JP2006276577A - Optical waveguide element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust the zero point of an optical waveguide element by controlling the area of contact between a phase adjusting substance and an optical waveguide without providing a control part to a buffer layer. <P>SOLUTION: The optical waveguide element has a plurality of optical waveguides 2a and 2b formed on a substrate 10 and is configured so that propagated lights of the plurality of optical waveguides 2a and 2b interfere or couple with each other. The refractive index adjusting substance 11 is mounted on a portion of the optical waveguide 2a and a portion of an outer edge of the refractive index adjusting substance 11 is in contact with a fluid control member 12 provided on the substrate 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical waveguide device.

For example, an optical waveguide device such as a light intensity modulator, variable attenuator, or optical switch in which a Mach-Zehnder type optical waveguide is provided on a substrate having an electro-optic effect or a thermo-optic effect propagates through each branched waveguide. The light interference state at the multiplexing part where the light is multiplexed is changed by the applied voltage, and the intensity of the output light is thereby changed.
Such an optical waveguide element is required to be in a predetermined light output state when the applied signal voltage is zero. Hereinafter, such a light output state when the signal voltage is zero is referred to as a zero point.
The zero point is set according to the required function and characteristics. For example, in the case of a light intensity modulator, when the signal voltage is zero, the output light intensity is set to be (1) maximum, (2) set to be minimum, and (3) between the maximum and minimum There are methods such as setting to be dots.
For that purpose, in the multiplexing part of the Mach-Zehnder type optical waveguide, the phase difference of the light between the branched waveguides is (1) 2nπ, (2) (2n + 1) π, and (3) 1/2 (2n + 1), respectively. It is necessary to set so as to be π.

However, even if a plurality of optical waveguide elements are manufactured under the same manufacturing conditions, in reality, the light output state when the signal voltage is zero, due to the influence of manufacturing error, internal stress during film formation, That is, the zero point is slightly different for each element, resulting in variations with respect to the design value.
Therefore, in order to adjust such variation, a method of correcting the zero point by applying a bias voltage (DC voltage) from the outside separately from the signal voltage is known.

However, since the zero point varies depending on various factors, it is necessary to provide a control circuit for controlling the DC voltage while always monitoring the zero point in actual use, resulting in a complicated apparatus.
In particular, when a LiNbO ₃ (LN) substrate is used as the substrate, if the zero point in the light intensity modulator is adjusted by applying a DC voltage, the zero point variation called DC drift caused by the applied DC voltage And greatly affects the operating life of the device.
Therefore, a technique is desired that can control the light output state at a zero point, that is, a state where the signal voltage is zero, by a method other than applying a DC voltage.

On the other hand, in an optical device such as an optical switch using a directional coupler type optical waveguide, the light coupling state between a plurality of optical waveguides changes depending on the applied voltage, and the intensity ratio (branching ratio) of the branched light changes. To do.
Even in such an optical element, it is necessary to set the light branching ratio at the zero point to a specific value. For that purpose, the effective refractive index of each optical waveguide and the coupling state of the propagation light between each optical waveguide, that is, It is necessary to accurately control the distance between the waveguides and the length of the proximity part in the proximity part (coupling part) where the optical waveguides are close to each other.
However, even if a plurality of optical waveguide elements are manufactured under the same manufacturing conditions, in reality, the refractive index changes due to dimensional errors during manufacturing, subtle variations in the refractive index control component amount, and internal stress during film formation. As a result, variations in the zero point, that is, variations in the branching ratio occur. In such an element, depending on the form of the electrode, even if a DC voltage is applied, the variation in the branching ratio may not be corrected, and there is also an element having a structure in which no electrode is provided. A technique for adjusting the branching ratio at the zero point is desired.

As a method for adjusting the zero point without applying a voltage, several methods have been proposed so far. For example, in Patent Document 1 below, an opening is provided in a buffer layer immediately above an optical waveguide, and A method is described in which the phase is adjusted by applying a phase adjusting material having an appropriate refractive index in the opening. In this method, the portion where the phase adjusting material applied in the opening and the optical waveguide are in contact contributes to the phase adjustment, that is, the zero point adjustment. Also, the amount of change at the zero point varies depending on the refractive index of the phase adjusting material.
JP-A-4-258918

In the above method, it is important to control the area of the portion where the phase adjusting material and the optical waveguide are in contact. For this reason, the application range of the phase adjusting material is regulated by the opening, and the phase adjustment is performed according to the size of the opening. The contact area between the substance and the optical waveguide is controlled.
However, in order to provide an opening in the buffer layer, it is necessary to form a buffer layer on the entire surface of the substrate, then form a pattern by photolithography, and provide an opening in the buffer layer by etching. is there. This not only complicates the process, but may cause deterioration of the buffer layer due to etching or the like. There is also a method of forming a buffer layer pattern having an opening by a lift-off method, but in this case, the adhesion strength between the buffer layer and the substrate is likely to be lowered, and there is a problem in quality.

  The present invention has been made in view of the above circumstances, and without providing an opening in a buffer layer, a phase adjusting substance is brought into contact with an optical waveguide, and a contact area between the phase adjusting substance and the optical waveguide is controlled, thereby providing an optical waveguide. The object is to adjust the effective refractive index of the optical waveguide in the waveguide element, to adjust the zero point in the interference type optical waveguide element, and to adjust the coupling ratio in the directional coupler type optical waveguide.

In order to achieve the above object, the present invention employs the following configuration.
That is, the optical waveguide element of the present invention is an optical waveguide element having a configuration in which a plurality of optical waveguides are formed on a substrate, and propagating light of each of the plurality of optical waveguides interferes or is coupled, A refractive index adjusting substance is loaded on a part of the optical waveguide, and a part of an outer edge of the refractive index adjusting substance is in contact with a flow control member provided on the substrate. .

  According to the present invention, the contact area between the refractive index adjusting substance loaded on the optical waveguide and the optical waveguide can be controlled by the flow control member. Therefore, adjustment of the zero point in the interference type optical waveguide device and adjustment of the coupling ratio in the directional coupler type optical waveguide can be performed without depending on the method of providing the opening in the buffer layer.

[First Embodiment]
FIG. 1 is a plan view schematically showing an optical waveguide device according to a first embodiment of the present invention.
In the optical waveguide device of this embodiment, a Mach-Zehnder type optical waveguide 2 (hereinafter sometimes simply referred to as an optical waveguide 2) is formed on the upper surface of a LiNbO ₃ (LN) substrate 10, and the buffer layer 3 is further formed on the LN substrate 10. The signal electrode 4 and the ground electrode 5 are provided through the gap, and is schematically configured. In this embodiment, an LN X-cut substrate is used.
In the present embodiment, it is arbitrary which of the left and right in the figure is the incident side with respect to the Mach-Zehnder type optical waveguide 2, but for convenience of explanation, the left side is the incident side and the right side is the emission side.

