JP2000241643A - Optical wave guide device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce polarization dependence loss(PDL) by providing a loss compensating portion having transmission loss corresponding to each polarization so that losses of light wave guide device for various polarizations are substantially the same. SOLUTION: This guide device comprises a light device 2 constituted with light wave guides, and a PDL compensating portion 1 having transmission loss corresponding to each polarization surface so that losses of a light wave guide device 2 for various polarizations are substantially same. The PDL compensating portion 1 is constituted so that loss for a polarized wave having large loss in the guide device 2 becomes smaller and loss for a polarization having small loss in the guide device 2 becomes larger. The loss amount for each polarization in the guide device 2 is compensated so that a ratio of longitudinal polarization 5 to transverse polarization 4 before input into the guide device 2 substantially matches to a ratio of longitudinal polarization 5b to transverse polarization 4b outputted from the PDL compensating portion 1. Thus, losses for respective polarizations of the optical device 2 and the PDL compensating portion 1 are constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As optical waveguide devices used for optical communication, there are optical filters and optical switches using a silica-based waveguide. In these optical devices, generally, due to the residual stress and the fabrication error at the time of forming a quartz film, the equivalent refractive indexes of the vertically and horizontally polarized waveguides are different from each other, and the loss depending on the polarization depends on the polarization dependent loss ( PDL: Polarization depende
nt loss). On the other hand, in a single mode optical fiber used in optical communication, it is known that the knitting wave state of signal light changes due to temperature change or bending. The change in the polarization state means that the polarization direction of the linearly polarized light rotates, or changes to elliptically polarized light or circularly polarized light.
Therefore, the optical device on the receiving side connected to the single mode optical fiber has a polarization dependent loss (PDL).
When the optical device has a dent loss, the loss of the optical device changes depending on the polarization state of the signal light, which causes a change in the receiving sensitivity of the optical signal in the system.

[0003]

As described above, since the conventional optical waveguide device has polarization dependence, it is necessary to suppress the change in the polarization state within an allowable range.
There is a problem that long distance transmission, high speed transmission, and the like have certain restrictions. In the future, it is expected that the necessity of reducing the polarization dependent loss (PDL) of an optical device will further increase with the advancement of an optical communication system.

Accordingly, the present invention provides a polarization dependent loss (PDL).
It is an object of the present invention to provide an optical waveguide device having a small size and a manufacturing method thereof.

[0005]

In order to achieve the above object, an optical waveguide device according to the present invention comprises an optical waveguide having a core portion and a clad portion on a substrate, and a part of the optical waveguide is formed by an optical waveguide. In the optical waveguide device operated as a device, a loss compensator having a transmission loss according to each polarization is provided so that the loss of the optical waveguide device for different polarizations is substantially the same. This allows
The loss can be compensated for the different polarizations in the optical device and output.

In an optical waveguide device according to the present invention,
The loss compensating part is configured such that, in a part of the core part of the optical waveguide, first regions and second regions having mutually different refractive indexes are alternately formed, and the incident surface of the first region has a loss in the optical device. In order to increase the loss for a small polarization, it can be configured by providing at a predetermined angle to the optical transmission direction.

In the optical waveguide device according to the present invention, the second region may have the same refractive index as the core.

Further, the loss compensator may be a grating in which the first region has an output surface substantially parallel to the incident surface.

The grating can be formed by irradiating a part of the core with ultraviolet light or X-ray through a diffraction grating.

[0010] The loss compensating portion can be formed by using a mask having an opening in a portion forming the first region, and irradiating the core portion with ultraviolet rays or X-rays through the mask.

Further, in the loss compensation section, the first region may be formed in a triangular prism shape or a trapezoidal prism shape having incident surfaces substantially parallel to each other.

The loss compensator may be provided with a metal clad near a part of the core.

Further, in the loss compensation section, the first region may be made of the same material as the clad, and the second region may be made of the same material as the core portion.

Further, in the optical waveguide device according to the present invention, it is preferable that the loss compensator is formed such that one end thereof coincides with the emission end or the incidence end of the optical waveguide device.

In the optical waveguide device, the loss compensator may be configured by inserting a material having a polarization dependent loss into a groove provided in the core.

Further, in the above optical waveguide device,
The loss compensation section may be configured by inserting a dielectric multilayer film into a groove provided in the core section.

Furthermore, it is preferable that the optical waveguide device has a curved optical waveguide on the output end or the input end side.

Further, when the optical waveguide device is a device having at least one reflection grating, the grating formed as the loss compensator may also serve as the reflection grating.

A first method for manufacturing an optical waveguide device according to the present invention is a method for manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate, wherein the core portion of the optical waveguide is provided. Partly including the step of irradiating ultraviolet rays or X-rays through a diffraction grating provided so that interference fringes are not orthogonal to the traveling direction of light to form a loss compensating section, wherein the optical waveguide device for different polarizations Is characterized in that an optical waveguide device having substantially the same loss is manufactured.

According to a second method of manufacturing an optical waveguide device according to the present invention, there is provided a method of manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate. In part, the method includes a step of irradiating ultraviolet rays or X-rays so as not to be orthogonal to the substrate through a diffraction grating provided so that the interference fringes are orthogonal to the traveling direction of light to form a loss compensation unit. And manufacturing an optical waveguide device in which the loss of the optical waveguide device for different polarizations is substantially the same.

Further, in the first or second method for manufacturing an optical waveguide device according to the present invention, after the diffraction grating is removed, the loss compensating section is further irradiated with ultraviolet rays or X-rays, and It is preferable to include a step of adjusting the loss compensation amount.

Still further, the first or second method for manufacturing an optical waveguide device according to the present invention may further include a step of performing high-pressure hydrogen treatment or high-pressure deuterium treatment before the step of forming the loss compensation section. preferable.

According to a third method of manufacturing an optical waveguide device according to the present invention, there is provided a method of manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate. A groove is formed at a predetermined interval so as not to be orthogonal to the traveling direction of light, and a cladding layer is grown so as to fill the groove. And forming a loss compensating section provided alternately, and manufacturing an optical waveguide device in which the loss of the optical waveguide device with respect to different polarizations is substantially the same.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram conceptually showing a basic configuration of an optical waveguide device according to the present invention. The optical waveguide device according to the present invention has a PDL compensator having a transmission loss according to the plane of polarization such that the optical device 2 configured using the optical waveguide has substantially the same loss of the optical device 2 for different polarizations. It consists of 1. That is, the optical device 2 has a longer vertical polarization 5
As shown in FIG. 1, when the PDL has a large loss with respect to the wavelength, the loss is different between the case where the vertically polarized light 5 is incident and the case where the horizontally polarized light 4 is incident.
Different as shown. In FIG. 1, the output light of the optical device 2 corresponding to the vertically polarized light 5 is referred to as 5a (hereinafter referred to as the vertically polarized light 5a).
That. ), And the outgoing light corresponding to the laterally polarized light 4 is indicated by the reference numeral 4a (hereinafter, referred to as laterally polarized light 4a). The horizontal polarization 4 and the vertical polarization 5 schematically show the direction and magnitude of the electric field vector of each polarization by the direction and length of the arrow, respectively. Also, 3 indicates incident light,
6 is light containing one or both of vertically and horizontally polarized light;
Output light is light that includes one or both of vertically and horizontally polarized light.

The PDL compensator 1 inputs the vertically polarized light 5a and the horizontally polarized light 4a output from the optical device 2 to the PDL compensator 1 and compensates each polarized light by a compensation amount corresponding to the loss in the optical device 2. Output. In FIG. 1, the light emitted from the PDL compensator 1 corresponding to the vertically polarized light 5 is indicated by the reference numeral 5b (hereinafter referred to as “vertically polarized light 5b”), and the light emitted from the PDL compensator 1 corresponding to the horizontally polarized light 4 is indicated. Are indicated by reference numerals 4b (hereinafter referred to as laterally polarized light 4b).

That is, the PDL compensator 1 is configured so that the loss with respect to the polarization with a small loss in the optical device 2 is increased and the loss with respect to the polarization with a small loss in the optical device 2 is increased. The ratio of the vertically polarized light 5 to the horizontally polarized light 4 before being input to the device 2, and P
The loss amount for each polarized light in the optical device 2 is compensated so that the ratio between the vertically polarized light 5b and the horizontally polarized light 4b output from the DL compensating unit 1 substantially matches. Thereby, the loss for each polarized light as a whole of the optical device 2 and the PDL compensator 1 is made constant.

The PDL compensator 1 for compensating PDL by such a method sets the loss for vertically and horizontally polarized light to predetermined values different from each other in consideration of the loss for each polarized light of the optical device 2. There is a need. Below, PDL
The specific configuration of the compensator will be described in each embodiment.

Embodiment 1 FIG. 2 is a plan view showing the configuration of the optical waveguide device according to the first embodiment of the present invention (a).
And a sectional view (b). The optical waveguide device according to the first embodiment is a 3 dB coupler formed by forming two optical waveguides 111a and 111b so as to be partially close to each other, and has four ports 1, 2, 3, and 4. Here, in the present 3 dB coupler, a part of the optical waveguides 111 a and 111 b on the output side (ports 3 and 4) is
a and 8b are formed and each is operated as a PDL compensator. FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. 2A. Also, in FIG.
Is a substrate, 10 is a lower cladding layer mainly composed of quartz of silicon oxide (SiO ₂ ), 11 is a core layer composed of quartz mainly composed of silicon oxide and doped with about 10% of germanium (Ge), 12 Is an upper cladding layer composed mainly of silicon oxide quartz. The configuration of the optical waveguide is the same in each of the following embodiments and examples.

The light 3 input from the port 3 in the 3 dB coupler of FIG.
The light propagates along the core layer of the optical waveguide 111a, and a part of the light propagates along the core layer of the optical waveguide 111b in a portion (hereinafter, referred to as a coupling portion) between the optical waveguide 111a and the optical waveguide 111b. . In this way, part of the light 3 input from the port 1 propagates through the optical waveguide 111b and is output from the port 4 via the diagonal grating 8b, and the remaining light propagates through the optical waveguide 111a to form the diagonal grating. Output from port 3 via 8a.

