JP2001083348A - Package structure for mounting quartz waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deviation of the center wavelength characteristics in an array waveguide diffraction grating formed by a quartz waveguide, by connecting a first package with an attaching part through a stress absorbing means and thereby preventing the stress from being propagated to the fixed quartz waveguide. SOLUTION: The attaching part 8 is connected to the first package 4 through the stress absorbing means 10 constituted of a corrugated plate material. Because of this connection, when a mechanical stress is generated in the attaching part 8 due to a minute dimensional errors, warpage or the like of each package, the stress is relaxed and absorbed by the deformation of the corrugated stress absorbing means 10, in screw-fixing the first package 4 to a second package 6. As a result, the stress can be reduced which is propagated to the first package 4 and the array waveguide diffraction grating 2 of the quartz waveguide 3 fixed on the first package 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silica-based waveguide, and more particularly to an optical multiplexer / demultiplexer for wavelength multiplexing using an arrayed waveguide diffraction grating.

[0002]

2. Description of the Related Art In a high-density wavelength division multiplexing transmission system for multiplexing and transmitting a plurality of signal lights having different wavelengths at intervals of about 1 nm with one optical fiber, an optical multiplexing system for multiplexing / demultiplexing a plurality of signal lights is used. A duplexer is used.

FIG. 4 shows a high-density wavelength division multiplexing transmission system.

As shown in FIG. 4, a high-density wavelength division multiplexing transmission system 30 multiplexes and demultiplexes a plurality of signal lights 31 having different wavelengths from λ1 to λn by an optical multiplexer / demultiplexer 32.

Here, an optical multiplexer / demultiplexer 32 using an arrayed waveguide diffraction grating made of a quartz material will be described with reference to FIG.

As shown in FIG. 5, the optical multiplexer / demultiplexer 32 has a structure in which an arrayed waveguide diffraction grating 36 and a slab waveguide 37 made of a quartz material are formed on a quartz substrate 35.

In the arrayed waveguide diffraction grating 36, a plurality of waveguides 38 are formed in parallel such that the optical path lengths are different by a fixed length ΔL (generally about several tens of microns). When the signal light propagates through each of the waveguides 38, the signal light is separated for each wavelength by using a phase difference of each wavelength with respect to the optical path length difference ΔL.

The array waveguide diffraction grating 36 is required to have a highly accurate center wavelength characteristic in order to multiplex and demultiplex signal light multiplexed at high density.

Generally, the arrayed waveguide diffraction grating 36
Is within ± 0.1 nm for 25 years.

Next, a package structure for mounting a silica-based waveguide such as a conventional optical multiplexer / demultiplexer will be described with reference to FIG.

As shown in FIG. 6, a package structure 40 for mounting a silica-based waveguide includes a first package 41 for bonding and fixing an optical multiplexer / demultiplexer 32 to an upper surface thereof with an adhesive, and a first package 41 of the first package 41. Heater 4 adhesively fixed to the lower surface
2 and a second package 43 for fixing the heater 42 and the first package 41 and enclosing the optical multiplexer / demultiplexer 32.

The second package 43 of the first package 41
Is fixed to the pedestal 46 provided on the second package 43.
And the fixing part 47 provided on the first package 41 is used for fixing by screwing.

The second package 43 is provided at both ends with introduction portions 45 for input and output optical fibers 44.

As described above, the array waveguide diffraction grating of the optical multiplexer / demultiplexer is required to have a high-accuracy center wavelength characteristic in order to multiplex / demultiplex the signal light multiplexed at high density. The refractive index of the material changes according to the temperature (0.01 nm).
/ ° C.) Due to the temperature dependence, the optical multiplexer / demultiplexer using a quartz-based material has a problem that the refractive index changes due to a change in temperature, and the center wavelength characteristic of the arrayed waveguide diffraction grating also fluctuates.

