JP2000047043A - Filter insertion type waveguide device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device in the production of which the wear of a blade at the time of fabricating a groove can be inhibited from occurring and which is adaptable to mass-production and also to provide a production method of the device. SOLUTION: This production comprises: forming a groove 13 across quartz- based glass waveguides (i.e., first and second input-output waveguides 3 and 4 and another waveguide 5) formed on a silicon substrate 1, in the substrate 1; inserting a dielectric multilayer film filter 14 into the groove 13; fixing the filter 14 in the groove 13 with a resin; and removing glass other than cores of the quartz-based glass waveguides 3, 4 and 5 and glass being in the vicinities of the cores, along the groove 13 to form projecting parts 23 to the outside of which an Si terrace is partly exposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component for optical communication or information processing, and more particularly, to a filter insertion type waveguide device using a silica-based optical waveguide formed on a silicon substrate. In particular, the present invention relates to a filter reflection type optical multiplexer / demultiplexer. Further, the present invention relates to a method for manufacturing such a filter insertion type waveguide device, particularly a filter reflection type optical multiplexer / demultiplexer.

[0002]

2. Description of the Related Art In recent years, a quartz-based planar lightwave circuit (hereinafter, referred to as a "planar wave circuit")
An optical transceiver module for subscribers is manufactured using a PLC hybrid integrated technology in which a laser diode (hereinafter abbreviated as LD) or a photodiode (hereinafter abbreviated as PD) is bonded and fixed on a PLC using a solder. (Eg, Inoue, Yamada, Yanagisawa, Fukuda, Uchida, Matsui, Horiguchi, “PLC hybrid integrated WDM optical transceiver module”, NTT R & D, vol. 46, No. 5, p.
p. 473-386, 1997). FIG. 12 shows the configuration. The module shown in FIG.
The waveguide layer 2 includes a first input / output waveguide 3, a second input / output waveguide 4, and a waveguide 5. The waveguide 5 is branched by a Y-branch 6, and one waveguide 6a faces the transmitting LD 7 and the other waveguide 6b faces the receiving PD 9, respectively. LD7 for transmission, monitor PD8 and PD9 for reception
Each is disposed on the LD / PD mounting unit 10 from which the glass has been removed. Electrical wiring 11 and 12 are LD7 for transmission
And the receiving PD 9. The waveguide layer 2 and the Si substrate 1 have first and second input / output waveguides 3,
A groove 13 is provided so as to separate the waveguide 4 and the waveguide 5, and a dielectric multilayer filter 14 is fixed in the groove 13 with an adhesive (not shown). The first input / output waveguide 3 is connected to the common port 15, and the second input / output waveguide 4 is connected to the common port 15.
They are connected to 55 ports 16 respectively. The end faces of the Si substrate and the waveguide layer 2 are in contact with the end faces of the fiber array 18. 1.31 / 1.5 for fiber array 18
The first fiber 19 through which 5 μm light propagates and 1.55 μm
m light propagates through the first and second fibers 20
, Respectively.

In this module, 1.55 μm light incident from the common port 15 is reflected by the dielectric multilayer filter 14 and output from the 1.55 μm port 16. An element for multiplexing / demultiplexing 1.31 μm light and 1.55 μm light is a filter reflection type optical wavelength multiplexer / demultiplexer. In
oue, T .; Oguchi, Y .; Hibino, S.M. S
uzuki, M .; Yanagisawa, K .; Mori
Waki, and Y. Yamada, “Filter
-Embedded wavelength-div
sion multiplexer for hybr
id-integrated transceiver
based on silica-based PL
C, "IEEE Electron Lett., Vo.
l. 32, no. 9, pp. 847-848, Apr.
1996. The importance of the optical component shown in FIG. 12 as a future optical transmission / reception module for subscribers is increasing.

