JP2005241762A - Flat surface optical circuit and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate mirror angle errors within a wafer surface in a flat surface optical circuit with a micromirror manufactured by using a diagonal vapor deposition process. <P>SOLUTION: In the flat surface optical circuit having a plurality of optical path changing mirrors within a substrate, a mirror surface direction (β) is so set that the prescribed mirror angle (δ) can be obtained based on the positional relations (D and θ) on the vapor deposition source and the substrate surface in a diagonal vapor deposition process. Namely, the respective mirror manufacturing positions (x and y) and mirror surface direction (β) are controlled by using prescribed formulas 1 and 2 in such a manner that the prescribed mirror angles (δ) (uniform within the substrate) can be obtained based on the positional relations between a vapor deposition source and the manufacturing positions (x and y) of the respective mirrors on the substrate in order to manufacture a plurality of the mirrors with good uniformity within the substrate using the diagonal vapor deposition process. The formulas 1 and 2 are similarly applicable in the case of using diagonal exposure in place of the diagonal vapor deposition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a planar optical circuit and a manufacturing method thereof. More specifically, the present invention relates to a planar optical circuit used in the fields of optical communication and optical information processing, particularly mounting and receiving elements such as photodiodes and surface-emitting lasers on a planar optical circuit and perpendicular to the planar optical circuit. The present invention relates to a vertical input / output structure of guided light, which is essential for optical fiber connection.

  In the fields of optical communication and optical information processing, a part or all of a light wave is taken out from one area of a planar optical circuit, and the intensity of the light wave is received using a photodiode (hereinafter referred to as “PD”) or vice versa. In addition, in order to realize a configuration in which output light from a semiconductor laser diode (hereinafter referred to as “LD”) is input to the planar optical circuit, optical coupling between the planar optical circuit and the light receiving and emitting element is required. As such an optical coupling structure between an optical element and a planar optical circuit, a structure has been proposed in which an optical path conversion mirror that reflects a light wave substantially perpendicular to the optical waveguide axis is provided at a desired minute portion of the planar optical circuit.

  FIGS. 1A to 1C show a conventional example having the same configuration as the optical path conversion mirrors described in Patent Document 1, Patent Document 2, and Patent Document 3, and FIG. (B) is a longitudinal cross-sectional view along the AA line, and (c) is a schematic diagram for explaining an oblique deposition process that plays a central role in mirror formation.

  A rectangular mirror groove 105 as shown in FIGS. 1A and 1B is provided at the end of an optical waveguide 104 formed of a core 102 and a clad 103 formed on a flat substrate 101. On the wall surface of the groove 105 facing the waveguide end, a slope 107 is formed by a liquid curable material supplied through a resin supply groove 106 provided in connection with the mirror groove 105. An optical path conversion mirror 108 is formed by covering the slope 107 with a gold thin film. With this mirror 108, a part of the propagation light in the optical waveguide 104 can be extracted from the surface of the substrate 101 upward in the drawing.

  Such an optical path conversion mirror 108 can be formed on the facing portion of the optical waveguide end 104A by, for example, the same method as in Patent Document 3 if the mirror groove 105 and the resin supply groove 106 are formed. This manufacturing process will be described with a specific example. First, Ti is obliquely deposited to a thickness of 0.1 μm from an angle of 35.3 degrees obliquely above the substrate 101 (ψ = 35.3 degrees). Then, the dot portion 109 in FIG. 1C becomes a shadow, and Ti does not adhere thereto. Next, while rotating the optical circuit, Cr is deposited on the entire surface to a thickness of 0.1 μm so that no shadow is formed. Next, when Cr is lifted off with Ti by dipping in a dilute fluorine solution, Cr remains in the halftone dot portion of FIG. 1C, that is, the shaded portion 109 during Ti oblique deposition. Next, the entire surface is subjected to a surface treatment so that the contact angle with respect to the liquid curable resin to be used later is 45 degrees or more. Next, when the surface treatment film is lifted off with a Cr etching solution, the area of the halftone dots 109 in FIG. 1C is good against the liquid cured resin, while the other areas have a contact angle of 45 degrees or more. As a result, the drip becomes worse with respect to the liquid curable resin. When the liquid curable resin is supplied to the mirror groove 105 exhibiting such a wetting property through the resin supply groove 106, as shown in FIG. A slope is formed. Here, the liquid curable resin is a resin material that is liquid when supplied to the mirror groove 105 as described above, and forms a slope by being cured after being supplied. If gold is deposited on the 45-degree slope as a reflecting material to form the vertical optical path conversion mirror 108, the guided light emitted from the waveguide end 104A is emitted perpendicular to the circuit surface.

The reason why the slope angle is 45 degrees by the above-described manufacturing process is that the angle φ shown on the coordinate axis in FIG. In other words, the vapor deposition direction χ = 45 degrees in the substrate surface, and the vapor deposition angle ψ is set to 35.3 degrees so that the slope angle φ is 45 degrees. That is, the vapor deposition angle ψ is equal to the desired slope angle φ.
ψ = atan (cos (χ) tan (φ)) (Formula 6)
It is set to satisfy the relationship.

Japanese Patent Laid-Open No. 9-026515 JP 9-318850 A Japanese Patent Laid-Open No. 11-084183

  By the way, when a plurality of optical path conversion mirrors are arranged in the substrate, the above-described conventionally proposed technique is not sufficient. In other words, if a plurality of mirror grooves designed as described above are shifted in position within the substrate and a mirror is formed by collectively performing an oblique deposition process, a mirror angle distribution is generated within the substrate and the accuracy is high. There was a point that an angle of 45 degrees could not be obtained. According to what the present inventors have implemented, a mirror angle error of about ± 6 degrees at maximum occurs within the 4-inch substrate surface. This mirror angle error corresponds to ± 12 degrees in terms of light reflection angle. This angle error is not a problem when a planar PD element having a large light receiving diameter of about 300 μm in diameter is mounted very close to the mirror on the upper surface of the substrate, but when mounting a PD having a small light receiving diameter, When the distance from the upper surface of the substrate is increased, a loss due to so-called “vignetting” occurs, resulting in a decrease in light receiving sensitivity, which is not preferable.

  The cause of such an angle error is the scattering phenomenon of the evaporated substance in the vapor deposition apparatus. That is, in the vapor deposition apparatus, since the distance between the vapor deposition source and the substrate is not sufficiently large, even if the in-plane vapor deposition direction χ and the vapor deposition angle ψ are set with respect to a certain mirror on the substrate, it is separated from it on the substrate. For the mirror at the position (xi, yi), the vapor deposition direction and the vapor deposition angle are slightly different, so that an error in the mirror angle occurs within the substrate surface. Conventionally, the design of a single mirror has been proposed, but the design and manufacturing method in detail considering the scattering phenomenon of the evaporated substance during the oblique deposition as described above have not been known. For this reason, when an attempt is made to produce a planar optical circuit in which a plurality of mirrors are actually arranged in the substrate, a large angle error has occurred.