Therefore, power is supplied from the outside to the heater 42 bonded to the lower surface of the first package 41, and the optical multiplexer / demultiplexer 32 is used at a constant temperature higher than the ambient temperature.

Further, the use of a double structure in which the first package 41 is fixed inside the second package 43 improves heat insulation.

Here, a mounting portion for fixing the first package 41 to the second package 43 will be described with reference to FIGS.

In the structure shown in FIG. 7, mounting holes 51 are formed at four corners around a fixing portion 50 of the first package 41 for adhering and fixing the optical multiplexer / demultiplexer.
It is screwed and fixed to the base of the package.

In the structure of FIG. 8, the first package 4
At the four corners 1, the mounting portions 5 protruding from the first package 41.
2, a mounting hole 53 is formed in the mounting portion 52, and the mounting hole 53 is used to fix the screw to the pedestal of the second package.

[0020]

However, FIG.
In the structure of the mounting portion as shown in FIG. 8, when the first package 41 is screwed to the second package 43, a mechanical stress is generated in the mounting portion due to a minute dimensional error or warpage of each package. When it occurs, there is a problem that the stress is applied to the first package 41.

The first package 41 includes an optical multiplexer / demultiplexer 32
Since the quartz-based waveguide such as is bonded and fixed, the stress applied to the first package 41 is also transmitted to the optical multiplexer / demultiplexer 32, which generates distortion therein and changes the effective refractive index. I will.

When an external stress is applied to the optical multiplexer / demultiplexer 32 to change the effective refractive index, there is a problem that the center wavelength characteristic of the arrayed waveguide diffraction grating 36 of the optical multiplexer / demultiplexer 32 fluctuates.

More specifically, when fixing the first package 41 to the second package 43, the center wavelength characteristic of the arrayed waveguide diffraction grating 36 is -0.03 nm to + 0.03n.
m.

When the second package 43 expands and contracts due to a change in ambient temperature in a state where the package is assembled, mechanical stress is fixed to the first package 41 and the first package 41 through the mounting portion. There is a problem that the center wavelength characteristic of the arrayed waveguide diffraction grating 36 fluctuates when transmitted to the optical multiplexer / demultiplexer 32.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to reduce the stress generated when assembling a package and the stress caused by a change in ambient temperature after assembling a package, in which a quartz-based waveguide is fixed. It is an object of the present invention to provide a package structure for mounting a silica-based waveguide, which can prevent transmission to the optical waveguide and suppress the deviation of the center wavelength characteristic of the arrayed waveguide diffraction grating formed of the silica-based waveguide.

[0026]

In order to achieve the above object, according to the first aspect of the present invention, a first package for fixing a quartz-based waveguide and a second package for fixing the first package are provided. And a mounting portion for mounting the first package to the second package, wherein the first package and the mounting portion are connected via a stress absorbing means. This is a package structure for mounting.

According to a second aspect of the present invention, the stress absorbing means includes a first
2. The package structure for mounting a quartz-based waveguide according to claim 1, wherein the package structure is made of a corrugated plate formed between the package and the mounting portion.

According to a third aspect of the present invention, there is provided the package structure for mounting a quartz-based waveguide according to the first aspect, wherein the thickness of the stress absorbing means near the center thereof is smaller than the thickness at both ends.

According to a fourth aspect of the present invention, there is provided the package structure for mounting a quartz-based waveguide according to the first aspect, wherein the stress absorbing means is made of a plate material provided with a narrow portion formed narrow in the width direction at least at one place. It is.

According to a fifth aspect of the present invention, the silica-based waveguide is an optical multiplexer / demultiplexer for wavelength multiplexing comprising an arrayed waveguide diffraction grating, wherein the first package is formed of a metal material and the first package is formed of a metal material. 5. The package structure for mounting a silica-based waveguide according to claim 1, wherein the package is screwed to the second package using a mounting portion.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of a package structure for mounting a silica-based waveguide according to the present invention, and FIGS.
It is a perspective view of the 1st package of other embodiments.

