JP4391770B2 - Optical switch and optical deflection element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical switch and an optical switch. deflection It relates to an element.
[0002]
[Prior art]
Optical signals are suitable for high-speed and large-capacity signal transmission, and signal transmission using optical signals has already been put into practical use in long-distance backbone communication systems. In such a system, an optical switch that switches an optical signal transmission path is essential. As a method for realizing this optical switch, a plurality of methods have been proposed. For example, an optical switch using an optical deflection element can be expected to perform a high-speed switching operation. The optical deflection element uses a crystal having an electro-optic effect whose refractive index changes with an electric field as an optical waveguide, and forms prism-like electrodes on the upper and lower sides of the optical waveguide and applies a voltage to propagate through the optical waveguide. To deflect light.
[0003]
FIG. 9 is a diagram showing a configuration example of a part of a conventional optical switch using an optical deflection element. FIG. 9A is a plan view of a part of the optical switch, and FIG. 9B is a cross-sectional view taken along line CC in FIG. 9A.
[0004]
FIG. 9 shows, as an example, components on the input side of an optical switch 200 having eight input channels. A light incident side waveguide section 220, a collimating section 230, and a light deflection element section 240 are provided on the input side of the optical switch 200, and a common optical waveguide 250 is provided on the output side thereof. In the optical switch 200, for example, the light incident side waveguide section 220, the collimating section 230, and the common optical waveguide 250 are integrally provided on the common substrate 201, and the light deflection element section 240 is further mounted on the substrate 201. Is done.
[0005]
In the light incident side waveguide section 220, a plurality of light incident side waveguides 221 corresponding to the respective input channels are formed. For example, an optical fiber or the like is connected to an incident end of each light incident side waveguide 221, and an optical signal is incident on each of the incident ends.
[0006]
A plurality of collimating lenses 231 corresponding to the light incident side waveguides 221 are formed in the collimating unit 230. Each collimator lens 231 includes a waveguide layer (two-dimensional lens) 232 that is a slab type optical waveguide to which an optical signal from each light incident side waveguide 221 is input, and a medium having a refractive index different from that of the waveguide layer 232. The gap filling layer 233 is filled. In the gap filling layer 233, for example, in order to prevent diffusion of light in the air gap region penetrating the core layer and the upper and lower cladding layers of the waveguide layer 232 (that is, Fresnel reflection due to a difference between the refractive index of the lens material and air) Filled with fluororesin or the like (to reduce loss). Then, the end surface of the waveguide layer 232 with respect to the gap filling layer 233 is formed into, for example, a cylindrical surface to form a lens curved surface 234 of the two-dimensional lens. With such a structure, in each collimator lens 231, an optical signal propagating radially from each light incident side waveguide 221 in the waveguide layer 232 is converted into parallel light on the lens curved surface 234, and the optical deflection element The light is emitted to the unit 240.
[0007]
The light deflection element unit 240 is provided with a light deflection element 241 corresponding to the input channel. In each optical deflection element 241, a voltage is applied to a slab type optical waveguide 242 made of a material having an electro-optic effect by a prism type electrode 243 that is a lower electrode and a conductive substrate 244 that is an upper electrode. Thus, the refractive index in the slab type optical waveguide 242 changes, and the propagation direction of the incident optical signal is changed.
[0008]
The common optical waveguide 250 is a slab type optical waveguide through which all optical signals whose connections are switched between the respective channels on the input / output side propagate in common, and propagates the optical signal that has passed through the optical deflection element section 240 to the output side. .
[0009]
Note that, on the output side of the common optical waveguide 250, the same components as those of the light incident side waveguide section 220, the collimating section 230, and the light deflection element section 240 shown in FIG. Is provided. That is, on the output side of the common optical waveguide 250, a plurality of light deflection elements, condensing lenses, and light output side waveguides are provided corresponding to the number of output channels, respectively, an output side light deflection element part, a light condensing part A light exit side waveguide is provided. Then, the optical signal propagated through the common optical waveguide 250 is incident on the corresponding condensing lens when the propagation direction is changed by the optical deflector on the output side, and the corresponding light output side waveguide is transmitted by the condensing lens. Is output from the light output side waveguide to the outside.
[0010]
With such a configuration, in the optical switch 200, the propagation direction of the input optical signal in the common optical waveguide 250 is controlled by controlling the voltage applied to the light deflection elements on the incident side and the emission side of the common optical waveguide 250. Changing, the connection between any input channel and output channel is switched.
[0011]
As a technique related to the present invention, Patent Document 1 discloses a structure in which an optical waveguide is wrapped with a light absorption layer. Patent Document 2 discloses a structure in which a light absorbing material is provided in an optical module.
[0012]
[Patent Document 1]
JP 2000-28837 A
[Patent Document 2]
JP 2000-75155 A
[0013]
[Problems to be solved by the invention]
By the way, in the optical switch 200 described above, in the collimating unit 230, the light propagated from each light incident side waveguide 221 through the waveguide layer 232 is collimated by the lens curved surface 234. However, the light emitted from the light incident side waveguide 221 spreads radially in the waveguide 232 and propagates. For this reason, in the waveguide layer 232, most of the incident light propagates through a region where collimation is possible on the lens curved surface 234, but part of the light actually propagates outside this region.
[0014]
Thus, light outside the region where collimation is possible propagates to the vicinity of the end of each lens curved surface 234 or to the adjacent lens curved surface 234, and stray light may be generated at these locations. For example, the light propagating through the end of the lens curved surface 234 is diffused in each direction in this portion, and the light propagated to the adjacent lens curved surface 234 is emitted from the lens curved surface 234 in a direction different from the original light. End up.
[0015]
In particular, in the case of the optical switch 200 having a plurality of input channels, the collimating unit 230 has a structure in which the lens curved surfaces 234 of the two-dimensional lenses corresponding to the respective input channels are arranged side by side. A major problem is that crosstalk occurs due to light propagating to 234.
[0016]
In addition, in the condensing lens of the condensing unit provided on the exit side of the common optical waveguide 250, a part of the light emitted from the preceding stage light deflection element is not imaged on the exit side light exit side waveguide. May cause stray light and crosstalk. In this case, a part of light may enter the cladding region surrounding each light emission side waveguide, and the optical signal propagating through the light emission side waveguide may be adversely affected.
[0017]
On the other hand, although the light deflection element unit 240 is manufactured separately from the light incident side waveguide unit 220, the collimator unit 230, and the common optical waveguide 250, there is a possibility that the light deflection element unit 240 may be warped by heat at the time of manufacturing. is there. In this case, when the optical deflection element unit 240 is mounted on the substrate 201, it becomes difficult to accurately align the optical deflection element unit 240 and the collimator unit 230 and the like, resulting in a loss of an optical signal passing through each channel. End up. Furthermore, even when the light deflection element unit 240 is used alone, there is a possibility that the incident optical signal may not be emitted in a desired direction due to the warp of the substrate.
