JP2001188141A - Optical waveguide circuit module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wave guide module with high reliability in which cracks are not generated in a housed optical waveguide circuit chip even under an environment of high temperature and high humidity. SOLUTION: An optical waveguide part 10 which is obtained by connecting an optical input waveguide 2, a first slab waveguide 3, juxtaposed plural array waveguides 4 with different lengths, a second slab waveguide 5, and juxtaposed plural light output waveguides 6 in this order is formed with quartz glass. An array waveguide type diffraction grafting with the optical waveguide part 10 formed on a substrate 1 is used as an optical wave guide circuit chip 25. Values of double refraction generated at the optical waveguide part 10 are specified by increasing the amount of B2O3 and P2O5 doped to an upper clad, and central wavelengths of transit spectrum for every polarized wave of TE mode and TM mode in the array waveguide type diffraction grating are approximated. The optical wave guide circuit chip 25 is housed in a case 26 charged with a non-water-soluble oil 28, water penetrates into the optical wave guide circuit chip 25, and thus the occurrence of cracks is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide circuit module such as an arrayed waveguide type diffraction grating used for optical communication and the like.

[0002]

2. Description of the Related Art In recent years, in optical communications, research and development on optical wavelength division multiplexing has been actively carried out as a method for dramatically increasing the transmission capacity, and practical use thereof has been progressing. Optical wavelength division multiplexing is, for example, wavelength multiplexing and transmitting a plurality of lights having different wavelengths from each other. In order to extract the light, it is indispensable to provide a light transmitting element or the like that transmits only light of a predetermined wavelength in the system.

As an example of a light transmitting element, for example, an arrayed waveguide type diffraction grating (AWG; Arra) as shown in FIG.
Yed Waveguide Grating). The arrayed waveguide type diffraction grating is obtained by forming a waveguide configuration as shown in FIG. 1 on a substrate 1, and this waveguide configuration is obtained by arranging one or more light input waveguides 2 arranged side by side. The first slab waveguide 3 is connected to the side, a plurality of array waveguides 4 arranged in parallel are connected to the output side of the first slab waveguide 3, and the output side of the array The two slab waveguides 5 are connected, and a plurality of light output waveguides 6 arranged side by side are formed on the emission side of the second slab waveguide 5.

[0004] The array waveguide 4 propagates light derived from the first slab waveguide 3 and is formed to have different lengths, and the lengths of adjacent array waveguides 4 are different from each other by ΔL. A diffraction grating is formed by these arrayed waveguides 4.

The optical input waveguide 2 and the optical output waveguide 6
Are provided in correspondence with the number of signal lights having different wavelengths to be demultiplexed or multiplexed by, for example, an arrayed waveguide type diffraction grating. However, in the figure, the number of each of the optical input waveguide 2, the array waveguide 4, and the optical output waveguide 6 is simply shown for simplification of the figure. Also, in the figure, the arrayed waveguide 4 is shown in an arc shape, but in actuality, the central part in the longitudinal direction of the arrayed waveguide 4 is formed closer to a straight line than shown in the figure.

An optical fiber (not shown) on the transmission side, for example, is connected to the optical input waveguide 2 so that wavelength-division multiplexed light is introduced. The light introduced into the slab waveguide 3 spreads due to the diffraction effect and enters each array waveguide 4, and the array waveguide 4
Is propagated.

The light that has propagated through the array waveguide 4 is transmitted to the second
Reaches the slab waveguide 5, and is further condensed and output to the optical output waveguide 6. Since the lengths of all the array waveguides 4 are different from each other, each of the individual The phase of the light is shifted, and the wavefront of the converged light is tilted according to the amount of the shift. Therefore, the light condensing positions of the lights having different wavelengths are different from each other, and by forming the light output waveguides 6 at the positions, the lights having different wavelengths are output from the different light output waveguides 6 for each wavelength. it can.

Further, since the array waveguide type diffraction grating utilizes the principle of reciprocity (reversibility) of an optical circuit, it has not only a function as an optical demultiplexer but also a function as an optical multiplexer. I have. That is, when a plurality of lights having different wavelengths from each other are made to enter from each of the optical output waveguides 6, these lights pass through the reverse propagation path and are multiplexed by the array waveguide 4,
The light is emitted from the optical input waveguide 2.

In such an arrayed waveguide type diffraction grating, as described above, since the wavelength resolution of the diffraction grating is proportional to the difference (ΔL) in the length of the arrayed waveguides 4 constituting the diffraction grating, ΔL is set to The large design enables the optical multiplexing and demultiplexing of wavelength-division multiplexed light with a narrow wavelength interval, which could not be realized by conventional diffraction gratings. , Ie, a function of demultiplexing or multiplexing a plurality of optical signals having a wavelength interval of 1 nm or less.