  An object of the present invention is to solve the above-described problems of the prior art and provide a planar optical circuit having an optical path conversion mirror structure with high mirror angle accuracy and a method for manufacturing the same.

  In order to achieve the above-mentioned object, the present inventors analyzed the scattering phenomenon of the evaporated substance in detail, and designed the mirror surface direction at each position in the substrate appropriately using a predetermined mathematical formula, thereby performing the oblique deposition process. It has been found that the angle error occurring in can be corrected, and that a desired mirror angle can be obtained at any position in the plane.

  That is, in order to achieve the above object, a planar optical circuit of the present invention includes an optical waveguide comprising a core and a clad on a flat substrate, a first end surface intersecting the core of the optical waveguide, and the first end surface. A groove having an opposing second end face and formed deeper than the core; and provided in contact with the second end face in the groove to guide output light from the optical waveguide to the upper side of the substrate And / or a planar optical circuit comprising N (N is an integer of at least 2) optical path conversion mirrors for guiding input light from above the substrate to the optical waveguide, wherein each of the optical path conversion mirrors includes: A substantially triangular shape having a first side in contact with the second end surface, a second side occupying a partial region of the bottom surface of the groove, and a third side constituting a surface inclined with respect to the substrate A reflecting material support layer formed in a cross section, and the third of the reflecting material support layer A reflecting material laid on the surface of the inclined surface of the side, and the second region when the groove is viewed from a predetermined fixed point obliquely above the substrate in the partial region of the bottom surface of the groove. In an xyz rectangular coordinate system that is defined as a region that is the shadow of the end face, and that the surface of the substrate is the xy plane, and the fixed point is included in the yz plane, between the origin of the coordinate system and the fixed point When the distance is constant D and the angle between the line segment connecting the fixed point and the origin and the z axis is constant θ, the i-th (i is 1 to N) where x and y coordinates (xi, yi) are set. ) With respect to a predetermined angle δi formed by the inclined surface of the optical path conversion mirror and the substrate surface, an angle βi formed by the second end surface of the i-th optical path conversion mirror and the x axis, that is, An angle βi representing the mirror surface direction in the xy plane is expressed by the following formulas 1 and 2. It is set to satisfy the relationship.

  According to another aspect of the planar optical circuit of the present invention, the partial region of the bottom surface of the groove becomes a ridge of the first end surface when the groove is viewed from a predetermined point obliquely above the substrate. The region is defined as an area excluding a portion, the depth of the groove is T, the distance between the first end surface and the second end surface is G, the surface of the substrate is an xy plane, and the substrate is obliquely above In an xyz rectangular coordinate system including the fixed point of γ in the yz plane, the distance between the origin of the coordinate system and the fixed point is a constant D, and the line segment connecting the fixed point and the origin is the z-axis. When the angle is a constant θ, a predetermined angle formed by the inclined surface of the optical path conversion mirror arranged at the i-th (i is 1 to N) with x, y coordinates (xi, yi) and the substrate surface With respect to δ2i, an angle βi formed by the second end face of the i-th optical path conversion mirror and the x-axis, that is, xy Angle βi representing the mirror surface direction of the, formula 3 below, Equation 4, characterized in that it is set to satisfy the relation represented by Equation 5.

  Here, the planar optical circuit has a plurality of identical unit optical circuit patterns arranged in the substrate surface, and the unit optical circuit pattern includes at least one or more optical path conversion mirrors, and the unit optical circuit. In the x′-y ′ coordinate system provided on the pattern, an angle formed by the second end face of the groove of the optical path conversion mirror and the x ′ axis is β ″, and the x ′ axis of the unit optical circuit pattern is When the angle between the x-axis and the x-axis in the xyz rectangular coordinate system is β ′, the sum of β and β ″ (β ′ + β ″) is expressed as the above-mentioned βi, the above-mentioned Formula 1 and Formula 2, Alternatively, the unit optical circuit patterns may be arranged so as to satisfy the formula 3, the formula 4, and the formula 5.

  Further, the predetermined fixed point is a position of an evaporation source used in an oblique evaporation process for forming the optical path conversion mirror or an exposure source position used in an oblique exposure process for forming the optical path conversion mirror. Can be a feature.

  In order to achieve the above object, a method for producing a planar optical circuit according to the present invention includes an optical waveguide composed of a core and a clad on a flat substrate, and an optical path for converting the optical path of the optical waveguide upward in the substrate. In a method for manufacturing a planar optical circuit in which N (N is an integer of at least 2) optical path conversion mirrors are formed, a first crossing the core of the waveguide at a predetermined site in the plane of the planar optical circuit. A groove forming step of forming a groove having a rectangular cross section deeper than the clad surface to the core, and a groove forming step having a second end face opposite to the first end face; An oblique deposition step of depositing a specific material from the deposition source located at a fixed point obliquely above the second end face toward the groove; and then, when the groove is viewed from the fixed point, the second end face Partial area of the bottom of the groove to be shaded A liquid curable substance is filled in a corner portion formed of the second end face, and thereafter, the liquid curable substance is cured to form an inclined surface, and then a reflecting material is attached on the inclined surface to form the optical path. A mirror forming step of forming a conversion mirror, and in the oblique vapor deposition step, the coordinates in the xyz rectangular coordinate system including the surface of the substrate as an xy plane and the fixed point in the yz plane The distance between the origin of the system and the fixed point is a constant D, the angle between the line connecting the fixed point and the origin and the z axis is the constant θ, and the i th coordinate is the x, y coordinate (xi, yi) The second end face of the i-th optical path conversion mirror is an x-axis with respect to a predetermined angle δi formed by the inclined surface of the optical path conversion mirror disposed at (i is 1 to N) with the substrate surface. Angle βi, that is, angle βi representing the mirror surface direction in the xy plane Is set in advance so as to satisfy the relationship represented by the above-described formulas 1 and 2, and the oblique angles of the N optical path conversion mirrors at a time with the same deposition distance D and the same deposition angle θ. Vapor deposition is performed.

  According to another aspect of the method for producing a planar optical circuit of the present invention, a predetermined substance is vapor-deposited toward the groove from a vapor deposition source located at a fixed point obliquely above the first end face with respect to the groove. An oblique deposition step, and then, at a corner portion formed by a partial region of the bottom surface of the groove and the second end surface, excluding a portion that is behind the first end surface when the groove is viewed from the fixed point Filling a liquid curable material, and then curing the liquid curable material to form an inclined surface, and then forming a mirror on the inclined surface by attaching a reflective material on the inclined surface. In the oblique deposition step, the depth of the groove is T, the distance between the first end face and the second end face is G, the surface of the substrate is an xy plane, and the fixed point is obliquely above the substrate. In the xyz rectangular coordinate system including the yz plane and the origin of the coordinate system When the distance between the points is a constant D and the angle between the line connecting the fixed point and the origin and the z axis is a constant θ, the i-th (i is the x, y coordinate (xi, yi)) 1 to N), the angle formed by the second end surface of the i-th optical path conversion mirror and the x-axis with respect to a predetermined angle δ2i formed by the inclined surface of the optical path conversion mirror disposed at 1 to N). βi, that is, the angle βi representing the mirror surface direction in the xy plane is set in advance so as to satisfy the relationship expressed by the above-described Equation 3, Equation 4, and Equation 5, and is the same as the same deposition distance D The N light path conversion mirrors are obliquely vapor-deposited collectively at the vapor-deposition angle θ.

