JP4531103B2 - Optoelectronic mixed substrate - Google Patents

Description

  The present invention relates to an optoelectronic mixed substrate used in an optical communication connection portion between electronic component substrates such as an optical communication system or a computer, or an optical signal conversion region between elements in the electronic component substrate, and in particular, temperature detection accuracy and sensor productivity. The present invention relates to an optoelectronic mixed substrate improved.

  In an optoelectronic mixed substrate used in an optical signal transmission system such as an optical communication system or a computer / exchanger, a device or material whose characteristics depend on temperature, or a part using temperature change is often used. For example, the threshold current of light emission changes with temperature for laser diodes, and the refractive index and density change with temperature for quartz and organic optical materials that form optical waveguides. Exists. Thus, the temperature is one of the important factors that influence the characteristics of the optical component, and detecting the temperature and controlling the temperature is a technique necessary for stable operation of the optical component.

  Conventionally, a case where a temperature sensor is used for such an optical component is mainly intended to detect an excessive temperature rise due to heat generation of a laser diode. FIG. 5 is a perspective view showing a conventional example of such a photoelectric mixed substrate.

  In the photopotential mixed substrate shown in FIG. 5, electric wiring and a V groove for mounting an optical fiber are formed on a silicon substrate 31 which is a support substrate for optical components, and a thermistor 33 as a laser diode 32 and a temperature sensor. Is mounted and electrically connected.

  An optical fiber 34 is mounted in the V groove, and transmits light from the laser diode 32. As described above, the thermistor 33 is generally used for temperature detection, and an electric wiring is formed on a support substrate for an optical component, and a thermistor 33 having a shape of an individual component such as a chip is provided on the substrate. The configuration to be implemented was taken. The substrate 31 is placed on a thermo module using a Peltier element, and is used by being radiated downward by heat conduction to the Peltier element.

On the other hand, quartz-based and organic-based optical materials are generally used as materials for optical waveguides that are optical components. Of these, quartz-based optical materials are manufactured by dry processes such as flame deposition, sputtering, or chemical vapor deposition, and are therefore susceptible to the unevenness of the surface of the substrate that forms the optical waveguide. The optical waveguide manufactured in the above tends to have a large loss. On the other hand, since an organic optical material is produced by applying and curing a solution containing a raw material, it tends not to be affected by unevenness on the substrate surface.
JP-A-1-152420

  However, in the opto-electronic mixed substrate using the temperature sensor with the individual parts as described above, the distance between the object to be measured (the laser diode 32 in the case of FIG. 5) and the temperature sensor (the thermistor 33 in the case of FIG. 5) is increased. Therefore, there is a problem that it is difficult to accurately measure the temperature of the object to be measured. In particular, since materials and structures with good heat dissipation are used as countermeasures against temperature rise due to parts that generate a large amount of heat, such as laser diodes, the higher the heat dissipation, the greater the location of the heat source on the board and the more distant from it. Since the temperature tends to have a large temperature difference, there is a problem that a value close to the temperature of the object to be measured cannot be obtained because the position of the temperature detection sensor is separated.

  Furthermore, when mounting a chip-shaped individual component temperature sensor such as a thermistor, a space of the size of the chip-shaped component is required, so it is arranged at a position somewhat away from the optical component that is the object to be measured. Since it is necessary to mount, it is necessary to form wiring and electrodes for mounting on the substrate, soldering the thermistor to the electrodes, etc., and there is a problem that the processing and mounting are troublesome. It was.

  Further, not only laser diodes but most optical materials have temperature dependence, and stabilization to an optimum temperature affects the performance of optical components. For example, some optical switches using the thermo-optic effect heat a part of the optical waveguide and switch using the change in refractive index due to the temperature rise, so that the temperature of the optical waveguide can be detected accurately. Therefore, the temperature can be controlled to eliminate the phase shift of the signal light and improve the switching performance. Even in such a case, if the temperature detecting element is arranged at a position far away from the part to be measured, it is difficult to detect the temperature of the heated part and the measurement accuracy cannot be improved.