The arrayed waveguide type diffraction grating is an optical waveguide circuit in which an optical waveguide section 10 having a lower clad, a core, and an upper clad formed of silica glass is formed on a silicon substrate 1. A lower clad is formed on a silicon substrate 1, a core having the above-described waveguide structure is formed above the lower clad, and an upper clad that covers the core is provided above the core. Conventionally, for example, the upper cladding was formed of quartz-based glass obtained by adding B ₂ O ₃ and P ₂ O ₅ to pure quartz in an amount of ₅ mole% each.

By the way, in the above-described arrayed waveguide type diffraction grating, polarization-dependent loss occurs because the propagation speed of light propagating in the arrayed waveguide 4 differs between the TE mode and the TM mode. It has been known.

In order to eliminate the polarization-dependent loss, conventionally, as shown in FIG. 6, one half-wave plate 18 is arranged so as to cross the longitudinal center of all the arrayed waveguides 4.
Is provided. The half-wave plate 18 is inserted into a slit 17 formed in a central portion in the longitudinal direction of the arrayed waveguide 4 in a manner orthogonal to the arrayed waveguide 4. 4 is provided in a manner orthogonal to the above.

If the half-wave plate 18 is provided at the center in the longitudinal direction of the arrayed waveguide 4, the TE mode is converted to the TM mode before and after the half-wave plate 18, and the TM mode is converted to the TE mode. By the conversion, the difference in the propagation speed between the TE mode and the TM mode, which occurs before the light propagating through the array waveguide 4 enters the half-wave plate 18, is canceled before the light propagates to the output side of the array waveguide 4. And the polarization dependent loss is eliminated.

[0014]

However, as described above, in order to form the arrayed waveguide type diffraction grating by inserting the half-wave plate 18, it is necessary to use a dicer or the like to form the half-wave plate 18.
Of the half-wave plate 18 is inserted into the slit, and the half-wave plate 18 is further formed using an adhesive or the like.
Must be fixed, so that the cost of the arrayed waveguide type diffraction grating increases, and a so-called return loss, that is, a part of the light incident on the half-wave plate 18 returns to the incident side of the optical input waveguide 2. There was a problem that it occurred. Therefore, there has been a demand for the development of an arrayed waveguide type diffraction grating that can suppress the influence of the polarization-dependent loss without providing the half-wave plate 18.

Therefore, the present inventor has proposed a polarization-independent type that can reduce the influence of polarization-dependent loss without providing the half-wave plate 18 of the conventional arrayed waveguide type diffraction grating shown in FIG. An arrayed waveguide grating was proposed.

In the proposed arrayed waveguide type diffraction grating
To dope B into the upper cladding ₂O₃And P₂O₅of
To the amount of doping in the conventional arrayed waveguide grating
The optical waveguide section 10 (the upper
Value of birefringence B generated in the lad, core and lower cladding)
Is | B | ≦ 5.34 × 10^-5And

As described above, when the amounts of B ₂ O ₃ and P ₂ O ₅ doped in the upper cladding are increased, when the value shown in the following equation (1) is a normalized composition, as shown in Table 1, The normalized composition in the proposed arrayed waveguide grating is
It is smaller than the normalized composition in the conventional arrayed waveguide type diffraction grating.

Normalized composition = (SiCl ₄ (gas)) / [SiCl ₄ (gas) + PCl ₃ (gas) + BCl ₃ (gas)] (1)

In the equation (1), SiCl ₄ (g
as), PCl ₃ (gas), and BCl ₃ (gas) are the amounts of gas (gas) of each composition supplied when applying the flame deposition method at the time of manufacturing the arrayed waveguide type diffraction grating.

[0020]

[Table 1]

As shown in Table 1, by reducing the normalized composition, the center wavelength shift amount of the transmission spectrum for each polarization of the TE mode and the TM mode (the transmission of the TM mode) in the arrayed waveguide type diffraction grating is reduced. The center wavelength of the spectrum [lambda] _TM- the center wavelength [lambda] _TE of the pass spectrum of the _TE mode can be made close to zero. That is, by reducing the normalized composition, the polarization-dependent loss due to the difference in the propagation speed between the TE mode and the TM mode of the light propagating through the arrayed waveguide 4 can be made close to zero.

However, as described above, the normalized composition is reduced, and B ₂ O ₃ and P ₂
It has been found by experiments of the present inventors that when the amount of O ₅ is increased, the reliability in a high-temperature and high-humidity environment decreases.
That is, when the state of the conventional arrayed waveguide type diffraction grating and the arrayed waveguide type diffraction grating of the proposed example was examined after the high temperature and high humidity test, no particular change was observed in the conventional arrayed waveguide type diffraction grating. On the other hand, in the arrayed waveguide type diffraction grating of the proposed example, there is a problem that a crack is generated in an end region of the arrayed waveguide type diffraction grating as shown by a broken line C in FIG.

