JP4777170B2 - Optical waveguide device - Google Patents

Description

  The present invention relates to an optical waveguide device provided with a heater.

As an optical waveguide element with a heater used in the field of optical communication, for example, there is a thermo-optic effect type optical switch. Examples of such an optical switch include those described in Patent Documents 1 to 3. Among these, the structure described in Patent Document 1 is shown in FIG. The optical switch 100 includes a Y-branch optical waveguide composed of a straight optical waveguide 101, a tapered optical waveguide 102, and a branch optical waveguide 103, and a thin film heater 105 along the Y-branch optical waveguide. The width of the portion of the thin film heater 105 in the region along the tapered optical waveguide 102 gradually increases from the branch optical waveguide 103 side toward the straight optical waveguide 101 side. As a result, the amount of heat generated at the portion of the thin film heater 105 on the straight optical waveguide 101 side is suppressed, and power consumption is reduced.
Japanese Patent Laid-Open No. 2000-241838 JP 2004-85744 A Japanese Patent No. 3471314

  However, in the conventional elements disclosed in Patent Documents 1 to 3, a heater is provided in a relatively wide area along the optical waveguide. Therefore, even if the above-described device is applied, a certain amount of power is consumed.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an optical waveguide element that can effectively reduce the power consumption of a heater.

In order to solve the above-described problems, a first optical waveguide device according to the present invention includes a polymer, and includes a core portion that guides single-mode light, and a cladding portion that has a refractive index smaller than that of the core portion. And a heater part for partially heating the optical waveguide layer. The core part includes an incident side core part, two emission side core parts, and one end of the incident side core part and two emission parts. A pair of first top portions, each having a widened portion that joins one end of each of the side core portions to each other, the heater portions being disposed on both sides of the widened portion of the core portion and being locally close to the core portion; A pair of first electrodes for receiving a control voltage to one of the first tops, a pair of first electrodes, and both ends of the first top, respectively. The other of the pair of first hems and the pair of first tops for connection A pair of second electrodes for receiving a control voltage to the top of one, and a pair of second hems for electrically connecting the pair of second electrodes and both ends of the other first top, respectively And the pair of first top portions are disposed on both sides of the core portion at a distance from the core portion when viewed from the thickness direction of the optical waveguide layer, and are connected to the pair of first top portions. A portion of the first and second skirts near the other end is arranged so that a portion of the first and second skirts near the other end is away from the core.

A second optical waveguide device according to the present invention includes a polymer, a core portion that guides single-mode light, and an optical waveguide layer that includes a cladding portion having a refractive index smaller than that of the core portion, A heater part for partially heating the waveguide layer, and the core part includes an incident side core part, two exit side core parts, one end of the entrance side core part, and one end of each of the two exit side core parts. A pair of first top portions that are arranged on both sides of the widened portion of the core portion and give fluctuation to the single mode light, and one of the pair of first top portions. A pair of first electrodes for receiving a control voltage to the first top of the pair, and a pair of first electrodes for electrically connecting the pair of first electrodes and both ends of the first top, respectively. Of the pair of first tops to the other first top A pair of second electrodes for receiving a voltage; a pair of second electrodes for electrically connecting the pair of second electrodes and both ends of the other first top portion; The pair of first top portions are disposed on both sides of the core portion with a space from the core portion as viewed from the thickness direction of the optical waveguide layer, and are connected to the pair of first top portions. The portion near the other end of the first and second hem portions is arranged so as to be away from the core portion with respect to the portion near the one end of the two skirt portions.

  In the first or second optical waveguide element, the heater portion has a pair of first top portions arranged on both sides of the core portion. The pair of first top portions are locally close to the core portion, and when one of them heats the optical waveguide layer, a local refractive index change occurs in the optical waveguide layer due to the thermo-optic effect. For this reason, the single mode light propagating through the core portion is fluctuated due to this local change in refractive index. Then, the single mode light travels to the emission side core portion arranged in the direction in which the single mode light fluctuates among the two emission side core portions.

  Thus, according to the first or second optical waveguide element, the traveling direction of the single mode light can be suitably controlled. Further, since the traveling direction of the single mode light can be changed by local heating by the first top portion of the heater portion, the heat generation portion of the heater can be reduced as compared with, for example, the conventional configuration shown in FIG. Therefore, the power consumption of the heater can be effectively reduced.

  In the present invention, the “locally close” position is preferably a position where the propagation of the single-mode light is not affected by the first top when the single-mode light propagates through the core. For example, when the diameter (width) of the core part is 8 μm, the distance between the core part and the first top part may be 10 μm or more. Further, both sides (sides) of the core part refer to both sides (sides) of the core part when viewed from the thickness direction of the optical waveguide layer.

The first or second optical waveguide element, a first apex of the pair of heater portion that are arranged on both sides of the widening section. Thereby, the single mode light can be effectively fluctuated and the traveling direction can be changed more reliably.

Further, in the first or second optical waveguide element, the heater portion further includes a pair of second top portions that are disposed on the sides of the two output-side core portions and are locally close to the respective output-side core portions. This may be a feature. By locally heating the exit-side core portion on the side on which the single-mode light does not travel with such a second apex, it is possible to change the refractive index of the exit-side core portion and suppress the entry of single-mode light. Therefore, according to this optical waveguide element, the extinction ratio in the output side core portion can be further increased. Further, in this case, the heater portion has a pair of third skirt portions for electrically connecting both ends of the second top portion of the pair of second top portions and the pair of first electrodes, respectively. And a pair of fourth skirts for electrically connecting both ends of the other second top and the pair of second electrodes, respectively, of the pair of second tops, The first top part and the one second top part are integrally formed by connecting one of the pair of first skirts and one of the pair of third skirts to each other, and the other first It is preferable that the top and the other second top are integrally formed by connecting one of the pair of second skirts and one of the pair of fourth skirts to each other . Thereby, the number of electrodes of the heater portion can be reduced.