As described above, in the first embodiment, the PDL
Oblique gratings 8a and 8b are used as specific means for realizing the compensator. Note that the grating refers to one in which the refractive index of the waveguide changes periodically. In the first embodiment, the diagonal grating 8 (8a and 8a) is used.
b), a first refractive index region 80a having a constant length L1 and a second refractive index having a constant length L2 in the light traveling direction, as shown in FIG. Area 8
0b are formed in parallel and alternately with each other, and each region is formed such that its incident surface is not orthogonal to the traveling direction of light. With this configuration, the oblique grating 8 can have different loss amounts for the horizontally polarized light and the vertically polarized light, and its period (number of repetitions), the first refractive index region 8a, and the second refractive index region Each loss amount can be set to a desired value in accordance with the angle between the light 8b and the light traveling direction.

Hereinafter, the principle will be described. As shown in FIG. 4, when light is obliquely incident on a plate-shaped medium 7 having a different refractive index from that of the surrounding medium, the transmittance differs depending on the polarization direction of the incident light. For example, as shown in FIG. 4A, the direction of the electric field vector is the longitudinal polarization 5 whose direction is parallel to the incident surface of the medium 7.
Is low because the light intensity after transmission is low because the reflectivity at the incident surface is large, and the reflectivity at the incident surface of the transversely polarized light 4 whose electric field vector is not parallel to the incident surface of the medium 7 is small. Later light intensity is greater than longitudinally polarized light 5. Further, in FIG. 4B, the direction of the electric field vector of the longitudinally polarized light 5 is not parallel to the incident surface of the medium 7, the reflectivity at the incident surface is reduced, and the light intensity after transmission can be increased. Is large on the incident surface of the laterally polarized light 4 whose direction is parallel to the incident surface of the medium 7, the light intensity after transmission is smaller than that of the vertically polarized light 5.

That is, the intensity of transmitted light of vertical and horizontal polarized light can be controlled independently by how the plate-like medium 7 is inclined. The reflectance of the medium 7 on the incident surface is determined by the angle between the electric field vector of each polarized light and the incident surface and the difference in the refractive index between the flat medium 7 and the surrounding medium. Here, the larger the difference in refractive index between the flat medium 7 and the surrounding medium, the larger the difference in reflectance (transmittance) between different polarized lights, and the larger the compensation amount when applied to the PDL compensator. it can.

In the first embodiment, the PDL compensator is configured using the oblique grating 8 based on the above principle. Generally, in such a grating, the refractive index difference between different media formed alternately cannot be increased,
Since the transmittance for vertical and horizontal polarized light can hardly be changed by only one cycle, a desired correction amount cannot be obtained. Therefore, in the first embodiment, by using the oblique grating 8 having a repetition period of several tens to several hundreds or more, a compensation amount applicable as a PDL compensator can be secured.

As described above, the optical waveguide device (3 dB coupler) according to the first embodiment includes the diagonal gratings 8a and 8b as the PDL compensator, so that the PDL of the entire device can be reduced. Further, the optical waveguide device (3 dB coupler) of the first embodiment includes an oblique grating 8a as a PDL compensator in a part of the optical waveguide.
8B, the PDL compensator can be formed relatively easily without increasing the size of the device itself.

The optical waveguide device (3 dB coupler) of Embodiment 1 supplies PVD to dissociate and vaporize atoms and molecules on a solid surface and deposit the same as a thin film on a substrate. Physical vapor depo
sition) method or a CVD (Chemical vapor deposition) method in which a volatile substance is used as a raw material to solidify through a chemical reaction, or another method may be used. However, in general, a CVD film has good adhesiveness to a substrate and wraparound, and can uniformly coat a substrate having a complicated shape. In addition, since the deposition rate is higher than other methods, mass production is relatively easy and the productivity is high. Therefore, in Example 1 described later, an ozone oxidation type CVD (Chemical
The 3 dB coupler of FIG. 2 was manufactured by using a (vapor deposition) method. Note that a specific method for manufacturing the oblique gratings 8a and 8b as the PDL compensating unit will be described in Examples.

By irradiating the PDL compensator with ultraviolet light, the refractive index of the compensator can be changed. Therefore, in the first embodiment, utilizing this fact, the PD
After manufacturing the L compensator, the PDL compensator may be directly irradiated with ultraviolet light to finely adjust the amount of PDL compensation.
Thereby, an optical waveguide device with a smaller PDL can be provided.

Embodiment 2 As shown in FIG. 9A, an optical waveguide device according to Embodiment 2 has an oblique grating 81 as a PDL compensator.
a, 81b are Y-branch waveguides. The Y-branch waveguide according to the second embodiment has a core portion formed in a Y-shape as shown in FIG. 10, and the optical waveguide 112 is divided into two optical waveguides 112a and 112b from the middle. You.
Here, in the second embodiment, the optical waveguides 112a, 112
2b, a part of the diagonal gratings 81a, 81
1b is formed as a PDL compensator. The oblique gratings 81a and 81b according to the second embodiment compensate for loss based on the same principle as the oblique gratings 8a and 8b according to the first embodiment. By etching an oblique groove in the core and depositing an upper cladding layer so as to fill the groove from above, the material of the core and the material of the upper cladding layer were provided alternately in a part of the optical waveguide. Oblique grating 81
a, 81b.

In the optical waveguide device (Y-branch waveguide) according to the second embodiment configured as described above, the light input to the optical waveguide 112 through the port 1
2a and 112b, the loss is compensated through the diagonal gratings 81a and 81b, respectively, and
And output from port 3.

As described above, the optical waveguide device (Y-branch waveguide) according to the second embodiment includes the diagonal gratings 81a and 81b as the PDL compensator, so that the PDL of the entire device can be reduced. Further, the optical waveguide device according to the second embodiment has a PDL
Since the oblique gratings 81a and 81b as the compensating portions are formed, the PDL compensating portion can be formed relatively easily without increasing the size of the device itself. Further, in the second embodiment, since the oblique gratings 81a and 81b in which the core material and the cladding layer material having a relatively large difference in refractive index with respect to light are formed alternately, the loss compensation amount is increased. it can.

Embodiment 3 Embodiment 3 according to the present invention
As in the second embodiment, one optical waveguide 112 has two optical waveguides 112 a and 112 a in the middle.
This is a Y-branch optical waveguide formed so as to branch to b.
As shown in FIG. 11, the optical waveguide device according to the third embodiment includes the oblique gratings 81a and 81b according to the second embodiment.
Instead of PD, the triangular refractive index distribution portions 26a and 26b
The configuration is the same as that of the second embodiment except that it is configured as an L compensator.

In the optical waveguide device according to the third embodiment, the triangular refractive index distribution portions 26a and 26b include a plurality of triangular prism-shaped refractive index regions 261 formed in the optical waveguides 112a and 112.
b is formed side by side with each core part,
The loss of each polarized light is compensated by the same principle as that of the oblique grating of FIGS. That is, each triangular prism-shaped refractive index region 26
By forming the triangular prism-shaped refractive index regions 261 such that the incident surface (one side surface of the triangular prism) of the light (polarized light) 1 is at a predetermined angle so as not to be orthogonal to the light propagation direction, the incident surface is formed. Is different for each polarization,
The operation can be performed in the same manner as the oblique gratings of the first and second embodiments. Here, the triangular refractive index distribution portions 26a and 26b according to the third embodiment mainly have a loss for each polarized light depending on the angle between the light transmitted through the waveguide and the incident surface of each triangular prism refractive index region 261. Although set, the loss can be finely adjusted by changing the angle of the output surface of the refractive index region with respect to the light transmission direction.
As a result, the degree of freedom in designing the loss setting for each polarized light is improved, so that the setting can be improved.

Accordingly, the optical waveguide device (optical branch waveguide) according to the third embodiment configured as described above can be operated in the same manner as in the second embodiment, and has the same effect.

Embodiment 4 FIG. Embodiment 4 according to the present invention
The optical waveguide device is an optical switch including PDL compensators 28a and 28b as shown in FIG. The optical switch according to the fourth embodiment includes optical waveguides 113a and 113b.
Are formed close to each other so as to be coupled at two places as shown in FIG. 13, and a coupler (directional coupler) 11
4, 115 are formed and two couplers 114, 115 are formed.
A heater 29 made of a chrome wire is formed around the optical waveguide 113a located between the two.

In the optical switch configured as described above, light enters from port 1 and is coupled by coupler 114 to 50:
Branched to 50. When no voltage is applied to the chrome wire 29 by the power supply 30, the chromium wire 29 is multiplexed again by the coupler 115 and output from the port 4. Further, when a certain voltage is applied to the chrome wire 29, the refractive index of the core 11 changes due to the thermo-optic effect, and the phase of light propagating through the core 11 changes, so that the light is multiplexed by the coupler 115. Light is output from port 3. As described above, by changing the phase of one optical waveguide 113a between the two couplers, it is possible to operate as an optical switch having an optical switching function, which is output from the port 4 when the voltage is OFF and from the port 3 when the voltage is ON. Can be.

In the fourth embodiment, FIG.
As shown in (b), PDL compensators 28a and 28b are formed by forming a metal clad 281 close to and sandwiching the core 11 of the optical waveguide switch. still,
FIG. 13B is a cross-sectional view taken along line BB ′ of FIG. As described above, the presence of the metal portion (metal clad 281) near the side surface of the core acts to increase the loss of the laterally polarized light, so that PDL can be compensated for by utilizing this. In the fourth embodiment, the loss amount can be easily set by changing the length of the metal clad 281.

Fifth Embodiment An optical waveguide device according to a fifth embodiment of the present invention is an optical switch similar to that of the fourth embodiment, and differs from the fourth embodiment in the following points. That is, as shown in FIG. 15, the optical switch according to the fifth embodiment is different from the PDL compensators 28a and 28b according to the fourth embodiment in that the optical switch 113a and the optical waveguide 113b are vertically grooved. Is formed, and a PDL compensator is manufactured by inserting a polarization dependent loss film 31 having a polarization dependent loss into the groove. FIG. 15B is a cross-sectional view taken along line CC ′ of FIG. In the figure, the same components as those in the first to fourth embodiments are denoted by the same reference numerals.