[0019]
The present invention has been made in view of such problems, To provide an optical switch capable of preventing the occurrence of crosstalk between channels and improving the quality of a propagating optical signal. With the goal .
[0020]
Furthermore, another object of the present invention is to provide an optical deflection element that can reduce the warpage of the substrate that occurs during fabrication, and an optical switch that includes the deflection element.
[0023]
[Means for Solving the Problems]
In the present invention, in the optical switch that switches the propagation path of the optical signal, a plurality of light incident side waveguides that receive the input of the optical signal from the outside, a plurality of light emission side waveguides that output the optical signal to the outside, A plurality of collimating lenses that individually collimate the optical signals that have passed through the respective light incident side waveguides, and the propagation directions of the optical signals that have passed through the respective collimating lenses are individually switched, and the first light absorbers are respectively provided. A plurality of input-side optical deflection elements arranged in common, a common optical waveguide through which each optical signal that has passed through each of the optical deflection elements propagates in common, and a propagation direction of the optical signal that has passed through the common optical waveguide individually Switching, a plurality of output-side light deflection elements respectively disposed via the second light absorber, and a plurality of light signals that have passed through each of the light deflection elements are individually imaged on the light-emitting side waveguides. With condensing lens The input side optical deflection element and the output side optical deflection element have a core layer, and the first optical absorber and the second optical absorber penetrate the core layer. An optical switch is provided.
[0024]
In such an optical switch, since the first light absorbers are disposed on both sides of the propagation region of the optical signal from each light incident side waveguide to the corresponding collimating lens, the light does not accurately enter each collimating lens. Excess light and scattered light from the end of the curved surface of the collimator lens are absorbed by the light absorber. In addition, since the second light absorbers are disposed on both sides of the propagation region of the optical signal from each condenser lens to the corresponding light output side waveguide, an extra portion that does not accurately enter each light output side waveguide is provided. Light is absorbed in the light absorber.
[0025]
Furthermore, in the present invention, the substrate, the waveguide layer formed on the substrate, the plurality of electrodes formed on the waveguide layer, and the waveguide layer in a region between the plurality of electrodes. A formed groove, and a light absorber filled in the groove; The waveguide layer has a core layer, and the light absorber penetrates the core layer. An optical deflection element is provided.
[0026]
According to such an optical deflection element, stray light of the optical signal is prevented by the light absorber filled in the groove, so that crosstalk is reduced and the quality of the optical signal is improved.
[0027]
In addition, since the light absorber is provided in the waveguide layer, the warp of the substrate due to heat when the waveguide layer is manufactured is absorbed by the light absorber, and the flatness of the waveguide layer is improved.
[0028]
Therefore, when such an optical deflecting element having good flatness is used as the input-side optical deflecting element of the above-described optical switch, the optical deflecting element and the collimating lens can be accurately aligned. Loss is reduced. Similarly, when this optical deflection element is used as an output side optical deflection element of an optical switch, alignment of the optical deflection element and the condenser lens is facilitated.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
(First embodiment)
FIG. 2 is a plan view illustrating a configuration example of an optical switch including the two-dimensional lens array according to the present embodiment.
[0031]
In FIG. 2, as an example, an optical switch 100 that switches and outputs optical signals of eight input channels as a whole to eight output channels is shown. The optical switch 100 includes an input side optical fiber array 110, a light incident side waveguide unit 120, a collimator unit 130, an input side optical deflection element unit 140, a common optical waveguide 150, an output side optical deflection element unit 160, and a condensing unit 170. . The light output side waveguide section 180 and the output side optical fiber array 190 are constituted. In this optical switch 100, the collimator 130 and the condenser 170 correspond to the two-dimensional lens array of the present invention.
[0032]
The input side optical fiber array 110 is provided with a plurality of optical fibers 111 corresponding to each input channel. Each light incident side waveguide section 120 is provided with a plurality of light incident side waveguides 121 corresponding to the respective optical fibers 111. The collimator unit 130 is provided with a plurality of collimator lenses 131 corresponding to the light incident side waveguides 121. The input side light deflection element unit 140 is provided with a plurality of input side light deflection elements 141 corresponding to the collimating lenses 131.
[0033]
In the input side optical fiber array 110, an optical signal is input from the outside through the optical fiber 111. Each optical fiber 111 is juxtaposed on the substrate 112. A plurality of V-shaped grooves are formed on the surface of the substrate 112, and each optical fiber 111 is installed on the groove, and its output end is the incident end of each light incident side waveguide 121 in the light incident side waveguide section 120. Connected to.
[0034]
In the light incident side waveguide section 120, each light incident side waveguide 121 receives the optical signal from each incident side optical fiber 111 and emits these optical signals to each collimating lens 131 of the collimating section 130. In the collimator unit 130, each collimator lens 131 individually converts the optical signal that is radially emitted from the incident-side light incident-side waveguide 121 to be converted into parallel light, and is transmitted to each input-side optical deflection element 141 on the emitting side. Make it incident. The detailed configuration of the collimator 130 will be described later with reference to FIGS. In the input side optical deflection element unit 140, each input side optical deflection element 141 changes the propagation direction of the optical signal from the corresponding collimating lens 131 on the incident side, and the output side optical deflection element unit via the common optical waveguide 150. To 160.
[0035]
The common optical waveguide 150 is configured by a slab type waveguide, and transmits the optical signal emitted from the input side optical deflection element unit 140 to the output side optical deflection element unit 160.
[0036]
The output side optical deflection element unit 160 is provided with a plurality of output side optical deflection elements 161 corresponding to the respective output channels. The condensing unit 170 is provided with a plurality of condensing lenses 171 corresponding to the output-side light deflection elements 161. The light emission side waveguide section 180 is provided with a plurality of light emission side waveguides 181 corresponding to the respective condensing lenses 171. The output side optical fiber array 190 is provided with a plurality of optical fibers 191 corresponding to the light output side waveguides 181.
[0037]
In the output-side optical deflection element 160, each output-side optical deflection element 161 changes the propagation direction of the optical signal incident from each input-side optical deflection element 141 via the common optical waveguide 150, and emits this optical signal. The light is incident on each of the condenser lenses 171 on the side. In the condensing unit 170, the light signal from each output-side light deflection element 161 is incident on each light-emitting side waveguide 181 formed by the respective condensing lenses 171. In addition, the condensing part 170 has the structure similar to the collimating part 130, The detail of this internal structure is mentioned later. In the light output side waveguide section 180, each light output side waveguide 181 individually outputs the optical signal received from each condensing lens 171 to each fiber 191 on the output side.