  Furthermore, when the temperature detection element is disposed close to the lower part of the optical waveguide and the optical waveguide is manufactured as an optical component using a quartz-based optical material, the temperature detection element is formed on the substrate, thereby causing unevenness. Since the optical waveguide is produced reflecting the irregularities, there is a problem that the optical waveguide has large irregularities and the loss is increased.

  The present invention has been made in view of the above-described problems in the prior art, and its purpose is to accurately measure the temperature close to the temperature of the optical waveguide, which is the object to be measured, and to reduce the number of parts and work. An object of the present invention is to provide an optoelectronic mixed substrate that can improve productivity by reducing the number of steps.

Optoelectronic mixed substrate of the present invention includes a substrate, disposed on the substrate, a surface placed is below the core part of the Ruhikarishirube waveguide having a core portion, and the optical waveguide and the substrate A temperature detection element made of metal or semiconductor for detecting the temperature of the optical waveguide, and a temperature control resistor provided above the core portion so as to sandwich the optical waveguide with the temperature detection element, It comprises .

  As described above, according to the first optoelectronic mixed substrate of the present invention, the temperature detection element made of a metal or a semiconductor disposed in the vicinity of the temperature measurement portion of the optical waveguide is formed with respect to the optical waveguide. Since a space for mounting a chip-shaped temperature sensor is not required unlike a conventional opto-electronic mixed substrate, the temperature sensor can be arranged very close to the object to be measured, and at a position close to the object to be measured. Accurate temperature detection is now possible. In addition, since it is not necessary to mount a temperature sensor as an individual component, the number of components can be reduced, the number of work processes can be reduced, and productivity can be improved.

  Further, according to the second opto-electronic mixed substrate of the present invention, the optical waveguide is made of an organic optical material, and a temperature detecting element made of metal or semiconductor is disposed close to the optical waveguide in the same manner as described above. Highly accurate temperature detection is possible, the number of parts can be reduced, the number of work steps can be reduced, productivity can be improved, and the height difference generated when the temperature sensor is arranged on the substrate is reduced. At the same time, the influence on the optical waveguide due to the height difference can be suppressed, and the optical waveguide having a small loss in which the bending of the optical waveguide in the vertical direction is suppressed to be small.

  As described above, according to the present invention, it is possible to accurately measure a temperature close to the temperature of the optical waveguide that is the object to be measured, and it is possible to improve the productivity by reducing the number of parts and the number of work steps. We were able to provide an optoelectronic mixed substrate.

According to the first opto-electronic mixed substrate of the present invention, from a metal or semiconductor that is a temperature sensor disposed in the vicinity of a part of an optical waveguide that is a target of temperature detection, that is, near the upper or lower portion of the temperature measurement unit. By forming the temperature detecting element, it is not necessary to provide a space for mounting a chip-shaped temperature sensor as in the prior art, so it is possible to place the temperature sensor very close to the optical waveguide that is the object to be measured. And an opto-electronic mixed board that can detect the temperature with high accuracy and does not require the mounting of temperature sensors for individual parts, and can reduce the number of parts and work processes to improve productivity. Become.

  According to the second optoelectronic mixed substrate of the present invention, the optical waveguide is made of an organic optical material such as siloxane polymer, polyimide, benzocyclobutene, PMMA, polycarbonate, norbornene resin, or fluorine resin. By forming a temperature detection element made of metal or semiconductor, which is a temperature sensor close to a part of the lower part of the optical waveguide, it is possible to detect the temperature with high accuracy as described above and reduce the number of parts. As a result, the productivity can be improved by reducing the number of work steps, and the height difference generated when the temperature detection element, which is a temperature sensor, is arranged on the substrate. Because optical waveguides made of organic optical materials that are not easily affected by this are formed, bending in the vertical direction of the optical waveguides is minimized. The optoelectronic mixed substrate having a small light waveguides loss.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an optoelectronic mixed substrate in which a Mach-Zehnder all-optical switch is formed as an example of an embodiment of the optoelectronic mixed substrate of the present invention. FIG. 2 is a cross-sectional view taken along line A-A ′.

  In the optoelectronic mixed substrate shown in FIGS. 1 and 2, a thin film temperature sensor resistor 12 which is a temperature detecting element made of metal or semiconductor is formed on a support substrate 11, and signal light and control light are formed thereon. An optical waveguide comprising a core portion 13 and a clad portion 14 for transmitting the light, and a temperature control resistor 15 are formed thereon. Reference numeral 16 denotes a semiconductor optical amplifying element which switches by changing the refractive index with control light and changing the phase.