In the fifth embodiment, a stretched film of an island-shaped gold thin film is used as the polarization dependent loss film, and the stretched film is inserted into a groove formed on the output side of the optical waveguide type switch, and an ultraviolet ray is applied. Bonded with a curable resin. The island-shaped metal thin film has a structure that is commonly seen in the very early stage of metal thin film formation, and has a structure in which nanometer-sized metal particles (islands) are two-dimensionally distributed. Such a thin film is optically isotropic in the plane of the thin film as it is, but when stretched in one direction, becomes a film having polarization selectivity and can be used as a PDL compensation material. The direction in which the film is stretched coincides with the long axis direction of the island. For example, in order to increase the loss of transversely polarized light, the film is inserted so that the long axis direction of the island is parallel to the horizontal direction.

The optical waveguide device of the fifth embodiment configured as described above operates in the same manner as the fourth embodiment and has the same effects.

Embodiment 6 FIG. Embodiment 6 according to the present invention
As shown in FIG. 16, the optical waveguide device includes two optical waveguides 116a and 116b provided close to each other in a part so as to couple between the waveguides in a part thereof.
This is an optical waveguide band-pass filter formed by forming a reflection grating 32 that reflects light of a predetermined wavelength on each of the optical waveguides 116a and 116b.
In the sixth embodiment, a diagonal groove is formed in the core on the output side (port 2 side) of the optical waveguide 116a, and a plurality of dielectric layers having different refractive indices are laminated thereon. Was inserted so that the laminated surface of each dielectric layer did not intersect orthogonally with the light propagation method of the core part, thereby forming a PDL compensation unit. The dielectric multilayer film 33 provided in this manner is
The PDL can be compensated by operating substantially in the same manner as the oblique grating, and setting the angle of the groove with respect to the light traveling direction to an angle that compensates for the PDL.

In the optical waveguide band-pass filter configured as described above, the light input from the port 1 to the optical waveguide 116a passes through the optical waveguides 116a and 116b at the coupling portion.
And light having a predetermined wavelength is reflected by the reflection grating 32. The reflected light is combined at the coupling portion and output from the port 2 via the optical waveguide 116a and the dielectric multilayer film 33. In this way, of the light input from port 1, only light having a predetermined wavelength is output from port 2. At this time, when the optical waveguides 116a and 116b propagate and pass through the coupling portion, the loss differs depending on the polarization.
3 is compensated by the PDL compensator composed of
A filter having a small L can be configured.

Seventh Embodiment An optical waveguide device according to a seventh embodiment of the present invention is shown in FIG.
As shown in FIG. 7, two optical waveguides 1 provided close to one another so as to couple between the waveguides in one part
17a and 117b, and optical waveguides 117a and 117b.
Are optical waveguide band-pass filters each formed by forming a reflection type oblique grating 34 that reflects light of a predetermined wavelength and also has a function of a PDL compensator.

The reflection type oblique grating 34 according to the seventh embodiment is provided so as to reflect light of a predetermined wavelength, and is provided obliquely so that the reflection surface is not orthogonal to the light traveling method. , PDL compensator. That is, as described in the operation of the oblique grating of the first embodiment, by making the reflecting surface oblique, the reflectance changes corresponding to each polarized light. Therefore, by setting the angle of the reflection surface with respect to the traveling direction of light to an angle that compensates for PDL, it is possible to function substantially the same as the oblique grating of the first embodiment, and to compensate for PDL. it can.

Embodiment 8 FIG. Embodiment 8 according to the present invention
As shown in FIG. 18, the optical waveguide device according to
a, 81b are formed such that their ends reach one side of the emission side of the substrate 9, and based on the result of measuring the loss of the manufactured Y-branch optical waveguide, the oblique grating portion is partially cut or polished. PDL by optimizing the length
Can be adjusted.

Embodiment 9 FIG. Embodiment 9 according to the present invention
Is similar to the second and third embodiments and the like.
Two optical waveguides 112a, two optical waveguides 112a,
This is a Y-branch optical waveguide formed to branch to 112b. As shown in FIG. 19, the optical waveguide device according to the ninth embodiment is configured such that trapezoidal refractive index distribution sections 36a and 36b are used as PDL compensation sections in optical waveguides 112a and 112b.

In the optical waveguide device according to the ninth embodiment, the trapezoidal refractive index distribution portions 36a and 36b have a plurality of trapezoidal columnar refractive index regions 361 as the optical waveguides 112a and 112.
Embodiment 3 is formed so as to be juxtaposed with each core part of Embodiment 3.
The loss of each polarized light is compensated by the same principle as that of the triangular refractive index distribution portions 26a and 26b described in the above. That is, the refractive index of each trapezoidal column is set so that the light (polarized light) incident surface (one side surface of the triangular prism) of each trapezoidal columnar refractive index region 361 is at a predetermined angle so as not to be orthogonal to the light propagation direction. Area 361
Is formed, since the reflectance of the incident surface is different for each polarized light, it is possible to operate similarly to the oblique gratings of the first and second embodiments.

Further, the trapezoidal refractive index distribution portions 36a and 36b in the optical waveguide device of the ninth embodiment are
As shown in FIG. 19, based on the result of measuring the loss of the manufactured Y-branch optical waveguide formed so that the end thereof reaches one side of the emission side of the substrate 9, for example, the reference numeral 35 in the figure is used. Trapezoidal shape refractive index distribution section 3 along the cutting line shown
It is configured such that the amount of PDL compensation can be adjusted by optimizing the length by partially cutting or polishing the portions 6a and 36b.

Embodiment 10 FIG. The optical waveguide device according to the tenth embodiment of the present invention has a PD as shown in FIG.
The optical switches of the fourth embodiment are configured in the same manner as the optical switch of the fourth embodiment, except that the L compensating portions 28a and 28b are formed so that the ends thereof reach one side surface on the emission side of the substrate 9. In other words, the optical switch according to the tenth embodiment, based on the result of measuring the loss of the manufactured optical switch, for example, along the cutting line indicated by reference numeral 35 in FIG.
The amount of PDL compensation can be adjusted by optimizing the length by partially cutting or polishing 28b.

Embodiment 11 FIG. The optical waveguide device according to the eleventh embodiment of the present invention is similar to the optical waveguide devices according to the second and third embodiments in that one optical waveguide 112 has two optical waveguides 11 in the middle.
This is a Y-branch optical waveguide formed so as to branch into 2a and 112b. In the optical waveguide device according to the eleventh embodiment, as shown in FIG. 22, a trapezoidal refractive index distribution section 36 having the same configuration as the PDL compensation section used in the ninth embodiment is added to the optical waveguide 112 before branching. The optical waveguides 112a and 112b are formed as compensating sections, and are configured without forming a PDL compensating section.

The Y-branch waveguide according to the eleventh embodiment configured as described above has the same function and effect as the Y-branch waveguide according to the other embodiments. In the eleventh embodiment, after the PDL compensator is manufactured, it is preferable to irradiate the PDL compensator with X-rays and finely adjust the PDL compensation amount. That is, it is possible to finely adjust the compensation amount by utilizing the fact that the irradiation of X-ray changes the refractive index of the PDL compensator.

Embodiment 12 FIG. The optical waveguide device according to the twelfth embodiment of the present invention has a structure as shown in FIG.
The optical waveguide band-pass filter according to the seventh embodiment shown in FIG. 7 is further provided with a curved waveguide portion 37, and is otherwise the same as the seventh embodiment. That is, in the optical waveguide band-pass filter according to the twelfth embodiment, in the curved waveguide portion 37,
A curved waveguide 371a continuous with the optical waveguide 117a and formed with a curved waveguide 371b continuous with the optical waveguide 117b
Is formed.

The optical waveguide band-pass filter of the twelfth embodiment configured as described above has the same configuration as the optical waveguide band-pass filter of the seventh embodiment except for the curved waveguide portion 37. The third embodiment has the same effects as the seventh embodiment, and further has the following effects. That is, since the curved optical waveguides 371a and 371b are formed in a curved shape,
Since a small PDL corresponding to the curvature is generated, the value of the PDL of the entire device can be finely adjusted by cutting or polishing this portion.

[0062]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. The optical waveguide device of Example 1 is the 3 dB coupler according to Embodiment 1, and is manufactured as follows. The vapor phase epitaxy method used when forming a thin film is a method in which physical energy is supplied to dissociate and vaporize atoms and molecules on a solid surface and deposit it as a thin film on a substrate.
(Physical vapor deposition) method and CVD (Chemi), which uses volatile substances as raw materials and solidifies through chemical reactions.
cal vapor deposition) method. In the PVD method, a thin film having basically the same composition as the solid of the raw material is generated, whereas in the CVD method, a specific component in the raw material gas decomposed through a chemical reaction is fixed as a film. Even when is used, the composition of the formed thin film changes greatly depending on the reaction conditions. However, in general, a CVD film is
It has good adhesion to the substrate and wraparound, and can even coat substrates with complicated shapes. In addition, in the first embodiment, the ozone oxidation type CVD (Chemical vapor deposition) method is used because the deposition rate is higher than other methods, and mass production is relatively easy and the productivity is high. The 3 dB coupler of FIG.

FIG. 5 is a schematic configuration diagram showing a film forming apparatus (CVD apparatus) for manufacturing the 3 dB coupler of the first embodiment. In FIG. 5, 13 is a carrier gas inlet, 14 is a flow controller, 15 is a raw material container, 16 is a reaction tube, 17 is an oxygen gas inlet, 18 is an ozonizer, and 19 is an outlet. The CVD apparatus shown in FIG. 5 includes three source containers 15 and can supply three types of CVD source vapors onto the substrate 9 at the same time. The raw materials used were tetraethyl orthosilicate (chemical formula: Si (OC ₂ H ₅ ) ₄ : hereinafter abbreviated as TEOS), boron tripropoxide (chemical formula B (OC
₃ H ₇ ) ₃ : hereinafter abbreviated as TEB), and germanium tetraoxide (chemical formula Ge (OC ₂ H ₅ ) ₄ : hereinafter abbreviated as TEG). The carrier gas introduced from the carrier gas inlet 13 and discharged from the outlet 19 was a high-purity argon gas. A flow controller 14 is attached to each raw material container 15, and the flow rate of the vapor of each raw material can be controlled independently.
Therefore, three kinds of alkoxide raw materials can be transported onto the substrate 9 in the reaction tube 16 at an arbitrary ratio. The refractive index of the CVD film can be controlled by the ratio of each raw material. Oxygen gas is introduced from the oxygen gas inlet 17 into the ozonizer 18, oxygen gas containing 8% ozone is introduced into the reaction tube 16, and the temperature of the substrate 9 is set to 300 ° C. to promote decomposition and reaction of raw materials. Then, a desired film is formed on the substrate 9 installed in the reaction tube 16. As the substrate 9, a silicon substrate having a diameter of 3 inches was used. The degree of vacuum is 50 Torr and the deposition rate is 1
0 μm / hour.