  The first or second optical waveguide element has a curved shape in which the side surface shape of the widened portion viewed from the layer thickness direction of the optical waveguide layer is continuous from the side surface of the incident side core portion to the side surface of the output side core portion. May be a feature. Alternatively, in the first or second optical waveguide element, the planar shape of the widened portion viewed from the layer thickness direction of the optical waveguide layer is such that one end of the incident side core portion and one end of each of the two output side core portions are individually provided. The two single mode optical waveguides to be coupled may have a shape obtained by superimposing the planar shapes. Since the widened portion has such a shape, fluctuations in the propagation mode of single mode light in the widened portion can be suppressed, and thus fluctuation can be effectively applied to the single mode light.

  Further, the first or second optical waveguide element may be characterized in that a side shape of the top portion of the heater portion viewed from the layer thickness direction of the optical waveguide layer is a curve. As a result, the current distribution at the top can be made uniform, and stress can be prevented from being concentrated on one point. Accordingly, it is possible to suppress the separation of the top portion from the optical waveguide layer due to long-term use.

  According to the optical waveguide device of the present invention, the power consumption of the heater can be reduced.

  Embodiments of an optical waveguide device according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, an embodiment of an optical waveguide device according to the present invention will be described. FIG. 1A is a plan view showing the configuration of the optical waveguide device according to the present embodiment. FIG. 1B is a cross-sectional view showing a II cross section of the optical waveguide element 1a shown in FIG. The optical waveguide element 1a of the present embodiment is a thermo-optic effect type optical switch element in which a heater portion is provided on a so-called embedded optical waveguide substrate.

  Referring to FIGS. 1A and 1B, the optical waveguide element 1 a of this embodiment includes a substrate 10, an optical waveguide layer 11, and a heater unit 3. The substrate 10 is made of a material such as silicon, quartz, glass epoxy resin, ceramic, or polyimide resin. The substrate 10 has a rectangular planar shape and has a main surface 10a.

  The optical waveguide layer 11 is provided on the main surface 10 a of the substrate 10. The optical waveguide layer 11 includes a core portion 15 that guides single-mode light, and a cladding portion 13 that has a refractive index smaller than that of the core portion 15. The clad portion 13 is formed in layers on the main surface 10 a of the substrate 10. The core portion 15 is formed inside the cladding portion 13 and is covered with the cladding portion 13. The core portion 15 has a Y-shaped planar shape connecting the opposing side surfaces of the optical waveguide layer 11, has a light incident end 15 e on one side surface of the optical waveguide layer 11, and two lights on the other side surface. It has the output ends 15f and 15g. The single mode light incident on the light incident end 15e is selectively emitted from one of the light emitting ends 15f and 15g by the action (thermo-optical effect) of the heater unit 3 described later.

  The core portion 15 includes an incident side core portion 15a extending from the light incident end 15e, and two emission side core portions 15c and 15d extending to the light emission ends 15f and 15g, respectively. Further, the core portion 15 connects one end of the incident side core portion 15a opposite to the light incident end 15e and one end of each of the emission side core portions 15c and 15d opposite to the light emission ends 15f and 15g to each other. It has the wide part 15b couple | bonded.

  The material constituting the optical waveguide layer 11 is preferably an organic polymer (polymer) mainly composed of polyimide resin, silicone resin, epoxy resin, acrylate resin, polymethyl methacrylate (PMMA) resin, benzocyclobutene resin, or the like. It is. Examples of such organic polymers include those in which H in the C—H group of each exemplified material is replaced with fluorine or deuterium.

  The heater unit 3 is a component for partially heating the optical waveguide layer 11, and is provided on the optical waveguide layer 11. The heater unit 3 includes two heater wires 3 a and 3 b disposed on both sides of the core unit 15 when viewed from the thickness direction of the optical waveguide layer 11. The two heater wires 3a and 3b are electrically connected to a power supply device or the like prepared outside the optical waveguide element 1a, and always energize only one of them. The heater wires 3a and 3b are preferably composed of a metal such as Cr, Au, WSi, or Ti, for example. Moreover, the thickness of the heater wires 3a and 3b is, for example, 0.1 μm to 2 μm.

  The heater wire 3a has a top portion 31a, skirt portions 32a and 33a, and electrodes 34a and 35a. Similarly, the heater wire 3b has a top portion 31b, skirt portions 32b and 33b, and electrodes 34b and 35b. The top portions 31 a and 31 b are a pair of first top portions in the present embodiment, and are disposed on both sides of the core portion 15 when viewed from the layer thickness direction of the optical waveguide layer 11. The cross-sectional areas of the top portions 31a and 31b are smaller than the cross-sectional areas of the bottom portions 32a, 33a and 32b, 33b of the heater wires 3a and 3b, respectively.

  The skirt portions 32a and 33a of the heater wire 3a are portions for electrically connecting the top portion 31a and the electrodes 34a and 35a. That is, one end of the skirt portions 32a and 33a is connected to one end and the other end of the top portion 31a, and the other end of the skirt portions 32a and 33a is connected to the electrodes 34a and 35a, respectively. The skirt portions 32 a and 33 a are arranged so that a portion near one end connected to the top portion 31 a is close to the core portion 15 and a portion near the other end is away from the core portion 15.

  Similarly, the skirt portions 32b and 33b of the heater wire 3b are portions for electrically connecting the top portion 31b and the electrodes 34b and 35b. One ends of the skirt portions 32b and 33b are connected to one end and the other end of the top portion 31b, respectively, and the other ends of the skirt portions 32b and 33b are connected to the electrodes 34b and 35b, respectively. The skirt portions 32 b and 33 b are arranged so that a portion near one end connected to the top portion 31 b is close to the core portion 15 and a portion near the other end is away from the core portion 15. With these configurations, the top portions 31a and 31b are portions that are locally close to the core portion 15 in the heater wires 3a and 3b, respectively.

  The electrodes 34a and 35a of the heater wire 3a are pad electrodes for receiving a control voltage to the heater wire 3a, and are electrically connected to a power supply device or the like prepared outside the optical waveguide element 1a. Similarly, the electrodes 34b and 35b of the heater wire 3b are pad electrodes for receiving a control voltage to the heater wire 3b, and are electrically connected to a power supply device or the like prepared outside the optical waveguide element 1a.