  The Mach-Zehnder type optical waveguide 2 is connected to a first optical waveguide 2a and a second optical waveguide 2b as a plurality of optical waveguides, and incident sides of the first and second optical waveguides 2a and 2b. It is composed of a branched optical waveguide 2c and a combined optical waveguide 2d connected to the emission side of the first and second optical waveguides 2a and 2b. In the present embodiment, the central portions in the length direction of the first and second optical waveguides 2a and 2b are parallel to each other.

The buffer layer 3 is provided for the purpose of preventing a part of the guided light propagating through the optical waveguide from being absorbed by the electrode and adjusting the traveling speed of the electric signal in the traveling wave type electrode. Generally, it is a layer having a thickness of about 0.5 to ₂ μm mainly composed of SiO ₂ .
In the present embodiment, the buffer layer 3 is provided so as to cover the incident side from the longitudinal center of the first and second optical waveguides 2a and 2b. The buffer layer 3 is not provided on the emission side.
The signal electrode 4 is made of a conductive material such as gold (Au). The central portion 4b of the signal electrode 4 in the present embodiment extends between the first optical waveguide 2a and the second optical waveguide 2b in parallel with the central portions of the first and second optical waveguides 2a and 2b. Yes. Both end portions 4a and 4c of the signal electrode 4 extend perpendicularly to the central portion 4b across the first optical waveguide 2a and the second optical waveguide 2b, respectively.
The ground electrodes 5 are provided on both the incident side and the emission side with the signal electrode 4 interposed therebetween with a predetermined distance from the signal electrode 4, and are grounded although not shown.

The refractive index adjusting substance 11 is loaded on a part of the first optical waveguide 2 a in the region on the emission side from the buffer layer 3. In the same region, a block-like flow control member 12 is provided at a position on the substrate 10 close to the first optical waveguide 2a. In the flow control member 12, a surface close to the first optical waveguide 2a among the rising surfaces from the substrate 10 (side surfaces of the block) is an uneven surface having at least two protrusions, and the refractive index A part of the outer edge of the adjusting substance 11 is in contact with the uneven surface. In the figure, reference numeral 12a indicates the top of the convex portion on the concave and convex surface, and reference numeral 12b indicates the inner surface of the concave portion formed between the adjacent convex portions.
The flow control member 12 is preferably provided on a region where the optical waveguide is not formed, that is, at a position where it does not overlap any of the optical waveguides 2 when viewed from above. In this embodiment, it is provided between the first optical waveguide 2a and the second optical waveguide 2b.

The refractive index adjusting substance 11 is made of a material whose refractive index is different from both the refractive index of air and the refractive index of the optical waveguide 2. The refractive index of the refractive index adjusting substance 11 is preferably smaller than the refractive index of the optical waveguide 2. The refractive index of the refractive index adjusting substance 11 is more preferably larger than the refractive index of air.
The refractive index adjusting material 11 is a material that is liquid when loaded on the substrate 10 and can be solidified after loading. In particular, a material that does not decrease in viscosity from the time of loading until it loses fluidity is preferable. For example, a method of using a photocurable material and solidifying in a short time by light irradiation is preferable. A material having a small shrinkage during curing is desirable.
Such materials include epoxy or acrylic ultraviolet (UV) curable adhesives and the like.

The refractive index adjusting material 11 is loaded by the following method. First, when the liquid refractive index adjusting substance 11 is dropped on the region surrounded by the concave inner surface 12b of the flow control member 12, the substance fills the concave part and further spreads on the first optical waveguide 2a. The convex portion 12a adjacent to both sides of the concave portion also spreads at the interface between the top portion 12a and the substrate 10, and stops at the end of the top portion 12a (position reaching the next concave portion). Thus, as shown in FIG. 1, the refractive index adjusting substance 11 fills one concave portion, and in the length direction of the first optical waveguide 2a, extends to the top ends of the convex portions adjacent to both sides of the concave portion. In the width direction of one optical waveguide 2a, it is loaded in a shape that extends beyond the first optical waveguide 2a, and is solidified in this state.
The length L of the first optical waveguide 2a covered with the refractive index adjusting substance 11 (hereinafter also referred to as the refractive index adjustment length L) is the top portion 12a in the length direction of the first optical waveguide 2a. The width W1 and the opening width W2 of the recess can be controlled. The spread width of the refractive index adjusting substance 11 in the width direction of the first optical waveguide 2a can be controlled by the viscosity and the dropping amount of the refractive index adjusting substance 11 at the time of dropping.

The number of convex portions on the uneven surface of the flow control member 12 may be two or more, but if it is three or more, the refractive index adjusting substance 11 is dropped onto two or more regions surrounded by the concave inner surface 12b. The refractive index adjustment length L is preferable because it can be expanded to a desired length.
The top 12a of the convex portion is a plane parallel to the first optical waveguide 2a. The angle θ1 formed by the surface forming the top portion 12a of the convex portion and the inner surface 12b of the concave portion is preferably 120 ° or less, more preferably 90 ° or less, and further preferably 80 ° or less. When the angle θ1 is 120 ° or less, the spread of the refractive index adjusting substance 11 can be stopped at the end of the top portion 12a (the angle θ1). In order to improve the controllability of the spread of the refractive index adjusting substance 11, the angle θ1 is preferably about 90 °, and more preferably less than 90 °. The lower limit value of the angle θ1 is not particularly limited and may be larger than zero, but is preferably 10 ° or more in terms of pattern formation on the uneven surface.
The shape of the recess is not particularly limited as long as the above θ1 is in a suitable range. In the present embodiment, θ1 is 90 °, and the planar shape of the recess is a rectangle.

If the distance between adjacent convex portions (opening width of the concave portion) W2 in the length direction of the first optical waveguide 2a is too small, it is difficult to drop a predetermined amount of the refractive index adjusting substance 11 in the concave portion, Since the fine adjustment becomes more difficult as the value is larger, it is set so that these disadvantages do not occur. A preferable range of W2 is about 10 to 50 μm.
If the width W1 of the top portion 12a of the convex portion in the length direction of the first optical waveguide 2a is too small, it becomes difficult to stop the spread of the refractive index adjusting substance 11 at the end portion of the top portion 12a of the convex portion, and is large. Since fine adjustment becomes more difficult, it is set so that these disadvantages do not occur. A preferable range of W1 is about 10 to 50 μm although it depends on the refractive index adjustment length L to be obtained.
If the depth D of the concave portion in the width direction of the first optical waveguide 2a is too small, it becomes difficult to drop a predetermined amount of the refractive index adjusting substance 11 in the concave portion. It is set so as not to cause inconvenience. D is preferably 30 μm or more.