The circled portion in the drawing is an enlarged view of the mounting portion and the stress absorbing means.

As shown in FIG. 1, a package structure 1 for mounting a silica-based waveguide has a first structure for bonding and fixing a silica-based waveguide 3 using an arrayed waveguide diffraction grating 2 to its upper surface.
Formed by a package 4, a heater 5 bonded and fixed to the lower surface of the first package 4, and a second package 6 for fixing the heater 5 and the first package 4 and enclosing the quartz-based waveguide 3. A double structure is used.

In the present embodiment, the material of the first package 4 is Super Invar, which is a metal.

The quartz waveguide 3 is used at a constant temperature higher than the ambient temperature by a heater 5 bonded to the lower surface of the first package 4.

Further, the use of a double structure in which the first package 4 is fixed inside the second package 6 enhances heat insulation.

Here, the attachment of the first package 4 and the second package 6, which is the gist of the present invention, will be described.

The first package 4 and the second package 6 are screwed together by using a pedestal 7 provided on the second package 6 and a mounting hole 9 formed in a mounting portion 8 connected to the first package 4. Fix with.

The mounting portion 8 is connected to the first package 4 via a stress absorbing means 10 made of a corrugated plate.

Since the mounting portion 8 is connected via the stress absorbing means 10 made of a corrugated plate material, when the first package 4 is screwed to the second package 6, a slight dimensional error of each package may be reduced. When mechanical stress is generated in the mounting portion 8 due to warping or the like, the wavy stress absorbing means 10 is deformed to relax and absorb the stress, and is fixed to the first package 4 and the first package 4. The stress transmitted to the arrayed waveguide diffraction grating 2 of the quartz-based waveguide 3 can be reduced.

In this embodiment, the deviation of the center wavelength characteristic of the arrayed waveguide diffraction grating 2 of the quartz-based waveguide 3 due to the stress generated when the first package 4 is fixed to the second package 6 is −0.004 nm. This is a measurement error range of +0.004 nm.

Similarly, when stress is generated by the expansion and contraction of the second package 6 due to a change in the ambient temperature in a state where the package is assembled, similarly, the stress is generated by the wavy stress absorbing means 10 being deformed. Stress that is relaxed and absorbed and transmitted to the first package 4 and the arrayed waveguide diffraction grating 2 of the silica-based waveguide 3 fixed to the first package 4 can be reduced.

Using the quartz waveguide mounting package structure 1 of this embodiment, the quartz waveguide 3
A continuous energization test was carried out while keeping the temperature of 75 ° C. constant.
Of the center wavelength characteristic of the arrayed waveguide diffraction grating 2 is −
It was 0.005 nm, which was within the range of measurement error.

Next, a first embodiment of another embodiment will be described with reference to FIG.
The package and the mounting part will be described.

In this embodiment, the first package 13
The mounting portion 14 for mounting to the second package is
The thickness near the center is connected to the first package 13 via the stress absorbing means 15 formed thinner than the thickness at both ends.

The stress supply means 15 has a thickness of 1 mm at both ends connected to the mounting portion 14 and the first package 13.
The thickness is gradually reduced toward the center and the thickness of the thinnest portion near the center is 0.5
mm.

When the stress absorbing means 15 whose thickness near the center is smaller than the thickness at both ends is bent, the stress generated at the time of screwing and the change of the ambient temperature after the package is assembled cause the second package to change. The stress generated by the expansion and contraction can be relaxed and absorbed, and the stress transmitted to the first package 13 and the arrayed waveguide diffraction grating of the silica-based waveguide fixed to the first package 13 can be reduced.

In this embodiment, the first package 13
Of the center wavelength characteristic of the arrayed waveguide diffraction grating of the silica-based waveguide due to the stress generated when fixing to the second package is within the measurement error range of -0.004 nm to +0.004 nm.

Next, another embodiment will be described with reference to FIG.