  Here, the configuration in the vicinity of the top portions 31a and 31b will be described in more detail. FIG. 2 is an enlarged plan view showing a configuration in the vicinity of the top portions 31a and 31b. In addition, in order to understand easily, illustration of the clad part 13 is abbreviate | omitted in FIG. As shown in FIG. 2, the top portions 31 a and 31 b of the present embodiment are on both sides of the widened portion 15 b of the core portion 15, that is, the branch position of the core portion 15 from the widening start position of the core portion 15 (one end 15 j of the widened portion 15 b). It arrange | positions at the both sides of the part to (the other end 15k of the wide part 15b). Further, the side surfaces of the top portions 31 a and 31 b as viewed from the thickness direction of the optical waveguide layer 11 are formed in a convex curve shape toward the core portion 15.

  Further, the widened portion 15b of the core portion 15 has the following planar shape. That is, the width of the widened portion 15b in the direction intersecting the direction in which the single mode light L is guided is the same as the width of the incident-side core portion 15a on the one end 15j side, and the two outgoing-side cores on the other end 15k side. The width is the same as the combined width of the portions 15c and 15d. Further, the shapes of the side surfaces 15h and 15i of the widened portion 15b are curved inwardly from the side surface of the incident side core portion 15a to the side surfaces of the emission side core portions 15c and 15d. And the width | variety of the wide part 15b seen from the layer thickness direction of the optical waveguide layer 11 is gradually expanded from the one end 15j to the other end 15k.

FIG. 3A is a plan view of the core portion 15 for explaining in detail the planar shape of the widened portion 15b. FIG. 3B is a plan view showing the shape of the optical waveguide in the conventional configuration shown in FIG. 21 for comparison. Referring to FIG. 3A, the planar shape of the widened portion 15b of the present embodiment viewed from the thickness direction of the optical waveguide layer 11 is a curved shape in which the shapes of the side surfaces 15h and 15i are inwardly convex. , also one end 15m and two exit-side core portions 15c and 15d each end 15n and 15p and a fictitious two single-mode optical waveguide _{W 1} and _{W 2} of the planar shape individually coupled to the incident-side core part 15a Overlapped shape. On the other hand, in the conventional configuration shown in FIG. 3B, the side shape of the tapered optical waveguide 102 connecting the linear optical waveguide 101 and the two branched optical waveguides 103 is linear.

  The effect of the optical waveguide device 1a of the present embodiment having the above configuration will be described. When a control voltage is supplied between the electrodes 34a and 35a (electrodes 34b and 35b) of the heater wire 3a (or 3b) of the heater part 3, the skirt part 32a, the top part 31a, and the skirt part 33a (the skirt part 32b and the top part 31b). , And the skirt 33b). At this time, since the cross-sectional area of the top part 31a (31b) is smaller than the cross-sectional area of the skirt parts 32a and 33a (32b and 33b), the top part 31a (31b) is compared with the skirt parts 32a and 33a (32b and 33b). High resistance. Therefore, power is consumed mainly at the top portion 31a (31b) and converted into heat. The heat generated in the top portion 31a (31b) is transmitted to the optical waveguide layer 11, and the optical waveguide layer 11 includes a polymer (polymer). Therefore, the heating portion of the optical waveguide layer 11 is heated by the thermo-optic effect. The refractive index is smaller than the refractive index of other portions.

  Since the top portion 31 a (31 b) is locally close to the core portion 15, the above refractive index change also acts locally on the core portion 15. At this time, the single-mode light L changes its path from a portion having a small refractive index to a portion having a large refractive index (that is, in a direction where the temperature is low). However, since the refractive index change is local, the single-mode light L is triggered by this refractive index change. The light L fluctuates. The manner in which the single mode light L fluctuates is clearly shown in FIGS. 14 to 16 (particularly, FIG. 15) of an embodiment described later. Then, the single mode light L travels to the emission side core portion 15c or 15d arranged in the direction in which the single mode light L fluctuates, of the two emission side core portions 15c and 15d. Here, the fluctuation does not necessarily require that the single mode light L reciprocate between the one side surface 15h and the other side surface 15i of the widened portion 15b. That is, as shown in FIG. 15 and FIG. 16, the light may enter the output-side core portion 15 c or 15 d immediately after being given a swinging trigger.

  Thus, the single mode light L selectively enters the exit-side core portion 15c or 15d in accordance with the heat generated by the heater wire 3a or 3b. A light emitting element such as an LED or a laser diode or an optical transmission medium such as an optical fiber is optically coupled to the light incident end 15e of the optical waveguide element 1a. A light receiving element such as a photodiode or an optical transmission medium is optically coupled to the light emitting ends 15f and 15g of the optical waveguide element 1a. The optical waveguide element 1a functions as an optical switch that selectively optically couples the light incident end 15e and the light emitting ends 15f and 15g.

  Here, FIG. 4A is a graph showing a simulation result of the correlation between the extinction ratio in the optical waveguide element 1a of the present embodiment and the closest position (vertex position) of the top portion 31a (31b) with respect to the core portion 15. It is. FIG. 4B is a graph showing a simulation result of the correlation between the input / output ratio in the optical waveguide element 1a of the present embodiment and the closest position (vertex position) of the top portion 31a (31b) with respect to the core portion 15. It is. FIG. 4A and FIG. 4B both show the case where the wavelength of the single mode light L is 1.3 μm.

  4A and 4B, the apex position of the top portion 31a (31b) is a numerical value based on the one end 15j of the widened portion 15b. In addition, the extinction ratio here is selected so that the single mode light L passes through (hereinafter referred to as the selection side) the outgoing light intensity from the core portion on the outgoing side and the single mode light L does not pass through ( Hereinafter, it is referred to as a ratio to the intensity of light emitted from the output-side core portion (referred to as non-selected side hereinafter). The input / output ratio here is the ratio of the incident light intensity to the incident-side core portion 15a and the emitted light intensity from the emission-side core portions 15c and 15d (that is, from the incident-side core portion 15a to the emission-side core portion). 15c and 15d). In FIG. 4B, the graph G11 shows the input / output ratio in the output side core portion on the selection side, and the graph G12 shows the input / output ratio in the output side core portion on the non-selection side.