  Here, an exposure light source is arranged instead of the vapor deposition source at the position of the fixed point, and exposure to the groove from the exposure light source makes it possible to fill the liquid curable substance in a partial region of the groove bottom surface. The oblique exposure step is used instead of the oblique vapor deposition step, and in the oblique exposure step, the βi is previously set so as to satisfy the formula 1 and the formula 2, or the formula 3, the formula 4, and the formula 5. It can be characterized by being set.

  The planar optical circuit includes a plurality of identical unit optical circuit patterns arranged on the substrate surface, and the unit optical circuit pattern includes at least one optical path conversion mirror, and the unit optical circuit pattern. In the x′-y ′ coordinate system provided above, an angle formed by the second end face of the groove of the optical path conversion mirror and the x ′ axis is β ″, and the x ′ axis of the unit optical circuit pattern and the unit When the angle between the x-axis and the x-axis in the xyz rectangular coordinate system is β ′, the sum of β and β ″ (β ′ + β ″) is the βi, and The arrangement of the unit optical circuit patterns may be set so as to satisfy the formula 3, the formula 4, and the formula 5.

Further, in the oblique vapor deposition step or the oblique exposure step, a shielding material is provided between the substrate and the vapor deposition source, or between the substrate and the exposure light source, and the shielding material has an opening in part, Through the opening, only the portions of the plurality of optical path conversion mirrors in which the mirror direction βi in the substrate plane is set with respect to the same D and θ are exposed to the vapor deposition source or the exposure light source, and other portions Can be characterized by masking.
Further, the opening of the shielding material may be slit-shaped.

As described above, according to the present invention, in a planar optical circuit with a micromirror, which has a plurality of optical path conversion mirrors in a substrate, and these mirrors are created using an oblique deposition process, the evaporation material is scattered during oblique deposition. In consideration of the phenomenon, based on the positional relationship between the deposition source, the substrate, and each mirror, each mirror creation position and mirror surface direction are expressed by the above formula so that a uniform predetermined mirror angle can be obtained within the substrate. Since it is set by using 1 or 2 or the above-mentioned mathematical formulas 3, 4 and 5, the following effects can be obtained.
(1) A plurality of mirrors arranged at arbitrary positions on a large-area substrate can be set at desired mirror angles, and high angular accuracy can be realized.
(2) With respect to the circuit or substrate for which the angle βi representing the mirror surface direction is designed, the same deposition angle θ and the same deposition distance D that are predetermined at the stage of designing the substrate or substrate (that is, in one deposition) In this case, a plurality of mirrors can be obliquely vapor-deposited at a time, thereby greatly reducing the number of processes.
(3) In addition to setting the individual mirror surface direction with respect to the optical circuit, the optical circuit itself can be inclined with respect to the substrate, so that the same optical circuit can be laid out on the substrate. This also simplifies design and inspection.
(4) By using a shielding material having an opening in the oblique deposition process, a more flexible mirror design is possible. In particular, the use of a slit-like opening often simplifies the design and increases the density of the optical circuit arrangement. It becomes effective for conversion.
(5) When oblique exposure is used instead of oblique vapor deposition, the same effect can be obtained and the same effect can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Basic configuration)
First, the basic configuration of the present invention common to the embodiments of the present invention will be described. Here, for the sake of brevity, only the basic points will be described, and other additional inventions and details will be described together with specific examples in individual embodiments to be described later.

  2 and 3 are schematic diagrams for explaining a coordinate system used in the present invention. 2A is a perspective view showing the entire system including the vapor deposition source 21 and the substrate 22 at the time of oblique vapor deposition, and FIG. 2B is a projection view on the xy plane. 3A is a perspective view showing the relationship between a mirror (not shown) disposed at a position (x, y) in the substrate surface and the vapor deposition source 21, and FIG. 3B is a diagram (a) in FIG. Is a cross-sectional view taken along a plane S including the vapor deposition source 21 and the mirror position (x, y) and perpendicular to the substrate.

  The coordinate system is an xyz rectangular coordinate system including the substrate 22 in the xy plane and the deposition source 21 in the yz plane, and the positive and negative directions are as illustrated. For simplicity, the coordinate origin O is set at the center of the substrate 22. In the figure, x and y are the x-coordinate and y-coordinate on the substrate, D is the distance between the vapor deposition source 21 and the coordinate origin, and θ is the angle formed by the line segment connecting the vapor deposition source 21 and the coordinate origin O with the z-axis. It corresponds to the oblique deposition angle. α is an angle formed by a straight line connecting each mirror and the evaporation source 21 with the substrate surface, and β is an angle formed by the second end surface of each mirror, that is, the end surface facing the waveguide end in the mirror groove, with the x axis. , Represents the mirror surface direction in the xy plane. γ is an angle between the projection of the straight line connecting the vapor deposition source 21 and each mirror onto the xy plane and the second end face of the mirror, and δ is the second end face of the mirror and the substrate surface 22. The projection of a straight line connecting the vapor deposition source and the 21 mirror onto a plane that intersects perpendicularly is the angle formed by the substrate surface and corresponds to the mirror angle. In the following description, the suffix i is used to mean the number assigned to each mirror.

  When the coordinate system is set as described above, the mirror angle δi in the i-th mirror can be expressed as follows.

here,

Using the relationship

Can be organized. Γi satisfies the following relationship.

  Equations 1 and 2 represent individual mirror angles δi. Conversely, in order to obtain a desired mirror angle δi, mirror surfaces arranged at mirror coordinates (xi, yi) so as to satisfy these relationships. The direction βi and the deposition source positions D and θ may be set. However, if the deposition source positions are individually set for a plurality of mirrors, only one mirror can be formed in one deposition process, so that many mirrors can be deposited in one deposition process set to the same D and θ as much as possible. It is important to apply treatment. For that purpose, the mirror surface direction βi may be appropriately designed in the substrate.

  In order to calculate a specific value, taking the arctangent of the above relational expression, it can be expressed as the following Expression 9 and Expression 10. Note that the inverse trigonometric function is a multivalent function, but here it takes the main value for convenience of calculation, and the angle range handled in the calculation is set to 0 to π and γ to −π to π. In addition, the cases are expressed as follows.

  FIGS. 4A and 4B show the mirror angle distribution obtained from the above mathematical expressions 9 and 10. FIG. Each is a contour map and a three-dimensional plot, and shows the distribution of mirror angles that occurs when mirrors of the same design, that is, mirrors with the same mirror surface direction β are arranged on a 10 cm square substrate without using the present invention. As described in the conventional example, the vapor deposition angle θ is 54.7 ° (equivalent to ψ = 35.3 ° in the conventional example), and the mirror surface direction β is 45 ° (equivalent to χ = 45 ° in the conventional example). It was. The distance D of the vapor deposition source was 50 cm. As can be seen from the figure, when the present invention is not used, an angle error of about ± 7 ° at the maximum occurs with a 4-inch substrate centering on a mirror angle of 45 degrees. At this time, there is a feature that no distribution is generated in the β direction, and a distribution that is uniformly inclined in the direction orthogonal thereto is generated.