In the first embodiment, a 3 dB coupler was manufactured through the process steps shown in FIGS. FIG. 6 is a diagram schematically showing a cross section of the substrate in each step.
In this step, first, only the vapors of TEOS and TEB are supplied onto the silicon substrate 9 using the film forming apparatus shown in FIG.
As shown in FIG. 6A, a lower clad layer 10 made of quartz containing silicon oxide containing boron (B) was formed. The thickness of the lower cladding layer 10 was about 20 μm. At this time, the refractive index of the lower cladding layer 10 was 1.4682. Next, alkoxides of TEOS and TEG were simultaneously supplied onto the substrate 9 to form a 6 μm thick core film 20 made of quartz containing silicon oxide and germanium (FIG. 6B). In the formation of the core film 20, the flow rate of the germanium alkoxide vapor was adjusted so that the germanium oxide content was about 10%. The temperature of the substrate 9 was the same as in the case of forming the lower cladding layer 10.

Next, a chromium mask 21 corresponding to a desired waveguide pattern is formed on the core film 20 by a photoengraving method using electron beam drawing (FIG. 6C), and reactive ion etching (RIE) is performed. Etching was performed to pattern the core layer 11 having a predetermined waveguide width (FIG. 6D). The shape of the core was as shown in FIG. Next, on the core layer 11, an upper cladding layer 12 containing boron in silicon oxide.
Was formed with a thickness of about 20 μm from a raw material of TEOS + TEB (FIG. 6E) to produce an optical waveguide. The substrate temperature at this time was 300 ° C. The refractive index is the upper cladding layer 12
1.4682, germanium-doped core layer 1
The value of 1.4 was 1.4788, and the refractive index difference was about 0.7%.

Laser light having a wavelength of 1.55 μm was incident on the port 1 of the manufactured 3 dB coupler, and the loss in vertical and horizontal polarization was measured. The results are shown in Table 1 before compensation. Even for the same port path, the loss is different between longitudinally polarized light and transversely polarized light.
That is, PDL has occurred.

[0067]

[Table 1]

Next, a method for manufacturing an oblique grating for compensating for PDL will be described. In the first embodiment, in order to fabricate a grating on the core, that is, to periodically change the refractive index of the core, FIG.
A method of irradiating ultraviolet light through the diffraction grating 22 as shown in FIG. When ultraviolet light is incident perpendicular to the surface of the diffraction grating 22, as shown in FIG.
1 ⁺ and L1 ^- are generated. When these two lights are irradiated on a plane at an angle, an intensity distribution of light having a certain period on the plane is generated. Assuming that the period of the diffraction grating is Λp, the period of the intensity distribution of light generated on the plane Λ = Λp / 2
Becomes When such ultraviolet light is irradiated on the germanium-doped core layer 11, the refractive index of the irradiated portion increases, and the light-induced refractive index change causes a change in the period 同 じ of the same shape as the shape of the intensity distribution of the ultraviolet light. A refractive index distribution or grating is formed. The magnitude of the change in the refractive index due to this phenomenon can be increased as the irradiation time or irradiation power of the ultraviolet light increases, and as a pretreatment, the optical waveguide is set to 100 to 100 μm.
By leaving it in an atmosphere of hydrogen or deuterium at about 150 atm for several days or more, the magnitude of change in the refractive index due to the intensity of ultraviolet light can be increased by an order of magnitude. Example 1
Then, such deuterium loading should be performed before UV irradiation.
The test was performed at 50 atm for 15 days.

According to the results shown in the column before compensation in Table 1,
It is necessary to reduce the transmittance of longitudinally polarized light in the port 1-3 route, and to reduce the transmittance of horizontal polarized light in the port 1-4 route. Therefore, the diffraction grating is inclined with respect to the optical waveguide in the port 1-3 route as shown in FIG. 7A, and the diffraction grating is inclined with respect to the incident direction of the ultraviolet light as shown in FIG. 7B in the port 1-4 route. The irradiation was performed with the optical waveguide tilted. The results of the loss measurement after the oblique grating production are shown in the column after correction in Table 1. Thus, the PDL was 0.4 dB before the correction, but was reduced to 0.1 dB after the correction.

Modification 1 The optical waveguide device of the first modification is the 3 dB coupler according to the first embodiment as in the first embodiment. In the first embodiment, the oblique grating is manufactured using ultraviolet light. By irradiating a line, an oblique grating was produced. In addition, it produced similarly to Example 1 except having replaced this ultraviolet light with X-ray. The refractive index of the upper cladding layer 12 is 1.4.
682, 1.4 in the core layer 11 doped with germanium.
788, and the refractive index difference was about 0.7%. In the first modification, a laser beam having a wavelength of 1.55 μm was incident on the port 1 of the 3 dB coupler before producing the PDL compensator 8 (before compensation), and the loss in vertical and horizontal polarization was measured.
The results are shown in the column before compensation in Table 2. Even with the same port route,
Loss differs between vertically polarized light and horizontally polarized light. That is, PDL has occurred.

[0071]

[Table 2]

Next, in the first modification for compensating for PDL, a grating was formed by irradiating the core with X-rays through the diffraction grating 22. When the core layer 11 doped with germanium is irradiated with X-rays, a refractive index distribution, that is, a grating having the same period と as the shape of the intensity distribution of the X-rays is formed due to the photoinduced refractive index change. The magnitude of the change in the refractive index due to this phenomenon increases as the irradiation time or irradiation power of X-rays increases, as in the case of irradiation with ultraviolet light.
By leaving it in an atmosphere of hydrogen or deuterium at about 0 atm for several days or more, the magnitude of the change in the refractive index increases by about one digit. In Modification 1, such deuterium loading was performed at 150 atm for 15 days before X-ray irradiation.

Looking at the values before compensation in Table 2, it is necessary to reduce the transmittance of the longitudinally polarized light in the port 1-3 route and the transmittance of the horizontal polarized light in the port 1-4 route before the oblique grating is manufactured. . Therefore, as in the first embodiment, the diffraction grating is inclined with respect to the optical waveguide in the port 1-3 path as shown in FIG. 7A, and the X-ray is incident in the port 1-4 path as shown in FIG. 7B. Irradiation was performed with the diffraction grating and the optical waveguide inclined with respect to the direction. The results of the loss measurement after the oblique grating was made are shown in the column after compensation in Table 2. That is, before compensation, PDL
Was 0.3 dB, but was reduced to 0.1 dB after the compensation.

Modification 2 In this modification, a 3 dB coupler manufactured in the same manner as in the first embodiment, the compensation amount is finely adjusted by irradiating the PDL compensator with ultraviolet light, and a 3 dB coupler having an extremely small PDL is manufactured. still,
In this modification, the refractive index is
It was 1.4688 and 1.4788 for the germanium-doped core layer 11, and the refractive index difference was about 0.7%.

After manufacturing the PDL compensator, the second modification example
Then, the PDL compensator was irradiated directly with ultraviolet light without passing through the diffraction grating to finely adjust the amount of PDL compensation. The compensation amount can be finely adjusted by changing the refractive index of the compensator by irradiating the ultraviolet light. Table 3 shows the PDL evaluation results before and after the fine adjustment. As described above, the value which was 0.1 dB before the fine adjustment was reduced to 0.02 dB.

[0076]

[Table 3]

Embodiment 2 FIG. The optical waveguide device according to the second embodiment is a Y-branch waveguide according to the second embodiment and provided with oblique gratings 81a and 81b as a PDL compensator, and is manufactured as follows. FIG. 10 shows Y of the second embodiment.
It is a schematic block diagram which shows the film-forming apparatus by the flame deposition method used for manufacture of a branch optical waveguide, In the figure, 23 is a hydrogen gas inlet, 24 is a burner, and 25 is a turntable. As shown in the figure, argon gas is supplied from a carrier gas inlet 13 through silicon chloride (SiCl ₄ ), boron chloride (BC).
l ₃ ) and a raw material container 15 containing liquid raw materials such as germanium chloride (GeCl ₄ ), and these starting materials are transported to an oxyhydrogen burner 24 using hydrogen gas and hydrolyzed in a flame. Thus, silicon oxide containing fine powdered boron is produced, and is sprayed and deposited on the substrate 9 on the turntable 25. A flow controller 14 is attached to each raw material container 15, and three types of starting raw materials can be transported onto the substrate 9 at an arbitrary ratio. The refractive index in the thickness direction of the optical waveguide film formed can be controlled by the ratio of each raw material. That is, at the beginning of the flame deposition, only silicon oxide containing boron is sprayed to form the lower cladding layer 10, and then about 10% of germanium is doped according to the refractive index to form a core film. However, it is necessary to perform a heat treatment for transparency at a temperature of 1000 to 1200 ° C. after the deposition of the silicon oxide fine particle film.

After the transparency treatment, a metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and a metal chromium film having a desired waveguide pattern is formed by a photoengraving method using electron beam drawing. Thereafter, the core film is etched by RIE (reactive ion etching) to remove the core film which is not covered with the metal chromium film.
The core layer 11 having a predetermined shape and a predetermined width is formed as shown in FIG. Thereafter, fine particles are deposited again by a flame deposition method using a silicon oxide composition containing boron and not containing germanium, and a high-temperature heat treatment is performed to form an upper cladding layer 12, thereby producing an optical waveguide. The shape of the core was as shown in FIG. 9, and two Y-branch optical waveguides were produced. The Y-branch optical waveguide A does not form a PDL compensator, and the Y-branch optical waveguide B has an oblique groove serving as a PDL compensator formed in the core. The refractive index of the optical waveguide is 1.4572 for the cladding layer and 1.46 for the core layer.
70, and the refractive index difference between the core layer and the cladding layer is 0.7%.
Met.

A laser beam having a wavelength of 1.55 μm was incident on the port 1 of the manufactured Y-branch optical waveguide, and the loss in vertical and horizontal polarization was measured. Table 4 shows the results. As shown in the column of no compensation in Table 4, in the Y-branch optical waveguide A without PDL compensation, the loss of the horizontally polarized light is larger than that of the vertically polarized light in both the port 1-2 path and the 1-3 path. . That is, P
DL has occurred. However, in the Y-branch optical waveguide B in which the PDL compensator is formed, as shown in the column with compensation in Table 4,
It can be seen that the PDL is smaller than in the case without the compensator.