[0038]
In the output side optical fiber array 190, the optical fibers 191 are arranged side by side on the substrate 192. Similar to the input-side optical fiber array 110, a plurality of V-shaped grooves are formed on the surface of the substrate 192, and each optical fiber 191 is installed on this groove, and the incident ends thereof are the respective light output-side waveguides 181. The optical signal from each light output side waveguide is output to the outside.
[0039]
Such an optical switch 100 operates as follows.
[0040]
The optical signal incident on the light incident side waveguide 121 from each optical fiber 111 is converted into parallel light by the collimator lens 131 and is incident on the input side optical deflection element 141. The input-side optical deflection element 141 changes the propagation direction of the incident optical signal arbitrarily by controlling the voltage applied to the prism-type electrode, and the output-side optical deflection element section 160 via the common optical waveguide 150. The light is incident on one of the output-side optical deflection elements 161.
[0041]
The output-side optical deflection element 161 changes the propagation direction of the optical signal by controlling the voltage applied to the prism-type electrode so that the incident optical signal enters the corresponding condenser lens 171 on the output side. Let The optical signal incident on the condenser lens 171 is imaged and incident on the corresponding light output side waveguide 181 on the output side, and this optical signal is output to the outside from the light output side waveguide 181 through the optical fiber 191. Is done.
[0042]
Thus, in the optical switch 100 described above, by controlling the applied voltage at each of the input-side optical deflection element 141 and the output-side optical deflection element 161, optical signals from a plurality of input channels can be sent to any output channel. It is possible to switch and output.
[0043]
Next, the structure of the collimating unit 130 and the light collecting unit 170 in the optical switch 100 will be described in detail.
[0044]
FIG. 1 is a plan view showing a configuration of a collimating unit 130 which is an embodiment of the two-dimensional lens array of the present invention and its surroundings. FIG. 3 is a cross-sectional view showing a configuration of the collimating unit 130 and its periphery.
[0045]
FIG. 1 shows an enlarged view of a part of the collimator 130 in the optical switch 100 shown in FIG. 3A shows a cross-sectional view along the line AA in FIG. 1, and FIG. 3B shows a cross-sectional view along the line BB.
[0046]
As shown in FIGS. 1 and 3, the light incident side waveguide section 120, the collimating section 130, the input side light deflection element section 140, and the common optical waveguide 150 are provided on the same substrate 101.
[0047]
The collimating unit 130 includes a waveguide layer 132 that is a slab type optical waveguide into which an optical signal from each light incident side waveguide 121 is incident, and a gap filling layer that is filled with a medium having a refractive index different from that of the waveguide layer 132. 133. In the gap filling layer 133, the air gap region penetrating the core layer and the upper and lower cladding layers of the waveguide layer 132 is filled with a filler for preventing light diffusion, here, a fluororesin. Here, the upper and lower cladding layers of the waveguide layer 132 are made of quartz, and the core layer is made of quartz whose refractive index is increased by doping Ge, and the fluororesin of the gap filling layer 133 is slightly refracted from these. The rate is low.
[0048]
The end face of the waveguide layer 132 with respect to the gap filling layer 133 has a center on the optical axis of the optical signal from each light incident side waveguide 121. Here, it is molded into, for example, a cylindrical surface, and this end surface serves as the lens curved surface 134 of the collimating lens 131 that is a two-dimensional lens. With such a structure, in each collimator lens 131, an optical signal that spreads radially from each light incident side waveguide 121 and propagates in the waveguide layer 132 is converted into parallel light on the lens curved surface 134, and input side light is transmitted. The light is emitted to each input side optical deflection element 141 of the deflection element unit 140.
[0049]
As shown in FIG. 3, the input side optical deflection element unit 140 disposed on the output side of the collimator unit 130 has a slab type optical waveguide layer 143 made of an electro-optic crystal formed on a conductive substrate 142. Further, the slab type optical waveguide 143 has a structure in which a prism type electrode 144 is provided on the surface facing the conductive substrate 142. In the input side optical deflection element section 140, when a voltage is applied between the prism type electrode 144 and the conductive substrate 142, the refractive index of the region in the optical waveguide layer 143 sandwiched between them changes. The propagation direction of the optical signal incident from each collimator lens 131 in the optical waveguide layer 143 is switched.
[0050]
By the way, in this collimator 130, the optical signal incident from the light incident side waveguide 121 spreads radially in the waveguide layer 132 and propagates. At this time, most of the propagated light passes through the lens curved surface 134 and is converted into parallel light. That is, in the waveguide 132, only the light that has propagated in a predetermined sector-shaped region that spreads toward the lens curved surface 134 with the exit end of the light incident side waveguide 121 as the center is correctly collimated by the lens curved surface 134. However, since there is actually light that has propagated outside this region, such light may diffuse at the end of the lens curved surface 134 or may be emitted directly to the adjacent lens curved surface 134. is there.
[0051]
Therefore, in the present invention, the light absorbers 135 are disposed on both sides of the propagation region of the light incident on each lens curved surface 134 in the waveguide layer 132. In the present embodiment, since the adjacent lens curved surfaces 134 are in contact with each other, one light absorber 135 is provided between the boundary portion of each lens curved surface and the incident end of the waveguide layer 132. The light absorber 135 is provided so as to penetrate the core layer and the upper and lower cladding layers of the waveguide layer 132 as shown in FIG. As a material of the light absorber 135, for example, a black resin material in which carbon is dispersed is used.
[0052]
Such a light absorber 135 absorbs light propagating through a region that is not correctly collimated by the lens curved surface 134 and prevents light from propagating to the adjacent lens curved surface 134. Therefore, in the optical signal emitted from the collimating unit 130, it is possible to prevent the occurrence of crosstalk between adjacent channels.
[0053]
The light absorber 135 is preferably formed so that the end in the emission direction is away from the end of each lens curved surface 134. Furthermore, it is desirable that the end of the light absorber 135 in the incident direction is formed so as to be away from the incident end of the waveguide layer 132. Thereby, as will be described later, the core layer and the cladding layer corresponding to the region where the light absorber 135 is disposed are removed from the waveguide layer 132 which is a uniform slab waveguide, and the removed region It is possible to easily provide the light absorber 135 by filling the resin material into a solidified material. However, in order to prevent light from leaking to the adjacent lens curved surface 134 and to suppress the amount of crosstalk, the region where the light absorber 135 is disposed, the end of the lens curved surface 134, and the incidence of the waveguide layer 132 The distance between the ends is preferably as short as possible.
[0054]
Further, in this embodiment, as an example, the light absorber 135 is formed so that the shape seen from the upper surface is a circle or an ellipse. With such a shape, for example, light emitted from each light incident side waveguide 121 is prevented from being scattered on the side surface of the light absorber 135. The length in the width direction (vertical direction in FIG. 1) of this circular or elliptical light absorber 135 is such that the light emitted from the light incident side waveguide 121 is at least inside the corresponding lens curved surface 134. It is set to enter. Further, it is desirable that the width of the light absorber 135 is set according to the width required for the collimated light emitted from the lens curved surface 134.