  On the other hand, according to the present invention, an optical circuit with high mirror angle accuracy is obtained by appropriately designing the mirror surface direction β for each mirror in consideration of the positional relationship between the vapor deposition source, the substrate, and the individual mirrors. Can be provided. That is, βi may be determined for the desired δi from the above relational expressions 1 and 2.

  In order to show a specific example, if it arranges about mirror surface direction (beta), it can represent like the following Numerical formulas 11 and 12. Note that there are two solutions β1 and β2 for the optimal βi when a desired δi is given. Therefore, in this case, the range of β to be handled is −π / 2 to π / 2, and the inverse trigonometric function takes the main value, and each of the two solutions is expressed by dividing into cases.

Or

  (A) and (b) of FIG. 5 show the optimal set value of β calculated by using the above-mentioned equation 11 on a 10 cm square substrate, and FIG. 5 (a) is a contour map. FIG. 5B is a three-dimensional plot. Similarly to FIG. 4 described above, the deposition source distance D was 50 cm, and the deposition angle θ was 54.7 °. From FIGS. 5A and 5B, it can be seen that the mirror surface direction in this case may be rotated about ± 10 ° at the end of the 4-inch substrate around 45 °. FIG. 5C shows the distribution of the mirror angle δ in such a case. From FIG. 5C, it can be seen that by applying the present invention as described above and performing appropriate mirror design and vapor deposition process design, a 45-degree mirror can be formed with high precision in the substrate.

  Furthermore, the case where Formula 12 is used is similarly shown to (a)-(c) of FIG. What is different from FIG. 5 is that the direction of distribution differs by 90 ° from that set around −45 degrees. Thus, given a desired δ, two solutions differing by 90 ° are obtained. Hereinafter, unless otherwise specified, description will be made using only Expression 11. However, it should be noted that a different β can be set.

  In the examples of FIGS. 5 and 6, for the sake of simplicity, the case where all the mirror angles in the substrate are 45 °, that is, the optical path is changed vertically, is shown. By setting the angle δi and determining the optimum mirror surface direction βi for each, it is possible to accurately give an arbitrary mirror angle to the mirror disposed at an arbitrary position in the substrate surface.

  Heretofore, only the basic contents of the present invention have been described. The greatest feature of the present invention is that the mirror surface direction and the deposition source positions D and θ are appropriately designed at each position in the substrate in consideration of the scattering phenomenon of the evaporated substance in the oblique deposition process. As a result, even when a plurality of optical path conversion mirrors are arranged on the substrate, the mirror angle can be set with high accuracy without increasing the number of steps.

(First embodiment)
Next, a specific example of the embodiment of the present invention will be described in detail. In all of the following embodiments, a description will be given on the assumption that a quartz-based planar optical circuit is used as an optical waveguide and a PD element is installed on the upper portion of the optical waveguide. Therefore, the present invention is not limited to this. Further, the structure of the mirror groove and the resin supply groove, and the resin supply method are the same as those in FIG. 1 mainly described in Patent Documents 2 and 3, and detailed description thereof is omitted here. This is because the gist of the present invention is the arrangement of the mirror surface and the manufacturing method thereof, and is not limited with respect to the structure of the mirror groove and the resin supply groove, and the resin supply method.

FIG. 7 is a plan view showing the configuration of the planar optical circuit according to the first embodiment of the present invention. Using a Si substrate 71 as a substrate, a quartz-based optical waveguide circuit made of glass containing SiO ₂ as a main component is manufactured using a flame deposition method and a dry etching method. The relative refractive index difference between the core and the clad is 0.5%, the thickness of the lower clad is 20 μm, the waveguide core is 7 μm square, and the total thickness including the upper and lower clads is 40 μm.

  This optical circuit is composed of 16 optical waveguides 72 and 16 optical path conversion mirrors 1 to 16 provided at each end thereof, and the optical path conversion mirrors 1 to 16 are arranged in 4 rows and 4 columns at intervals of 5 mm. It is. This planar optical circuit can be used as a 16-channel PD array component by mounting a planar PD built in a 4 mm diameter CAN package on the top of each mirror 1-16.

  The structure of each mirror part 1-16 is the same as that of the prior art example shown in FIG. That is, a mirror groove 73 having a width W of 190 μm and a depth of 40 μm reaching the Si substrate 71 as shown in FIG. 1 is formed at the end of the waveguide, and a resin having a width of 37 μm connected to the mirror groove 73 and extending to the optical circuit end. The supply groove 74 is formed by dry etching. At the bottom of the mirror groove 73, a region having a good wetting property with respect to the mirror-forming resin is provided in contact with the second end surface facing the first end surface including the waveguide end. The supplied mirror-forming resin forms an inclined surface between the second end surface and the region having good wetting on the bottom of the groove. Furthermore, gold is vapor-deposited on the surface to constitute the optical path conversion mirrors 1-16. Each of the optical path conversion mirrors 1 to 16 has a mirror angle of approximately 45 degrees, and the output light from the waveguide 72 is emitted vertically upward with respect to the substrate 71 by the optical path conversion mirrors 1 to 16. Yes.

  Such a planar optical circuit can be manufactured as follows. First, a lower cladding layer is deposited on the silicon substrate 71 by a flame deposition method, then a core layer is deposited on the lower cladding layer, and a waveguide 72 is formed by reactive ion etching as shown in FIG. The formed waveguide 72 is buried with the upper clad layer. Subsequently, mirror grooves 73 and resin supply grooves 74 are formed at 16 waveguide end portions by reactive ion etching.

  As described in the conventional example, if such a mirror groove 73 and a resin supply groove 74 are formed, the optical path conversion mirror 1 is formed at the opposite portion of the optical waveguide end by a method similar to the method described in Patent Document 3. ~ 16 can be formed. That is, as already described with reference to FIG. 1, the mirror groove bottom is controlled by surface treatment and oblique deposition, and then a liquid cured resin is supplied to form a slope, and gold is deposited on the top surface of the slope. Then, the optical path conversion mirrors 1 to 16 are obtained.

  In the present embodiment, the first feature unique to the present invention is that the mirror surface directions of the 16 mirrors 1 to 16 are not the same, and are designed to have appropriate values. FIG. 7 shows together the coordinate system used for the design and an enlarged view showing the mirror surface direction β of mirror number 1 and mirror number 4. Further, detailed design values of each mirror surface direction β are as shown in FIG. As can be seen from FIG. 8, the mirror surface direction β is set to a different value from 43.4 degrees to 46.4 degrees according to the position coordinates (x, y) of the mirror. Here, the reflection center of the light beam is taken as the position coordinate of the mirror. It is desirable that the line connecting the reflection center of the light beam and the vapor deposition source and the upper surface of the clad should be set correctly. However, the mirror groove 73 has a size of about several hundred μm, and the angular distribution in this range can be almost ignored. Even if the reflection center of the light beam is taken as the position coordinates of the mirror, no problem actually occurs.