[0004]

In the optical transmitting / receiving module shown in FIG. 12, a groove is formed by using a dicing saw after a waveguide is manufactured in order to manufacture a filter reflection type optical wavelength multiplexer / demultiplexer. Generally, when a groove is formed with a dicing saw, the amount of wear of the blade (the teeth of the dicing saw) greatly changes depending on the material of the sample. Quartz glass has a remarkably large blade wear compared to silicon. For this reason, when the grooves shown in FIG. 12 are machined, the wear of the blade is large, and it is difficult to manufacture many samples. Accordingly, an object of the present invention is to provide a filter insertion type waveguide device suitable for mass production and capable of suppressing abrasion of a blade during groove processing, and a method of manufacturing the same.

[0005]

As a means for solving the above-mentioned problems, a quartz glass at a position where a groove is to be formed is removed in advance by, for example, reactive ion etching (RIE). Accordingly, the amount of glass cut by the blade is reduced, so that wear of the blade can be suppressed. In addition, in the case of an optical transceiver module that includes the removal of quartz glass as an essential step, the removal of this glass is not an additional process, but also serves as a part of the process of fabricating the optical transceiver module, thereby increasing the burden on the fabrication process. The removal of the quartz-based glass is realized without causing the removal.

That is, the filter insertion type waveguide device according to the first aspect of the present invention provides a quartz glass optical waveguide formed on a silicon substrate, and a groove formed across the quartz glass optical waveguide. In a filter insertion type waveguide device comprising a dielectric multilayer filter inserted in the groove and a resin for fixing the dielectric multilayer filter in the groove, the quartz glass optical waveguide is formed along the groove. It is characterized in that glass other than the core of the waveguide and the glass in the vicinity thereof has been removed.

According to a second aspect of the present invention, there is provided the filter insertion type waveguide device according to the first aspect, wherein a projection is formed on a portion of the silicon substrate where the glass is removed. It is characterized by being.

According to a third aspect of the present invention, there is provided the filter insertion type waveguide device according to the first or second aspect, wherein the shape of the tip of the glass removing portion is an acute angle. Features.

According to a fourth aspect of the present invention, in the method of manufacturing a filter insertion type waveguide device, a quartz glass optical waveguide is formed on a silicon substrate, and a groove is formed across the quartz glass optical waveguide. In a method of manufacturing a filter insertion type waveguide device in which a dielectric multilayer filter is inserted into a groove and the dielectric multilayer filter is fixed to the groove with a resin, the core of the silica-based glass optical waveguide along the groove and the core thereof are provided. The method is characterized by including a step of removing glass other than glass in the vicinity.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a filter insertion type waveguide device according to the fourth aspect, wherein the filter insertion manufactured in the hybrid integrated optical module is provided. Forming a substrate convex portion for mounting an optical element and simultaneously forming a substrate convex portion in a region corresponding to the glass removing portion in the manufacture of the optical waveguide device; and removing glass for forming the optical element mounting portion. And forming a glass removing portion along the filter insertion groove at the same time as performing the above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be widely applied to a filter insertion type waveguide device in which a groove is provided in the middle of a waveguide and a filter is inserted into the groove. It is particularly effective to apply to an insertion type waveguide device.

Hereinafter, a case where the present invention is applied to a filter reflection type optical multiplexer / demultiplexer will be described in detail with reference to the drawings. However, the present invention is not limited to this, and a filter insertion type waveguide is generally used. Of course, it can be widely applied to devices.

It is an object of the present invention to suppress abrasion of a blade and reduce a load applied to the blade when the above groove processing is performed by a dicing saw. The groove has a width of 20 μm and a depth of 150 μm to suppress radiation loss of light.
It is extremely thin with μm. Therefore, the thickness of the blade used is extremely small. For this reason, there is a problem that the shape of the groove is deformed by a load applied to the thin blade. On the other hand, quartz-based glass has higher strength than silicon and exerts a large load on the blade. FIG. 1 shows the relationship between the total groove processing length (m) and the groove width (μm) when grooves are actually formed in silicon and quartz glass. It can be seen that the blade wears rapidly when the quartz glass is processed. That is, it can be seen that when performing groove processing, the load on the blade can be reduced by reducing the amount of quartz-based glass required for processing.