The angle (space side) formed by the surface forming the top 12a of the convex portion and the surface of the substrate 10 is not particularly limited, but is preferably about 90 ° ± 15 °. In this embodiment, it is about 90 °. The same applies to the angle (space side) between the inner surface 12b of the recess and the surface of the substrate 10.
The thickness of the flow control member 12 in the direction perpendicular to the surface of the substrate 10 may be any thickness that can control the flow of the refractive index adjusting substance 11, but if it is too thin, the flow control cannot be sufficiently performed. Although it depends on the dropping amount of the refractive index adjusting substance 11, it is preferably 1 μm or more, more preferably 4 μm or more.

In the present embodiment, the distance d1 from the midpoint in the width direction of the first optical waveguide 2a to the flow control member 12 is such that the presence of the flow control member 12 affects the light propagating through the first optical waveguide 2a. It is necessary to ensure a certain distance, and the distance is set to be larger than ½ of the width of the first optical waveguide 2a.
The material of the flow control member 12 is not particularly limited and can be arbitrarily selected.

According to the optical waveguide element having such a configuration, the refractive index adjusting substance 11 is loaded so as to cover a predetermined length (refractive index adjustment length L) of the first optical waveguide 2a, so that the first optical waveguide element can be compared with that before the loading. The effective refractive index of one optical waveguide 2a changes.
That is, at the portion where the outer peripheral portion of the first optical waveguide 2a is in contact with the air layer, the refractive index different from the refractive index of the first optical waveguide 2a and the refractive index of air on the first optical waveguide 2a. By loading the refractive index adjusting substance 11 having the above, a part of the interface between the first optical waveguide 2a and the air layer is changed to the interface between the first optical waveguide 2a and the refractive index adjusting substance 11, The effective refractive index of the first optical waveguide 2a changes. The amount of change in the effective refractive index can be controlled by the refractive index of the refractive index adjusting substance 11.
For example, a Mach-Zehnder type optical waveguide used for an optical intensity modulator, an optical attenuator, an optical wavelength filter, etc. branches one input light into a plurality of branched optical waveguides (first and second optical waveguides 2a, 2b), the phase of each guided light is controlled and then combined, but the effective refractive index in a specific portion (refractive index adjustment length L) of the first optical waveguide 2a as in this embodiment. By changing, the effective total length (optical path length) of the first optical waveguide 2a can be changed, whereby the phase in the multiplexing section can be adjusted.
The amount of change in the effective total length (optical path length) can be controlled by the refractive index and refractive index adjustment length L of the refractive index adjusting substance 11.
Thus, the zero point can be adjusted by controlling the phase of the light from each branch optical waveguide (first and second optical waveguides 2a, 2b) in the multiplexing section.

When the zero point is adjusted by such a method, it is important to control the area of the portion where the refractive index adjusting substance 11 and the first optical waveguide 2a are in contact with each other. A liquid refractive index adjusting material 11 is loaded on one optical waveguide 2a, and the range of the refractive index adjusting material 11 is controlled using the flow control member 12 and using the surface tension of the refractive index adjusting material 11 itself. Therefore, the zero point can be adjusted by controlling the refractive index adjustment length L without using the conventional method of providing an opening in the buffer layer.
Therefore, since the refractive index adjusting substance 11 is only loaded on the first optical waveguide 2a and no other processing is performed, the first optical waveguide 2a is not compared with the conventional method of providing an opening in the buffer layer. The influence on the optical characteristics in the optical waveguide 2a is small. The manufacturing process is also simple.

In the present embodiment, since the flow control member 12 is provided so as not to overlap the optical waveguide 2, the flow control member 12 is not affected on the guided light, and is zero while suppressing deterioration of the characteristics of the optical waveguide element. Point adjustments can be made.
Moreover, since there is no influence by the material of the flow control member 12, the design freedom of the flow control member 12 is high.

[Second Embodiment]
FIG. 2 is a plan view schematically showing an optical waveguide device according to the second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The present embodiment is greatly different from the first embodiment in that two flow control members 22 and 23 are provided on the substrate 10 with the first optical waveguide 2a interposed therebetween. The outer edge of the refractive index adjusting material 21 loaded on a part is in contact with both the flow control members 22 and 23.
The refractive index adjusting substance 21 can use the same material as in the first embodiment.

Of the two flow control members 22 and 23 in the present embodiment, the flow control member provided outside the first optical waveguide 2a is the first flow control member 22, the first optical waveguide 2a and the second flow control member. The flow control member provided between the optical waveguides 2b is referred to as a second flow control member 23.
The first flow control member 22 can have the same shape as the flow control member 12 in the first embodiment.
The second flow control member 23 has a block shape without an uneven surface, and a side surface 23a adjacent to the first optical waveguide 2a is a plane parallel to the first optical waveguide 2a. The length of the second flow control member 23 in the length direction of the first optical waveguide 2 a may be the same as the length of the first flow control member 22. The thickness of the second flow control member 23 in the direction perpendicular to the surface of the substrate 10 is preferably the same as the thickness of the first flow control member 22.

In this embodiment, the refractive index adjusting substance 21 is loaded by the following method. First, when the liquid refractive index adjusting material 21 is dropped on the region surrounded by the concave inner surface 12b of the first flow control member 22, the material fills the concave portion and further spreads onto the first optical waveguide 2a. The interface between the top part 12a of the convex part adjacent to both sides of the dropped concave part and the substrate 10 spreads in a shape that extends, and also spreads in a shape that connects the interface between the second flow control member 23 and the substrate 10. The refractive index adjusting substance 21 extends in the length direction through the interface between the second flow control member 23 and the substrate 10, and is a capillary tube in the gap between the first flow control member 22 and the second flow control member 23. It is thought to be due to the phenomenon.
Then, the refractive index adjusting substance 21 stops and spreads to the end of the top portion 12a of the convex portion of the first flow control member 22 (position reaching the next concave portion), and is solidified in this state.