  In addition, the second feature of the present invention is that the oblique deposition process is performed by setting the relationship between the deposition source, the substrate, and each mirror position to a predetermined setting together with the mirror design. That is, the relationship between the vapor deposition source and the substrate is set so that the xy coordinate axes in FIG. 7 are equivalent to the xy axes in FIG. D = 50 cm and θ = 54.7 °. Here, D is the distance between the vapor deposition source and the coordinate origin, and θ is the angle formed by the line segment connecting the vapor deposition source and the coordinate origin with the z axis, which corresponds to the oblique vapor deposition angle.

  As shown in FIG. 8, a mirror angle δ with an extremely high accuracy of 45 ° ± 0.03 ° can be expected by the above design and manufacturing method. Incidentally, if the mirror surface directions are all the same without applying the present invention, an angular error distribution of about 1.5 ° in the entire width is generated.

  When the actually produced planar optical circuit of the present embodiment was measured, the light emitted from the mirror was almost 90 ° with respect to the substrate, and had a good angular accuracy of ± 1 ° or less. That is, the mirror angle was 45 ° ± 0.5 ° or less.

  As described above, it is possible to realize a planar optical circuit in which a plurality of optical path conversion mirrors whose mirror angles are set with high accuracy are arranged on a substrate by a single oblique deposition process according to the present invention.

(Second Embodiment)
FIG. 9 is a plan view showing a unit optical circuit chip according to the second embodiment of the present invention. FIG. 10 shows the unit optical circuit chip 68 on a 4 inch (10.16 cm) silicon substrate. It is a top view which shows the layout of the planar optical circuit which has chip arrangement | positioning.

  As shown in FIG. 9, the 8-channel PD array circuit serving as the unit optical circuit 90 is composed of a silica-based optical waveguide, and includes eight optical waveguides 92 and eight optical path conversion mirrors 1 to 8 provided at the ends thereof. Become. The unit optical circuit 90 has a circuit size of 4 mm in length and 15 mm in width, and the optical path conversion mirrors 1 to 8 are arranged in 2 rows and 4 columns at a pitch of 2.54 mm.

  Since the structures of the mirror portions 1 to 8 are the same as those of the conventional example and the first embodiment of the present invention, detailed description thereof will be omitted, but the mirror surface direction is shown in FIG. Was set as follows. That is, as a coordinate system of the unit optical circuit, an x′-y ′ coordinate system having a midpoint of the mirror numbers 4 and 5 as the origin O is provided, and the mirror plane direction β ″ with respect to the x ′ axis is based on 45 °. Mirror numbers 1 and 8 were set to + 2.7 °, mirror numbers 2 and 7 were set to + 1.8 °, mirror numbers 3 and 6 were set to + 0.9 °, and mirror numbers 4 and 5 were set to 0 °.

The 8-channel PD array circuit set as described above was used as the unit optical circuit 90, and 68 chips were laid out on the substrate 95 as shown in FIG. That is, the angle β ′ of the x′-axis defined by each unit optical circuit with respect to the x-axis of the substrate xy coordinate with the center of the substrate 95 as the origin O is sequentially set to 7. The angles were set to 2 °, 1.5 °, -4.4 °, and −11.3 °. Therefore, the individual mirror surface direction β with respect to the x-axis of the substrate 95 is
β = β ′ + β ″
Specifically, β is a maximum of 54.9 ° and a minimum of 33.7 ° over the entire surface of the substrate. Here, all β are set so as to satisfy the above formulas 1 and 2 so as to realize a desired mirror angle of 45 ° ± 1 ° including a tolerance. Thus, by appropriately selecting the mirror surface direction in the optical circuit and the rotation angle of the optical circuit with respect to the substrate so that the mirror surface direction β on the substrate has a predetermined width, the same optical circuit is mounted on the substrate. Can be laid out.

  In the present embodiment, since the dicing saw cuts out the unit optical circuit at the time when the production of the substrate is completed, a plurality of pieces are collectively arranged in a bar shape so as to facilitate the cutting operation (FIG. 10). reference).

  The unit optical circuit manufacturing process is the same as that of the first embodiment of the present invention. Of course, here, the setting at the time of oblique deposition is as shown in FIG. 2, and the xy axis in FIG. 10 is set to coincide with the xy axis in FIG. However, the distance D between the deposition source and the coordinate origin was set to 27 cm, and the oblique deposition angle θ was set to 54.7 °.

  When the planar optical circuit of the present embodiment was actually manufactured, the mirror angle was 45 ° ± 0.5 ° in the unit optical circuit and 43 ° to 46 ° even in the entire 4-inch substrate, and sufficient setting accuracy was obtained. Obtained.

  In the present invention, the mirror surface direction is appropriately set according to the mirror position. However, when a large number of optical circuit chips having the same function are laid out on a large-area substrate, an inconvenient surface also arises. In other words, it is troublesome to redesign all the mirror surface directions for each chip, and the inspection process has a different circuit layout, which reduces work efficiency and delays finding problems. Sometimes.

  On the other hand, the feature of the present embodiment is that in addition to the setting of the individual mirror surface directions, the chip itself is rotated and arranged with respect to the substrate. It is possible to lay out a plurality of wafers on the wafer, and thereby, an extremely large practical effect is obtained that the design and inspection of the optical circuit can be greatly simplified. It is not obvious that such a design is possible. As described above, the present inventors have found that the distribution of the angle error is substantially uniform as a result of examining the phenomenon of occurrence of the angle error, and the present invention can be achieved only by utilizing this characteristic.

(Third embodiment)
FIG. 11 shows a planar optical circuit according to the third embodiment of the present invention, in which the unit optical circuit 84 chip of FIG. 9 used in the second embodiment of the present invention is laid out on a 4-inch substrate. Is shown. As shown in FIG. 11, bars (arrays) 96 in which chips are arranged in the vertical direction are arranged in order from the left of the substrate 95 to the first, second, and fifth rows. Further, the xy coordinate axes in the figure are set with the center of the substrate as the origin O as in the second embodiment of FIG.

  The feature of the present embodiment, which is different from the second embodiment of the present invention, is that the chip 90 is laid out in a grid pattern as usual without rotating the chip. Second, a shielding material described later provided with a slit-like opening during oblique deposition is used. These features and their effects are described below.

  FIG. 12 is a schematic diagram showing the settings during oblique deposition in the present embodiment. This embodiment is different from the first and second embodiments of the present invention in that a shielding material 99 having a slit-like opening 98 is provided between the substrate 95 and the vapor deposition source 97. It is. Here, the shielding material 99 is an aluminum plate having a thickness of 1 mm, and the slit opening 87 has a width of 10 mm and a length of 12 cm so that eight mirror portions of the unit optical circuit 90 in FIG. 9 can be exposed. The shielding plate 99 is placed 1 mm away from the surface of the substrate 95 in parallel with the substrate 95, and the angle βs formed by the long side direction of the slit opening 98 and the x coordinate axis is equal to the inclination of the bar 96. Set as shown in FIG.