  As shown in FIGS. 4A and 4B, the extinction ratio and the input / output ratio in the optical waveguide device 1a of the present embodiment vary depending on the apex position of the top portion 31a (31b), but as an optical switch. It turns out that it is a favorable value. Note that the extinction ratio and the input / output ratio vary depending on the apex position of the top portion 31a (31b) because the optical waveguide element 1a of the present embodiment changes the traveling direction of the single mode light L by a local refractive index change. Due to the fact that That is, the incident efficiency of the single mode light L to the output side core portion on the selection side differs depending on the position where the trigger of the fluctuation of the single mode light L is given. From this also, it can be understood that the traveling direction of the single mode light L can be suitably controlled by the optical waveguide element 1a of the present embodiment that locally heats the optical waveguide layer 11.

  As described above, according to the optical waveguide device 1a of the present embodiment, the traveling direction of the single mode light L can be suitably controlled. And since the advancing direction of the single mode light L can be changed by local heating by the top part 31a or 31b of the heater part 3, compared with the conventional structure shown in FIG. 21, for example, the heat generating part of the heater can be made small. . Therefore, the power consumption of the heater can be effectively reduced.

As shown in FIG. 3A, the planar shape of the widened portion 15b viewed from the layer thickness direction of the optical waveguide layer 11 is from the side surface of the incident side core portion 15a to the side surfaces of the output side core portions 15c and 15d. A continuous curve is preferred. Alternatively, the planar shape of the widened portion 15b is such that the one end 15m of the incident-side core portion 15a and the two imaginary single-mode optical waveguides W ₁ that individually couple the one ends 15n and 15p of the two exit-side core portions 15c and 15d, respectively. and is preferably a shape obtained by superimposing the planar shape of W _2. Thereby, since the fluctuation | variation of the propagation mode of the single mode light L which propagates the inside of the wide part 15b can be suppressed, the single mode light L can propagate stably even if a core width is expanded. Therefore, the fluctuation of the single mode light L due to local heating of the optical waveguide layer 11 can be effectively provided.

  In addition, as in the present embodiment, it is preferable that the side surfaces of the top portions 31a and 31b viewed from the thickness direction of the optical waveguide layer 11 are curved. Thereby, the current distribution in the top portions 31a and 31b can be made uniform, and stress can be prevented from being concentrated on one point. Therefore, peeling of the top portions 31a and 31b from the optical waveguide layer 11 due to long-time use can be suppressed.

(First modification)
FIG. 5 is a plan view showing a configuration of an optical waveguide device 1b according to a first modification of the embodiment. The difference between the optical waveguide element 1b according to this modification and the optical waveguide element 1a of the above-described embodiment is the shape of the heater portion. The optical waveguide element 1b of this modification includes a heater unit 4 instead of the heater unit 3 of the above embodiment. The heater unit 4 of this modification is provided on the optical waveguide layer 11. The heater unit 4 includes two heater wires 4 a and 4 b disposed on both sides of the core unit 15 when viewed from the thickness direction of the optical waveguide layer 11. The constituent materials and thicknesses of the heater wires 4a and 4b are the same as those of the heater wires 3a and 3b in the above embodiment.

  The heater wires 4a and 4b of this modification are configured in a V shape. Specifically, the heater wire 4a has a top portion 41a, skirt portions 42a and 43a, and electrodes 44a and 45a. Similarly, the heater wire 4b has a top portion 41b, skirt portions 42b and 43b, and electrodes 44b and 45b.

  One end of the skirt 42a of the heater wire 4a is connected to one end of the skirt 43a, and the other end of the skirt 42a is connected to the electrode 44a. The other end of the skirt 43a is connected to the electrode 45a. The skirt portions 42a and 43a are arranged so that a portion near one end connected to each other is close to the core portion 15 (widened portion 15b) and a portion near the other end is away from the core portion 15. And the connection part of the skirt parts 42a and 43a is the top part 41a (1st top part) in this modification. The top portion 41b, the bottom portions 42b and 43b, and the electrodes 44b and 45b of the heater wire 4b also have the same configuration as the heater wire 4a. That is, the top portions 41a and 41b are disposed on both sides of the widened portion 15b of the core portion 15 when viewed from the thickness direction of the optical waveguide layer 11, and are locally close to the widened portion 15b.

  The pair of first apexes in the present invention may be V-shaped apexes as in the present modification, in addition to the curvilinear shapes such as the apexes 31a and 31b of the above embodiment. Even if it is such a structure, the effect demonstrated by the said embodiment can be acquired suitably.

(Second modification)
FIG. 6A is a plan view showing a configuration of an optical waveguide element 1c according to a second modification of the embodiment. FIG. 6B is a cross-sectional view showing a II-II cross section of the optical waveguide device 1c shown in FIG. FIG. 7 is a cross-sectional view showing a III-III cross section of the optical waveguide device 1c shown in FIG. The difference between the optical waveguide element 1c according to this modification and the optical waveguide element 1a of the above-described embodiment is the shape of the heater portion. The optical waveguide element 1c of this modification includes a heater unit 5 instead of the heater unit 3 of the above embodiment. The heater unit 5 includes two heater wires 5 a and 5 b disposed on both sides of the core unit 15 when viewed from the thickness direction of the optical waveguide layer 11. The constituent materials and thicknesses of the heater wires 5a and 5b are the same as those of the heater wires 3a and 3b in the above embodiment.

  The heater wire 5a has a top portion 51a, skirt portions 52a and 53a, and electrodes 54a and 55a. Similarly, the heater wire 5b has a top portion 51b, skirt portions 52b and 53b, and electrodes 54b and 55b. The top portions 51 a and 51 b are a pair of first top portions in this modification, and are disposed on both sides of the widened portion 15 b of the core portion 15 when viewed from the layer thickness direction of the optical waveguide layer 11. Further, the planar shape of the heater wires 5a and 5b of the present modification viewed from the layer thickness direction of the optical waveguide layer 11 is the same as the planar shape of the heater wires 3a and 3b of the above embodiment.

  However, unlike the above embodiment, the heater wires 5a and 5b of this modification are arranged inside the optical waveguide layer 11. That is, the heater wires 5 a and 5 b are buried at the same position in the layer thickness direction as the core portion 15 on both sides of the widened portion 15 b in the optical waveguide layer 11 and are covered with the cladding portion 13. The electrodes 54a, 55a and 54b, 55b of the heater wires 5a and 5b are exposed at the bottoms of the recesses formed in the cladding portion 13 by dicing and dry etching.