In this embodiment, in order to control the refractive index adjusting substance 21 to flow to the end of the top portion 12a of the convex portion of the first flow control member 22 and stop here, the first flow control member The distance d2 between the second flow control member 23 and the second flow control member 23 is a range where capillary action occurs here, and the distance d3 obtained by combining the d2 and the depth D of the concave portion of the first flow control member 22 is It is preferable that the capillarity does not occur.
In addition, when the interval between adjacent convex portions (opening width of the concave portion) W2 is too small with respect to d2, the capillary phenomenon in the concave portion is caused between the first flow control member 22 and the second flow control member 23. In some cases, the amount of the refractive index adjusting substance 21 acting more strongly than the capillary phenomenon in the gap and spreading in the length direction may be reduced. In order to reduce the dropping amount of the refractive index adjusting substance 21, W2 is preferably equal to or more than a half value of d2, and d2 <W2.

Further, the distance d2 between the first flow control member 22 and the second flow control member 23 indicates that the presence of the first flow control member 22 and the second flow control member 23 is the first optical waveguide 2a. It is necessary to secure a distance that does not affect the light propagating through the light. From this point, d2 should be larger than the width of the first optical waveguide 2a.
The depth D of the recess in the width direction of the first optical waveguide 2a is set so that d3 is a distance at which capillary action does not occur, in addition to the setting conditions in the first embodiment. For example, D is preferably 30 μm or more.
The opening width W2 of the recess is set in consideration of the strength of the capillary phenomenon in the recess in addition to the setting conditions in the first embodiment. For example, W2 is preferably in the range of 10 to 50 μm.

  According to the present embodiment, the same operational effects as those of the first embodiment can be obtained, and in particular, the flow control member (the first control member that regulates the spread of the refractive index adjusting substance 21 on both sides of the first optical waveguide 2a). By providing the flow control member 22 and the second flow control member 23), the controllability in the range where the refractive index adjusting substance 21 spreads is improved.

  Particularly in this embodiment, since the second flow control member 23 provided between the first optical waveguide 2a and the second optical waveguide 2b is in a block shape without an uneven surface, a relatively small region. Can also be provided. Therefore, it is effective when the distance between the first optical waveguide 2a and the second optical waveguide 2b is narrow.

[Third Embodiment]
FIG. 3 is a plan view schematically showing an optical waveguide device according to the third embodiment of the present invention. In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The present embodiment is greatly different from the second embodiment in that the second flow control member 53 provided between the first optical waveguide 2a and the second optical waveguide 2b is different from the first optical waveguide 2a. It is the point which is the same shape as the 1st flow control member 22 provided in the outside. The first flow control member 22 and the second flow control member 53 are provided so that the concave and convex surfaces face each other and the top portions 12a of the convex portions face each other.
The refractive index adjusting substance 51 can use the same material as in the first embodiment.

In the present embodiment, the refractive index adjusting substance 51 is loaded by the following method. First, when the liquid refractive index adjusting substance 51 is dropped on the region surrounded by the concave inner surface 12b of the first flow control member 22 and the region surrounded by the concave inner surface 12b of the second flow control member 53, the refractive index. The adjustment material 51 fills the inside of the recess, further spreads on the first optical waveguide 2a, and spreads so as to connect the interface between the top portion 12a of the projection and the substrate 10 adjacent to both sides of the dropped recess. It is considered that the refractive index adjusting substance 51 spreads between the first flow control member 22 and the second flow control member 53 in the length direction due to a capillary phenomenon.
The refractive index adjusting substance 51 spreads to the end of the top portion 12a of the convex portion of the first flow control member 22 and the second flow control member 53 (position reaching the next concave portion) and stops in this state. Is done.
Alternatively, the liquid refractive index adjusting substance 51 may be dropped between the recess opening of the first flow control member 22 and the recess opening of the second flow control member 53 facing the first opening. Also in this case, the refractive index adjusting substance 51 extends in the length direction between the first flow control member 22 and the second flow control member 53, and the first flow control member 22 and the second flow control member 53. It spreads to the end of the convex portion 12a (the position reaching the next concave portion) and stops, and is solidified in this state.

In the present embodiment, in order to control the refractive index adjusting substance 51 to flow to the ends of the top portions 12a of the convex portions of the first flow control member 22 and the second flow control member 53 and stop here. The distance d2 between the first flow control member 22 and the second flow control member 23 is within a range where capillary action occurs here, and the d2, the first flow control member 22 and the second flow control member 23 It is preferable to set the distance d4, which is combined with the depth D of the concave portion of the control member 53, within a range in which capillary action does not occur.
The relationship between the distance between adjacent convex portions (opening width of the concave portion) W2 and d2 is the same as in the second embodiment.

  The positions of the first flow control member 22 and the second flow control member 53 and the dimensions of the first flow control member 22 and the second flow control member 53 in the present embodiment are set conditions in the second embodiment. It is set in consideration of the same conditions as.

  According to the present embodiment, the same effects as those of the second embodiment can be obtained, and in particular, the first flow control member 22 and the second flow control that have uneven surfaces on both sides of the first optical waveguide 2a. By providing the member 53, the difference between d2 (a size at which the capillary phenomenon occurs) and d4 (a size at which the capillary phenomenon does not occur) can be made larger than that in the second embodiment. Controllability in the range where the substance 51 spreads further improves.

[Fourth Embodiment]
FIG. 4 is a plan view schematically showing an optical waveguide device according to the fourth embodiment of the present invention. In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The present embodiment is greatly different from the second embodiment in that the second flow control member 63 provided between the first optical waveguide 2a and the second optical waveguide 2b is the first optical waveguide 2a. This is that the first flow control member 22 provided on the outer side has an uneven surface with a different pitch. The first flow control member 22 and the second flow control member 63 are provided so that the uneven surfaces face each other.
That is, the width W3 of the top 63a of the second flow control member 63 provided between the first optical waveguide 2a and the second optical waveguide 2b in the length direction of the first optical waveguide 2a is It is smaller than W1 of one flow control member 22.
Further, the opening width W4 of the concave portion in the length direction of the first optical waveguide 2a of the second flow control member 63 is smaller than W2 of the first flow control member 22.
The length of the second flow control member 63 in the length direction of the first optical waveguide 2 a may be the same as the length of the first flow control member 22. The thickness of the second flow control member 63 in the direction perpendicular to the surface of the substrate 10 is preferably the same as the thickness of the first flow control member 22.