  In this state, the oblique deposition process is performed in five steps as follows. That is, as shown in FIG. 12A, the mask (shielding plate) 99 is set so that the mirror part of the bar in the first row is exposed from the slit opening 98 with respect to the vapor deposition source 97, and the vapor deposition angle θ1. The first oblique deposition is performed.

  Next, the mask 99 is moved in parallel in the direction of the arrow in FIG. 12A so that the mirror part of the second row of bars 96 is exposed. In addition, as shown in FIG. The orientation of the substrate 95 and the mask 99 with respect to the vapor deposition source 97 is changed so that the angle becomes θ2. In this state, the second oblique deposition is performed. Thereafter, similarly to this, the mask 99 is sequentially moved in parallel from the third row to the fifth row, and the third to fifth oblique depositions are performed. At this time, the distance D between the vapor deposition source 97 and the coordinate origin is constant at 27 cm, and the substrate 95 and the mask 99 are respectively attached to a rotating shaft (not shown), and only the vapor deposition angle θ and the mask opening position are changed. The specific deposition angle θ is θ1 = 50.6 °, θ2 = 53.2 °, θ3 = 55.8 °, θ4 = 58.4 ° with respect to the bar 96 in the fifth row from the first example. , Θ5 = 61 °. The steps other than the oblique deposition are exactly the same as those described in the first and second embodiments of the present invention.

  The mirror angle of the planar optical circuit of the present embodiment actually manufactured as described above was accurately manufactured in the range of 44 ° to 46 ° over the entire surface of the substrate.

  Such high mirror angle accuracy was obtained because the angular distribution produced by oblique deposition does not occur in the direction along the mirror surface direction β, and is uniform in the direction perpendicular to this. This is because the circuit layout and the vapor deposition process are designed by applying the phenomenon described above. That is, in the present embodiment, the chips 90 are arranged in a bar shape along the direction βs that is substantially the same as the mirror surface direction β, and the oblique deposition process is performed with the bar 96 as a unit. In this way, even if the same oblique deposition process is performed collectively, the mirror angle on the bar can be made uniform. The deposition source distance D and the deposition angle θ may be determined so as to satisfy βs and Equations 1 and 2. On the other hand, since an angle distribution is generated in a direction orthogonal to the bar 96, the angles of the remaining bars 96 are shifted when the same deposition source distance D and deposition angle θ are set. Therefore, the vapor deposition angle θ is changed for each bar 96, and the vapor deposition angle θ is set so as to satisfy Equations 1 and 2 so that a desired mirror angle can be obtained in any case. Note that any of D, θ, and βs may be changed or a combination thereof may be used, but here, the resetting of θ that can be easily performed is selected simply by using a rotating shaft (not shown).

  According to the second embodiment of the present invention described above, it is possible to process a plurality of mirrors formed on the substrate in the same vapor deposition process, but on the one hand, the design in the mirror direction is limited. When a very large number of micromirrors are provided, or when high-density integration with other optical circuits is performed, it may be inconvenient. In such a case, taking into account the increase in the deposition process and the ease of design, the deposition process with different settings of D and θ may be performed a plurality of times as required, as in this embodiment.

  Such a process can be performed by providing a shielding material 99 having an opening 98 exposing only a predetermined mirror for a certain vapor deposition process between the substrate 95 and the vapor deposition source 97. At this time, the opening 98 may be a plurality of random holes, which may be used according to the case, but the shielding material 99 having the straight slit-shaped opening 98 as shown in the present embodiment is used. That is often effective. This is because, as described above, the error distribution of the mirror angle occurs in one direction in the substrate surface, and the error distribution is small in the direction orthogonal to the one direction. That is, if the slit-shaped opening 98 is provided along the direction in which the error distribution of the mirror angle is small, it is efficient because many mirrors can be processed in the same vapor deposition process. In addition, as can be seen from FIG. The optical circuit layout on the substrate 95 is simple, and a great advantage is obtained that a large number of chips can be arranged.

(Fourth embodiment)
FIG. 13 is a schematic diagram for explaining a form of an optical path conversion mirror in which the vapor deposition direction is reversed and a manufacturing method thereof according to the fourth embodiment of the present invention.

  In the first to third embodiments described above, as in the prior art, oblique deposition is performed from the end face side facing the waveguide end so that the slope forming region at the bottom of the mirror groove is shaded. (Refer to FIG. 1) On the other hand, it is possible to produce an optical path conversion mirror as shown in FIG. 1 by using an oblique deposition process in which the waveguide end side is shaded. Regarding the latter vapor deposition method, as described in Patent Document 2, a second wettability control substance having good wettability with respect to the liquid curable resin may be obliquely vapor deposited from the waveguide end side, or Further, it is possible to apply a process of obliquely depositing Cr or the like as a sacrificial layer for lift-off from the same direction, and then applying a surface treatment coat with poor wettability to the liquid cured resin and removing this by lift-off of Cr. .

  The gist of the present invention can be similarly applied even when the vapor deposition direction is reversed. That is, as shown in FIG. 13, in the groove width G, the region d2 excluding the region d1 that is shaded by the oblique deposition is smooth against the liquid cured resin, and this region d2 faces the waveguide end. Since the inclined surface with the mirror angle δ2 is formed between the wall surface and the wall surface, only this point needs to be considered in the discussion of the first to third embodiments.

  The mirror angle δ2 is determined by using the wall surface of the groove depth T and the region d2.

Can be written. In addition, the angle δ1 of the slope formed by d1 in the area that is the shadow of oblique deposition and the end face on the waveguide side is:

Because

It is. In addition, i is displayed as the meaning of the i-th mirror. Here, the angle δ1i corresponds to the mirror angle itself in the oblique deposition process from the end face facing the waveguide end that has been treated so far, and therefore, the equations 1 and 2 can be used as they are.

  As described above, Formulas 3, 4, and 5 are relationships that parameters such as the mirror surface direction βi and the mirror angle δ2i should satisfy when the vapor deposition direction is reversed. Using these mathematical formulas 3, 4, and 5, it is sufficient to design and manufacture in the same manner as in the first to third embodiments.

(Fifth embodiment)
In the first to fourth embodiments of the present invention described above, the optical path conversion mirror manufacturing method using oblique vapor deposition has been described as the method of forming the optical path conversion mirror in the region of the mirror groove bottom. However, the present invention is not limited to this.

  FIG. 14 shows a fifth embodiment of the present invention, and is a schematic view showing an example of a production process when oblique exposure is used instead of oblique vapor deposition.

  As shown in FIG. 14 (1), after forming the mirror groove 141, as shown in FIG. 14 (2), Cr 142 having a thickness of 0.1 μm is deposited on the entire surface, and a photoresist 143 is further applied.