FIG. 2 is a perspective view showing a WDM optical transmission / reception module using the filter reflection type optical multiplexer / demultiplexer of the present invention. 3 is an enlarged sectional view taken along line AA 'in FIG. 2, FIG. 4 is an enlarged sectional view taken along line BB' in FIG. 2, and FIG.
FIG. 6 is an enlarged sectional view taken along line DD 'of FIG. 2.

The configuration of the WDM optical transmitting / receiving module of the present invention shown in FIG. 2 is almost common to the conventional optical transmitting / receiving module shown in FIG. 12, and the same or equivalent members are denoted by the same reference numerals. In the WDM optical transmission / reception module of the present invention, the groove 13 is provided substantially at the center of the Si terrace 21 which is a projection on the substrate. Since the end 22 of the waveguide layer 2 opposed to both side surfaces of the groove 13 is not present on the top of the Si terrace 21 except for a part, the protrusion 23 is formed. That is, in the longitudinal direction of the groove 13, the glass is removed with a constant width in other regions except for the core portion of the waveguide and its neighboring region, and the Si terrace 21 is exposed. Here, the width from which the glass is removed may be large enough to prevent the blade from being applied during the groove processing.

As shown in FIG. 3, in the cross section taken along the line AA 'in FIG. 2, the waveguide layer 2 comprises a lower cladding layer 24, a second lower cladding layer 25, and an upper cladding layer 26.
The lower cladding layer 24 and the top surface of the Si terrace 21 are at the same height, and the remaining gap and the glass removing portion (the exposed terrace surface and the second lower cladding layer 25 and The space defined by the total height of the upper cladding layer 26 and the space excluding the portion occupied by the dielectric multilayer filter) is filled with an adhesive 27 to fix the dielectric multilayer filter 14. The exposure width W of the terrace 21 may be any size as long as the load applied to the blade during the groove processing during module production does not become too large and a module of stable quality can be obtained.

As shown in FIG. 4, in the section taken along the line BB 'in FIG. 2, the Si terrace 21 is not provided, and the end face 22 of the waveguide layer 2 forms the same plane as the side face 13a of the groove 13. (See FIG. 7B and reference numeral 24a in FIG. 8).

As shown in FIG. 5, the exposed Si terrace 2
2, the projection 23 of the waveguide layer 2 includes a lower cladding layer 24, a second lower cladding layer 25, an upper cladding layer 26, and an upper cladding layer 2.
6 comprises a core 28 embedded therein. That is, the core 28
And only the waveguide layers (the lower cladding layer 24, the second lower cladding layer 25, and the upper cladding layer 26) in the vicinity thereof have a glass constituting a waveguide layer, and a Si terrace 21 of the same material as the Si substrate 1 is present on both sides. It is exposed. Groove 1 of protrusion 23
The length L along the length direction of 3 needs to be 50 μm or more in consideration of the propagation loss of light.

As shown in FIG. 6, in the section taken along the line DD 'in FIG. 2, the receiving PD 9 includes the electric wiring and the solder 11a.
Are mounted on the Si terrace 21 and the lower cladding layer 24 through the intermediary. Although not shown here, the transmission LD 7 and the monitor PD 8 are also mounted on the Si terrace 21 and the lower cladding layer 24 via the electrical wiring and the solder 11a. That is, the LD / PD mounting unit 10 of FIG. 2 is one in which electric wiring and solder are provided on the Si terrace 21 and the lower cladding layer 24.