In this embodiment, the refractive index adjusting substance 61 is loaded by the following method. First, when the liquid refractive index adjusting substance 61 is dropped on the region surrounded by the concave inner surface 12b of the first flow control member 22 and the region surrounded by the concave inner surface 63b of the second flow control member 63, each refraction is made. The rate adjusting substance 61 fills the inside of the concave portion, and further spreads on the first optical waveguide 2a so as to be integrated with each other, and the interface between the top portions 12a, 63a of the convex portions adjacent to both sides of the dropped concave portion and the substrate 10 is formed. It spreads in the form of a song. It is considered that the refractive index adjusting substance 61 spreads in the length direction between the first flow control member 22 and the second flow control member 63 due to a capillary phenomenon.
Then, the refractive index adjusting substance 61 spreads and stops to the tops 12a and 63a of the convex portions of the first flow control member 22 and the second flow control member 63 (positions reaching the next concave portion). Solidified in state.

In the present embodiment, the refractive index adjusting substance 61 is controlled to flow to the ends of the top portions 12a and 63a of the convex portions of the first flow control member 22 and the second flow control member 63 and stop here. For this purpose, the distance d2 between the first flow control member 22 and the second flow control member 63 is set to a range where capillary action occurs here, and the d2, the first flow control member 22 and the second flow control member 22 It is preferable to set the distance d4, which is the sum of the depth D of the recesses of the flow control member 63, within a range in which capillary action does not occur.
The relationship between the intervals between adjacent convex portions (opening width of the concave portions) W2, W4 and d2 is the same as in the second embodiment.

W3 and W4 in the second flow control member 63 are set in consideration of the same conditions as W1 and W2 of the first flow control member 22 in the second embodiment.
The position of the second flow control member 63 and the dimensions of the second flow control member 63 other than W3 and W4 are the same as the setting conditions of the first flow control member 22 in the second embodiment. Set in consideration.

  According to the present embodiment, the same operational effects as those of the second embodiment can be obtained. In particular, the first flow control member 22 and the second flow control member 63 have a concave and convex pitch on the concave and convex surfaces. Since they are different, the range in which the refractive index adjusting substance 11 is loaded (refractive index adjustment length L) can be adjusted in small increments. For example, the refractive index adjusting material 11 is dropped into two adjacent recesses of the second flow control member 63, and the refractive index adjusting material 11 is dropped into one recess facing the refractive index adjusting material 11. The refractive index adjustment length L can be made longer than that in FIG.

[Fifth Embodiment]
FIG. 5 is a plan view schematically showing an optical waveguide device according to the fifth embodiment of the present invention. In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment differs greatly from the second embodiment in the region on the emission side from the ground electrode 5 and in the region where the optical waveguide 2 is not provided, the light shielding films 71, 72, 73 is provided.
That is, in the present embodiment, the first light shielding film 71 is provided outside the first optical waveguide 2a, and the first flow control member 22 is provided thereon. A second light shielding film 72 is provided between the first optical waveguide 2a and the second optical waveguide 2b, and the second flow control member 23 is provided thereon. A third light shielding film 73 is provided outside the second optical waveguide 2b. No flow control member is provided here.
In this embodiment, the refractive index adjusting substance 21 is made of a photocurable material and is solidified by light irradiation.

  The first to third light shielding films 71, 72, 73 are provided to prevent light irradiated when the refractive index adjusting substance 21 is solidified from reaching the substrate 10, and are light absorbing materials. Or a light-reflective material.

The thickness of the first to third light shielding films 71, 72, 73 in the normal direction of the substrate 10 needs to be sufficient to prevent the substrate 10 from being irradiated with light. When the flow control member is provided on the film, the flow controllability of the refractive index adjusting substance 21 by the flowability control member decreases as the thickness increases. Further, the first to third light shielding films 71, 72, 73 provided on the same substrate 10 are preferably formed collectively in the manufacturing process, and preferably have the same thickness.
Therefore, the thickness of the first to third light shielding films 71, 72, 73 in this embodiment is larger than the thickness of the first flow control member 22 and the second flow control member 23 in the normal direction of the substrate 10. The thickness is preferably thin, more preferably ¼ or less of the thickness of the first flow control member 22 and the second flow control member 23, and further preferably 1/10 or less. The lower limit value of the thickness of the first to third light shielding films 71, 72, and 73 differs depending on the material and is not particularly limited, but is, for example, about 0.2 to 0.3 μm.

  Although the region where the first to third light shielding films 71, 72, 73 are formed is not particularly limited, the region is formed so as to include a region close to the first optical waveguide 2a on which the refractive index adjusting substance 21 is loaded. Is preferred.

According to the present embodiment, the influence on the substrate due to light irradiation when the refractive index adjusting substance 21 is solidified can be reduced.
That is, the light (for example, ultraviolet light) irradiated to solidify the refractive index adjusting material 21 is normally irradiated not only on the portion where the refractive index adjusting material 21 is loaded but also on a wide area around it. For this reason, a refractive index change may be induced by irradiating light to a substrate or an optical waveguide. According to the present embodiment, it is possible to suppress the influence of the irradiation light on the substrate.

[Sixth Embodiment]
FIG. 6 is a plan view schematically showing an optical waveguide device according to the sixth embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line AA in FIG. In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment differs greatly from the second embodiment in that, in addition to the first flow control member 22 and the second flow control member 23, the third flow control member 84 is provided outside the second optical waveguide 2b. Is a point provided.
The shape of the third flow control member 84 is the same as that of the first flow control member 22.

As shown in FIG. 7, the first flow control member 22, the second flow control member 23, and the third flow control member 84 are symmetrical planes of the first optical waveguide 2a and the second optical waveguide 2b. It is symmetrical about P.
That is, the shape and position of the first flow control member 22 and the second flow control member 23 viewed from the first optical waveguide 2a, and the second flow control member 23 and the second flow control member 23 viewed from the second optical waveguide 2b. The shape and position of the three flow control members 84 are equal to each other.

According to the present embodiment, the same operational effects as those of the second embodiment can be obtained, and the first flow control member 22, the second flow control member 23, and the third flow control member 84 are symmetrical planes P. Therefore, the stability of characteristics against external changes such as temperature changes is improved.
That is, in order to adjust the zero point, flow control members (first flow control member 22 and second flow control member 23) are provided in the vicinity of one optical waveguide (first optical waveguide 2a). It is sufficient that the refractive index adjusting substance 21 can be loaded on the optical waveguide. However, if the structure in the vicinity of the first optical waveguide 2a is different from the structure in the vicinity of the second optical waveguide 2b, the influence on the optical characteristics due to an external change such as a temperature change will be reduced. It is different between the optical waveguide 2a and the second optical waveguide 2b, and as a result, the zero point may fluctuate.
According to the present embodiment, the third flow control member 84 is provided in the vicinity of the second optical waveguide 2b, and the structure in the vicinity of the first optical waveguide 2a and the structure in the vicinity of the second optical waveguide 2b are mutually connected. By constituting so as to be symmetric, the fluctuation of the zero point due to such an external change can be reduced.