  Thereafter, as shown in FIG. 14 (3), the UV lamp 144 is irradiated from obliquely above the substrate to expose the photoresist 143. At this time, the resist in the shaded area of the end face is not exposed.

  Thereafter, as shown in FIG. 14 (4), the developed and exposed portions are removed, and as shown in FIG. 14 (5), if Cr is removed by etching, Cr 142 is left only in a desired region. Can do.

  From here onward, the process is the same as in the case of oblique deposition. That is, if a surface treatment agent 145 is coated as shown in (5) of FIG. 14 and this coated surface treatment agent 145 is lifted off by Cr as shown in (6) of FIG. Only the pattern from which the surface treating agent 145 has been removed is completed. As shown in FIG. 14 (7), a mirror resin 147 is supplied to the mirror forming portion 146 to form a slope, and then a mirror 148 can be formed by depositing gold on the surface of the slope.

  Even when the optical path conversion mirror is formed by the method as described above, the basic concept is the same as that shown in the first to fourth embodiments of the present invention, and this embodiment is used. Thus, the mirror angle can be designed and produced with high accuracy. Further, according to the present embodiment, a special oblique vapor deposition apparatus is unnecessary, and a large area can be obtained without an exposure machine equipped with an expensive optical system that converts UV light from a light source into uniform parallel light. There is an advantage that an optical path conversion mirror can be formed on the substrate.

It is a figure which shows an example of the conventional optical path conversion mirror, (a) is the perspective view, (b) is the sectional drawing, (c) is a perspective view explaining the state at the time of the diagonal vapor deposition. It is a typical figure which shows the setting at the time of the diagonal vapor deposition in this invention, and the whole coordinate system, Comprising: (a) is the perspective view, (b) is the xy surface projection figure. In the setting and coordinate system at the time of diagonal vapor deposition in this invention, it is a schematic diagram which shows the relationship between each mirror and a vapor deposition source, Comprising: (a) is the perspective view, (b) is sectional drawing in the S surface It is. It is a figure which shows an example of the mirror angle distribution when not using this invention, Comprising: (a) is the contour map, (b) is the three-dimensional plot figure. It is a figure which shows an example of the design of mirror surface direction (beta) at the time of using Formula 11 in this invention, and mirror angle distribution (delta), (a) is the contour map of the beta, (b) is the three-dimensional plot of the beta FIG. 4C is a three-dimensional plot of the δ. It is a figure which shows an example of the design of mirror surface direction (beta) at the time of using Formula 12 in this invention, and mirror angle distribution (delta), (a) is the contour map of the beta, (b) is the three-dimensional plot of the beta FIG. 4C is a three-dimensional plot of the δ. 1A and 1B are a plan view and a partially enlarged view showing a configuration of a planar optical circuit according to a first embodiment of the present invention. It is the figure which put together an example of the concrete design value of the 1st Embodiment of this invention. It is the top view and partial enlarged view which show the structure of the unit plane optical circuit of the 2nd Embodiment of this invention. It is a top view which shows the board | substrate layout of the 2nd Embodiment of this invention. It is a top view which shows the board | substrate layout of the 3rd Embodiment of this invention. (A), (b) is a schematic diagram which shows the setting at the time of diagonal vapor deposition of the 3rd Embodiment of this invention. It is the perspective view (a) and sectional drawing (b) which show the structure of the 4th Embodiment of this invention. (1)-(7) is a schematic diagram which shows the optical path conversion mirror preparation process of the 5th Embodiment of this invention.

Explanation of symbols

1-16 Optical path conversion mirror 21 Deposition source 22 Substrate 71 Si substrate 72 Optical waveguide mirror groove 73
74 Resin supply groove 90 Unit optical circuit (chip)
92 Optical waveguide 95 Substrate 93 Mirror groove 94 Resin supply groove 96 Bar 97 Deposition source 98 Slit-shaped opening 99 Shielding material (mask)
101 Substrate 102 Core 103 Cladding 104 Optical waveguide 104A Optical waveguide end 105 Mirror groove 106 Resin supply groove 107 Slope 108 Optical path conversion mirror 109 Shaded portion (halftone dot portion) during oblique deposition
141 Mirror groove 142 Cr
143 Photoresist 144 UV lamp 145 Surface treatment agent 146 Mirror formation site 147 Mirror resin 148 Mirror

Claims (10)