  The pair of first top portions in the present invention may be embedded in the optical waveguide layer 11 as in the present modification. Even if it is such a structure, the effect demonstrated by the said embodiment can be acquired suitably.

(Third Modification)
FIG. 8 is a plan view showing a configuration of an optical waveguide device 1d according to a third modification of the embodiment. The difference between the optical waveguide element 1d according to this modification and the optical waveguide element 1a of the above embodiment is the shape of the heater portion. The optical waveguide element 1d of this modification includes a heater unit 6 instead of the heater unit 3 of the above embodiment. The heater unit 6 includes heater wires 6 a to 6 d provided on the optical waveguide layer 11. The constituent materials and the thicknesses of the heater wires 6a to 6d are the same as those of the heater wires 3a and 3b in the above embodiment.

  The heater wire 6a has a top portion 61a, skirt portions 62a and 63a, and electrodes 64a and 65a. Similarly, the heater wire 6b has a top portion 61b, skirt portions 62b and 63b, and electrodes 64b and 65b. The top portions 61 a and 61 b are a pair of first top portions in this modification, and are disposed on both sides of the widened portion 15 b of the core portion 15 when viewed from the layer thickness direction of the optical waveguide layer 11. Further, the planar shape of the heater wires 6a and 6b of the present modification viewed from the layer thickness direction of the optical waveguide layer 11 is the same as the planar shape of the heater wires 3a and 3b of the above embodiment.

  The heater wire 6c has a top portion 61c, skirt portions 62c and 63c, and electrodes 64c and 65c. Similarly, the heater wire 6d has a top portion 61d, skirt portions 62d and 63d, and electrodes 64d and 65d. The top portions 61c and 61d are a pair of second top portions in the present modification, and are respectively disposed on the side of the emission side core portions 15c and 15d of the core portion 15 when viewed from the layer thickness direction of the optical waveguide layer 11. . The cross-sectional areas of the top portions 61c and 61d are smaller than the cross-sectional areas of the skirt portions 62c, 63c and 62d and 63d of the heater wires 6c and 6d, respectively, and the heater wires 6c and 6d mainly generate heat at the top portions 61c and 61d. .

  The skirt portions 62c and 63c of the heater wire 6c are portions for electrically connecting the top portion 61c and the electrodes 64c and 65c. That is, one end of the skirt 62c is connected to one end of the top 61c, and the other end of the skirt 62c is connected to the electrode 64c. In addition, one end of the skirt 63c is connected to the other end of the top 61c, and the other end of the skirt 63c is connected to the electrode 65c. The skirt portions 62c and 63c are arranged such that a portion near one end connected to the top portion 61c is close to the core portion 15 (the emission side core portion 15c) and a portion near the other end is away from the core portion 15.

  Further, the skirt portions 62d and 63d of the heater wire 6d are portions for electrically connecting the top portion 61d and the electrodes 64d and 65d. One end of the skirt 62d is connected to one end of the top 61d, and the other end of the skirt 62d is connected to the electrode 64d. One end of the skirt 63d is connected to the other end of the top 61d, and the other end of the skirt 63d is connected to the electrode 65d. The skirt portions 62b and 63b are arranged such that a portion near one end connected to the top portion 61b is close to the core portion 15 (light emitting side core portion 15d) and a portion near the other end is away from the core portion 15. With these configurations, the top portions 61c and 61d are portions that are locally close to the exit-side core portions 15c and 15d in the heater wires 6c and 6d, respectively.

  The heater unit 6 of the present modification has a pair of second top portions 61c and 61d that are arranged on the sides of the two output side core portions 15c and 15d and are locally close to the output side core portions 15c and 15d. . As a result, the non-selection-side exit-side core portion 15c or 15d is locally heated by the top portions 61c and 61d, and the refractive index of the non-selection-side exit-side core portion 15c or 15d is lowered to enter the single mode light L. Can be suppressed. Therefore, according to this modification, the extinction ratio of the optical waveguide element can be further increased.

(Fourth modification)
FIG. 9 is a plan view showing a configuration of an optical waveguide device 1e according to a fourth modification of the embodiment. The difference between the optical waveguide element 1e according to this modification and the optical waveguide element 1a of the above-described embodiment is the shape of the heater portion. The optical waveguide element 1e of the present modification includes a heater unit 7 instead of the heater unit 3 of the above embodiment. The heater unit 7 includes heater wires 7 a and 7 b provided on the optical waveguide layer 11. The constituent materials and thicknesses of the heater wires 7a and 7b are the same as those of the heater wires 3a and 3b in the above embodiment.

  The heater wire 7a has three top portions 70a to 72a, four skirt portions 73a to 76a, and electrodes 77a and 78a. Similarly, the heater wire 7b has three top portions 70b to 72b, four skirt portions 73b to 76b, and electrodes 77b and 78b. The cross-sectional areas of the top portions 70a to 72a of the heater wire 7a are smaller than the cross-sectional areas of the skirt portions 73a to 76a, and the heater wire 7a mainly generates heat at the top portions 70a to 72a. Similarly, the cross-sectional areas of the top portions 70b to 72b of the heater wire 7b are smaller than the cross-sectional areas of the skirt portions 73b to 76b, and the heater wire 7b mainly generates heat at the top portions 70b to 72b.

  The top portions 70 a and 70 b are a pair of first top portions in this modification, and are respectively disposed on both sides of the widened portion 15 b when viewed from the layer thickness direction of the optical waveguide layer 11. The top portions 71a and 71b are a pair of second top portions in the present modification, and the top portions 72a and 72b are another pair of second top portions in the present modification. The top portions 71 a and 72 a are respectively arranged on the side of the emission side core portion 15 c when viewed from the layer thickness direction of the optical waveguide layer 11. The top portions 71 b and 72 b are respectively disposed on the side of the emission-side core portion 15 d when viewed from the layer thickness direction of the optical waveguide layer 11.