In the above high-temperature and high-humidity test, each arrayed waveguide type diffraction grating was placed in an atmosphere of 120 ° C. and 100% humidity, and 100 hours passed in that state. Based on the enlarged photograph of the end region of each arrayed waveguide grating after this test,
FIGS. 7A to 7D schematically show the state of occurrence of the crack C. FIG. 3A shows the state of a conventional arrayed waveguide type diffraction grating.
FIG. 3B shows the state of the arrayed waveguide type diffraction grating of Proposal Example 1, and FIG. 3C shows the state of the arrayed waveguide type diffraction grating of Proposed Example 2. In d), the state of the arrayed waveguide type diffraction grating of Proposal 3 is shown.

Table 2 shows the results of measuring the distance (CL in FIG. 7) of each crack from the end face of the arrayed waveguide type diffraction grating.

[0025]

[Table 2]

As apparent from FIG. 7 and Tables 1 and 2,
It was found that as the normalized composition becomes smaller, the polarization dependence of the arrayed waveguide grating can be reduced, but cracks are more likely to occur in the end region of the arrayed waveguide grating. Therefore, the present inventor has proposed an arrayed waveguide type diffraction grating having a configuration in which the polarization dependence is reduced without providing the half-wave plate 18 by setting the normalized composition to a small value, as in the above proposed example. 120 ° C, 100% humidity
It was considered necessary to propose a highly reliable configuration that does not crack even in a very severe high-temperature and high-humidity environment equivalent to the high-temperature and high-humidity test described above.

It is known that the arrayed waveguide type diffraction grating has a temperature dependence of the light transmission center wavelength due to the difference in the length of the arrayed waveguides 4 arranged side by side. In order to eliminate the temperature dependence of the light transmission center wavelength, the present inventor has proposed an arrayed waveguide type diffraction grating as shown in FIG.

An arrayed waveguide type diffraction grating shown in FIG. 1 is an optical waveguide section 1 formed of quartz glass on a substrate 1.
0 is formed. As in the conventional example, one optical input waveguide 2, a first slab waveguide 3, a plurality of array waveguides 4, a second slab waveguide 5, and a plurality of optical output waveguides 6, the array waveguide 4,
The optical output waveguides 6 are arranged side by side at predetermined waveguide intervals. In the arrayed waveguide type diffraction grating shown in FIG. It is cut and separated at a cutting surface 8 that intersects the path of light passing through the slab waveguide 3.

Further, in the arrayed waveguide type diffraction grating shown in FIG. 5, the substrate 1 and the optical waveguide section 10 are also moved along with the cutting of the first slab waveguide 3 at the cut surface 8.
The optical waveguide portion 10b on the side where the separated slab waveguide 3b, the arrayed waveguide 4, the second slab waveguide 5, and the optical output waveguide 6 are formed, and the substrate 1 thereunder are Is fixed to a base 9 formed of a material having a low coefficient of thermal expansion such as quartz glass or an Invar lot.

On the other hand, the optical waveguide portion 10a on the side where the separation slab waveguide 3a is formed and the substrate 1 thereunder are slidable along the surface of the base 9 in the directions of arrows A and B in the figure. Are located. Optical waveguide 10
One end of “a” is fixed to the high thermal expansion coefficient member 7 via the adhesive 13, and the other end is position-regulated by the position restricting member 14.

The characteristic of the arrayed waveguide type diffraction grating shown in FIG. 5 is that, as described above, the first slab waveguide 3
Are cut and separated into separated slab waveguides 3a and 3b at a cutting plane 8 intersecting with a light path passing through the slab waveguide 3 in the direction of reducing the temperature-dependent fluctuation of each light transmission center wavelength of the arrayed waveguide type diffraction grating. That is, a slide moving mechanism for sliding the separated slab waveguide 3a side along the cut surface 8 is provided. In the arrayed waveguide type diffraction grating shown in FIG.
The high thermal expansion coefficient member 7, the base 9, and the position regulating member 14
Are provided to constitute the slide moving mechanism.

The high coefficient of thermal expansion member 7 is
0a is an L-shaped member having an upper plate portion 7a provided along the upper surface and a side plate portion (not shown) provided along the side surface of the optical waveguide portion 10a, and the side plate portion is a fixed portion. At 11 it is fixed to the base 9. The high thermal expansion coefficient member 7 has, for example, a thermal expansion coefficient of 2.5 × 10 ⁻⁵ (1 / K).
Of aluminum (Al).

The position restricting member 14 is provided in the optical waveguide section 10.
a is a member having a shape having an upper plate portion 14a provided along the upper surface of the optical waveguide portion 10a and a side plate portion (not shown) provided along the side surface of the optical waveguide portion 10a.
2 is fixed to the base 9. The inner wall of the upper plate portion of the position regulating member 14 is in contact with the upper surface of the optical waveguide portion 10a, and when the optical waveguide portion 10a slides, the optical waveguide portion 10a is positioned above the base 9 (perpendicular to the XY plane). Na Z
(Axial direction). The inner wall of the side plate and the side surface of the optical waveguide 10a are spaced from each other, so that the optical waveguide 10a can be slid and moved without any trouble.