[0080]

[Table 4]

Embodiment 3 FIG. The optical waveguide device of Example 3 is a Y-branch waveguide according to Embodiment 3 and provided with triangular refractive index distribution portions 26a and 26b as a PDL compensating portion, and is manufactured as follows. In the third embodiment, each layer was manufactured in the same manner as in the second embodiment by using a film deposition apparatus using the same flame deposition method as in the second embodiment.

After the transparentizing treatment was performed in the same manner as in Example 2, a metal chromium film was formed on the core film by sputtering or vapor deposition, and the desired waveguide was formed by photolithography using electron beam lithography. A metal chromium film having a pattern is formed. Thereafter, the core film is etched by RIE (reactive ion etching) to remove the core film not covered with the metal chromium film, thereby forming a core having a predetermined width. Thereafter, fine particles are deposited again by a flame deposition method using a silicon oxide composition containing boron and not containing germanium, and a high-temperature heat treatment is performed to form an upper cladding layer, thereby producing an optical waveguide. The shape of the core was as shown in FIG. The refractive index of the optical waveguide was 1.4572 for the cladding layer and 1.4670 for the core layer, and the difference in refractive index between the core layer and the cladding layer was 0.7%.

A laser beam having a wavelength of 1.55 μm was incident on the port 1 of the manufactured Y-branch optical waveguide, and the loss in vertical and horizontal polarization was measured. The results are shown in Table 5 before compensation.
As is clear from the results, the loss of the horizontally polarized light is larger in both the port 1-2 path and the 1-3 path compared to the vertically polarized light. That is, PDL has occurred.

[0084]

[Table 5]

Next, a method of forming a triangular refractive index distribution 26 for compensating for PDL will be described. The principle is the same as that of the grating forming method of the first embodiment, and a photo-induced refractive index change phenomenon is used. Also in Example 3, as a pretreatment for increasing the change in the refractive index, the optical waveguide was left in an atmosphere of deuterium at about 150 atm for 15 days or more, and deuterium loading was performed. Upper cladding layer 1 after loading
12, a chromium film is formed by a sputtering method, a chrome mask 27 is provided by a general photoengraving method using electron beam lithography as shown in FIG. 12, and ultraviolet light is directly passed through the chrome mask 27 to the optical waveguide. By irradiation, a triangular refractive index distribution is formed on the core.

Laser light having a wavelength of 1.55 μm was incident on the port 1 of the manufactured Y-branch waveguide, and the loss in vertical and horizontal polarization was measured. Table 5 shows the results before and after compensation. As described above, the PDL that was 0.4 dB before the compensation was reduced to 0.1 dB after the compensation.

Embodiment 4 FIG. The optical waveguide device according to the fourth embodiment is different from the optical waveguide device according to the fourth embodiment in that the PDL compensators 28a and 28b
And is manufactured as follows.
In the third embodiment, each layer is manufactured in the same manner as in the second embodiment by using a film forming apparatus using the same flame deposition method as in the second embodiment.
A heat treatment for transparency was performed at a temperature of 00 ° C.

After the transparency treatment, a metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and a metal chromium film having a desired waveguide pattern is produced by a photoengraving method using electron beam drawing. Thereafter, the core film is etched by RIE (Reactive Ion Etching) to remove the core film not covered with the metal chromium film, thereby forming the core layer 11 having a predetermined width. Thereafter, fine particles are deposited again by a flame deposition method using a silicon oxide composition containing boron and not containing germanium, and a high-temperature heat treatment is performed to form an upper cladding layer 5 to produce an optical waveguide. The shape of the core was a pattern as shown in FIG. The refractive index of the optical waveguide was 1.4572 for the cladding layer and 1.4670 for the core layer, and the difference in refractive index between the core layer and the cladding layer was 0.7%. Next, a chromium film is formed on the upper cladding layer 12 by sputtering, and a chromium film heater 29 is formed as shown in FIG. 13 by a general photoengraving method using electron beam lithography. Was prepared.

A laser beam having a wavelength of 1.55 μm was incident on the port 1 of the fabricated optical waveguide switch before compensation, and the loss in vertical and horizontal polarization was measured when the voltage was ON and when the voltage was OFF. The results are shown in Table 6 before compensation. As shown in the results, the loss of the horizontally polarized light is smaller in each of the ports 1-3 and 1-4 than in the case of the vertically polarized light. That is, PDL has occurred.

[0090]

[Table 6]

In the fourth embodiment, in order to compensate for PDL,
A metal part was formed near the core. The presence of the metal portion near the side surface of the core acts to increase the loss of the transverse polarization, so that the PDL can be compensated. The method for forming the metal part will be described below. First, a chromium film is formed on the upper cladding layer 12 by a sputtering method, and a chrome mask 2 is formed by a photoengraving method using electron beam drawing as shown in FIG.
Mask with 7. Next, as shown in FIG. 14B, the upper clad layer 11 is removed along the side surface of the core by wet etching, and then a metal clad 280 is formed by a sputtering method (FIG. 14C). Thereafter, the unnecessary metal film formed other than the groove was removed by polishing to form a metal clad 281 as shown in FIG.

After forming the metal cladding 281, a wavelength of 1.55 μm was applied to the port 1 of the manufactured optical waveguide switch.
And the loss in vertical and horizontal polarized light was measured when the voltage was ON and when the voltage was OFF. The results are shown in the column after compensation in Table 6. Thus, the PDL was originally 0.3
What was dB was reduced to 0.1 dB.

Embodiment 5 FIG. The optical waveguide device according to the fifth embodiment is an optical switch including the polarization dependent loss film 31 according to the fifth embodiment, and is manufactured as follows. In the fifth embodiment, each layer is formed in the same manner as in the second embodiment using a film forming apparatus by the same flame deposition method as in the second embodiment, and after a silicon oxide fine particle film is deposited, a temperature of 1000 to 1200 ° C. And heat treatment for transparency was performed.

After the transparency treatment, a metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and a metal chromium film having a desired waveguide pattern is produced by a photoengraving method using electron beam drawing. Thereafter, the core film is etched by RIE (reactive ion etching) to remove the core film that is not covered with the metal chromium film, thereby forming a core 3 having a predetermined width. Thereafter, fine particles are deposited again by a flame deposition method using a silicon oxide composition containing boron and not containing germanium, and a high-temperature heat treatment is performed to form an upper cladding layer 5 to produce an optical waveguide. The shape of the core was as shown in FIG. The refractive index of the optical waveguide is 1.4 for the cladding layer.
572, the core layer was 1.4670, and the refractive index difference between the core layer and the cladding layer was 0.7%.

Next, a chromium film is formed on the upper cladding layer 12 by a sputtering method, and a chrome electrode portion 29 is formed as shown in FIG. 15A by a photolithography method using a general electron beam drawing. An optical waveguide switch was manufactured.

Thus, the wavelength 1.55 μm is applied to the port 1 of the optical waveguide switch on which the chromium electrode portion 29 is formed.
m laser light was incident, and the loss in vertical and horizontal polarization was measured when the voltage was ON and when the voltage was OFF. The results are shown in the column after compensation in Table 7. Port 1-
In each of the three paths and the 1-4 paths, the loss of the horizontally polarized light is smaller than that of the vertically polarized light. That is, PDL has occurred.

[0097]

[Table 7]

Next, in the fifth embodiment, a film obtained by forming an island-shaped gold thin film is stretched to form a polarization dependent loss film 31.
And inserted into a groove formed on the output side of the optical waveguide switch, and bonded with an ultraviolet curable resin. An island-shaped metal thin film is a structure that is commonly seen at the very early stage of metal thin film formation, and has nanometer-sized metal particles (islands).
Is a thin film having a structure two-dimensionally distributed. Such a thin film is optically isotropic in the plane of the thin film as it is,
Stretching in one direction results in a film having polarization selectivity.
That is, it can be applied as a PDL compensation material.

Since the direction in which the film is stretched coincides with the major axis direction of the island, the loss of the transverse polarization is small according to Table 7, so that the major axis direction of the island is horizontal so that the loss of the transverse polarization is large. The film was inserted as shown.

A laser beam having a wavelength of 1.55 μm was incident on the port 1 of the optical waveguide switch manufactured as described above, and the loss in the vertical and horizontal polarizations when the voltage was ON and when the voltage was OFF was measured. The results are shown in the column after compensation in Table 7. Thus, what originally had a PDL of 0.3 dB has been reduced to 0.1 dB.

Embodiment 6 FIG. The optical waveguide device of Example 6 is an optical waveguide type band-pass filter according to Embodiment 6 and including, as a PDL compensation unit, a dielectric multilayer film 33 in which a plurality of dielectric layers having different refractive indexes are stacked. Yes,
It is produced as follows.

The quartz film was formed by a thermal decomposition CVD method.
The apparatus used for the thermal decomposition CVD method is an ozone oxidation type CV.
It is the same as the device of FIG. Nitrous oxide gas (N ₂ O) is introduced into the reaction tube 16, and the temperature of the substrate 9 is reduced to 950.
When the temperature is set to ° C., the decomposition and reaction of the raw materials are accelerated by heat, and a film is formed on the substrate 9 provided. As the substrate 9, a silicon substrate having a diameter of 3 inches was used. The deposition rate was 4 μm / hour. In the thermal decomposition CVD method, a film having a smaller loss can be formed as compared with an ozone oxidation CVD method, a plasma CVD method, or the like.

In the sixth embodiment, first, an ozone oxidation type CVD
As in the case of the method, a lower cladding layer 10 containing boron in silicon oxide is formed to a thickness of 20 μm (the material is TEOS +
TEB), and then a core film containing germanium in silicon oxide is formed (the raw material is TEOS + TEG). Thereafter, a metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and a metal chromium film having a desired waveguide pattern is formed by a photoengraving method using electron beam drawing. After that, the core film is etched by RIE (reactive ion etching) to remove the core film not covered with the metal chromium film, thereby forming the core layer 11 having a predetermined width. Thereafter, a CVD film is deposited again with a silicon oxide composition containing boron and not containing germanium to produce an optical waveguide (the raw material is TEOS + TEB). The shape of the core was as shown in FIG.