Next, a method of manufacturing the WDM optical transceiver module shown in FIG. 2 will be briefly described with reference to FIGS. 7 (a) to 7 (f) and FIG. First, a flat silicon substrate 1 is patterned to form a Si terrace 2 as a projection on the substrate.
1, ie, S for LD / PD mounting unit (10 in FIG. 2)
The portions other than the i terrace 21a and the grooved portion Si terrace 21b are etched to a certain depth (for example, about 30 μm). A glass layer serving as the lower cladding layer 24 is formed thereon by a flame deposition method (FIG. 7A). Thereafter, flattening polishing is performed until silicon on the Si terraces 21a and 21b is exposed on the surface (FIG. 7B). This polished surface 29 is LD
/ PD is the height reference plane for the waveguide when mounting. FIG. 8 shows a top view in this state. As shown in FIG. 8, the top of the Si terrace 21a is a silicon exposed portion 21c, which is a space for the LD / PD mounting portion. The portion corresponding to the grooved portion does not have the Si terrace 21b in a part thereof, and the silicon exposed portion 21d corresponding to the top of the Si terrace 21b is formed by the lower clad layer 24 existing up to the polished surface (reference surface) 29 described above. Are separated. That is, the lower cladding layers 24 are connected by bridges 24a having a width L. The value of L is as described above. Subsequently, a second lower cladding layer 25 serving as a height adjusting layer and a core layer 28a are deposited, for example, to about 7 μm (FIG. 7C). After the core layer 28a is etched into a waveguide pattern to form the core 28, the upper clad layer 26 is deposited. The core 28 is made of Si
It extends beyond the terrace 21b to just before the Si terrace 21a (FIG. 7D). Here, the flame deposition method was used for depositing all of the cladding layer and the core layer. Then, L
The glass is etched until the silicon of the D / PD mounting portion 10 (21c in FIG. 8) and the groove processing portion (21d in FIG. 8) are exposed again, and the electrode wiring of the LD / PD and the mounting solder 11a are deposited (FIG. 7 (e)).

Finally, a groove 13 for inserting the dielectric multilayer filter is formed (FIG. 7 (f)), and the dielectric multilayer filter is inserted into the groove 13 and fixed with an adhesive.
The optical transmitting and receiving module shown in FIG.

FIG. 9 shows a WD according to a second embodiment of the present invention.
3 shows an M optical transmitting / receiving module. This embodiment differs from the configuration of the WDM optical transmitting and receiving module shown in FIG. 2 in that the pattern for removing the silica-based glass in the groove processing portion is not rectangular but has an acute-angled tip. That is, the protrusion 23
a has a trapezoidal shape, and the length L1 of the upper base (tip side) is smaller than the length L2 of the lower base (base side) (L1 <L2).
I have.

FIG. 10 shows a third embodiment of the present invention.
An example of a waveguide-type filter module in which a dielectric multilayer filter is inserted into a waveguide that does not include an LD / PD will be described. Members that are the same as or equivalent to those shown in FIG. 2 are given the same reference numerals, and detailed description is omitted. In FIG. 10, 30
Is 1.31 port, 31 is fiber array, 32 is 1.
This is a third fiber through which 31 μm light propagates. In this module, 1.31 / 1.55 μm mixed light propagating through the first input / output waveguide from the common port 15 is reflected by the dielectric multilayer filter 14 at 1.55 μm, and the reflected light is reflected at 1.55 port. 1.31 μm which propagated through the second fiber and passed through the dielectric multilayer filter 14
The light is taken out from the third fiber 32 through the 1.31 port 30. In this embodiment, the Si terrace for mounting the LD / PD is not required, so that the filter mounting portion (grooved portion) is not provided with a Si terrace, as shown in FIG. Formed on the surface. Then, a dielectric multilayer filter 14 is inserted into the groove 13 traversing the waveguide, and the quartz glass around the filter is removed as in the case of the module shown in FIG.

FIGS. 11A to 11E show the steps of fabricating the waveguide filter module of the present embodiment. Si substrate 1
A lower cladding layer 24 is formed thereon (FIG. 11A), and a core layer 28 is formed on the lower cladding layer 24 (FIG. 11A).
(B)) Further, an upper clad layer 26 is formed thereon to form a quartz glass waveguide including the Si substrate 1, the lower clad layer 24, the core layer 28a, and the upper clad layer 26 (FIG. 11C). ). Next, the portion where the dielectric multilayer film is to be mounted, that is, the quartz glass waveguide layer in the region of the grooved portion is etched until the Si substrate 1 is exposed to remove the glass (FIG. 11D). The groove 13 was formed with a blade (FIG. 11E). In the etching of the silica-based glass waveguide layer, the etching time was increased by the thicker lower clad layer as compared with the method shown in FIG. On the other hand, the removal of the thick quartz glass layer significantly reduces the load on the blade.