In the arrayed waveguide type diffraction grating shown in FIG. 3, the first slab waveguide 3 is separated from the separated slab waveguide 3 by a cut surface 8 which intersects a light path passing through the first slab waveguide 3.
When the operating environment temperature of the arrayed waveguide type diffraction grating changes, the separated slab waveguide 3a is moved to the temperature of each light transmission center wavelength of the arrayed waveguide type diffraction grating by the slide moving mechanism. In the direction in which the dependent variation is reduced (the direction of arrow A or the direction of arrow B in FIG. 5),
The separation slab waveguide 3a and the optical input waveguide 2 slide by this sliding movement.

Therefore, according to the proposed arrayed waveguide type diffraction grating, even if the operating environment temperature of the arrayed waveguide type grating changes, the shift of the light transmission center wavelength due to the temperature change can be eliminated. By forming the arrayed waveguide grating as described above, a so-called temperature-independent arrayed waveguide grating that does not depend on the use environment temperature can be obtained.

The inventor of the present invention has proposed that in the proposed temperature-independent arrayed waveguide type diffraction grating, reflection at the cut surface 8 is prevented, and connection loss between the separated slab waveguides 3a and 3b is reduced. In order to suppress this, matching grease whose refractive index matches that of the quartz glass is applied to the cut surface 8. However, the temperature-independent array waveguide type diffraction grating was subjected to the high temperature and high humidity test,
Examination of the state of the arrayed waveguide type diffraction grating after the passage of the high-temperature and high-humidity test revealed that the matching grease evaporated and it was difficult to suppress the connection loss.

Therefore, the present inventor has proposed that a cut surface is formed on an arrayed waveguide type diffraction grating, and a refractive index of a matching grease or the like is formed on the cut surface 8 as in the above-mentioned proposed temperature independent arrayed waveguide type diffraction grating. In an arrayed waveguide type diffraction grating having a configuration in which a matching agent is provided to suppress connection loss due to light reflection at the cut surface 8, the cutting is performed even in a very severe high-temperature and high-humidity environment corresponding to the high-temperature and high-humidity test. It is considered necessary to propose a highly reliable configuration that can suppress an increase in connection loss on the surface 8.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical waveguide circuit module having high reliability even under high temperature and high humidity conditions. That is, an object of the present invention is to firstly, for example, dope B ₂ O ₃ and P ₂ doped in the upper cladding of an optical waveguide circuit chip.
It is an object of the present invention to provide an optical waveguide circuit module capable of suppressing the occurrence of cracks under high-temperature and high-humidity conditions even when the amount of a dopant such as O ₅ is increased. An object of the present invention is to provide an optical waveguide circuit module that can suppress an increase in connection loss at a cut surface under a high-temperature and high-humidity condition even if it has a configuration that transmits light.

[0039]

In order to achieve the above-mentioned object, the present invention has the following structure to solve the problem. That is, the first invention solves the problem by a configuration in which an optical waveguide circuit chip formed by forming an optical waveguide portion formed of quartz glass on a substrate is housed in a housing filled with water-insoluble oil. Means to do that.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a first slab waveguide is connected to an emission side of one or more optical input waveguides arranged side by side. A plurality of side-by-side arrayed waveguides of different lengths for transmitting light derived from the first slab waveguide are connected to the output side of the slab waveguide. A second slab waveguide is connected to the side, and a plurality of light output waveguides arranged in parallel are connected to the output side of the second slab waveguide. A plurality of optical signals of different wavelengths input from the optical input waveguide are propagated with a phase difference for each wavelength by the arrayed waveguide, and are incident on different optical output waveguides for each wavelength, Has a function to output light of different wavelengths from different light output waveguides And a means for solving the problems with the configuration that forms the array waveguide diffraction grating.

Further, according to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the water-insoluble oil has a refractive index matching property with the quartz glass forming the optical waveguide. It is a means to solve the problem with the configuration.

In the present invention having the above structure, since the optical waveguide circuit chip is housed in a case filled with water-insoluble oil, the optical waveguide circuit module can be applied to the optical waveguide circuit chip even in a high-temperature and high-humidity environment. Can be suppressed, and the optical waveguide circuit chip is hardly affected by this environment. Therefore, for example, B ₂ O ₃ and P ₂ doped in the optical waveguide portion of the optical waveguide circuit chip
O ₅ or the like of the dopant amount is increased to also as susceptible arrangement the influence of moisture, it is possible to suppress the occurrence of cracks under the conditions of high temperature and high humidity.

In the present invention, since the optical waveguide circuit chip is housed in a case filled with a water-insoluble oil, the optical waveguide circuit module can be used even in a high-temperature and high-humidity environment. It is possible to suppress evaporation of the refractive index matching agent provided on the cut surface. In particular, if the housing is filled with a water-insoluble oil having a refractive index matching with the silica-based glass forming the optical waveguide portion and the optical waveguide circuit chip is provided, the water-insoluble oil is cut. Even if it enters between the surfaces, the connection loss due to light reflection on the cut surface can be suppressed.