[0055]
Next, FIG. 4 is a cross-sectional view showing the configuration of the light condensing unit 170 and its periphery.
[0056]
FIG. 4 shows an enlarged view of a part of the condensing unit 170 in the optical switch 100 shown in FIG. 2 and its periphery. The output side light deflection element part 160, the light condensing part 170, and the light emission side waveguide part 180 shown in FIG. 4 are provided on the same substrate 101 (not shown) as the light incident side waveguide part 120 and the like described above. It has been.
[0057]
Further, the output side light deflecting element unit 160, the light condensing unit 170, and the light emitting side waveguide unit 180 are the same as the input side light deflecting element unit 140, the collimating unit 130, and the light incident side waveguide unit 120, respectively. The configuration is the same as that provided when facing the waveguide 150.
[0058]
That is, the condensing unit 170 includes a waveguide layer 172 that is a slab waveguide for propagating an optical signal to each output-side waveguide 181, and a gap filled with a medium having a refractive index different from that of the waveguide layer 172. And a filling layer 173. In the gap filling layer 173, the air gap region penetrating the core layer and the upper and lower cladding layers of the waveguide layer 172 is filled with a fluororesin for preventing light diffusion. Here, similarly to the collimating part 130, the upper and lower cladding layers of the waveguide layer 172 are formed of quartz, and the core layer is formed of quartz doped with Ge to increase the refractive index. The fluororesin of the gap filling layer 173 Has a refractive index slightly lower than these.
[0059]
The end surface of the waveguide layer 172 with respect to the gap filling layer 173 is molded into a cylindrical surface having a center on the optical axis of each light emission side waveguide 181, and this end surface is a two-dimensional lens. The lens curved surface 174 is used. With such a structure, in each condensing lens 171, an optical signal emitted from each output-side optical deflecting element 161 and passing through the gap filling layer 173 propagates from the lens curved surface 174 to the waveguide layer 172, thereby causing each light. The light is imaged and incident on the incident end of the output side waveguide 181.
[0060]
Similarly to the collimating unit 130, in the waveguide layer 172, light absorbers 175 are disposed on both sides of a propagation region of light propagating so as to form an image on each light incident side waveguide 181 from each lens curved surface 174. Has been. For example, the light absorber 175 is provided so as to penetrate the core layer and the upper and lower cladding layers of the waveguide layer 172. As a material of the light absorber 175, for example, a black resin material in which carbon is dispersed is used.
[0061]
In this condensing unit 170, the optical signal incident from each output-side optical deflecting element 161 is substantially parallel light, but errors (factors on the input side (collimator unit, The width of light passing through the lens curved surface 174 (the length in the vertical direction in the drawing) is not necessarily constant due to stray light generated in the light polarizing element section), variation in performance of each output-side light deflection element 161 (stray light), or the like. It may not be. In such a case, all of the light that has passed through the lens curved surface 174 is not imaged at the incident end of the light exit side waveguide 181, and excess light is emitted to the area around the light exit side waveguide 181. This light may adversely affect the optical signal propagating through the light output side waveguide 181. Alternatively, the quality of the optical signal may be deteriorated by, for example, extra light being reflected from the emission side end face of the waveguide layer 172, returning into the condensing unit 170, and entering the adjacent lens curved surface 174.
[0062]
For this reason, by arranging the light absorbers 175 on both sides of the propagation region of the optical signal in the condensing unit 170, excess light propagating through the region that is not correctly condensed by the lens curved surface 174 is absorbed, and the light emission side guide is provided. Noise components included in the optical signal incident on the waveguide 181 can be reduced, and the quality of the propagating optical signal can be improved.
[0063]
As described above, according to the present invention, a high-performance optical switch in which crosstalk between channels and noise of each optical signal are reduced is realized.
[0064]
Next, a method for manufacturing the optical switch 100 will be described.
[0065]
FIG. 5 is a diagram for explaining a manufacturing method of the optical switch 100. FIG. 5 shows a cross section of a portion corresponding to FIG. 3B in the optical switch 100.
[0066]
In the optical switch 100, the light incident side waveguide section 120, the collimating section 130, the common optical waveguide 150, the light collecting section 170 and the light emitting side waveguide section 180 are integrally formed on the substrate 101. The input side optical deflection element unit 140 and the output side optical deflection element unit 160 are mounted thereon, and the input side optical fiber array 110 and the output side optical fiber array 190 are further connected.
[0067]
First, as shown in FIG. 5A, a uniform slab waveguide 102 is formed on a substrate 101. Quartz, Si wafer or the like is used as the substrate. In the case of quartz, the substrate 101 also functions as a lower cladding layer of the slab type waveguide layer 102 formed thereon. On this substrate 101, a core layer is formed from quartz in which Ge is diffused to increase the refractive index, and an upper clad layer is formed thereon from quartz. The core layer and the upper cladding layer are formed by, for example, MOCVD (Metal Organic Chemical Vapor Deposition) method.
[0068]
Next, an etching mask made of a metal film is formed on the surface of the upper cladding layer of the slab type optical waveguide 102 by photolithography and sputtering. Then, using this as a mask, the upper cladding layer and the core layer are collectively etched by reactive ion etching (RIE) using a fluorine-based gas or the like. As a result, as shown in FIG. 5B, the light incident side waveguide 121 and the common optical waveguide 150 are formed, and the air gap 133a, the waveguide 132, the lens curved surface 134, and the light absorption in the collimator 130 are formed. A filling part 135a for filling the body 135 and a mounting part 140a for mounting the input side optical deflection element part 140 are formed.
[0069]
For example, when the core width of each light incident side waveguide 121 is 5 μm and the pitch between each light incident side waveguide 121 is 2.5 mm, the width of the optical signal collimated by the lens curved surface 134 is 0.6 mm. The size of the filling portion 135a is set so that
[0070]
Here, the region of the filling portion 135 a of the light absorber 135 is formed so as to be separated from the end portion of the lens curved surface 134 and the incident end of the waveguide layer 132. Thereby, the filling part 135a of the light absorber 135 is formed in a concave shape surrounded by the waveguide layer 132 as shown in FIG.
[0071]
Although not shown, at the time of the collective etching described above, the air gap in the condensing unit 170, the waveguide layer 172, the lens curved surface 134, the filling unit for filling the light absorber 175, and the output side light deflection element unit 160. A mounting portion for mounting is formed on the substrate 101 at the same time.
[0072]
Thereafter, an electrode 140b for connecting to the prism-type electrode 144 of each input-side light deflection element 141 is provided on the bottom surface of the mounting part 140a for mounting the input-side light deflection element part 140. These electrodes 140b are formed by applying a resist on the bottom surface of the mounting portion 140a and performing patterning, and then laminating a titanium film by a sputtering method and further laminating a platinum film by a lift-off method.