  Here, the location where the temperature is to be detected and detected is the portion of the optical waveguide located under the temperature control resistor 15, and the temperature sensor resistor 12 serving as the temperature detection element is located below the optical waveguide. It is formed in close proximity. As a result, the temperature can be detected by measuring the change in the resistance value of the resistor 12 with respect to the temperature at a location very close to the object to be measured.

  The substrate 11 serving as a base material of the opto-electronic mixed substrate functions as a support substrate for the optical waveguide, and various substrates used as substrates for handling optical signals such as an optical integrated circuit substrate and an opto-electronic mixed substrate, such as silicon substrates, An alumina ceramic substrate, a glass ceramic substrate, a multilayer ceramic wiring substrate, a plastic electric wiring substrate, or the like can be used.

  The temperature sensor resistor 12 that is a temperature detecting element is made of metal or semiconductor and may be any material that can measure a change in resistance value due to temperature. Various materials used for the side temperature resistor and thermistor. Can be used. It is also possible to use a thermocouple that generates an electromotive force by the Seebeck effect by connecting different kinds of metals.

  It goes without saying that various alloys can be used for the metal used in the temperature detection element, but platinum is suitable as a side temperature resistance material because it is chemically and thermally stable and can be obtained with high purity. The characteristics of platinum are that the resistivity is 1.06 × 10 −7 Ωm and the temperature coefficient of resistance is + 0.392% / ° C. at room temperature.

  The resistance value of the temperature detection element must be 1.0 Ω or more because the resistance value is less affected by the temperature dependence of the wiring resistance that is higher than the resistance of the wiring conductor connected to it to measure the change in resistance value. Is desirable. On the other hand, if the resistance value is too large, the detection value of the current will be small unless a high voltage is applied to the detection of the resistance value, and the detection sensitivity will be low. Since self-heating occurs, it becomes unsuitable as a temperature detection element. Accordingly, the resistance value is desirably 10 kΩ or less.

  Further, it is preferable to form the temperature detecting element as a thin film made of a metal or a semiconductor because the flatness of the substrate surface is kept good and various shapes can be easily formed by patterning. In the case of forming as a thin film, it may be prepared by vacuum deposition, sputtering, plating, screen printing, or the like. If the optical waveguide is formed on it, it is difficult to fabricate it in a flat shape because the thickness of the film is too thick. preferable.

  When such a temperature detection element is arranged close to a part of the optical waveguide, the temperature measurement part of the optical waveguide, particularly the core part 13, is arranged at the lower part or at the upper part or the side part. If it is a position where the temperature can be measured at a very close location, it may be appropriately arranged according to the specifications of the photoelectron mixed substrate, the formation conditions of the optical waveguide, and the like. In particular, when the temperature detection element is disposed below the core portion 13 of the optical waveguide, the temperature detection element can be produced on the substrate by a thin film process similar to that for producing the electrical wiring on the electrical wiring board. A combination having good adhesion to the substrate can be selected.

  Further, in the second optoelectronic mixed substrate of the present invention, the temperature detecting element is disposed close to the lower part of the optical waveguide temperature to be measured. In this manner, the temperature detecting element is disposed close to the lower part of the optical waveguide, that is, temperature detection. By forming an optical waveguide made of an organic optical material on the upper part of the element, the unevenness caused by placing the temperature detecting element close to the lower part can be flattened by the coating process of the organic optical material. On the other hand, it is possible to form an optical waveguide with little distortion in the vertical direction and therefore with little loss.

  The core portion 13 and the clad portion 14 of the optical waveguide can be made of an inorganic or organic optical material such as quartz, but the first photoelectron mixed substrate of the present invention and the second photoelectron mixed of the present invention. When using an organic optical material for the substrate, it is preferable to use siloxane polymer, polyimide, benzocyclobutene, PMMA, polycarbonate, norbornene resin, fluorine resin, etc. as described above. It is possible to produce an optical waveguide that is difficult and has excellent flatness. These may be formed by a spin coating method, a roll coating method, a spray coating method, or the like, and a photolithography method and an RIE (Reactive Ion Etching) processing may be used for processing the core portion 13. Note that, regardless of which optical material is used, the refractive index of the core portion 13 is selected so as to be larger than the refractive index of the cladding portion 14.