[0044]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same parts as those in the conventional example, and the overlapping description will be omitted. FIG. 1 is a cross-sectional view of a main part of an optical waveguide circuit module according to a first embodiment of the present invention, which is cut in a horizontal direction.

As shown in the figure, the optical waveguide circuit module of the present embodiment has a case 26. Case 2
6, an arrayed waveguide type diffraction grating as the optical waveguide circuit chip 25 is accommodated in the chip accommodation portion 27, and the chip accommodation portion 27 is filled with a water-insoluble oil. In the same figure, the filling region of the water-insoluble oil 28 is indicated by oblique lines. In the present embodiment, a silicone oil (product name: OF-38E (1000)) manufactured by Shin-Etsu Chemical Co., Ltd. is applied as the water-insoluble oil 28.

Although not shown in the figure, a lid member 30 (see FIGS. 2C and 2D) is provided above the case 26, and the case 26 and the lid member 30 are connected to each other. Thus, a housing for housing the optical waveguide circuit chip 25 is formed. The housing is disposed in a module case (not shown) to form the optical waveguide circuit module of the present embodiment.

In the case 26, fitting recesses 33 of the optical fiber arrays 21 and 22 in which a plurality of optical fibers are arranged and fixed are formed, and the fitting recesses 33 on the left and right sides are respectively provided with the optical fiber arrays 21 and 22. 22 is fitted and fixed. Each of the optical fiber arrays 21 and 22 has a plurality of optical fiber ribbons 2 in which a plurality of optical fibers are juxtaposed.
3, 24 are connected. Optical fiber arrays 21 and
The fitting recess 33 in which 2 is installed, the case 26 and the lid member 30 are sealed with an epoxy-based adhesive. A specific example is Cemedine High Super 5. However, the sealing adhesive is not limited to the epoxy-based adhesive, and the water-insoluble oil 28 in the module case may be used.
Any material can be used as long as it can be sealed so as not to leak.

The optical waveguide circuit chip 25 is the polarization-independent arrayed waveguide type diffraction grating of Proposal 3 proposed by the present inventors. That is, the optical waveguide circuit chip 25
Has a waveguide configuration similar to that of the conventional arrayed waveguide type diffraction grating shown in FIG. 6, and is configured by omitting the slit 17 and the half-wave plate 18. Further, in the optical waveguide circuit chip 25, the amounts of B ₂ O ₃ and P ₂ O ₅ doped into the upper clad of the optical waveguide portion 10 are made larger than the doping amounts of the conventional arrayed waveguide type diffraction grating. The birefringence value B generated in the optical waveguide portion 10 (the upper cladding, the core, and the lower cladding) is set to | B | ≦ 5.34 × 10 ⁻⁵ .

Each optical input waveguide 2 of the optical waveguide circuit chip 25
The optical fibers arrayed in the optical fiber array 21 are connected to the input ends of the optical fiber arrays 21, and the optical fibers arrayed in the optical fiber array 22 are connected to the output ends of the optical output waveguides 6, respectively. Have been.

On the substrate 1 side of the optical waveguide circuit chip 25, a temperature adjusting element (not shown) such as a Peltier element is provided, and the temperature adjusting element keeps the temperature of the optical waveguide circuit chip 25 at a constant temperature. It is configured to be held.

The present embodiment is configured as described above. Next, a method of manufacturing the optical waveguide circuit module of the present embodiment will be described. First, a case 26 shown in FIGS. 2A and 2B and a lid member 30 shown in FIGS. 2C and 2D are prepared. (A) and (c) of FIG.
A plan view of the case 26 and the lid member 30 is shown, respectively, and (b) and (d) of FIG.
6 and a side view of the lid member 30 are shown.

As shown in these figures, the case 26
Is formed with a temperature adjustment element accommodation hole 29 having a diameter smaller than that of the chip accommodation section 27 and communicating with the chip accommodation section 27. The temperature adjustment element accommodation hole 29 is formed as a through hole. In addition, the fitting recess 33 is formed in the case 26 as described above. An oil injection hole 31 and an air vent hole 32 are formed through the lid member 30.

As shown in FIG. 3A, the optical waveguide circuit chip 25 is accommodated in the chip accommodation hole 27 of the case 26, and the Peltier is accommodated in the temperature adjustment element accommodation hole 29 (not shown in FIG. 3). Insert a temperature control element such as an element. The optical waveguide circuit chip 25 and the optical fiber arrays 21 and 22 are fixed with the optical fibers of the optical fiber arrays 21 and 22 aligned with the optical input waveguide 2 and the optical output waveguide 6 of the optical waveguide circuit chip 25. I do. Then, the optical waveguide circuit chip 25
Is fixed in the chip accommodation hole 27 and the optical fiber array 2
1 and 22 are fitted and fixed in the fitting concave portion 33.