[0073]
Here, the input side optical deflection element unit 140 is manufactured as follows. The input side optical deflection element unit 140 has a structure in which a slab type optical waveguide layer 143 is formed on a conductive substrate 142 and a prism type electrode 143 is further provided. As the conductive substrate 142, STO (SrTiO, which is a ferroelectric material). _Three 1) is doped with Nb to give conductivity. The optical waveguide layer 143 includes PZT (Pb (Zr _y Ti _1-y O _Three ), PLZT (Pb _x La _1-x (Zr _y Ti _1-y O _Three )) Are used as the core and upper and lower claddings, respectively. The optical waveguide layer 143 is laminated on the conductive substrate 142 by heteroepitaxial growth using the sol-gel method, the PLD (Pulsed Laser Deposition) method, the MOCVD method, or the like in the order of PZT, PLZT, and PZT.
[0074]
Thereafter, triangular prism electrodes 144 are formed in parallel on the surface of the optical waveguide layer 143 facing the conductive substrate 142 by the amount corresponding to the input channel. These prism type electrodes 144 are formed by forming a film by a photolithography method and a sputtering method using a metal such as a platinum film, and then polishing to a predetermined size.
[0075]
Note that the output-side optical deflection element unit 160 also has the same structure as the input-side optical deflection element unit 140, and is manufactured by the same process.
[0076]
Next, the input side optical deflection element unit 140 and the output side optical deflection element unit 160 are mounted on the substrate 101. In the case of the input side optical deflection element section 140, as shown in FIG. 5B, the surface on which the prism type electrode 144 is provided faces the substrate 101 side, and the prism type electrode 144 and the corresponding electrode 140b on the substrate 101 are provided. Are connected by solder bumps or the like to fix the input side optical deflection element section 140. At this time, it is necessary to accurately align the optical waveguides positioned on the incident side and the emission side. Note that the output-side light deflection element unit 160 is also mounted on the substrate 101 in the same manner.
[0077]
Next, as shown in FIG. 5C, the air gap 133 a between the waveguide layer 132 of the collimator unit 130 and the input side deflection element unit 140 is filled with a thermosetting fluororesin. This fluororesin has a refractive index slightly lower than that of quartz constituting the waveguide layer 132. The gap filling layer 133 is formed by applying heat to the filled fluororesin and curing it. At this time, the gap filling layer 173 of the condensing part 170 is also formed simultaneously by the same method.
[0078]
The air gap may be used as it is without being filled with fluororesin. In this case, since the refractive index of air is different from that of fluororesin, it is necessary to change the curvature of the lens curved surface. However, in the case of an air gap, the light that has passed through the lens curved surface is likely to diffuse, so it is desirable to fill a material that prevents the diffusion of light, such as a fluororesin.
[0079]
Next, as shown in FIG. 5C, the filling portion 135a in the collimating portion 130 is filled with the material of the light absorber 135 by screen printing. As this material, for example, a black resin material in which carbon is dispersed is used and solidified after filling. Here, since the filling portion 135a is formed in a concave shape surrounded by the waveguide layer 132, the light absorber 135 and the material of the gap filling layer 133 are not mixed. Therefore, both the light absorber 135 and the gap filling layer 133 can be easily formed simply by filling each concave region with each material. Although not shown, the filling portion formed in the light collecting portion 170 at this time is also filled with the material of the light absorber.
[0080]
In the manufacturing method of the optical switch 100 described above, a uniform slab type waveguide 102 is formed on a common substrate 101, and the slab type optical waveguide 102 absorbs light together with a light incident side waveguide and an air gap. The filling portion of the body 135 can be formed collectively by etching. For this reason, the filling portion of the light absorber 135 can be formed without greatly changing the conventional manufacturing process. Further, by forming the filling portion as a region surrounded by the waveguide layer, the light absorber 135 can be easily formed only by injecting a material into this region.
[0081]
Therefore, according to the present invention, it is possible to efficiently manufacture an optical switch in which crosstalk between channels is reduced and the quality of a propagated optical signal is improved.
[0082]
In the above embodiment, in the collimating unit 130 and the condensing unit 170, a material having a lower refractive index than that of the waveguide layer is used for the gap filling layer. However, the air gap layer has a high refractive index such as an epoxy resin. It is also possible to use materials. In this case, it is necessary to change the lens curved surface from a concave lens to a convex lens shape.
[0083]
Further, in the collimating unit 130 and the condensing unit 170 described above, the lens shapes of the collimating lens 131 and the condensing lens 171 are cylindrical, but an aspherical lens may be applied.
[0084]
Furthermore, in the collimating unit 130 and the condensing unit 170 described above, the lens curved surface is provided only on one of the incident side and the output side with the gap filling layer interposed therebetween, but the lens curved surface is provided on each of the incident side and the output side. You may provide so that it may oppose. In this case, for example, in the case of the collimating portion 130, the waveguide layer is arranged not only on the incident side of the gap filling layer 133 but also between the emission side and the mounting portion of the input side optical deflection element portion 140. . Similarly, in the case of the condensing unit 170, a waveguide layer is also disposed between the incident side of the gap filling layer 173 and the mounting portion of the output side optical deflection element unit 160.
[0085]
Further, in the above-described embodiment, the adjacent lens curved surfaces are joined together in both the collimating unit 130 and the light collecting unit 170, and the gap filling layer is integrally provided for all the channels. The adjacent lens curved surfaces may be separated. In this case, the gap filling layer is provided individually corresponding to each curved surface of the lens as a region surrounded by the waveguide layer.
[0086]
In the above embodiment, the light incident side waveguide 121 is connected to the collimating unit 130 and an optical signal is input. For example, an optical fiber is connected to the incident end of the waveguide layer 132 of the collimating unit 130. May be directly connected. Similarly, with regard to the condensing unit 170, an optical fiber may be directly connected to the emission end of the waveguide layer 172.
[0087]
In the above embodiment, an example in which the two-dimensional lens array of the present invention is applied to an optical switch as a collimating unit and a condensing unit has been described. The present invention can also be applied to other optical devices having a propagation region.
[0088]
(Second Embodiment)
In the first embodiment described above, the light absorbers 135 are provided on both sides of the collimator lens 131 and the condenser lens 171. However, the present invention is not limited to this, and the input side light deflection element unit 140 and the output side light deflection element. The portion 160 may be provided with a light absorber.
[0089]
Therefore, hereinafter, a case where a light absorber is provided in the input side optical deflection element unit 140 and the output side optical deflection element unit 160 will be described with reference to FIGS. 6 to 7 are perspective views showing the method of manufacturing the optical deflection element according to the second embodiment of the present invention in the order of steps. In these drawings, members already described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted below.