  Next, specific examples of the optoelectronic mixed substrate of the present invention will be described.

  [Example 1] A resistor 11 made of a metal film is disposed on the lower surface of the object to be measured as a temperature detecting element, so that the substrate 11 and the temperature sensor as shown in FIGS. A Mach-Zehnder all-optical switch A having an optical waveguide comprising a resistor 12, a core part 13 and a clad part 14, a temperature control resistor 15 and a semiconductor optical amplifier (SOA) 16 was produced. This Mach-Zehnder type all-optical switch A performs switching by inputting signal light and control light from the outside through an optical fiber or the like and changing the refractive index of the SOA 16. Here, although the Mach-Zehnder type all-optical switch has the advantage of downsizing as a feature, there is a possibility that the phase shifts due to a position shift of a small size and the loss increases, so that the temperature control resistor 15 A thin film heater was provided, and an attempt was made to correct the phase shift using the thermo-optic effect.

  The size of the substrate 11 is 20 mm long × 10 mm wide × 0.5 mm thick, the substrate material is aluminum nitride (thermal conductivity: 150 W / m · K), and the SOA 16 is 1 mm long × 0.3 mm wide × 0.15 mm thick Two things were implemented. The SOA 16 has two driving wirings each made of Ti / Pt / Au.

  Further, a thin linear temperature sensor resistor 12 that passes under the thin film heater that is the temperature control resistor 15 is formed, and the temperature detection portion under the temperature control thin film heater is Ti / Pt, temperature detection Except the part, it was composed of Ti / Pt / Au. The resistance value of the temperature detector is 100Ω, otherwise it is 0.2Ω. The film thicknesses of Ti and Pt were 0.1 μm and 1.0 μm, respectively.

  The optical waveguide 13 was formed by heat treatment at 85 ° C./30 minutes and 270 ° C./30 minutes by applying a mixed solution of siloxane polymer and tetra-n-butoxy titanium to the cladding portion 14 and the core portion 13. The optical waveguide material was removed from the SOA mounting portion and the electrode by the RIE method. Then, the SOA 16 was disposed so that the positional deviation with respect to the optical waveguide was small, and was electrically connected by soldering and wire bonding.

  As a comparative example, a conventional Mach-Zehnder type all-optical switch B having the same configuration as described above and shown in a perspective view in FIG. 4 and a cross-sectional view along the line B-B ′ in FIG. Here, the dimensions of the substrate 21 are 20 mm long × 10 mm wide × 0.5 mm thick, the substrate material is aluminum nitride (thermal conductivity: 150 W / m · K), and the size of the SOA 26 is 1 mm long × 0.3 mm wide × Two pieces having a thickness of 0.15 mm were mounted. The SOA 26 has two driving wirings each made of Ti / Pt / Au. Unlike the Mach-Zehnder all-optical switch A having the configuration of the present invention, the thermistor 22 and the electrical wiring for the thermistor 22 are provided near the portion of the optical waveguide located under the temperature control resistor. In addition, an optical waveguide including a core portion 23 and a cladding portion 24 is formed under a thin film heater which is a drive wiring and a temperature control resistor 25. This optical waveguide was formed by heat treatment at 85 ° C./30 minutes and 270 ° C./30 minutes by applying a mixed solution of siloxane polymer to the cladding portion 24 and a siloxane polymer and tetra-n-butoxy titanium at the core portion 23. As the temperature control resistor 25, an aluminum film was formed by sputtering. The optical waveguide material was removed from the SOA mounting portion and the electrode by the RIE method. The SOA 26 was arranged so that the positional deviation with respect to the optical waveguide was small, and was electrically connected by soldering and wire bonding. A thermistor 22 as a temperature detection element was used for surface mounting, and was mounted on an electrode portion on a substrate and soldered.

  For these Mach-Zehnder type all-optical switches A and B, current was passed through the temperature control resistors 15 and 25 to generate heat at a room temperature of 23 ° C., and the temperatures were measured by the temperature sensors 12 and 22 respectively of A and B. The measurement results of the relationship between the heat generation amount and the temperature are shown in FIG.