Thereafter, as shown in FIG. 3B, the case 26 is covered with the lid member 30, and the case 26 and the lid member 30 are attached or packed. In this embodiment, the fitting recess 33 in which the optical fiber arrays 21 and 22 are installed, the case 26 and the cover member 30 are sealed with an epoxy adhesive. In this state, the water-insoluble oil 28 is injected from the oil injection hole 31, and the inside of the chip housing hole 27 is filled with the water-insoluble oil 28. Then, as shown in (c) of the figure, a sealing agent 34 is provided in the oil injection hole 31 and the air vent hole 32 and sealed, and the water-insoluble water is contained in the housing formed by the case 26 and the lid member 30. Oil 28
Is filled in a liquid-tight state, and the optical waveguide circuit chip 25 is housed. Finally, the housing is disposed and fixed in a module case (not shown).

The present embodiment is manufactured as described above. When the high-temperature and high-humidity test is performed on the optical waveguide circuit module of this embodiment, the optical waveguide circuit in the optical waveguide circuit module is obtained. No crack C was generated in the chip 25. In addition, the optical waveguide circuit module was placed in a similar environment, a test was performed, and the transmission characteristics were examined. As a result, it was found that the matching grease could be prevented from evaporating and the connection loss could be suppressed.

According to the present embodiment, since the optical waveguide circuit chip 25 is housed in a case filled with the water-insoluble oil 28 to form a module, the optical waveguide circuit module can be used in a high-temperature and high-humidity environment. , Optical waveguide circuit chip 25
Water can be suppressed from entering the optical waveguide circuit chip 25.
Is hardly affected by the high temperature and high humidity environment. Therefore, as in the present embodiment, the optical waveguide circuit chip 25
Even if the amount of dopant such as B ₂ O ₃ and P ₂ O ₅ to be doped into the optical waveguide portion 10 is larger than the amount of dopant in the conventional arrayed waveguide type diffraction grating, as described above, under the condition of high temperature and high humidity, Cracks can be suppressed.

Further, according to the present embodiment, the polarization independent array waveguide type diffraction grating without the half-wave plate of the proposed example proposed by the present inventor is used as the optical waveguide circuit chip 25. Since the wave circuit chip 25 is housed in the housing, it is possible to avoid various problems that have been a problem in the conventional arrayed waveguide type diffraction grating provided with the half-wave plate 18, and as described above. Furthermore, an excellent optical waveguide circuit module having high reliability even under conditions of high temperature and high humidity can be obtained.

FIG. 4 shows a manufacturing process of the second embodiment of the optical waveguide circuit module according to the present invention. In the description of the second embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and the duplicate description will be omitted.

The feature of the second embodiment different from the first embodiment is that the optical waveguide circuit chip 25 is
And a refractive index matching with the silica-based glass forming the optical waveguide section 10 as the water-insoluble oil 28 as shown in FIG. In other words, a non-water-soluble oil (hereinafter, referred to as a matching oil) 28 is applied.

As an example of the matching oil 28 applied to this embodiment, a product name OF-38E manufactured by Shin-Etsu Chemical Co., Ltd. (viscosity 7 to 10,000 m at 25 ° C.)
m ² / s (cSt)), product name OP-101 manufactured by Dow Corning Toray Co., Ltd., product name X38-7427 manufactured by Shin-Etsu Chemical Co., Ltd., product name X38-45 manufactured by Toray Dow Corning Co., Ltd.
Second magnitude.

In FIG. 5, the optical waveguide circuit chip 25 has the first slab waveguide 3 cut by the cut surface 8 in the X-axis direction in FIG. The optical waveguide circuit chip 25 applied to the wave circuit module includes:
As shown in FIG. 4C, the first slab waveguide 3 is cut obliquely to form a separated slab waveguide 3a and a separated slab waveguide 3b. In FIG. 4, the high thermal expansion coefficient member 7 and the position regulating member 14 in FIG. 5 are omitted, but the optical waveguide circuit chip 25 of the optical waveguide circuit module of the second embodiment is provided with these components. A slide movement mechanism having a member for performing the slide movement.

As in the second embodiment, when the first slab waveguide 3 is cut obliquely to form an arrayed waveguide type diffraction grating which is an optical waveguide circuit chip 25, the array waveguide shown in FIG. As in the case of the waveguide type diffraction grating, in the direction of reducing the temperature-dependent variation of each light transmission center wavelength of the arrayed waveguide type diffraction grating,
By sliding the separation slab waveguide 3a side along the cut surface 8, the same effect as that of the arrayed waveguide type diffraction grating of FIG. 5 can be obtained.

Further, in the second embodiment, even if the temperature control element such as the Peltier element provided in the first embodiment is not provided, the slide movement by the slide movement mechanism allows the arrayed waveguide type diffraction grating to be formed. The temperature control element is omitted because the temperature-dependent fluctuation of the light transmission center wavelength can be reduced. Then, corresponding to this, the case 26
Has no temperature control element insertion hole as shown in FIGS. 4 (a) and 4 (b).