An optical waveguide comprising a core and a clad, a first end surface intersecting with the core of the optical waveguide, and a second end surface facing the first end surface are formed deeper than the core on a flat substrate. A groove formed in contact with the second end face in the groove, and guides output light from the optical waveguide to the upper side of the substrate and / or guides input light from the upper side of the substrate to the optical waveguide. A planar optical circuit including N optical path conversion mirrors (N is an integer of at least 2) for
Each of the optical path conversion mirrors includes a first side in contact with the second end surface, a second side that occupies a partial region of the bottom surface of the groove, and a third surface that is inclined with respect to the substrate. A reflecting material support layer formed in a substantially triangular cross section having sides, and a reflecting material laid on the surface of the inclined surface of the third side of the reflecting material support layer,
The partial region of the bottom surface of the groove is defined as a region that is behind the second end surface when the groove is viewed from a predetermined fixed point obliquely above the substrate, and the surface of the substrate is defined as xy And a distance between the origin of the coordinate system and the fixed point is constant D in an xyz rectangular coordinate system including the fixed point in the yz plane, and a line segment connecting the fixed point and the origin is z When the angle made with the axis is a constant θ,
With respect to a predetermined angle δi that the inclined surface of the optical path conversion mirror arranged at the i-th (i is 1 to N) having x, y coordinates (xi, yi) and the substrate surface, the i-th The angle βi formed by the second end face of the optical path conversion mirror and the x-axis, that is, the angle βi representing the mirror surface direction in the xy plane, is set so as to satisfy the relationship represented by the following expressions 1 and 2. Planar optical circuit characterized by being made.
An optical waveguide comprising a core and a clad on a flat substrate, a first end face intersecting with the core of the optical waveguide, and a second end face facing the first end face and substantially parallel to the first end face. A groove formed deeply and in contact with the second end face in the groove to guide output light from the optical waveguide to the upper side of the substrate and / or input light from the upper side of the substrate. In a planar optical circuit including N (N is an integer of at least 2) optical path conversion mirrors for guiding to a waveguide,
Each of the optical path conversion mirrors includes a first side in contact with the second end surface, a second side that occupies a partial region of the bottom surface of the groove, and a third surface that is inclined with respect to the substrate. A reflecting material support layer formed in a substantially triangular cross section having sides, and a reflecting material laid on the surface of the inclined surface of the third side of the reflecting material support layer,
The partial region of the bottom surface of the groove is defined as a region excluding a portion that becomes a ridge of the first end surface when the groove is viewed from a predetermined point obliquely above the substrate, and the depth of the groove X, z, which includes a fixed point on the diagonally upper side of the substrate in the yz plane, and the distance between the first end surface and the second end surface is G, the surface of the substrate is the xy plane. In a rectangular coordinate system, when the distance between the origin of the coordinate system and the fixed point is a constant D, and the angle between the line segment connecting the fixed point and the origin to the z axis is a constant θ,
With respect to a predetermined angle δ2i that the inclined surface of the optical path conversion mirror arranged at the i-th (i is 1 to N) having x, y coordinates (xi, yi) and the substrate surface, the i-th An angle βi formed by the second end surface of the optical path conversion mirror with the x axis, that is, an angle βi representing the mirror surface direction in the xy plane satisfies the relationships represented by the following formulas 3, 4, and 5. A planar optical circuit characterized by being set as follows.
The planar optical circuit has a plurality of identical unit optical circuit patterns arranged on the substrate surface,
The unit optical circuit pattern includes at least one optical path conversion mirror,
In the x′-y ′ coordinate system provided on the unit optical circuit pattern, an angle formed by the second end face of the groove of the optical path conversion mirror and the x ′ axis is β ″, and the unit optical circuit pattern When the angle between the x ′ axis and the x axis in the xyz rectangular coordinate system is β ′,
The unit optical circuit patterns are set such that the sum (β ′ + β ″) of β and β ″ satisfies the formula 1 and the formula 2, or the formula 3, the formula 4, and the formula 5 as the βi. The planar optical circuit according to claim 1, wherein the planar optical circuit is arranged.   The predetermined fixed point is a position of an evaporation source used in an oblique evaporation process for forming the optical path conversion mirror or an exposure source position used in an oblique exposure process for forming the optical path conversion mirror, The planar optical circuit according to claim 1. An optical waveguide composed of a core and a clad and N optical path conversion mirrors (N is an integer of at least 2) for converting the optical path of the optical waveguide in the upward direction of the substrate were formed on a flat substrate. In a method for producing a planar optical circuit,
A first end face that intersects the core of the waveguide and a second end face that faces the first end face at a predetermined portion in the plane of the planar optical circuit; and from the cladding surface to the core. A groove forming step for forming a deep rectangular cross-section groove;
Next, an oblique deposition step of depositing a specific substance toward the groove from an evaporation source located at a fixed point obliquely above the second end face with respect to the groove;
Next, when the groove is viewed from the fixed point, a liquid curable substance is filled into a corner portion formed by a partial region of the bottom surface of the groove and the second end surface which is behind the second end surface, and thereafter Forming a tilted surface by curing the liquid curable material, and then forming a light path conversion mirror by attaching a reflective material on the tilted surface,
In the oblique vapor deposition step, the surface of the substrate is the xy plane, and the vapor deposition distance between the origin of the coordinate system and the fixed point is the same in an xyz rectangular coordinate system including the fixed point in the yz plane. D, and the vapor deposition angle formed by the line connecting the fixed point and the origin to the z axis is the same θ, and is arranged at the i-th (i is 1 to N) with x, y coordinates (xi, yi). With respect to a predetermined angle δi formed by the inclined surface of the optical path conversion mirror and the substrate surface, an angle βi formed by the second end surface of the i-th optical path conversion mirror and the x axis, that is, in an xy plane The angle βi representing the mirror surface direction is set in advance so as to satisfy the relationship represented by the following formulas 1 and 2, and N at the same time with the same deposition distance D and the same deposition angle θ. The planar optical circuit is characterized in that the optical path conversion mirror is obliquely deposited. Manufacturing method.
An optical waveguide composed of a core and a clad on a flat substrate and N optical path conversion mirrors (N is an integer of at least 2) for converting the optical path of the optical waveguide in the upward direction of the substrate were formed. In a method for producing a planar optical circuit,
A first end face that intersects the core of the waveguide and a second end face that faces the first end face at a predetermined portion in the plane of the planar optical circuit; and from the cladding surface to the core. A groove forming step for forming a deep rectangular cross-section groove;
Next, an oblique deposition step of depositing a predetermined substance toward the groove from a deposition source located at an obliquely upper fixed point on the first end face side with respect to the groove;
Then, when the groove is seen from the fixed point, a liquid curable substance is filled in a corner portion formed by a partial region of the bottom surface of the groove and a portion of the second end surface excluding a portion that is shaded by the first end surface. Thereafter, the liquid curable material is cured to form an inclined surface, and then a reflecting material is attached on the inclined surface to form the optical path conversion mirror,
In the oblique deposition step, the depth of the groove is T, the distance between the first end face and the second end face is G, the surface of the substrate is the xy plane, and the fixed point obliquely above the substrate is y. -In the xyz rectangular coordinate system included in the -z plane, the distance between the origin of the coordinate system and the fixed point is a constant D, and the angle between the line segment connecting the fixed point and the origin to the z axis is constant. With respect to a predetermined angle δ2i formed by the inclined surface of the optical path conversion mirror disposed at the i-th (i is 1 to N) having x, y coordinates (xi, yi) and the substrate surface, θ An angle βi formed by the second end face of the i-th optical path conversion mirror and the x-axis, that is, an angle βi representing the mirror surface direction in the xy plane is expressed by the following Expression 3, Expression 4, and Expression 5. Is set in advance so as to satisfy the relationship, and the same deposition distance D and the same deposition angle θ. A method for producing a planar optical circuit, wherein oblique deposition of N optical path conversion mirrors is performed collectively.
  An oblique exposure that allows an exposure light source to be disposed in place of the vapor deposition source at the fixed point, and allows exposure to the groove from the exposure light source so that a partial region of the groove bottom can be filled with the liquid curable substance. The process is used instead of the oblique vapor deposition process, and in the oblique exposure process, the βi is set in advance so as to satisfy the expression 1 and the expression 2, or the expression 3, the expression 4, and the expression 5. The method for producing a planar optical circuit according to claim 5 or 6, wherein: The planar optical circuit has a plurality of identical unit optical circuit patterns arranged on the substrate surface,
The unit optical circuit pattern includes at least one optical path conversion mirror,
In the x′-y ′ coordinate system provided on the unit optical circuit pattern, an angle formed by the second end face of the groove of the optical path conversion mirror and the x ′ axis is β ″, and the unit optical circuit pattern When the angle between the x ′ axis and the x axis in the xyz rectangular coordinate system is β ′,
The unit optical circuit patterns are set such that the sum (β ′ + β ″) of β and β ″ satisfies the formula 1 and the formula 2, or the formula 3, the formula 4, and the formula 5 as the βi. The method for manufacturing a planar optical circuit according to claim 5, wherein the arrangement of the planar optical circuit is set. In the oblique vapor deposition step or the oblique exposure step, a shielding material is provided between the substrate and the vapor deposition source, or between the substrate and the exposure light source,
The shielding material has an opening in a part, and through the opening, only the portions of the plurality of optical path conversion mirrors in which the mirror direction βi in the substrate plane is set with respect to the same D and θ are the deposition source or 9. The method for producing a planar optical circuit according to claim 5, wherein the planar light circuit is exposed to the exposure light source and masks other portions.   The method for manufacturing a planar optical circuit according to claim 9, wherein the opening of the shielding material has a slit shape.