Next, in order to form a grating on the core, that is, to periodically change the refractive index of the core, a method of irradiating ultraviolet light through a diffraction grating was adopted. Assuming that the period of the diffraction grating is Λp, the period of the grating written on the core is Λ = Λp / 2. In this embodiment, deuterium loading was performed at 150 atm for 15 days before irradiation with ultraviolet light in order to facilitate the distribution of the refractive index.

Next, a diagonal groove was formed on the core, a dielectric multilayer film 33 was inserted therein, and bonded with an ultraviolet curing resin. Port 1 of the fabricated optical waveguide bandpass filter
Wavelength 1.55 μm, which is the reflection wavelength of the grating.
Of the signal output from the port 2
DL was measured before and after compensation, respectively. Table 8 shows the results. Thus, the PDL was 0.4 dB before the insertion of the dielectric multilayer film (before compensation), but was reduced to 0.1 dB after the insertion (after compensation).

[0106]

[Table 8]

Embodiment 7 FIG. The optical waveguide device of Example 7 is an optical waveguide type band-pass filter provided with a reflection type diagonal grating having a function of a PDL compensator according to Embodiment 7, and is manufactured as follows. The film formation of the quartz film and the formation of the core were performed by the same thermal decomposition CV as in Example 6.
The method was performed using the D method, and the shape of the core was as shown in FIG.

Next, in order to produce a grating on the core, that is, to periodically change the refractive index of the core, a method of irradiating ultraviolet light through a diffraction grating was adopted. Since the grating is written diagonally, FIG.
Irradiation with ultraviolet light was performed in such an arrangement. The period of the diffraction grating is
Assuming that p, the period of the grating written on the core is Λ = Λp / (2 cos θ). In this embodiment, in order to easily cause a change in the refractive index, deuterium loading was performed at 150 atm for 15 days before irradiation with ultraviolet light.

A wavelength 1.5, which is the reflection wavelength of the grating, is applied to port 1 of the manufactured optical waveguide band-pass filter.
A laser beam of 5 μm was incident, and the PDL of the signal output from the port 2 was measured. Table 9 shows the results. In Table 9,
For comparison, vertical writing of a grating was simultaneously made and measured, and the results are also shown. As described above, when the grating was written vertically, the PDL was 0.4 dB, but when the grating was inclined, the PDL was reduced to 0.1 dB.

[0110]

[Table 9]

Embodiment 8 FIG. The optical waveguide device according to the eighth embodiment is the optical waveguide device according to the eighth embodiment.
1a and 81b are formed so that their ends reach one side surface on the emission side of the substrate 9, and based on the result of measuring the loss of the manufactured Y-branch optical waveguide, the oblique grating portion is partially cut or polished. PDL by optimizing the length
Can be adjusted.

In the eighth embodiment, the ozone oxidation type CVD (C
The Y-branch optical waveguide of FIG. 18 was produced by a chemical vapor deposition method. The film forming apparatus for manufacturing the Y-branch optical waveguide of the eighth embodiment is shown in FIG. 5 used in the first embodiment, and the film forming conditions of each layer are the same as those of the first embodiment. That is, the raw materials used were tetraethyl orthosilicate (chemical formula: Si (OC ₂ H ₅ ) ₄ : hereinafter abbreviated as TEOS),
Boron tripropoxide (chemical formula B (OC ₃ H ₇ ) ₃ :
(Hereinafter abbreviated as TEB) and germanium tetraoxide (chemical formula Ge (OC ₂ H ₅ ) ₄ : hereinafter abbreviated as TEG). The carrier gas is introduced from the inlet 13 and the outlet 19
The carrier gas discharged from was a high-purity argon gas. A flow controller 14 is attached to each raw material container 15, and the flow rate of the vapor of each raw material can be controlled independently. Therefore,
The three types of alkoxide raw materials can be transported onto the substrate 9 in the reaction tube 16 at an arbitrary ratio. The refractive index of the CVD film can be controlled by the ratio of each raw material. Oxygen gas inlet 1
Oxygen gas was introduced from 7 into the ozonizer 18 to generate 8
% Of ozone is introduced into the reaction tube 16, and the temperature of the substrate 9 is set to 300 ° C. to accelerate the decomposition and reaction of the raw material to form a desired film on the substrate 9 installed in the reaction tube 16. I do. As the substrate 9, a silicon substrate having a diameter of 3 inches was used. The degree of vacuum is 50 Torr, and the deposition rate is 10 μm /
Time.

Hereinafter, a Y-branch optical waveguide shown in FIG. 18 was fabricated in the same manner as in the fabrication of the Y-branch optical waveguide of Example 2. That is, only the vapor of TEOS and TEB was supplied onto the silicon substrate 9 to form the lower cladding layer 10 made of quartz containing silicon oxide containing boron (B). The thickness of the lower cladding layer 10 was about 20 μm. At this time, the refractive index of the lower cladding layer 10 was 1.4682. next,
TEOS and alkoxides of TEG were simultaneously supplied onto the substrate 9 to form a core film 20 made of quartz containing silicon oxide and germanium to a thickness of 6 μm. Core film 2
0, the germanium oxide content is about 10%
The flow rate of the germanium alkoxide vapor was adjusted such that The temperature of the substrate 9 was the same as in the case of forming the lower cladding layer 10.

Next, a chromium mask 21 having a desired waveguide pattern was formed on the core film 20 by photolithography using electron beam drawing, and was etched by RIE to be patterned into the core layer 11 having a predetermined waveguide width. . Figure 1 shows the core shape
It was like 8. Next, an upper clad layer 12 containing boron in silicon oxide is formed on the core layer 11 by TEOS + TE.
An optical waveguide was formed with a thickness of about 20 μm using the material B. The substrate temperature at this time was 300 ° C. The refractive index is
The upper cladding layer 12 had a value of 1.4682, and the germanium-doped core layer 11 had a value of 1.4788, and the difference in refractive index was about 0.7%.

Next, an oblique grating for compensating for PDL was manufactured. In order to fabricate a grating on the core, that is, to periodically change the refractive index of the core, a method of irradiating ultraviolet light through a diffraction grating as shown in FIG. 7A was adopted. In this embodiment, deuterium loading was performed at 150 atm for 15 days before irradiation with ultraviolet light in order to easily cause a change in the refractive index.

As a result of measuring the loss of the manufactured Y-branch optical waveguide, the PDL was 0.20 dB. Thereafter, the oblique grating portion on the emission side was partially cut and polished to optimize the length, thereby adjusting the amount of PDL compensation. Table 10 shows the loss measurement results before and after the fine adjustment. As shown by the results, after the adjustment, the PDL was as small as 0.03 dB.

[0117]

[Table 10]

Embodiment 9 FIG. The optical waveguide device according to the ninth embodiment is different from the optical waveguide device according to the ninth embodiment in that the trapezoidal refractive index distribution section 36 is used.
a and 36b are Y-branch optical waveguides to which a PDL compensator is applied. In this embodiment, the ozone oxidation type CV shown in FIG.
The Y-branch optical waveguide of FIG. 19 was manufactured by the D (Chemical vapor deposition) method. This apparatus can control the refractive index of the CVD film by the ratio of each raw material. Oxygen gas inlet 17
Oxygen gas is introduced into the ozonizer 18 from the
Oxygen gas containing ozone is introduced into the reaction tube 16, and the temperature of the substrate 9 is set to 300 ° C. to accelerate the decomposition and reaction of the raw material to form a desired film on the substrate 9 installed in the reaction tube 16. . As the substrate 9, a silicon substrate having a diameter of 3 inches was used. The degree of vacuum is 50 Torr, and the deposition rate is 10 μm /
Time.

In the ninth embodiment, a Y-branch optical waveguide was manufactured through the same process steps as in the second embodiment. That is, using the film forming apparatus shown in FIG.
Only the vapors of OS and TEB were supplied to form a lower cladding layer 10 made of quartz containing boron (B) in silicon oxide. The thickness of the lower cladding layer 10 was about 20 μm. At this time, the refractive index of the lower cladding layer 10 is 1.46.
82. Next, alkoxides of TEOS and TEG were simultaneously supplied onto the substrate 9 to form a core film 20 made of quartz containing silicon oxide and germanium to a thickness of 6 μm. In the formation of the core film 20, the flow rate of the germanium alkoxide vapor was adjusted so that the germanium oxide content was about 10%. The temperature of the substrate 9 is
It was the same as the case of forming the lower cladding layer 10.

Next, a chromium mask having a desired waveguide pattern was formed on the core film 20 by photolithography using electron beam drawing, and was etched by RIE to pattern the core layer 11 having a predetermined waveguide width. The shape of the core was as shown in FIG. Next, on the core layer 11, an upper cladding layer 12 containing boron in silicon oxide was formed with a thickness of about 20 μm using a raw material of TEOS + TEB, thereby producing an optical waveguide.
The substrate temperature at this time was 300 ° C. The refractive index of the upper cladding layer 12 was 1.4682, and the refractive index of the germanium-doped core layer 11 was 1.4788, and the refractive index difference was about 0.7%.

Next, a method of forming a trapezoidal refractive index distribution for compensating PDL will be described. The principle is the same as the method of forming a triangular refractive index distribution, and a photo-induced refractive index change is used. Also in this example, as a pretreatment for increasing the change in the refractive index, the optical waveguide was left in an atmosphere of deuterium at about 150 atm for 15 days or more, and deuterium loading was performed. After loading, a chromium film was formed on the upper clad layer 5 by a sputtering method, and was masked as shown in FIG. 20 by a general photolithography method using electron beam drawing.
By irradiating the optical waveguide directly with ultraviolet light through the chrome mask, a trapezoidal refractive index distribution is formed on the core.

As a result of measuring the loss of the manufactured Y-branch optical waveguide, the PDL was 0.18 dB. Thereafter, the oblique grating portion on the emission side was partially cut and polished to optimize the length, thereby adjusting the amount of PDL compensation. Table 11 shows the loss measurement results before and after the fine adjustment. As shown by the results, after the adjustment, the PDL was as small as 0.02 dB.

[0123]

[Table 11]

Embodiment 10 FIG. The optical waveguide device according to the tenth embodiment is the optical switch according to the tenth embodiment. In the tenth embodiment, as in the fourth embodiment, a PDL compensator was manufactured by forming a metal part near the core of the optical waveguide switch. In Example 10, the metal portion was formed so as to be in contact with the end face on the output side, and after measuring the characteristics, the PDL compensation amount was optimized by cutting and polishing.