As shown in FIG. 9C, in the second embodiment, the optical fiber arrays 21 and 22 are accommodated in the chip accommodation hole 27 of the case 26 together with the optical waveguide circuit chip 25. Therefore, the fitting recess 33 is
The optical fiber tapes 23 and 24 connected to the optical fiber arrays 21 and 22 are fitted and fixed. Note that also in the second embodiment, the optical fiber array 2
The fitting recess 33 in which the first and second fittings 22 are installed, the case 26, and the lid member 30 are sealed with the same epoxy adhesive as in the first embodiment. The sealing adhesive is not limited to the epoxy adhesive as in the first embodiment, but may be any as long as it can be sealed so that the matching oil 28 in the module case does not leak.

In the second embodiment, the case 2 shown in FIGS. 4A and 4B is substantially the same as the first embodiment.
6 into the chip accommodation hole 27 as shown in FIG.
The optical waveguide circuit chip 25 is fixed, and (d) of FIG.
As shown in (2), the matching oil 28 is injected from the oil injection hole 31 by covering the lid member 30 to seal the oil injection hole 31 and the air vent hole 32, thereby producing the optical waveguide circuit module.

The second embodiment is manufactured and configured as described above. The optical waveguide circuit module of the second embodiment is placed in an atmosphere of 85 ° C. and 85% humidity, and is kept in this state for 336 hours. After performing the test for elapse, the transmission characteristics were examined. The transmission characteristics after the test were not different from those before the test. The connection loss caused by cutting the first slab waveguide 3 at the cut surface 8 was as small as 0.4 dB or less before and after the test.

According to the second embodiment, since the optical waveguide circuit chip 25 is housed in the casing filled with the matching oil 28, the matching grease is prevented from volatilizing, and the optical waveguide circuit module is heated and humid. In the environment described above, the evaporation of the matching grease of the refractive index matching agent provided on the cut surface 8 of the optical waveguide circuit chip 25 can be suppressed. The matching oil 28 used in the second embodiment has a refractive index matching with the silica-based glass forming the optical waveguide portion 10 of the optical waveguide circuit chip 25. Even if it enters between the cut surfaces 8, connection loss due to light reflection on the cut surface 8 can be suppressed.

Therefore, according to the second embodiment, a highly reliable optical waveguide circuit module can be provided which does not cause an increase in connection loss at the cut surface 8 even under high temperature and high humidity conditions. .

Further, according to the second embodiment, the temperature-independent arrayed waveguide type diffraction grating proposed by the present inventor is used as the optical waveguide circuit chip 25. Is accommodated in the housing, so that even if the use environment temperature of the optical waveguide circuit module changes, an excellent optical waveguide circuit module in which the light transmission center wavelength of the arrayed waveguide type diffraction grating does not change can be obtained. .

Further, according to the second embodiment, the center wavelength of the light transmission of the arrayed waveguide type diffraction grating changes depending on the temperature without providing a temperature control element such as a Peltier element as in the prior art. As compared with an optical waveguide circuit module having an arrayed waveguide type diffraction grating provided with a temperature control element, the configuration of the apparatus can be simplified, and power supply to the temperature control element is not required. And cost can be reduced.

The present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, in the first embodiment, the optical waveguide circuit chip 25 is a polarization-independent array waveguide type diffraction grating having a small normalized composition, and in the second embodiment, the optical waveguide circuit chip 2
Reference numeral 5 denotes a temperature-independent arrayed waveguide type diffraction grating obtained by cutting the first slab waveguide 3 at the cut surface 8, but the optical waveguide circuit chip 25 used in the optical waveguide circuit module of the present invention.
In the case where is an arrayed waveguide type diffraction grating, the composition and configuration are not particularly limited, and are appropriately set.

For example, the array provided in the second embodiment
In the optical waveguide circuit chip 25 of the waveguide type diffraction grating,
As in the first embodiment, the upper cladding is doped.
B ₂O₃And P₂O₅To increase the amount of light
The value B of the birefringence generated in the waveguide section 10 is set as | B | ≦ 5.
34 × 10^-5Then, the optical waveguide circuit chip 25 is heated
Degree-independent and polarization-independent array waveguide
Type diffraction grating.

As described above, the optical waveguide chip 25 is
If the optical waveguide circuit chip 25 is housed in a housing filled with the matching oil 28 as a temperature-independent and polarization-independent array waveguide type diffraction grating, and an optical waveguide circuit module is constructed, An arrayed waveguide type diffraction grating can suppress both the polarization dependence and the temperature dependence of the wavelength of multiplexed and demultiplexed light, and furthermore, provides an excellent optical waveguide circuit module with high reliability even under high temperature and high humidity conditions. Can be configured.