  In FIG. 6, the horizontal axis represents the heat generation amount (W), the vertical axis represents the temperature (° C.), and the black square and the white square show the temperature measurement results in the Mach-Zehnder all-optical switches A and B, respectively. From this result, compared with the temperature measured by the thin film temperature sensor in the optical switch A, the temperature measured by the thermistor in the optical switch B becomes larger in temperature difference from the measurement result in the optical switch A as the calorific value increases. It can be seen that the optical switch A having a higher detection temperature measures a temperature closer to the temperature of the heating element. Thereby, it was confirmed that the optical switch A has better temperature measurement accuracy.

  In addition, in the optical switch A, a thin film temperature sensor as a temperature detecting element is only manufactured using a thin film process, so that the number of chip components such as the thermistor in the optical switch B can be reduced and a process such as soldering is required. In addition, the optical switch A was superior in terms of productivity.

  Accordingly, it was confirmed that the photoelectron mixed substrate of the present invention can detect the temperature at a position near the object to be measured, and can be a photoelectron mixed substrate having good temperature measurement accuracy.

  [Example 2] As a comparative example, a Mach-Zehnder all-optical switch C, which is a photoelectron mixed substrate having the same configuration as the optical switch A of the above [Example 1] and having no temperature sensor resistor, was produced.

  For these optical switches A and C, light from a laser diode with a power of 10 dBm and a wavelength of 1.3 μm was incident on the optical waveguide through a single mode optical fiber and propagated through the optical waveguide. Then, the intensity of the emitted light was examined by optically connecting a single mode optical fiber to the other end face of the optical waveguide. As a result, the intensity of the emitted light from the optical waveguide showed the same intensity within the error range. Accordingly, it was found that the optical waveguide produced using the siloxane polymer, which is an organic optical material, has a good optical characteristic because the loss is suppressed to a low level without affecting the flatness of the base.

  Thereby, it was confirmed that the second photoelectron mixed substrate of the present invention is a photoelectron mixed substrate having small optical loss and good optical characteristics.

  Note that the above are merely examples of the embodiments of the present invention, and the present invention is not limited to these embodiments, and various modifications and improvements may be made without departing from the scope of the present invention. . For example, a plurality of temperature detection elements may be provided to provide a photoelectron mixed substrate that can accurately detect the temperature distribution.

It is a perspective view which shows the optoelectronic mixed board | substrate which formed the Mach-Zehnder all-optical switch as an example of embodiment of the optoelectronic mixed board | substrate of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of the optoelectronic mixed substrate shown in FIG. 1. It is a perspective view which shows the optoelectronic mixed board | substrate which formed the Mach-Zehnder type all-optical switch as a comparative example. FIG. 4 is a cross-sectional view taken along line B-B ′ of the photoelectron mixed substrate shown in FIG. 3. It is a perspective view which shows the prior art example of a photoelectric mixed board | substrate. It is a diagram which shows the measurement result of the relationship of the emitted-heat amount and temperature in the Example and comparative example of this invention.

Explanation of symbols

11: Board
12: Temperature sensor resistor (temperature detection element)
13: Core part of optical waveguide
14: Clad part of optical waveguide
15: Resistor for temperature control

Claims (5)

A substrate,
Disposed on the substrate, and Ruhikarishirube waveguide having a core portion,
Is placed below the core portion or at the interface between the optical waveguide and the substrate, a temperature detection element formed of a metal or a semiconductor for detecting temperature of said optical waveguide,
A temperature control resistor provided above the core so as to sandwich the optical waveguide with the temperature detection element;
An optoelectronic mixed substrate comprising: The optoelectronic mixed substrate according to claim 1, wherein the temperature detection element is formed as a thin film . The optoelectronic mixed substrate according to claim 1 or 2, wherein the temperature detecting element has a thickness of 10 µm or less . The core is a first core part,
4. The optoelectronic mixed substrate according to claim 1, further comprising a second core portion that is provided on the substrate and is provided alongside the first core portion . 5. The optoelectronic mixed substrate according to claim 4, which functions as a Mach-Zehnder type optical switch .

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