In the present embodiment, the refractive index adjusting substance 21 is loaded on the first optical waveguide 2a in the example shown in the figure, but the refractive index adjusting substance 21 may be loaded on the second optical waveguide 2b. Alternatively, the refractive index adjusting substance 21 may be loaded on both optical waveguides (first and second optical waveguides 2a and 2b).
Here, when the refractive index adjusting material 21 is loaded on the first optical waveguide 2a and when the refractive index adjusting material 21 is loaded on the second optical waveguide 2b, the zero point change directions are opposite to each other. Therefore, in this embodiment, it is possible to select which of the first and second optical waveguides 2a and 2b is loaded with the refractive index adjusting material 21 in accordance with a desired change direction of the zero point. Further, for example, when the refractive index adjusting material 21 is loaded on the first optical waveguide 2a, when the amount of change in the zero point is too large, the refractive index adjusting material 21 is loaded on the second optical waveguide 2b to achieve zero. The zero point adjustment can also be corrected by changing the point in the reverse direction.
Further, the first flow control member 22 and the third flow control member 84 may be configured to have different pitches of the uneven surfaces, and according to such a configuration, the flow control member having the larger pitch is used. The zero point can be coarsely adjusted, and the zero point can be finely adjusted using the flow control member having the smaller pitch.

[Seventh Embodiment]
FIG. 8 is a plan view schematically showing an optical waveguide device according to the seventh embodiment of the present invention.
In the optical waveguide element of this embodiment, a directional coupler type optical waveguide 92 is formed on the upper surface of a LiNbO ₃ (LN) substrate 10.
The directional coupler type optical waveguide 92 includes a first optical waveguide 92a and a second optical waveguide 92b. The two optical waveguides 92a and 92b are directed inward from one end of the substrate 10. In the vicinity of the central portion of the substrate 10, a parallel coupling portion 90 is formed in the vicinity of the central portion of the substrate 10, and the other end portion of the substrate 10 is gradually separated from each other outward. In this embodiment, an LN X-cut substrate is used.
In a region outside the coupling portion 90, electrodes 94 and 95 facing each other across the coupling portion 90 are provided close to the first optical waveguide 92a and the second optical waveguide 92b, respectively. The electrodes 94 and 95 are made of a conductive material such as gold (Au).
In the present embodiment, it is arbitrary which of the left and right in the figure is the incident side with respect to the directional coupler type optical waveguide 92, but for convenience of explanation, the left side is the incident side and the right side is the emission side.

In a part of the coupling portion 90, the refractive index adjusting substance 91 is loaded all together on the first optical waveguide 92a and the second optical waveguide 92b. In the vicinity of the refractive index adjusting substance 91, the two first flow control members 22 and the second flow control member 53 sandwich the coupling portion 90 so that the concave and convex surfaces face each other and the top portion 12a of the convex portion. It is provided so as to face each other.
The first flow control member 22 and the second flow control member 53 can have the same configuration as that of the third embodiment.
The refractive index adjusting substance 91 can use the same material as in the first embodiment.

The refractive index adjusting substance 91 is loaded by the same method as in the third embodiment.
In the arrangement of the first flow control member 22 and the second flow control member 53 and the setting of the dimensions of the first flow control member 22 and the second flow control member 53 in the present embodiment, the third implementation is performed. In addition to considering the same conditions as the configuration, in particular, the first flow control member 22 and the second flow control member 53 are not affected by the presence of the first flow control member 22 and the second flow control member 53, so It is necessary to increase the distance d5 between the control member 22 and the second flow control member 53. The preferred range of d5 depends on the distance (distance) between the first optical waveguide 92a and the second optical waveguide 92b in the coupling portion 90. For example, d5 = “width of the first optical waveguide 92a” + “first” The width of the second optical waveguide 92b "+" the distance between the first optical waveguide 92a and the second optical waveguide 92b "or a larger value is set.

According to the optical waveguide element having such a configuration, the refractive index adjusting substance 91 is formed so as to cover the first optical waveguide 92a and the second optical waveguide 92b in the coupling portion 90 by the same length (refractive index adjustment length L). As a result of loading, the effective refractive indexes of the first optical waveguide 92a and the second optical waveguide 92b change by equal amounts compared to before loading. The amount of change in the effective refractive index can be controlled by the refractive index adjustment length L.
In the directional coupler type optical waveguide 92, the powers of the light propagating through the two optical waveguides (first and second optical waveguides 92a and 92b) in the coupling unit 90 shift to each other, and the first Are distributed to each of the second optical waveguides 92a and 92b. The transition state of the optical power between the two optical waveguides (first and second optical waveguides 92 a and 92 b) can be controlled by the optical path length in the coupling portion 90. Therefore, by changing the effective refractive indexes of the first optical waveguide 92a and the second optical waveguide 92b by the same amount as in the present embodiment, the effective efficiency of the first optical waveguide 92a and the second optical waveguide 92b is changed. The total length (optical path length) can be changed by the same amount, whereby the coupling state in the coupling unit 90 can be controlled to adjust the branching ratio.

[Eighth Embodiment]
FIG. 9 is a plan view schematically showing an optical waveguide device according to the eighth embodiment of the present invention.
In the present embodiment, the same components as those in the sixth and seventh embodiments are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment differs greatly from the sixth embodiment in that the output side of the first optical waveguide 2a and the second optical waveguide 2b constituting the interference system of the Mach-Zehnder optical waveguide is the same as that of the combined optical waveguide 2d. However, it is connected to the first optical waveguide 92a and the second optical waveguide 92b constituting the directional coupler type optical waveguide, respectively.
In the directional coupler type optical waveguide according to the present embodiment, the powers of the light propagating through the two optical waveguides (first and second optical waveguides 92a and 92b) in the coupling unit 90 are shifted to each other. The second optical waveguides 92a and 92b are distributed at a specific ratio and emitted.
In a part of the coupling portion 90 of the directional coupler type optical waveguide, a refractive index adjusting substance 91 is collectively loaded on the first optical waveguide 92a and the second optical waveguide 92b. In the vicinity of the refractive index adjusting substance 91, the two first flow control members 22 and the second flow control member 53 sandwich the coupling portion 90 so that the concavo-convex surfaces face each other, and the top portions 12 a of the convex portions are mutually opposed. Are also provided to face each other. A part of the outer edge of the refractive index adjusting substance 91 is in contact with the first flow control member 22 and the second flow control member 53.