[0090]
First, steps required until a structure shown in FIG.
[0091]
First, the ferroelectric STO (SrTiO _Three ) Is used as the substrate 142, and a coating solution for PLZT is applied on the substrate 142 by a spin coating method at a rotation speed of 3000 rpm and a coating time of 30 seconds. Thereafter, the solvent component in the coating solution is dried at a substrate temperature of 140 ° C. for 5 minutes. Next, the obtained coating film is heated at a substrate temperature of 320 ° C. for 5 minutes, and then crystallization annealing is performed under conditions of a substrate temperature of 650 ° C. for 5 minutes. Such a series of steps is repeated as many times as necessary to increase the film thickness, thereby forming a PLZT film having a thickness of about 2 to 3 μm, which is used as the upper cladding layer 143a.
[0092]
In addition, it is conceivable to perform crystallization annealing in a lump after laminating the coating film instead of crystallization annealing for the coating film formed by spin coating as described above. This is not preferable because cracks may occur in the coated film due to crystallization annealing.
[0093]
The film forming method as described above is usually called a sol-gel method, but in some cases, it may also be called a chemical solution deposition method (CSD method: Chemical Solution Deposition method) or a coating pyrolysis method.
[0094]
Subsequently, a wavelength of 165 nm and an energy density of 200 W / cm are passed through a window of a metal mask (not shown) such as chromium with respect to the upper cladding layer 143a in a portion to be filled with the light absorber later. ² Irradiate UV rays. Then MeOH / H ₂ O and HNO _Three The solution is prepared so that the pH is 1.7, and the upper clad layer 143a irradiated with ultraviolet rays is wet-etched with this solution to form the opening 147.
[0095]
Next, steps required until a structure shown in FIG.
[0096]
First, a PZT film is formed on the upper clad layer 143a to a thickness of about 5 μm by the above-described sol-gel method using a coating solution for PZT, and this is used as the core layer 143b. The material constituting the core layer is not limited to PZT, and a ferroelectric material other than PZT can also be used. Then, an opening overlapping the opening 147 is formed in the core layer 143b by using the ultraviolet irradiation method described above.
[0097]
Further, using a method similar to that for the upper clad layer 143a, PLZT is formed to a thickness of about 2 to 3 μm on the core layer 143b, and this is used as the lower clad layer 143c. Thereafter, an opening overlapping the opening formed in the core layer 143b is formed in the lower cladding layer 143c by using the above-described ultraviolet irradiation method.
[0098]
As a result, a waveguide layer 143 formed by epitaxially growing the upper cladding layer 143a, the core layer 143b, and the lower cladding layer 143c in this order is formed on the substrate 142, and a groove 148 that overlaps the opening 147 of the upper cladding layer 143a is formed. That is, the waveguide layer 143 is formed. A plurality of the grooves 148 are formed with an interval of, for example, about several hundred μm.
[0099]
Next, steps required until a structure shown in FIG.
[0100]
First, on the lower clad layer 143c, a tungsten film having good adhesion to the PLZT constituting the lower clad layer 143c and having a low resistance is formed to a thickness of, for example, 15 μm by sputtering. Thereafter, the tungsten film is patterned by photolithography to form a plurality of prism-type electrodes 144 on the optical path of the waveguide 143.
[0101]
Subsequently, as shown in FIG. 7B, a black resin material in which carbon is dispersed is filled into the grooves 148 by a screen printing method, and then the black resin material is solidified to form a light absorber 146. .
[0102]
If the light absorber 146 is filled in the groove 148 before forming the prism type electrode 144, the black resin material protrudes from the groove 148 on the lower clad layer 143 where the prism type electrode 144 is to be formed. There is a possibility that a black resin material may be interposed between the mold electrode 144 and the waveguide layer 143. In this case, a part of the voltage applied between the prism-type electrode 144 and the substrate 142 is absorbed by the black resin material, the net voltage applied to the core layer 143b is reduced, and the amount of deflection of the optical signal is reduced. End up. Therefore, it is preferable to fill the black resin after forming the prism-type electrode 144 as in this embodiment.
[0103]
Further, when the light absorber 146 is filled, if the groove 148 protrudes from the end surface A of the waveguide layer 143, the light absorber 146 spills out from the end surface A. Therefore, the groove 148 is inside the end surface A. Is preferably formed.
[0104]
As described above, the basic structure of the optical deflection element according to this embodiment is completed. In this optical deflection element, prism type electrodes 144 corresponding to the optical paths are formed on the plurality of optical paths of the waveguide layer 143, and by adjusting the potential difference between each prism type electrode 144 and the substrate 142, The optical signal can be deflected by a deflection angle corresponding to the potential difference. Note that since the conductivity of the STO constituting the substrate 142 is low, a large deflection angle may not be obtained unless a relatively large voltage is applied between the substrate 142 and the prism-type electrode 144. In that case, a solid metal film, for example, a Pt film, is formed as an upper electrode between the substrate 142 and the waveguide layer 143, and a voltage is applied between the upper electrode and the prism-type electrode 144. That's fine. By configuring the upper electrode with a metal film having good conductivity in this way, a voltage can be effectively applied to the waveguide layer 143 even if the potential difference between the upper electrode and the prism-type electrode 144 is small. The optical signal can be greatly deflected.
[0105]
According to the above-described embodiment, the groove 148 is formed in the waveguide layer 143 beside each optical path, and the optical absorber 146 is filled in the groove 148, so that an optical signal propagating in one optical path is caused by stray light. Is prevented from entering the light path. Thereby, crosstalk between the optical paths can be prevented, and the quality of the optical signal propagating through each optical path is improved.
[0106]
Since the optical signal propagates through the core layer 143b of the waveguide layer 143, the groove 148 may be formed at a depth that penetrates the core layer 143b in order to prevent the stray light as described above.
[0107]
Further, when the waveguide layer 143 is formed by the sol-gel method, thermal history is applied to the waveguide layer 143 several times by crystallization annealing and the substrate 142 is warped by the heat, but the light absorber 146 Since the warp is absorbed, the flatness of the waveguide layer 143 can be improved.
[0108]
According to the investigation results of the present inventors, when the thickness of the waveguide layer 143 is 10 μm, the substrate 142 is warped by about 3 μm when the groove 148 and the light absorber 146 are not provided. It was confirmed that when the groove 148 and the light absorber 146 are provided in this, the warpage can be suppressed to about 1 μm.
[0109]
Such an advantage can also be obtained when the waveguide layer 143 is formed by another film forming method in which a thermal history is applied to the waveguide layer 143, for example, MOCVD.
[0110]
On the other hand, in Patent Document 1, since the waveguide layer is made of an ultraviolet curable resin, the above-described thermal history is not applied to the waveguide layer, and the advantages of the present invention cannot be obtained.
