concavo-convex processing by etching.

Further, a positioning marker for mounting light and electronic parts such as light emitting element, light receiving element, electrode wiring, and semiconductor element may be separately provided. By using this, for example, the alignment of the optical waveguide core with the LD or PD can be performed with high accuracy, and a low-loss connection can be made.

(Embodiment 2) A method of manufacturing an optical waveguide component according to Embodiment 2 of the present invention will be described.

First, a plurality of optical members are manufactured by using a molding method (FIGS. 5A and 5B). The grooved optical waveguide patterns on the plurality of optical members are connected continuously.
The details are the same as in the first embodiment, and a description thereof will be omitted.

Next, as shown in FIG. 5C, the first optical member 54 is directly bonded and fixed on the base substrate 56 on the surface on which the grooved optical waveguide pattern 52 is formed. At this time, as in the first embodiment, the positioning markers 53 and 59 produced by molding are used.
This is performed using

In this direct bonding, the base substrate 56 and the optical member 54 are cleaned and then heat-treated at a high temperature for bonding, so that the bonding strength can be increased. The optical member 54 and the base substrate 56 are preferably made of the same material, and particularly preferably glass, but may be any material that can be directly bonded and formed.

Next, a material having a higher refractive index than the optical member 54 and the base substrate 56 is filled in the optical waveguide groove 52 which has been hollowed by bonding as shown in FIG. This functions as an optical waveguide core.

As the filling material, an ultraviolet curable resin or a thermosetting resin which has a small viscosity and can be solidified after filling is desirable. As a filling method, for example, if the capillary phenomenon is used under reduced pressure, the resin can be filled in the cavity without bubbles.

After that, as shown in FIG. 9E, after the resin is cured, the end face of the optical waveguide of the optical member is coated with the thin-film wavelength filter 511 directly.

For filling, if the end of the optical waveguide groove is sealed with a thin polyimide film, it is not necessary to solidify the filling material. If an optical thin film is coated on a polyimide film to be sealed to form an element, the structure of the optical waveguide component of the present invention can be obtained.

Finally, as shown in (f), the second optical member 5
5 is adhered to the base substrate 56 in the same manner as the first optical member, and the optical waveguide groove 52 is filled with a high refractive material to complete the optical waveguide component.

As for the positioning of the second optical member, the positioning can be performed with high accuracy on the base substrate by using the positioning marker formed by molding.

Thus, the optical waveguide groove pattern formed on the first optical member and the optical waveguide groove pattern formed on the second optical member can be arranged with almost no displacement. In addition, by setting the V-groove to a specific depth, the optical fiber and the optical waveguide that will be fixed to the V-groove later can be easily coupled.

Thus, an optical waveguide component similar to that of FIG. 3 is completed. The configuration and function of this optical waveguide component are the same as those described in the first embodiment, and will not be described here.

In the method of manufacturing an optical waveguide component according to the second embodiment, since the optical member and the base substrate are firmly attached by using direct bonding, the mechanical strength can be extremely increased.

[0068]

As described above, according to the present invention, an optical module having an optical element such as a wavelength filter can be easily mass-produced at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing procedure of an optical waveguide component according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a base substrate of the optical waveguide component according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an optical waveguide component according to the first embodiment of the present invention.

FIG. 4 is a view of a fiber set in the optical waveguide component according to the first embodiment of the present invention shown in FIG. 3, viewed from above.

FIG. 5 is a diagram showing a manufacturing procedure of the optical waveguide component according to the second embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional wavelength multiplexing optical module.

FIG. 7 is a view showing a manufacturing procedure of a conventional optical waveguide.

FIG. 8 is a diagram showing a state where a wavelength filter in the optical module of FIG. 6 is inserted into a groove;

[Explanation of symbols]

 11, 51 Optical member 12, 52 Groove optical waveguide pattern 13, 19, 21, 53 Alignment marker 14, 32, 54 First optical member 15, 33, 55 Second optical member 16, 31, 56 Base substrate 17,23,35,36,57 V groove 18,22,58 Flat stage 110,34,43,511 Thin film wavelength filter 37 Optical waveguide groove (UV resin filling) 41 Input fiber 42,44,46,61 82 Optical waveguide 62 Interference film filter 63 Laser (LD) 64 Photodiode (PD) 65 Power monitor PD 66, 71 Si substrate 67 Common port 68 Port 2 72 Lower cladding film 73 Core film 74 Upper cladding film 81 Polyimide with interference film filter Substrate 83 Groove 84 Adhesive

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H037 AA01 BA21 CA34 DA02 DA04 DA12 DA17 2H047 KA04 MA05 PA28 QA00 QA04 QA05 TA31 TA42

Claims (8)

[Claims] 1. A plurality of optical members having optical waveguide grooves are provided on a substrate on which a fixing groove for fixing an optical fiber is formed, such that the optical waveguide grooves are connected to each other. An optical element is arranged between a plurality of optical members having an optical waveguide groove, and the substrate and a material having a higher refractive index than the optical member are filled in the concave portion of the optical waveguide groove. Optical waveguide component. 2. A glass-based material or a transparent resin is used as the substrate, and an ultraviolet-curing resin or a thermosetting resin is used as a material filled in the concave portion of the optical waveguide groove. The optical waveguide component according to claim 1. 3. The optical waveguide according to claim 1, wherein a single-layer or multi-layer optical thin film is used as the optical element, and the thin film is formed directly on an end face of the optical member. Wave parts. 4. A fixing groove for fixing an optical fiber on a substrate and first, second,..., N (n is an integer of 2 or more) optical members, respectively. , ... n-th
A first step of forming an optical waveguide groove, and applying a resin on the first optical member or the substrate, and forming the first optical member on the surface on which the first optical waveguide groove is formed. A second step of adhering to the substrate and curing the resin, a third step of additionally forming another optical element on an end surface of the first optical member, and a step of forming the second optical member or on the substrate. A resin is applied to the second optical member,
A fourth step of curing the resin by bonding the second optical waveguide groove to the substrate on the surface on which the second optical waveguide groove is formed so that the second optical waveguide groove is connected to the third optical waveguide groove; Wherein the third step to the fourth step are performed for the optical member described above. 5. A fixing groove for fixing an optical fiber on a substrate, and first and second optical members on first, second,... N-th (n is an integer of 2 or more) optical members, respectively. , ... n-th
A first step of forming an optical waveguide groove, a second step of directly joining the first optical member to the substrate at a surface on which the first optical waveguide groove is formed, and a first step of forming the first optical member. A third step of filling the waveguide groove with a core material, a fourth step of additionally forming an optical element on an end face of the first optical member, and a step of connecting the second optical member to the first and second light guides. A fifth step of directly bonding to the substrate on the surface where the second optical waveguide groove is formed so that the waveguide grooves are connected; and a sixth step of filling the second optical waveguide groove with a core material. A method of manufacturing an optical waveguide component, comprising: performing the fourth to sixth steps on the third,..., N-th optical members. 6. The optical waveguide component according to claim 4, wherein a single-layer or multilayer optical thin film is used as the optical element, and the thin film is formed directly on an end face of the optical member. Production method. 7. The first step includes: forming the optical waveguide groove on the optical member by molding with a mold having irregularities on its surface, and cutting the optical waveguide groove so as to cross the optical waveguide groove; , The second,... N-th optical member,
The method for manufacturing an optical waveguide according to claim 4, wherein the first, second,..., N-th optical waveguide grooves are obtained. 8. The substrate and the first, second,...
6. The n-th optical member is provided with a positioning marker, and the positioning marker is formed by molding with a mold having irregularities on the surface. A method for manufacturing an optical waveguide component.