  The skirt portions 73a to 76a of the heater wire 7a are portions for electrically connecting the top portions 70a to 72a and the electrodes 77a and 78a to each other. That is, one end of the skirt portion 73a is connected to the electrode 77a, and the other end of the skirt portion 73a is connected to the top portion 70a. One end of the skirt portion 74a is connected to the top portion 70a, and the other end of the skirt portion 74a is connected to the top portion 71a. One end of the skirt 75a is connected to the top 71a, and the other end of the skirt 75a is connected to the top 72a. One end of the skirt portion 76a is connected to the top portion 72a, and the other end of the skirt portion 76a is connected to the electrode 78a. The skirt portions 73 a to 76 a are arranged so that the portions near the top portions 70 a to 72 a are close to the core portion 15 and the other portions are away from the core portion 15. With these configurations, the top portions 70a to 72a are portions that are locally close to the core portion 15 in the heater wire 7a.

  The heater wire 7b has the same configuration as the heater wire 7a. That is, one end of the skirt 73b is connected to the electrode 77b, and the other end of the skirt 73b is connected to the top 70b. One end of the skirt portion 74b is connected to the top portion 70b, and the other end of the skirt portion 74b is connected to the top portion 71b. One end of the skirt 75b is connected to the top 71b, and the other end of the skirt 75b is connected to the top 72b. One end of the skirt portion 76b is connected to the top portion 72b, and the other end of the skirt portion 76b is connected to the electrode 78b. The skirt portions 73 b to 76 b are arranged such that portions near the top portions 70 b to 72 b are close to the core portion 15 and other portions are away from the core portion 15. With these configurations, the top portions 70b to 72b are portions that are locally close to the core portion 15 in the heater wire 7b.

  In this modification, one of the pair of first tops (top 70a) and one of the pair of second tops (tops 71a and 72a) are formed integrally, and the other of the pair of first tops (top 70b). ) And the other of the pair of second top portions (top portions 71b and 72b) are integrally formed. With this configuration, the number of electrodes in the heater portion can be reduced.

  The result of trial manufacture of the optical waveguide device 1a of the above embodiment will be described. FIG. 10A is a diagram showing a plane pattern of the heater section 3 in the vicinity of the top portions 31a and 31b of the optical waveguide element 1a manufactured as a trial and a plane pattern of the core section 15 in the vicinity of the widened section 15b. FIG. 10B is a graph showing the change over time of the ratio (input / output ratio) of the outgoing light intensity with respect to the incident light intensity in the optical waveguide element 1a made as a prototype. Further, FIG. 11A is a diagram showing a plane pattern of the core portion 15 and the heater wires 110a and 110b in an optical waveguide device that is experimentally manufactured for comparison. The heater wires 110a and 110b have a conventional configuration extending from the incident side core portion 15a of the core portion 15 to the emission side core portions 15c and 15d. FIG. 11B is a graph showing the change over time of the ratio (input / output ratio) of the emitted light intensity to the incident light intensity in the optical waveguide element that was prototyped for comparison.

In addition, in Fig.10 (a) and FIG.11 (a), the width | variety of the core part 15 is 8-9 micrometers. 10B and 11B, graphs G21 and G31 indicate input / output ratios in the output-side core portion on the selection side, and graphs G22 and G32 in the output-side core portion on the non-selection side. The input / output ratio is shown. Further, in FIGS. 10B and 11B, the heater wire 3a or 3b is heated in a certain section t _{1 to} t _{2 so} that the single mode light L is incident on the output side core portion on the selection side. The time change of the input / output ratio when operating is shown.

  Compared with the conventional optical waveguide element (FIGS. 11A and 11B), in the optical waveguide element 1a of the present embodiment (FIGS. 10A and 10B), the output side core on the selection side It was shown that the emitted light intensity of the part is sufficiently larger than the emitted light intensity of the non-selected emission side core part, and a good extinction ratio can be obtained.

Table 1 below shows current values and voltage values required for the heater wires 3a and 3b of the optical waveguide device 1a (FIG. 10A) prototyped in this example, and power consumption values calculated from these values. It is a table | surface which shows. Table 1 also shows current values and voltage values required for the heater wires 110a and 110b of the conventional optical waveguide device (FIG. 11A), and power consumption values calculated from these values. . As is apparent from Table 1, according to the optical waveguide device 1a of the above embodiment, the power required for controlling the traveling direction of the single mode light L can be effectively reduced.

  The results of examining the difference in the output characteristics of the optical waveguide element 1a depending on the positions of the top portions 31a and 31b of the heater unit 3 will be described. FIG. 12 is a view showing both the planar pattern of the heater section 3 near the top portions 31a and 31b of the optical waveguide element 1a and the planar pattern of the core section 15 near the widened portion 15b. In the present embodiment, an element in which the top portions 31a and 31b are arranged at the position A in the drawing, an element arranged at the position B in the drawing, and an element arranged at the position C in the drawing are respectively prototyped, The input / output ratios of the output side core part and the non-selected side output side core part were measured. In addition, in order to make an understanding easy, in FIG. 12, the top parts 31a and 31b arrange | positioned in position AC are shown collectively.

FIGS. 13A to 13C are graphs showing the change with time of the input / output ratio in each element in which the top portions 31a and 31b are arranged at the positions A to C, respectively. 13A to 13C, graphs G41, G51, and G61 indicate input / output ratios at the output side core portion on the selection side, and graphs G42, G52, and G62 indicate output side cores on the non-selection side. The input / output ratio in the section is shown. 13A to 13C, the heater wire 3a or 3b is heated in a certain section t _{1 to} t _{2 so} that the single mode light L is incident on the emission side core portion on the selection side. The time change of the input / output ratio is shown.

  As shown in FIGS. 13A to 13C, the output characteristics of the optical waveguide device 1a vary greatly depending on the positions of the top portions 31a and 31b. In this embodiment, as shown in FIG. 12, the position A is set on both sides of the incident-side core portion 15a (that is, in front of the widened portion 15b), the position B is set on both sides of the widened portion 15b, and the position C Are set on both sides of the exit side core portions 15c and 15d (that is, behind the branch position). The results shown in FIGS. 13A to 13C show that the extinction ratio in the optical waveguide device 1a is the best when the top portions 31a and 31b are arranged on both sides of the widened portion 15b.

  14 to 16 are simulation results showing how the single mode light L propagates through the core portion 15 in each of the elements in which the top portions 31a and 31b are arranged at positions A to C. FIG. Referring to FIGS. 14 to 16, it was observed that the single mode light L fluctuates starting from the positions of the top portions 31a and 31b. It was also observed that the incident rate to the output side core portion on the selection side varies greatly depending on the position where the fluctuation is applied.