  According to the present embodiment, the first optical waveguide 2a and the second optical waveguide 2b constituting the interference system can obtain the same operational effects as the sixth embodiment, and configure the directional coupler type optical waveguide. For the first optical waveguide 92a and the second optical waveguide 92b, the same effects as those of the seventh embodiment are obtained.

[Modification (1)]
In the first to eighth embodiments, the flow control member may be formed of a conductive material.
When the flow control member is formed of a conductive material, use the same material as other electrodes provided on the same substrate, for example, the signal electrode 4, the ground electrode 5, and the electrodes 94 and 95 in the seventh embodiment. In this case, the flow control member can be formed at the same time in the process of forming another electrode, which can contribute to the reduction in the number of manufacturing processes.

When the flow control members are provided on both sides of the first optical waveguide 2a as in the second to eighth embodiments, the flow control member is formed of a conductive material, and the flow control member has a voltage. By providing a means for applying the pressure, the flow control member can also serve as an electrode. In such a configuration, an electric field is applied to the first optical waveguide 2a by applying a control voltage to one of the flow control members on both sides of the first optical waveguide 2a and grounding the other flow control member. Can be applied.
When the flow control member 12 is provided only on one side of the first optical waveguide 2a as in the first embodiment, the flow control member 12 is opposed to the first optical waveguide 2a. An electrode may be provided in a position where the control voltage is applied to one of the electrode and the flow control member 12 and the other is grounded.
When the flow control member also serves as an electrode in this way, a combination with other electrodes provided on the same substrate, for example, the signal electrode 4 and the ground electrode 5 and the electrodes 94 and 95 in the seventh embodiment. Thus, it is possible to reduce the driving voltage of the photoconductive element.

[Modification (2)]
In the fifth and sixth embodiments, the light shielding films 71, 72, 73 may be formed of a conductive material.
When the light shielding films 71, 72, and 73 are formed of a conductive material, the same material as that of other electrodes (signal electrode 4 and ground electrode 5) provided on the same substrate can be used. In the process of forming the ground electrode 5, the light shielding films 71, 72, and 73 can be formed at the same time, which can contribute to the reduction in the number of manufacturing processes.

Further, the light shielding films 71, 72, 73 are formed of a conductive material, and flow control members (first, second, and third flow control members 22, 23, 73 formed on and in contact therewith are also conductive. In this case, by providing a means for applying a voltage to one or both of the adjacent flow control members, the integrated structure of the flow control member and the light shielding film therebelow serves as an electrode. For example, by applying a control voltage to one of the first and second flow control members 22 and 23 on both sides of the first optical waveguide 2a and grounding the other, the first optical waveguide An electric field can be applied to 2a.
According to such a configuration, since the light shielding film can be provided closer to the optical waveguide than the flow control member, the flow control member and the light shielding film are integrated as compared with the case where only the flow control member acts as an electrode. By acting as an electrode, an electric field due to the applied control voltage is intensively generated with respect to the optical waveguide, so that a reduction in driving voltage can be expected.

[Modification (3)]
In each of the above embodiments and modifications, the planar shape of the recess in the flow control member is not limited to a rectangle, and can be changed as appropriate.
FIG. 10 shows a variation of the second embodiment in which the angle θ1 formed by the surface forming the top 32a of the convex portion and the inner surface 32b of the concave portion in the first flow control member 32 is in the range of 90 ° to 120 °. An example is shown. In this example, the planar shape of the concave portion of the first flow control member 32 is a substantially trapezoid in which the opening width in the length direction of the first optical waveguide 2a is gradually reduced toward the bottom.
The refractive index adjusting substance 31 can use the same material as in the first embodiment.
In this example, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[Modification (4)]
FIG. 11 shows an example in which the planar shape of the recess in the first flow control member 42 is wider inward than the opening as a modification of the second embodiment.
In the concave portion of the first flow control member 42 in this example, the opening width in the length direction of the first optical waveguide 2a is expanded inward of the opening portion, and the partition wall portion 42c between the adjacent concave portions is formed. The planar shape is substantially T-shaped.
The refractive index adjusting substance 41 can use the same material as that of the first embodiment.
In this example, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
According to such a configuration, since the inside of the concave portion is widened, the allowable range of the dropping position when dropping the refractive index adjusting substance 41 is widened, and the productivity is improved.

[Modification (5)]
In the above embodiments and modifications, the uneven pitch on the uneven surface of one flow control member may not be uniform, and a portion with a large pitch and a portion with a small pitch are mixed on one uneven surface. Also good.
FIG. 12 shows an uneven surface of the first flow control member 102 as a modification of the second embodiment.
An example in which a fine adjustment portion 102a having a small uneven pitch and a coarse adjustment portion 102b having a larger uneven pitch is provided.
In this example, the width W1 of the top portion 12a and the interval between adjacent convex portions (opening width of the concave portion) W2 can be appropriately set within a range in which the loading amount of the refractive index adjusting substance 21 can be controlled.
In this example, the same components as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
According to such a configuration, the refractive index adjustment length L can be finely adjusted by appropriately selecting the position where the refractive index adjusting substance 21 is dropped.

  It should be noted that the configuration of the optical waveguide in each of the above embodiments and modifications can be changed as appropriate. For example, the plurality of optical waveguides of the Mach-Zehnder type optical waveguide (the first optical waveguide 2a and the second optical waveguide 2b) may not be parallel to each other. The lengths of the plurality of optical waveguides (the first optical waveguide 2a and the second optical waveguide 2b) may not be equal to each other. That is, the planar shapes of the first optical waveguide 2a and the second optical waveguide 2b do not have to be symmetric with each other, and the difference between the lengths of the first optical waveguide 2a and the second optical waveguide 2b from the design time is different. A desired initial phase difference may be provided. Further, in the plurality of optical waveguides (the first optical waveguide 2a and the second optical waveguide 2b), there is a difference in the structure of the plurality of optical waveguides, such as making the width of each optical waveguide and the concentration of the refractive index control component different from each other. Thus, a desired initial phase difference may be provided by providing a difference in effective refractive index between the plurality of optical waveguides.