[0111]
In addition, Patent Document 2 is different from the present invention in which a thermal history is added to the waveguide layer because the waveguide layer is not formed on the substrate.
[0112]
By the way, although the usage method of the above-mentioned optical deflection element is not particularly limited, it is preferable to use it for the optical switch described in the first embodiment. The optical switch is manufactured by the same manufacturing method as in the first embodiment, and the plan view thereof is as shown in FIG.
[0113]
In such an optical switch, the light deflection elements of this embodiment are used for the input side light deflection element unit 140 and the output side light deflection element unit 160. Since the input side optical deflection element unit 140 is suppressed from warping as described above, when the input side optical deflection element unit 140 is mounted on the substrate 101, the input side deflection element unit 140 and the collimator lens 130 are accurately aligned. And loss of the optical signal can be reduced. Similarly, the alignment between the output side deflection element unit 160 and the condenser lens 171 is facilitated, and the loss of the optical signal can be suppressed.
[0114]
In addition, in the collimating unit 130 and the light collecting unit 170 in FIG. 8, the lens curved surfaces are provided to face the incident side and the emission side of the gap filling layer, respectively. However, as in the first embodiment, the gap filling is performed. A lens curved surface may be provided on only one of the incident side and the emission side across the layers.
[0115]
The features of the present invention are added below.
[0116]
(Appendix 1) A plurality of slab type optical waveguides having end faces for entering and exiting a plurality of optical signals, and a plurality of optical signals formed on the boundary surface of the slab type optical waveguide with respect to another medium having a different refractive index corresponding to each optical signal. In a two-dimensional lens array having a lens curved surface of
2. A two-dimensional lens array, wherein light absorbers are disposed on both sides of a propagation area of each optical signal between the input / output end face and each lens curved surface.
[0117]
(Supplementary note 2) The two-dimensional lens array according to supplementary note 1, wherein the light absorber is disposed in a region away from an end portion of each curved surface of the lens in the direction of the end surface for input and output.
[0118]
(Additional remark 3) The said light absorber is arrange | positioned in the area | region in the said slab type | mold optical waveguide away from the said end surface for entrance / exit, The two-dimensional lens array of Additional remark 1 characterized by the above-mentioned.
[0119]
(Supplementary note 4) The two-dimensional lens array according to Supplementary note 1, wherein the light absorber is disposed in a region where the core layer and the clad layer of the slab type optical waveguide are provided.
[0120]
(Supplementary note 5) The two-dimensional lens array according to supplementary note 1, wherein the light absorber is made of a black resin in which carbon is dispersed.
[0121]
(Additional remark 6) When each optical signal which propagated through the said slab type | mold optical waveguide is said to each said lens curved surface, when the optical signal is incident by the light-incidence side waveguide or the optical fiber from the end surface for said entrance / exit, The two-dimensional lens array according to appendix 11, wherein the two-dimensional lens array is formed into a shape that passes through the lens curved surface and is converted into parallel light.
[0122]
(Supplementary note 7) The distance between the light absorbers across the propagation area of the optical signal depends on the width of the light incident side waveguide or optical fiber and the width of the parallel light required after passing through the lens curved surface. The two-dimensional lens array according to appendix 6, wherein the two-dimensional lens array is set as follows.
[0123]
(Appendix 8) In an optical switch that switches the propagation path of an optical signal,
A plurality of light incident side waveguides for receiving an optical signal input from the outside;
A plurality of light exit waveguides for outputting optical signals to the outside;
A plurality of collimating lenses that individually collimate the optical signals that have passed through the light incident side waveguides;
A first light absorber disposed on both sides of a propagation area of an optical signal from each light incident side waveguide to each corresponding collimating lens;
A plurality of input side optical deflection elements that individually switch the propagation direction of the optical signal that has passed through each of the collimating lenses;
A common optical waveguide through which the optical signals that have passed through the optical deflection elements propagate in common;
A plurality of output-side optical deflection elements that individually switch the propagation direction of the optical signal that has passed through the common optical waveguide;
A plurality of condensing lenses that individually image the optical signals that have passed through the respective light deflection elements on the respective light output side waveguides;
A second light absorber disposed on both sides of the propagation region of the optical signal from the respective condensing lens to the corresponding light output side waveguide;
An optical switch comprising:
[0124]
(Supplementary Note 9) The first light absorber is disposed in a region away from an end of the incident-side lens curved surface of the collimator lens in a direction in which the light incident-side waveguide is disposed, The second light absorber is disposed in a region away from the end of the curved surface of the lens on the exit side of the condenser lens in the direction in which the light exit side waveguide is disposed. The optical switch according to appendix 8.
[0125]
(Additional remark 10) In the optical switch which switches the propagation path of an optical signal,
A plurality of light incident side waveguides for receiving an optical signal input from the outside;
A plurality of light exit waveguides for outputting optical signals to the outside;
A plurality of collimating lenses that individually collimate the optical signals that have passed through the light incident side waveguides;
A plurality of input side optical deflection elements that individually switch the propagation direction of the optical signal that has passed through each of the collimating lenses;
A first light absorber disposed on both sides of an optical path of the optical signal passing through the input side optical deflection element;
A common optical waveguide through which the optical signals that have passed through the optical deflection elements propagate in common;
A plurality of output-side optical deflection elements that individually switch the propagation direction of the optical signal that has passed through the common optical waveguide;
A second light absorber disposed on both sides of the optical path of the optical signal passing through the output side optical deflection element;
A plurality of condensing lenses that individually image the optical signals that have passed through the respective light deflection elements on the respective light output side waveguides;
An optical switch comprising:
[0126]
(Additional remark 11) In the manufacturing method of the two-dimensional lens array which has a some two-dimensional lens which collimates or condenses the optical signal which propagates in a two-dimensional optical waveguide,
A uniform slab type optical waveguide having end faces for entering and exiting a plurality of optical signals is formed on a substrate,
The core layer and the clad layer of the slab type optical waveguide are removed to form a plurality of lens curved surfaces corresponding to each optical signal on the end surface, and the light between the input / output end surface and each lens curved surface The core layer and the cladding layer of the slab type optical waveguide are removed and filled on both sides of the signal propagation region and in a region away from the portion where the core layer and the grad layer are removed in the direction of the input and output end faces. Forming a hole,
Filling the filling hole with a resin having a light absorption property and solidifying the resin;
A method for manufacturing a two-dimensional lens array.
[0127]
(Supplementary Note 12) a substrate;
A waveguide layer formed on the substrate;
An electrode formed on an optical path of an optical signal passing through the waveguide layer on an upper surface of the waveguide layer;
A groove formed in the waveguide layer beside the optical path;
A light absorber filled in the groove;
An optical deflection element comprising:
[0128]
(Additional remark 13) The said groove | channel is provided in the both sides of the optical path of the said waveguide layer 1 each, The optical deflection | deviation element of Additional remark 12 characterized by the above-mentioned.