  From the results of this example, by arranging the top portions 31a and 31b on both sides of the widened portion 15b in the core portion 15, the single mode light L can be effectively fluctuated and the traveling direction can be changed more reliably. It was shown that.

  The result of examining in more detail the difference in output characteristics depending on the positions of the top portions 31a and 31b of the heater unit 3 will be described. In this example, a plurality of optical waveguide elements 1a, in which the positions of the top portions 31a and 31b arranged on both sides of the widened portion 15b are slightly different in the optical axis direction, were manufactured, and the extinction ratio and the input / output ratio were measured. FIG. 17 is a graph showing the correlation between the positions of the top portions 31a and 31b and the extinction ratio. In FIG. 17, a graph G71 shows a case where the wavelength of the single mode light L is 1.3 μm, and a graph G72 shows a case where the wavelength of the single mode light L is 1.5 μm. Moreover, the setting of the vertical axis (extinction ratio [dB]) and the horizontal axis (vertex position [μm] of the top portions 31a and 31b) in FIG. 17 is the same as that in FIG. 4A of the above embodiment.

  FIGS. 18A and 18B are graphs showing the correlation between the positions of the top portions 31a and 31b and the input / output ratio when the wavelength of the single mode light L is 1.3 μm and 1.5 μm, respectively. is there. In FIGS. 18A and 18B, graphs G81 and G91 indicate input / output ratios at the output-side core portion on the selection side, and graphs G82 and G92 indicate input / output at the output-side core portion on the non-selection side. The ratio is shown.

  From the results shown in FIG. 17, FIG. 18 (a), and FIG. 18 (b), the extinction ratio and the input / output ratio in the optical waveguide device 1a of the above embodiment vary depending on the vertex position of the top portion 31a (31b). It was shown to be a good value as an optical switch. In addition, although there are fluctuations depending on various conditions such as the wavelength of the single mode light L and the voltage value applied to the heater unit 3, there are positions of the tops 31a and 31b where the extinction ratio and the input / output ratio are optimum values. It was done.

  The results of examining the difference in output characteristics of the optical waveguide device 1b depending on the positions of the top portions 41a and 41b of the heater unit 4 according to the first modification example (see FIG. 5) will be described. FIG. 19 is a diagram showing a plane pattern of the heater portion 4 near the top portions 41a and 41b of the optical waveguide element 1b that has been prototyped and a plane pattern of the core portion 15 near the widened portion 15b. In the present embodiment, an element in which the top portions 41a and 41b are arranged at the position A, an element arranged at the position B, and an element arranged at the position C are respectively prototyped, and the output-side core portion on the selection side and the non-selection-side side The input / output ratio in the output core portion was measured. In addition, like the said Example 2, in FIG. 19, the top parts 41a and 41b arrange | positioned in position AC are shown in figure.

20 (a) to 20 (c) are graphs showing the change with time of the input / output ratio in each of the elements in which the top portions 41a and 41b are arranged at positions A to C, respectively. 20A to 20C, graphs G101, G111, and G121 indicate input / output ratios at the output side core portion on the selection side, and graphs G102, G112, and G122 indicate output side cores on the non-selection side. The input / output ratio in the section is shown. 20 (a) to 20 (c), the heater wire 4a or 4b is heated in a certain section t _{1 to} t _{2 so} that the single mode light L is incident on the emission side core portion on the selection side. The time change of the input / output ratio is shown. From the results shown in FIGS. 20A to 20C, the extinction ratio is the best when the top portions 41a and 41b are arranged on both sides of the widened portion 15b also in the optical waveguide device 1b according to the second modification. It has been shown.

Table 2 below shows current values and voltage values required for the heater wires 4a and 4b of the optical waveguide element 1b (FIG. 20B) prototyped in this example, and power consumption values calculated from these values. It is a table | surface which shows. Table 2 also shows these numerical values for the conventional heater wires 110a and 110b shown in Example 1 for comparison. As is apparent from Table 2, according to the optical waveguide device 1b according to the first modification, the power required for controlling the traveling direction of the single mode light L can be significantly reduced.

  The optical waveguide device according to the present invention is not limited to the above-described embodiments and modifications, and various other modifications are possible. For example, in the above-described embodiment and modification, the case where the pair of first top portions of the heater portion is curved or V-shaped has been shown, but the pair of first top portions of the present invention is locally applied to the core portion. As long as it is close to the surface, various other shapes are possible. Moreover, although the case where one optical switch is provided on one substrate is shown in the above embodiment and the modification, the present invention is also applied to an optical integrated device in which a plurality of optical switches and other various optical components are integrated. Applicable.