Example 1
The zero point of the optical modulator was adjusted using the configuration shown in FIG.
An LN substrate was used as the substrate 10, and the Mach-Zehnder type optical waveguide 2 was formed by a titanium (Ti) diffusion method.
The buffer layer 3 was made of SiO ₂ and had a thickness of about 1 μm.
Gold (Au) is used as a material for the signal electrode 4, the ground electrode 5, the first flow control member 22, the second flow control member 23, the third flow control member 84, and the light shielding films 71, 72, and 73. These were formed by plating.
The thickness of the light shielding films 71, 72, 73 was 0.2 μm. The thickness of the first flow control member 22, the second flow control member 23, and the third flow control member 84 from the substrate surface was 5 μm.
The shapes of the first flow control member 22 and the third flow control member 84 were comb-like shapes as shown in FIG. The angle (rise angle) formed by the uneven surface and the substrate 10 is about 90 °. Each dimension was as follows.
W1 = 50 μm,
W2 = 50 μm,
D = 40 μm,
d2 = 40 μm,
d3 = 90 μm,
θ1 = 90 °

As the refractive index adjusting substance 21, an acrylic ultraviolet curable adhesive was used.
The liquid refractive index adjusting substance 21 was dropped on the region surrounded by the inner surface of the recess of the flow control member 22. The dropped refractive index adjusting substance 21 fills the concave portion, and further spreads in the length direction and the width direction of the first optical waveguide 2a as shown in FIG. 6, until the top end of the convex portion (position reaching the next concave portion). Spread and stopped.
When stopped, the refractive index adjusting substance 21 was solidified by irradiating with ultraviolet rays from an ultraviolet lamp.
The length L (refractive index adjustment length L) covered with the refractive index adjusting substance 21 in the first optical waveguide 2a is about several mm, which is the designed length.

It was confirmed that the refractive index control substance 21 was loaded by changing the number of dropping points and the dropping position, and the loading region of the refractive index control substance 21, that is, the refractive index adjustment length L could be controlled as designed. It was also confirmed that the zero point changed in proportion to the refractive index adjustment length L.
The three optical modulators were loaded with the refractive index adjusting material 21 under the same conditions, the zero point and the transmission loss were measured before and after loading, and the amount of change before and after the loading of the refractive index adjusting material 21 was obtained. . When converted into a phase difference, the zero point change amount was about 22 ° per 1 mm of the refractive index adjustment length L = 1 mm.
No increase in light transmission loss due to loading of the refractive index adjusting material 21 was observed.

(Example 2)
In Example 1, it was the same except that it was changed to θ1 = 60 °. That is, in the shapes of the first flow control member 22 and the third flow control member 84, the planar shape of the recesses was changed to a substantially trapezoid as shown in FIG. Other dimensions in the first flow control member 22 and the third flow control member 84 are the same as those in the first embodiment.
Also in this example, as in Example 1, it was confirmed that the refractive index adjustment length L could be controlled as designed.

It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is sectional drawing which follows the AA line in FIG. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention. It is a top view which shows one Embodiment of the optical waveguide element which concerns on this invention.

Explanation of symbols

2. Mach-Zehnder type optical waveguide (optical waveguide)
2a, 92a ... 1st optical waveguide 2b, 92b ... 2nd optical waveguide 3 ... Buffer layer 4 ... Signal electrode 5 ... Ground electrode 10 ... Substrate 11, 21, 31, 41, 51, 61, 91 ... Refractive index adjustment Substance 12 ... Flow control member 12a, 32a, 42a, 63a ... Top of convex part 12b, 32b, 42b, 63b ... Inner surface of concave part 22, 32, 42, 102 ... First flow control member 23, 53, 63 ... First Two flow control members 71 ... first light shielding film 72 ... second light shielding film 73 ... third light shielding film 84 ... third flow control member 90 ... coupling portion 92 ... directional coupler type optical waveguides 94, 95 …electrode

Claims (19)

  A plurality of optical waveguides are formed on a substrate, and an optical waveguide element having a configuration in which propagating light of each of the plurality of optical waveguides interferes or is coupled, and is refracted on a part of the optical waveguide An optical waveguide element, wherein a rate adjusting material is loaded, and a part of an outer edge of the refractive index adjusting material is in contact with a flow control member provided on the substrate.   2. The optical waveguide element according to claim 1, wherein the flow control member is provided on a region of the substrate where the optical waveguide is not formed.   3. The optical waveguide device according to claim 1, wherein the refractive index adjusting material is a material that is liquid when loaded on the substrate and can be solidified after loading.   The flow control member has a concavo-convex surface having at least two convex portions on a rising surface from the substrate, and a part of the outer edge of the refractive index adjusting substance is at least two adjacent convex portions. The optical waveguide element according to claim 1, wherein the optical waveguide element is in contact with the top of the optical waveguide element.   Two flow control members are provided on the substrate with the optical waveguide interposed therebetween, and a part of the outer edge of the refractive index adjusting substance is in contact with both flow control members. The optical waveguide device according to any one of claims 1 to 3.   One of the two flow control members has a concavo-convex surface provided with at least two convex portions on a surface facing the other flow control member among the rising surfaces from the substrate, and the refraction 6. The optical waveguide element according to claim 5, wherein a part of the outer edge of the rate adjusting substance is in contact with the tops of at least two adjacent convex portions.   Of the rising surfaces from the substrate of the two flow control members, the surfaces facing each other have a concavo-convex surface provided with at least two convex portions, and one of the outer edges of the refractive index adjusting substance. 6. The optical waveguide element according to claim 5, wherein the portion is in contact with the tops of at least two adjacent convex portions of both flow control members.   8. The optical waveguide element according to claim 7, wherein the two flow control members have the same concave and convex surfaces.   8. The optical waveguide device according to claim 7, wherein the two flow control members have different concave and convex surfaces.   The optical waveguide element according to claim 1, wherein the flow control member is made of a conductive material.   11. The optical waveguide device according to claim 10, further comprising means for applying a voltage to the flow control member.   The said refractive index adjusting substance consists of a photocurable material, and the light-shielding film is provided in the area | region where the said optical waveguide on the said board | substrate is not provided. The optical waveguide device according to item.   13. The optical waveguide element according to claim 12, wherein the light shielding film is made of a conductive material.   14. The optical waveguide element according to claim 13, wherein the flow control member is made of a conductive material, and the light shielding film is in contact with the flow control member.   15. The optical waveguide device according to claim 14, further comprising means for applying a voltage to the flow control member.   The flow control member is made of a conductive material, and an electrode is provided on the substrate separately from the flow control member, and the flow control member and the electrode are made of the same material. The optical waveguide element as described in any one of 1-15.   The optical waveguide element according to claim 1, wherein the plurality of optical waveguides formed on the substrate constitute a Mach-Zehnder type optical waveguide.   The optical waveguide device according to any one of claims 1 to 16, wherein the plurality of optical waveguides formed on the substrate constitute a directional coupler type optical waveguide. The flow control member is provided in the vicinity of all of the plurality of optical waveguides, and the flow control members are symmetric with respect to the symmetry plane of the plurality of optical waveguides. The optical waveguide device according to any one of the above.

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