The refractive index of the optical waveguide was 1.4572 for the cladding layer and 1.4670 for the core layer, and the difference in refractive index between the core layer and the cladding layer was 0.7%. Laser light having a wavelength of 1.55 μm was incident on port 1 of the manufactured optical waveguide switch, and the loss in vertical and horizontal polarization was measured when the voltage was ON and when the voltage was OFF. Table 12 shows the results. Thus, what originally had a PDL of 0.3 dB has been reduced to 0.1 dB.

[0126]

[Table 12]

As a result of measuring the loss at the time of voltage ON and at the time of voltage OFF before cutting (before fine adjustment) of the manufactured optical waveguide switch, the PDL was 0.14 dB. Thereafter, the metal part on the emission side was partially cut and polished to optimize the length, thereby adjusting the amount of PDL compensation. Table 12 shows the loss measurement results before and after the fine adjustment. As shown in the results, after the adjustment, the PDL was as extremely small as 0.02 dB.

Embodiment 11 FIG. The optical waveguide device of Example 11 is a Y-branch optical waveguide according to Embodiment 11,
The trapezoidal refractive index distribution section 36 is provided in the optical waveguide 112 before branching.
Is formed as a PDL compensator. Example 1
In the first method, a trapezoidal refractive index distribution is formed on the core of the Y-branch optical waveguide by irradiating X-rays through a mask to form a PD.
After the L compensator was fabricated and the mask was removed, the PDL compensator was finely adjusted by irradiating the PDL compensator with X-rays to produce a Y-branch optical waveguide with a very small PDL.

In the eleventh embodiment, a film was formed in the same manner as in the third and fourth embodiments by using a film deposition apparatus according to the flame deposition method shown in FIG. After forming a core film and performing a heat treatment for transparency at a temperature of 1000 to 1200 ° C., a metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and photolithography using electron beam drawing is performed. A metal chromium film having a desired waveguide pattern is formed by the method. Then, the core film is etched by RIE (reactive ion etching),
The core film not covered with the metal chromium film is removed to form a core layer 11 having a predetermined width. Thereafter, fine particles are deposited again by a flame deposition method using a silicon oxide composition containing boron and not containing germanium, and a high-temperature heat treatment is performed to form an upper cladding layer 12, thereby producing an optical waveguide. The shape of the core was as shown in FIG. The refractive index of the optical waveguide was 1.4572 for the cladding layer and 1.4670 for the core layer, and the difference in refractive index between the core layer and the cladding layer was 0.7%.

Next, a method of forming a trapezoidal refractive index distribution for compensating PDL will be described. The principle is Example 1
The method is the same as the method of forming the grating described above, and the photoinduced refractive index change is used. Also in this example, as a pretreatment for increasing the change in the refractive index, the optical waveguide was left in an atmosphere of deuterium at about 150 atm for 15 days or more, and deuterium loading was performed. After the loading, a chromium film was formed on the upper cladding layer 12 by a sputtering method, and was masked as shown in FIG. 23 by a general photolithography method using electron beam drawing. By irradiating the optical waveguide directly with X-rays through the chrome mask, a trapezoidal refractive index distribution is formed on the core. In this embodiment, a PDL compensator was manufactured on the incident side of the Y-branch waveguide.

In this embodiment, after the chromium mask 29 was removed by etching, the PDL compensator was irradiated with X-rays to finely adjust the amount of PDL compensation. The compensation amount can be finely adjusted by irradiating X-rays and changing the refractive index of the compensation unit. Table 13 shows the PDL evaluation results before and after the fine adjustment.
Thus, the value of 0.15 dB before the fine adjustment is changed to 0.0.
It was as small as 2 dB.

[0132]

[Table 13]

Embodiment 12 FIG. The optical waveguide device according to the twelfth embodiment is the optical waveguide band-pass filter according to the twelfth embodiment, which is different from the optical waveguide band-pass filter according to the seventh embodiment in that a curved waveguide portion 37 is further provided. Except for this, it is manufactured in the same manner as in Example 7.

The quartz film is formed by the thermal decomposition CVD method using the apparatus shown in FIG. That is, three types of source vapors can be supplied onto the substrate 9 at the same time.
Each raw material is filled in a closed vessel 15 whose temperature can be controlled, and the flow rate of each vapor can be independently controlled by a flow controller 14 capable of accurately controlling the flow rate of the raw material vapor. And the substrate 9 in the reaction tube 16
It is possible to transport it up. Thereby, the refractive index of the CVD film can be controlled. Nitrous oxide gas (N 2 O) was introduced into the reaction tube 9, and the temperature of the substrate 9 was set to 950 ° C.
Substrate 9 installed by promoting decomposition and reaction of raw materials by heat
Is formed. As the substrate 9, a silicon substrate having a diameter of 3 inches was used. The deposition rate was 4 μm / hour. Pyrolysis C
The VD method can form a film having a smaller loss than the ozone oxidation CVD method, the plasma CVD method, or the like.

In this embodiment, first, as in the case of the ozone oxidation type CVD method, the lower cladding layer 10 containing boron in silicon oxide is formed to a thickness of 20 μm (the material is TEOS + T
EB) Then, a core film containing germanium is formed in silicon oxide (the raw material is TEOS + TEG). afterwards,
A metal chromium film is formed on the core film by a sputtering method or a vapor deposition method, and a metal chromium film having a desired waveguide pattern is formed by a photoengraving method using electron beam drawing. afterwards,
The core film is etched by RIE (Reactive Ion Etching) to remove the core film not covered with the metal chromium film, thereby forming the core layer 11 having a predetermined width. afterwards,
Again, a CVD film is deposited with a silicon oxide composition containing boron and no germanium to produce an optical waveguide (the raw material is TEOS + TEB). The shape of the core was as shown in FIG.

Next, in order to produce a grating on the core, that is, to periodically change the refractive index of the core, a method of irradiating ultraviolet light through a diffraction grating was adopted. Since the grating is written diagonally, FIG.
Irradiation with ultraviolet light was performed in such an arrangement. The period of the diffraction grating is
Assuming that p, the period of the grating written on the core is Λ = Λp / (2 cos θ). In this embodiment, in order to easily cause a change in the refractive index, deuterium loading was performed at 150 atm for 15 days before irradiation with ultraviolet light.

A wavelength 1.5, which is the reflection wavelength of the grating, is applied to port 1 of the manufactured optical waveguide band-pass filter.
A laser beam of 5 μm was incident, and the PDL of the signal output from the port 2 was measured. Table 14 shows the results. Since the PDL of the coupler section is compensated to some extent by the diagonal grating, the value of the PDL is as small as 0.09 dB. Since a small PDL is also generated in the curved optical waveguide portion, the PD of the device is cut or polished by cutting or polishing this portion.
The value of L can be finely adjusted. Table 14 shows the PDL evaluation results after cutting a part of the curved waveguide.
Was very small as 0.01 dB.

[0138]

[Table 14]

[0139]

As described in detail above, the optical waveguide device according to the present invention has a transmission loss corresponding to each polarization such that the loss of the optical waveguide device for different polarizations is substantially the same. Since the optical waveguide device is provided with the loss compensator, it is possible to compensate for and output the loss for different polarizations in the optical device, and to reduce the polarization dependent loss (PDL) of the entire optical waveguide device.

In the optical waveguide device according to the present invention,
First regions and second regions having different refractive indices are alternately formed in a part of a core portion of the optical waveguide, and an incident surface of the first region is provided for a polarization having a small loss in the optical device. By forming the above-mentioned loss compensating part by providing it at a predetermined angle with respect to the optical transmission direction so as to increase the loss, it can be formed relatively easily, so that the cost can be reduced.

Further, in the optical waveguide device according to the present invention, if the second region has the same refractive index as the core, the structure can be simplified and the cost can be reduced.

Further, the loss compensating section may be a grating in which the first region has an output surface substantially parallel to the incident surface. In this case, a general method of manufacturing a grating can be used. , And can be easily manufactured.

When the grating is formed by irradiating a part of the core with ultraviolet light or X-rays through a diffraction grating, the first grating having an incident surface in a desired direction can be obtained.
Since the region can be formed relatively easily, the loss for each polarized light can be easily adjusted.

Further, the loss compensating section can more easily use the mask in which the portion forming the first region is opened, and irradiate the core section with ultraviolet rays or X-rays through the mask, so that the first compensating section can be more easily formed. A region can be formed and the cost can be reduced.

Further, in the above-mentioned loss compensating section, the first region is formed in the shape of a triangular prism or trapezoid having substantially parallel incident surfaces, so that the angle of formation of the light output surface in each triangular prism or each trapezoidal prism is obtained. Thus, the amount of loss can be adjusted, and the degree of freedom in designing the loss compensator can be improved.

The loss compensating section can be formed by providing a metal clad near a part of the core section. In this case, the loss compensating section is formed by using ordinary photolithography and film forming techniques. And easily and inexpensively.

Further, in the above-mentioned loss compensating part, the first region is made of the same material as that of the clad, and the second region is made of the same material as the core part. .

In the optical waveguide device according to the present invention, the loss compensating portion is formed so that one end thereof coincides with the emission end or the incident end of the optical waveguide device. Since the length of the compensator can be adjusted, the loss compensation amount can be finely adjusted, and loss compensation can be performed with high accuracy.

In the above-mentioned optical waveguide device, when the loss compensating portion is formed by inserting a material having a polarization dependent loss into the groove provided in the core portion, the polarization compensating portion having a predetermined loss can be separately provided. Since the dependent loss material can be prepared and used, the loss amount can be set relatively freely.

Further, in the above optical waveguide device,
When the loss compensating portion is formed by inserting a dielectric multilayer film into a groove provided in the core portion, a dielectric multilayer film having a predetermined loss can be separately manufactured and used.
The amount of loss can be set relatively freely.

Furthermore, in the above optical waveguide device, if a curved optical waveguide is provided on the output end or the input end side, a portion of a predetermined length is cut from the output end or the input end so that the polarization can be reduced. The dependent loss can be adjusted, and the loss can be accurately compensated.

In the case where the optical waveguide device is a device having at least one reflection grating, the grating formed as the loss compensating portion also serves as the reflection grating, so that a separate loss compensating portion is formed. Since there is no need to perform this, it is possible to reduce the size and cost.