In this embodiment, the case where the filter mounting portion does not have the Si terrace is shown. However, it is possible to manufacture the filter mounting portion having the Si terrace also by using the process shown in FIG. Further, as shown in FIG. 9, by making the shape of the protrusion 23 trapezoidal, the load on the blade can be further reduced, and the shape deformation of the groove can be suppressed.

The quartz glass in the region to be grooved by the dicing saw may be removed in advance by another method, for example, reactive ion etching. However, in practice, the WD shown in the above-described embodiment is better than the application in which the step of removing the quartz-based glass imposes a new process burden.
An application example in which the removal of the silica-based glass does not add a new process load as in the application example of the M optical transmission / reception module is more effective.

In the above-described embodiment, an example of the filter reflection type optical demultiplexer having the wavelength demultiplexing function has been described. However, as the optical multiplexer / demultiplexer, a device which branches the optical power at a fixed ratio can be used. .

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 In this example, a filter reflection type multiplexer / demultiplexer having the structure shown in FIG. 1 was manufactured with a chip width of 3 mm, a groove width of 20 μm, and a depth of 150 μm. Of these, except for the 100 μm portion of the waveguide (that is, L = 100 μm in FIG. 7), the quartz-based glass used for the groove processing was removed by the above-described method.

Thus, the load on the blade can be reduced,
The wear of the blade was suppressed, and the deformation of the groove shape was suppressed.

Embodiment 2 A WDM optical transceiver module according to a second embodiment having the configuration shown in FIG. 9 was manufactured. In the present embodiment, the pattern for removing the quartz-based glass in the grooved portion is not rectangular but has a sharp edge at the tip.
Is different from the configuration of the WDM optical transceiver module shown in FIG. That is, the protrusion 23a has a trapezoidal shape, and the length L1 of the upper base (tip side) and the length L2 of the lower base (base side) are defined as L1 <
L2. By thus determining the shape of the protrusion and etching the glass, the load on the blade is further reduced, and the step of inserting the dielectric multilayer filter into the narrow groove is further facilitated.

(Embodiment 3) An LD / LD having the configuration shown in FIG.
A waveguide-type filter module in which a dielectric multilayer filter was inserted into a waveguide containing no PD was manufactured. In the etching of the silica-based glass waveguide layer, the etching time was increased by the thickness of the lower clad layer, but the load on the blade was significantly reduced by removing the thick silica-based glass layer. It was possible to produce a groove with no change in shape even when using.

[0033]

According to the filter insertion type waveguide device and the method of manufacturing the same of the present invention, the core other than the glass of the silica glass optical waveguide and the glass other than the core in the vicinity of the core are removed along the groove processing part, so that the groove processing at the time of groove processing is performed. A filter insertion type waveguide device suitable for mass production and a method for manufacturing the same capable of suppressing blade wear can be provided, and a low-cost WDM optical transceiver module can be realized.

Further, the LD formed on the silicon substrate
By providing the Si terrace formed simultaneously with the Si terrace for mounting the / PD on the dielectric multilayer filter mounting part, it is possible to remove the glass with a small process load, and furthermore, a filter insertion type waveguide device suitable for mass production. And a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in groove width depending on a total processing groove length.

FIG. 2 is a diagram illustrating a W using a filter reflection type optical multiplexer / demultiplexer according to the present invention;
It is a perspective view which shows a DM optical transmission / reception module.