(A) It is a top view which shows the structure of the optical waveguide element which concerns on embodiment. (B) It is sectional drawing which shows the II cross section of the optical waveguide element shown to (a). It is an enlarged plan view which shows the structure of the top part vicinity of a heater part. (A) It is a top view of the core part for demonstrating in detail the planar shape of a wide part. (B) It is a top view which shows the shape of the optical waveguide in the conventional structure for a comparison. (A) It is a graph which shows the simulation result about the correlation of the extinction ratio in an optical waveguide element, and the nearest position (vertex position) to the core part in a top part. (B) It is a graph which shows the simulation result about the correlation with the input-output ratio in an optical waveguide element, and the closest position (vertex position) to the core part in a top part. It is a top view which shows the structure of the optical waveguide element which concerns on a 1st modification. (A) It is a top view which shows the structure of the optical waveguide element which concerns on a 2nd modification. (B) It is sectional drawing which shows the II-II cross section of the optical waveguide element shown to (a). It is sectional drawing which shows the III-III cross section of the optical waveguide element shown to Fig.6 (a). It is a top view which shows the structure of the optical waveguide element which concerns on a 3rd modification. It is a top view which shows the structure of the optical waveguide element which concerns on a 4th modification. (A) It is a figure which shows collectively the planar pattern near the top part of the heater part of the optical waveguide element made as an experiment, and the planar pattern near the wide part of a core part. (B) It is a graph which shows the time change of the ratio (input-output ratio) of the emitted light intensity with respect to incident light intensity in the optical waveguide element made as an experiment. (A) It is a figure which shows together the plane pattern of the core part and heater wire in the conventional type optical waveguide device made as an experiment for comparison. (B) It is a graph which shows the time change of the ratio (input-output ratio) of the emitted light intensity with respect to incident light intensity in the optical waveguide element made as an experiment for the comparison. It is a figure which shows together the plane pattern near the top part of the heater part of the optical waveguide element made as an experiment, and the plane pattern near the wide part of a core part. (A)-(c) It is a graph which shows the time change of input-output ratio in each element which has arrange | positioned the top part to position AC. 5 is a photograph showing a state in which single mode light propagates through a core portion in an optical waveguide element having a top portion disposed at position A. 6 is a photograph showing a state in which single mode light propagates through a core portion in an optical waveguide element having a top portion disposed at a position B. 5 is a photograph showing a state in which single mode light propagates through a core portion in an optical waveguide element having a top portion disposed at a position C. It is a graph which shows the correlation with the position of the top part of a heater part, and an extinction ratio. (A) It is a graph which shows the correlation with the position of a top part, and input-output ratio in case the wavelength of single mode light is 1.3 micrometers. (B) It is a graph which shows the correlation of the position of a top part, and input-output ratio in case the wavelength of single mode light is 1.5 micrometers. It is a figure which shows collectively the plane pattern near the top part of the heater part of the optical waveguide element concerning the 1st modification made as an experiment, and the plane pattern near the wide part of a core part. (A) It is a graph which shows the time change of the input-output ratio at the time of arrange | positioning the top part in the position A in the optical waveguide element which concerns on a 1st modification. (B) It is a graph which shows the time change of the input-output ratio at the time of arrange | positioning a top part in the position B. FIG. (C) It is a graph which shows the time change of the input-output ratio at the time of arrange | positioning a top part in the position C. FIG. It is a figure which shows the structure of the conventional optical switch.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a-1e ... Optical waveguide element, 3-7 ... Heater part, 3a-7a, 3b-7b, 6c, 6d ... Heater wire, 10 ... Board | substrate, 11 ... Optical waveguide layer, 13 ... Cladding part, 15 ... Core part, 15a ... Incident side core part, 15b ... Widened part, 15c, 15d ... Outgoing side core part, 31a, 31b, 41a, 41b, 51a, 51b, 61a-61d, 71a, 71b ... Top part.

Claims (7)

An optical waveguide layer that includes a polymer and has a core portion that guides single-mode light, and a cladding portion that has a refractive index smaller than that of the core portion;
A heater portion for partially heating the optical waveguide layer,
The core portion includes an entrance-side core portion, two exit-side core portions, and a widening portion that connects one end of the entrance-side core portion and one end of each of the two exit-side core portions,
The heater section is
A pair of first top portions disposed on both sides of the widened portion of the core portion and locally adjacent to the core portion;
A pair of first electrodes for receiving a control voltage to one of the pair of first peaks;
A pair of first skirts for electrically connecting the pair of first electrodes and both ends of the first top, respectively,
A pair of second electrodes for receiving a control voltage to the other first top of the pair of first tops;
A pair of second skirts for electrically connecting the pair of second electrodes and both ends of the other first top, respectively,
The pair of first top portions are disposed on both sides of the core portion at a distance from the core portion as viewed from the thickness direction of the optical waveguide layer,
The portions near the other ends of the first and second hem portions are moved away from the core portion with respect to the portions near the one ends of the first and second skirt portions connected to the pair of first top portions. An optical waveguide device characterized by being arranged as described above. An optical waveguide layer that includes a polymer and has a core portion that guides single-mode light, and a cladding portion that has a refractive index smaller than that of the core portion;
A heater portion for partially heating the optical waveguide layer,
The core portion includes an entrance-side core portion, two exit-side core portions, and a widening portion that connects one end of the entrance-side core portion and one end of each of the two exit-side core portions,
The heater section is
A pair of first apexes arranged on both sides of the widened portion of the core portion to give fluctuation to the single mode light;
A pair of first electrodes for receiving a control voltage to one of the pair of first peaks;
A pair of first skirts for electrically connecting the pair of first electrodes and both ends of the first top, respectively,
A pair of second electrodes for receiving a control voltage to the other first top of the pair of first tops;
A pair of second skirts for electrically connecting the pair of second electrodes and both ends of the other first top, respectively,
The pair of first top portions are disposed on both sides of the core portion at a distance from the core portion as viewed from the thickness direction of the optical waveguide layer,
The portions near the other ends of the first and second hem portions are moved away from the core portion with respect to the portions near the one ends of the first and second skirt portions connected to the pair of first top portions. An optical waveguide device characterized by being arranged as described above. The said heater part further has a pair of 2nd top part which is arrange | positioned in the side of each of said two output side core parts, and adjoins locally each output side core part, The Claim 1 or 2 characterized by the above-mentioned. 2. An optical waveguide device according to 1. The heater section is
A pair of third skirts for electrically connecting both ends of the second top of the pair of second tops and the pair of first electrodes, respectively;
A pair of fourth skirts for electrically connecting both ends of the other second top of the pair of second tops and the pair of second electrodes, respectively;
The one first top portion and the one second top portion are integrally formed by connecting one of the pair of first skirt portions and one of the pair of third skirt portions to each other. And
The other first top portion and the other second top portion are integrally formed by connecting one of the pair of second skirt portions and one of the pair of fourth skirt portions to each other. The optical waveguide device according to claim 3 , wherein the optical waveguide device is provided. The side surface shape of the widened portion viewed from the layer thickness direction of the optical waveguide layer is a curved line continuous from the side surface of the incident side core portion to the side surface of the output side core portion. the optical waveguide device according to any one of the 4. Two single-mode light beams in which the planar shape of the widened portion viewed from the layer thickness direction of the optical waveguide layer individually couples the one end of the incident side core portion and the one end of each of the two output side core portions. characterized in that it is a shape obtained by superimposing waveguide planar shape, the optical waveguide device according to any one of claims 1-4. The optical waveguide device according to any one of claims 1 to 6 , wherein a side shape of the top portion of the heater portion viewed from the layer thickness direction of the optical waveguide layer is a curve.

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