In each of the above embodiments, the optical waveguide circuit chip 25 is an arrayed waveguide type diffraction grating, but the optical waveguide circuit chip 25 provided in the optical waveguide circuit module of the present invention is not necessarily an arrayed waveguide chip. The optical waveguide module is not limited to the waveguide type diffraction grating, but can be configured by providing various optical waveguide circuit chips formed by forming an optical waveguide portion formed of quartz glass on a substrate.

[0075]

According to the present invention, since the optical waveguide circuit chip is accommodated in the casing filled with the water-insoluble oil, the optical waveguide circuit module can be used as an optical waveguide circuit chip even in a high-temperature and high-humidity environment. Water can be suppressed from entering, and the optical waveguide circuit chip is hardly affected by this environment. Therefore, for example, even if the amount of dopant such as B ₂ O ₃ and P ₂ O ₅ to be doped into the optical waveguide portion of the optical waveguide circuit chip is increased to make the structure susceptible to moisture, cracks may occur under high temperature and high humidity conditions. This can be suppressed.

Further, according to the present invention, since the optical waveguide circuit chip is housed in the casing filled with the water-insoluble oil, the optical waveguide circuit module can be used even in a high-temperature and high-humidity environment. Since the evaporation of the refractive index matching agent provided on the cut surface can be suppressed, even if an optical waveguide circuit module is formed using the optical waveguide circuit chip having the cut surface, the connection loss due to light reflection on the cut surface Can be suppressed.

In particular, according to the present invention, in which the water-insoluble oil has a refractive index matching with the silica-based glass forming the optical waveguide, even if the water-insoluble oil enters between the cut surfaces, Since the connection loss due to light reflection at the cut surface can be suppressed, even if the optical waveguide circuit module is formed using the optical waveguide circuit chip having the cut surface, the connection loss at the contact section can be more reliably suppressed. .

Further, according to the present invention, in which the optical waveguide circuit chip has an arrayed waveguide type diffraction grating, it is possible to suppress the occurrence of cracks in the arrayed waveguide type diffraction grating, and it is possible to suppress the occurrence of cracks in the arrayed waveguide type diffraction grating having a cut surface. In order to suppress the connection loss at the cut surface of the grating, the polarization-independent arrayed-waveguide grating module and the temperature-independent arrayed waveguide can be configured by appropriately configuring the arrayed-waveguide grating. And a highly reliable optical waveguide circuit module having high reliability under high-temperature and high-humidity conditions.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of an optical waveguide circuit module according to the present invention.

FIG. 2 is an explanatory view showing a case and a cover member used in the embodiment.

FIG. 3 is an explanatory view showing a manufacturing process of the embodiment.

FIG. 4 is an explanatory view showing a second embodiment of the optical waveguide circuit module according to the present invention with reference to its manufacturing process.

FIG. 5 is an explanatory diagram showing the configuration and operation of a temperature-independent arrayed waveguide type diffraction grating previously proposed by the present inventors.

FIG. 6 is an explanatory view showing an example of a conventional arrayed waveguide type diffraction grating.

FIG. 7 is a schematic diagram showing a difference in a crack generation state after a high-temperature and high-humidity test due to a difference in normalized composition of an arrayed waveguide type diffraction grating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Optical input waveguide 3 First slab waveguide 3a, 3b Separation slab waveguide 4 Array waveguide 5 Second slab waveguide 6 Optical output waveguide 7 High thermal expansion coefficient member 8 Cut surface 9 Base 10, 10a , 10b Optical waveguide section 25 Optical waveguide circuit chip 26 Case 27 Chip accommodating section 28 Non-water-soluble oil 30 Lid member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneyoshi Saito 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Takeshi Nakajima 2-6-1 Marunouchi, Chiyoda-ku, Tokyo No. F-term in Furukawa Electric Co., Ltd. (reference) 2H047 KA01 LA18 LA21 QA04 QA07 TA22

Claims (3)

[Claims] 1. An optical waveguide circuit, wherein an optical waveguide circuit chip formed by forming an optical waveguide portion made of quartz glass on a substrate is housed in a housing filled with water-insoluble oil. module. 2. A first slab waveguide is connected to an output side of one or more optical input waveguides arranged side by side, and the first slab waveguide is connected to an output side of the first slab waveguide. A plurality of array waveguides having different lengths for transmitting light derived from the array waveguides are connected, and a second slab waveguide is connected to an output side of the plurality of array waveguides. The slab waveguide has a waveguide configuration formed by connecting a plurality of side-by-side optical output waveguides to the output side of the slab waveguide, and a plurality of wavelengths different from each other input from the optical input waveguide. A function of propagating an optical signal with a phase difference for each wavelength by the arrayed waveguide, causing each of the wavelengths to enter a different optical output waveguide, and outputting light of different wavelengths from the different optical output waveguides. Characterized by having an arrayed waveguide type diffraction grating The optical waveguide circuit module according to claim 1. 3. The optical waveguide circuit module according to claim 1, wherein the water-insoluble oil has a refractive index matching property with the quartz glass forming the optical waveguide portion.