In the first method of manufacturing an optical waveguide device according to the present invention, a diffraction grating provided on a part of the core portion of the optical waveguide is provided such that interference fringes are not orthogonal to the light traveling direction. And forming a loss compensating portion by irradiating ultraviolet rays or X-rays, thereby forming a loss compensating portion having a large loss of longitudinally polarized light.

Further, in the second method of manufacturing an optical waveguide device according to the present invention, a part of the core portion of the optical waveguide is provided with a diffraction grating provided so that interference fringes are orthogonal to a traveling direction of light. In addition, since the method includes the step of irradiating the substrate with ultraviolet rays or X-rays so as not to be orthogonal to the substrate, the loss compensating section is formed, so that the loss compensating section having a large loss of the transverse polarization can be formed.

Further, in the first and second manufacturing methods of the optical waveguide device according to the present invention, after the diffraction grating is removed, the loss compensating portion is further irradiated with ultraviolet rays or X-rays so that the loss compensating portion is irradiated. By including the step of adjusting the loss compensation amount, the loss compensation amount can be adjusted.
An optical waveguide device having an accurate loss compensator can be manufactured.

Still further, in the first and second manufacturing methods of the optical waveguide device according to the present invention, a step of performing a high-pressure hydrogen treatment or a high-pressure deuterium treatment before the step of forming the loss compensating part is provided. Since the refractive index difference between the first region and the second region can be increased, the loss compensation amount can be increased.

Further, in a third method of manufacturing an optical waveguide device according to the present invention, a groove is formed in a part of a core portion of the optical waveguide at a predetermined interval so as not to be orthogonal to a traveling direction of light. By growing the cladding layer so as to fill the groove, a step of forming a loss compensating portion in which the core material and the cladding material are alternately provided in the part of the core portion is included. A large amount of loss compensating part can be formed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic concept of an optical waveguide device according to the present invention.

FIG. 2 is a plan view (a) and a cross-sectional view (b) showing a configuration of an optical waveguide device (3 dB coupler) according to the first embodiment of the present invention.

FIG. 3 is a plan view showing an oblique grating according to the first embodiment.

FIG. 4 is a diagram for explaining the principle of loss compensation according to the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a film forming apparatus used for manufacturing Example 1 according to the present invention.

FIG. 6 is a diagram illustrating each step in a process of manufacturing the 3 dB coupler according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a method for manufacturing an oblique grating in Example 1 according to the present invention.

FIG. 8 is a diagram illustrating a principle of forming a grating in the first embodiment according to the present invention.

FIG. 9 is a plan view showing a configuration of a Y-branch waveguide according to a second embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of a film forming apparatus used for manufacturing a Y-branch waveguide according to a second embodiment of the present invention.

FIG. 11 is a plan view showing a configuration of a Y-branch optical waveguide according to a third embodiment of the present invention.

FIG. 12 is a plan view illustrating a method of forming a triangular refractive index distribution in a Y-branch optical waveguide according to a third embodiment of the present invention.

13A and 13B are a plan view and a cross-sectional view illustrating an optical waveguide switch according to a fourth embodiment of the present invention.

FIG. 14 is a diagram illustrating a part of the manufacturing process of the optical waveguide switch according to the fourth embodiment.

15A and 15B are a plan view and a sectional view showing an optical waveguide switch according to a fifth embodiment of the present invention.

FIG. 16 is a plan view showing an optical wavelength filter according to a sixth embodiment of the present invention.

FIG. 17 is a plan view showing an optical wavelength filter according to a seventh embodiment of the present invention.

FIG. 18 is a plan view showing a Y-branch optical waveguide according to an eighth embodiment of the present invention.

FIG. 19 is a plan view showing a Y-branch optical waveguide according to a ninth embodiment of the present invention.

FIG. 20 is a plan view showing a method of forming a trapezoidal refractive index distribution in the Y-branch optical waveguide according to the ninth embodiment.

FIG. 21 is a plan view showing an optical waveguide switch according to a tenth embodiment of the present invention.

FIG. 22 is a plan view showing a Y-branch optical waveguide according to an eleventh embodiment of the present invention.

FIG. 23 is a plan view showing a method of forming a trapezoidal refractive index distribution in the Y-branch optical waveguide according to the eleventh embodiment.

FIG. 24 is a plan view showing an optical wavelength filter according to a twelfth embodiment of the present invention.

[Explanation of symbols]

1, 28a, 28b PDL compensator, 2 optical devices,
3 incident light, 4 horizontally polarized light, 5 vertically polarized light, 6 outgoing light, 7
Refractive index medium, 8, 8a, 8b, 81a, 81b diagonal grating, 9 substrate, 10 lower cladding layer, 11
Core, 12 Upper cladding layer, 13 Carrier gas inlet, 14 Flow controller, 15 Raw material container, 16 Reaction tube, 17 Oxygen gas inlet tube, 18 Ozonizer, 19
Outlet, 20 core film, 21 waveguide pattern, 22 diffraction grating, 23 hydrogen gas inlet, 24 burner, 25
Turntable, 26, 26a, 26b triangular refractive index distribution part, 27 chrome mask, 28 metal clad,
29 heater, 30 AC power supply, 31 polarization dependent loss film, 32 reflection type grating, 33 dielectric multilayer film, 34 reflection type oblique grating, 35 cutting position, 36, 36a, 36b trapezoidal refractive index distribution, 80a
First refractive index region, 80b Second refractive index region, 111a,
111b, 112, 112a, 112b, 113a, 1
13b, 116a, 116b, 117a, 117b Optical waveguide, 114, 115 coupler, 261 triangular prism-shaped refractive index region, 281 metal clad, 361 trapezoidal refractive index region.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Gen Takeya 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Takeyuki Maekawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd. (72) Inventor: Akira Miyashita 2-3-2, Marunouchi, Chiyoda-ku, Tokyo, Japan Mitsui Electric Co., Ltd. (72) Inventor: Hideko Uchikawa 2-3-2, Marunouchi, Chiyoda-ku, Tokyo, Japan Rishi Electric Co., Ltd. F term (reference) 2H047 KA04 LA12 PA04 PA05 PA30 QA04 RA08 TA21 2H079 AA06 AA12 BA01 CA05 EA04 EB05 KA20

Claims (19)

[Claims] 1. An optical waveguide device comprising: an optical waveguide having a core portion and a cladding portion on a substrate, wherein a part of the optical waveguide is operated as an optical device. An optical waveguide device comprising: a loss compensator having a transmission loss according to each polarization so as to be identical. 2. The loss compensating part according to claim 1, wherein a first region and a second region having different refractive indexes are alternately formed in a part of a core portion of the optical waveguide, and an incident surface of the first region is formed. 2. The optical waveguide device according to claim 1, wherein the optical waveguide device is provided at a predetermined angle with respect to the optical transmission direction such that the loss increases with respect to the polarization having a small loss in the optical device. 3. The optical waveguide device according to claim 2, wherein said second region has the same refractive index as said core portion. 4. The optical waveguide device according to claim 2, wherein said loss compensator is a grating in which said first region has an output surface substantially parallel to said incident surface. 5. The optical waveguide device according to claim 4, wherein said grating is formed by irradiating a part of said core portion with ultraviolet light or X-ray through a diffraction grating. 6. The loss compensating part is formed by using a mask having an opening in a portion forming the first region, and irradiating the core part with ultraviolet rays or X-rays through the mask. 4. The optical waveguide device according to 3. 7. The optical waveguide device according to claim 2, wherein in the loss compensating section, the first region has a triangular prism shape or a trapezoidal prism shape having incident surfaces substantially parallel to each other. 8. The optical waveguide device according to claim 1, wherein said loss compensating part is provided with a metal clad near a part of said core part. 9. The optical waveguide device according to claim 2, wherein the first region is made of the same material as the clad, and the second region is made of the same material as the core. 10. The optical waveguide according to claim 2, wherein the loss compensator is formed such that one end thereof coincides with an emission end or an incidence end of the optical waveguide device. device. 11. The optical waveguide device according to claim 1, wherein the loss compensating part is formed by inserting a material having a polarization dependent loss into a groove provided in the core part. 12. The optical waveguide device according to claim 1, wherein said loss compensating part is formed by inserting a dielectric multilayer film into a groove provided in said core part. 13. The optical waveguide device according to claim 1, wherein the optical waveguide device has a curved optical waveguide at an output end or an incident end. 14. An optical waveguide device comprising at least one
A device having two reflection gratings,
The optical waveguide device according to claim 4, wherein the grating formed as the loss compensator also serves as the reflection grating. 15. A method of manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate, wherein an interference fringe is formed on a part of the core portion of the optical waveguide so as not to be orthogonal to a traveling direction of light. Forming a loss compensator by irradiating ultraviolet rays or X-rays through a diffraction grating provided in the optical waveguide device, wherein the loss of the optical waveguide device with respect to different polarizations is substantially the same. A method for manufacturing an optical waveguide device. 16. A method of manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate, wherein a part of the core portion of the optical waveguide has an interference fringe orthogonal to a traveling direction of light. Forming a loss compensation section by irradiating the substrate with ultraviolet rays or X-rays so as not to be orthogonal to the substrate via the diffraction grating provided in the optical waveguide device, wherein the loss of the optical waveguide device for different polarizations is substantially the same. A method for manufacturing an optical waveguide device, comprising manufacturing an optical waveguide device. 17. In the manufacturing method, after the diffraction grating is removed, the ultraviolet light or X
17. The method of manufacturing an optical waveguide device according to claim 15, comprising a step of irradiating a line to adjust a loss compensation amount of the loss compensation unit. 18. The photoconductive device according to claim 15, further comprising a step of performing high-pressure hydrogen treatment or high-pressure deuterium treatment before the step of forming the loss compensation section. Manufacturing method of waveguide device. 19. A method for manufacturing an optical waveguide device having an optical waveguide having a core portion and a clad portion on a substrate, wherein a part of the core portion of the optical waveguide is provided at a predetermined interval and orthogonal to a light traveling direction. Forming a groove so as not to fill the groove, and growing a cladding layer so as to fill the groove, thereby forming a loss compensation portion in which a core material and a cladding material are alternately provided in the part of the core portion. A method of manufacturing an optical waveguide device, comprising manufacturing an optical waveguide device having substantially the same loss of the optical waveguide device for different polarizations.