FIG. 3 is an enlarged sectional view taken along the line AA ′ in FIG. 2;

FIG. 4 is an enlarged sectional view taken along the line BB ′ of FIG. 2;

FIG. 5 is an enlarged sectional view taken along the line CC ′ of FIG. 2;

FIG. 6 is an enlarged sectional view taken along line DD ′ of FIG. 2;

FIGS. 7A and 7B are cross-sectional views illustrating a manufacturing process of the filter insertion type waveguide device (WDM optical transceiver module) according to the first embodiment of the present invention. FIG. The device at the stage of deposition, (b) is a device at the stage where silicon is exposed by flattening and polishing, (c)
Is an element in a stage where a second lower clad layer (height adjusting layer) and a core layer are deposited, (d) is an element in a stage where a core is formed and an upper clad is deposited, and (e) is an electrode wiring for LD / PD. And the element at the stage where the mounting solder is deposited, and (f) shows the element after the groove processing.

FIG. 8 is a top view of the device at the stage of FIG. 7 (b).

FIG. 9 is a perspective view illustrating a WDM optical transceiver module according to a second embodiment of the present invention.

FIG. 10 is a perspective view illustrating a WDM optical transceiver module according to a third embodiment of the present invention.

FIGS. 11A and 11B are cross-sectional views illustrating a process of manufacturing a WDM optical transceiver module according to a third embodiment of the present invention, wherein FIG. 11A shows an element in which a lower clad layer is deposited, and FIG. (C) shows an element in which an upper clad layer has been deposited, (d) shows an element in which glass near the core has been removed, and (e) shows an element in which grooves have been formed.

FIG. 12 is a perspective view showing a configuration of a conventional optical transceiver module.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Si substrate 2 waveguide layer 3 first input / output waveguide 4 second input / output waveguide 5 waveguide 6 Y branch 6 a, 6 b waveguide 7 transmission LD 8 monitor PD 9 reception PD 10 mounting LD / PD Part 11, 12 Electric wiring 11a Electric wiring and solder 13 Groove 13a Side surface of groove 14 Dielectric multilayer film filter 15 Common port 16 1.55 port 17 Reinforced glass 18 Fiber array 19 First fiber 20 Second fiber 21, 21a , 21b Si terrace 21c, 21d Silicon exposed part 22 End part 23, 23a Projection part 24 Lower cladding layer 24a Bridge 25 Second lower cladding layer (height adjustment layer) 26 Upper cladding layer 27 Adhesive 28 Core 28a Core layer 29 Polishing Surface 30 1.31 port 31 Fiber array 32 Third fiber L In groove of protrusion Cormorants direction of the upper base length L1 protrusion of the lower base of the length L2 projecting portion length W terrace exposed width

Claims (5)

[Claims] 1. A quartz glass optical waveguide formed on a silicon substrate, a groove formed across the quartz glass optical waveguide, a dielectric multilayer filter inserted in the groove, and the dielectric In a filter insertion type waveguide device composed of a resin for fixing a multilayer filter to the groove, glass other than glass near the core of the silica glass optical waveguide and the vicinity thereof is removed along the groove. A waveguide device having a filter inserted therein, characterized in that: 2. The filter insertion type waveguide device according to claim 1, wherein a projection is formed on a portion of the silicon substrate from which the glass is removed. 3. The filter insertion type waveguide device according to claim 1, wherein the tip of the glass removing portion has an acute angle. 4. A quartz glass optical waveguide is formed on a silicon substrate, a groove is formed across the quartz glass optical waveguide, and a dielectric multilayer filter is inserted into the groove. A method of manufacturing a filter-inserted waveguide device in which the glass is fixed to the groove with a resin, comprising a step of removing glass other than glass along the groove and the core of the silica-based glass optical waveguide along the groove. A method of manufacturing a filter insertion type waveguide device. 5. In manufacturing a filter insertion type waveguide device manufactured in a hybrid integrated type optical module, when a substrate convex portion for mounting an optical element is formed, the substrate convex portion is simultaneously formed in a region corresponding to the glass removing portion. 5. The filter according to claim 4, further comprising a step of forming a portion, and a step of forming a glass removing portion along the filter insertion groove at the same time as removing the glass for forming the optical element mounting portion. Manufacturing method of insertion type waveguide device.