In this embodiment, the first package 17
The mounting portion 18 for mounting the to the second package is
The first package 1 is connected to the first package 1 via a stress absorbing means 19 made of a plate material provided with a narrow portion 19a formed narrow in the width direction.
7.

The stress supply means 19 has a width of 5 m at both ends connected to the mounting portion 18 and the first package 17.
m, and the width of the constricted portion 19a provided near the center is 2.5 mm.

The constricted portion 19a may be formed in at least one place, and there is no restriction on the shape and the number.

At least at one place, the stress absorbing means 19 provided with the narrowed portion 19a formed narrow in the width direction is bent, so that the stress generated at the time of screwing and the change of the ambient temperature after the package is assembled. Reduces and absorbs the stress generated by the expansion and contraction of the second package, and reduces the stress transmitted to the first package 17 and the arrayed waveguide diffraction grating of the silica-based waveguide fixed to the first package 17. be able to.

In this embodiment, the first package 17
Of the center wavelength characteristic of the arrayed waveguide diffraction grating of the silica-based waveguide due to the stress generated when fixing to the second package is within the measurement error range of -0.004 nm to +0.004 nm.

[0056]

In summary, according to the present invention, since the mounting portion for mounting the first package to the second package is connected to the first package via the stress supply means, the first package is screwed to the second package. The stress supply means relaxes and absorbs the stress generated at the time of stopping and the stress generated by the expansion and contraction of the second package due to a change in the ambient temperature after the package is assembled.
Stress transmitted to the arrayed waveguide diffraction grating of the silica-based waveguide fixed to the package and the first package can be reduced.

That is, the stress generated at the time of assembling the package and the stress generated due to the change in the ambient temperature after the assembly of the package are prevented from being transmitted to the arrayed waveguide diffraction grating of the fixed silica-based waveguide. In addition, the shift of the center wavelength characteristic of the arrayed waveguide diffraction grating can be suppressed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing one embodiment of a package structure for mounting a silica-based waveguide according to the present invention.

FIG. 2 is a perspective view of a first package according to another embodiment.

FIG. 3 is a perspective view of a first package according to another embodiment.

FIG. 4 is a conceptual diagram of a high-density wavelength division multiplexing transmission system.

FIG. 5 is a diagram showing an optical multiplexer / demultiplexer for wavelength multiplexing using an arrayed waveguide diffraction grating.

FIG. 6 is a diagram illustrating a package structure of an optical multiplexer / demultiplexer for wavelength multiplexing.

FIG. 7 is a diagram illustrating a configuration example of a conventional first package.

FIG. 8 is a diagram illustrating a structure example of a conventional first package.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 package structure for mounting quartz-based waveguide 3 quartz-based waveguide 4 first package 6 second package 8 mounting portion 10 stress absorbing means

Claims (5)

[Claims] 1. A first package for fixing a silica-based waveguide, a second package for fixing the first package, and a mounting portion for mounting the first package to the second package. A package structure for mounting a silica-based waveguide, wherein the first package and the mounting portion are connected via a stress absorbing means. 2. The package structure for mounting a quartz-based waveguide according to claim 1, wherein the stress absorbing means is formed of a corrugated plate formed between the first package and the mounting portion. 3. The package structure for mounting a quartz-based waveguide according to claim 1, wherein the stress absorbing means has a thickness near the center thereof smaller than thicknesses at both ends. 4. The method according to claim 1, wherein the stress absorbing means is provided in at least one place.
2. The package structure for mounting a quartz-based waveguide according to claim 1, comprising a plate material provided with a narrow portion formed narrow in the width direction. 5. A quartz waveguide is a wavelength division multiplexing optical multiplexer / demultiplexer comprising an arrayed waveguide diffraction grating, wherein a first package is formed of a metal material, and the first package is attached to a second package. The package structure for mounting a quartz-based waveguide according to claim 1, wherein the package is screwed using a portion.