[0129]
(Supplementary note 14) The light deflection element according to supplementary note 12, wherein the light absorber is made of a black resin in which carbon is dispersed.
[0130]
(Supplementary note 15) The optical deflection element according to supplementary note 12, wherein the waveguide layer includes a core layer made of a ferroelectric.
[0131]
(Additional remark 16) The said groove | channel is an optical deflection | deviation element of Additional remark 15 characterized by being formed through the said core layer.
[0132]
(Supplementary Note 17) A step of forming a waveguide layer on a substrate;
Forming a groove in the waveguide layer;
Forming an electrode on the waveguide layer next to the groove;
Filling the groove with a light absorber;
A method of manufacturing an optical deflection element comprising:
[0133]
(Additional remark 18) The said waveguide layer is formed by the sol-gel method or MOCVD method, The manufacturing method of the optical deflection | deviation element of Additional remark 17 characterized by the above-mentioned.
[0134]
(Additional remark 19) The said groove | channel is formed inside the end surface of the said optical waveguide layer, The manufacturing method of the optical deflection | deviation element of Additional remark 17 characterized by the above-mentioned.
[0135]
【The invention's effect】
As described above, according to the two-dimensional lens array of the present invention, for example, when an optical signal propagates in a slab optical waveguide with respect to a curved lens surface, both sides of the propagation region of the optical signal in the slab optical waveguide are provided. Since the light absorber is disposed, extra light that does not accurately enter the lens curved surface and scattered light from the end of the lens curved surface and the like are absorbed by the light absorber. For this reason, light is prevented from entering the adjacent lens curved surface, and the occurrence of crosstalk between adjacent channels is reduced. In addition, when an optical signal enters the slab type optical waveguide from the lens curved surface, excess light propagating outside the predetermined range of the emission end after passing through the lens curved surface is absorbed by the light absorber. Therefore, only necessary light is emitted from the emission side, and the quality of the propagating optical signal is improved.
[0136]
In the optical switch according to the present invention, the first light absorbers are disposed on both sides of the propagation region of the optical signal from each light incident side waveguide to each corresponding collimating lens, so that each collimating lens is accurately provided. Excess light that does not enter and scattered light from the end of the curved surface of the collimator lens are absorbed by the light absorber. For this reason, light is prevented from entering the adjacent lens curved surface, and the occurrence of crosstalk between adjacent channels is reduced. In addition, since the second light absorbers are disposed on both sides of the propagation region of the optical signal from each condenser lens to the corresponding light output side waveguide, an extra portion that does not accurately enter each light output side waveguide is provided. Light is absorbed in the light absorber. For this reason, only the necessary light is emitted from the light emission side waveguide, and the quality of the propagating optical signal is improved.
[0137]
Furthermore, according to the optical deflection element of the present invention, since the groove is provided in the waveguide layer and the groove is filled with the light absorber, the light absorber prevents stray light of the optical signal and reduces crosstalk. The quality of the optical signal can be improved.
[0138]
Moreover, by providing the groove in the waveguide layer in this way, the warp of the substrate caused by the heat at the time of producing the waveguide layer is absorbed by the light absorber, thereby improving the flatness of the waveguide layer. be able to.
[0139]
Accordingly, when such an optical deflecting element with good flatness is used as the input-side optical deflecting element of the optical switch described above, the optical deflecting element and the collimating lens can be accurately aligned, so that the optical signal Loss is reduced. Similarly, when this optical deflection element is used as an output side optical deflection element of an optical switch, alignment of the optical deflection element and the condenser lens is facilitated.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a collimating unit and its periphery of a two-dimensional lens array according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a configuration example of an optical switch including a two-dimensional lens array according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a configuration of a collimating portion and its periphery of the two-dimensional lens array according to the first embodiment of the present invention.
FIG. 4 is a plan view showing a configuration of a condensing unit and its periphery of the two-dimensional lens array according to the first embodiment of the present invention.
FIGS. 5A to 5C are cross-sectional views for explaining a method of manufacturing an optical switch according to the first embodiment of the present invention.
FIGS. 6A and 6B are perspective views (No. 1) showing a method for manufacturing an optical deflection element according to the second embodiment of the present invention. FIGS.
FIGS. 7A and 7B are perspective views (No. 2) showing the method of manufacturing the optical deflection element according to the second embodiment of the present invention. FIGS.
FIG. 8 is a plan view of an optical switch including an optical deflection element according to a second embodiment of the present invention.
FIG. 9 is a plan view showing a part of an optical switch according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Optical switch 110 ... Input side optical fiber array, 111 ... Optical fiber, 120 ... Light incident side waveguide part, 121 ... Light incident side waveguide, 130 ... Collimating part, 131 ... Collimating lens, 132 ... Waveguide layer DESCRIPTION OF SYMBOLS 133 ... Gap filling layer, 134 ... Lens curved surface, 135 ... Light absorber, 140 ... Input side optical deflection element part, 141 ... Input side optical deflection element, 142 ... Conductive substrate, 143 ... Waveguide layer, 143a ... Upper part Cladding layer, 143b ... core layer, 143c ... lower cladding layer, 144 ... prism type electrode, 146 ... light absorber, 147 ... opening, 150 ... common optical waveguide, 160 ... output side light deflection element part, 161 ... output side light Deflection element, 170 ... Condensing part, 171 ... Condensing lens, 180 ... Light exit side waveguide part, 181 ... Light exit side waveguide, 190 ... Output side optical fiber array, 19 ... optical fiber.

Claims (2)

In an optical switch that switches the propagation path of an optical signal,
A plurality of light incident side waveguides for receiving an optical signal input from the outside;
A plurality of light exit waveguides for outputting optical signals to the outside;
A plurality of collimating lenses that individually collimate the optical signals that have passed through the light incident side waveguides;
A plurality of input-side optical deflecting elements respectively disposed via first light absorbers, individually switching the propagation direction of the optical signal that has passed through each of the collimating lenses;
A common optical waveguide through which the optical signals that have passed through the optical deflection elements propagate in common;
Individually switching the propagation direction of the optical signal that has passed through the common optical waveguide, and a plurality of output-side optical deflection elements respectively disposed via the second light absorbers;
A plurality of condensing lenses that individually image the optical signals that have passed through the respective light deflection elements on the respective light output side waveguides ;
The input side optical deflection element and the output side optical deflection element have a core layer,
The optical switch, wherein the first light absorber and the second light absorber penetrate the core layer . A substrate,
A waveguide layer formed on the substrate;
A plurality of electrodes formed on the waveguide layer;
A groove formed in the waveguide layer in a region between the plurality of electrodes;
A light absorber filled in the groove ,
The waveguide layer has a core layer;
The light deflection element, wherein the light absorber penetrates the core layer .

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