WO2023238279A1 - Optical power supply converter - Google Patents

Optical power supply converter Download PDF

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Publication number
WO2023238279A1
WO2023238279A1 PCT/JP2022/023117 JP2022023117W WO2023238279A1 WO 2023238279 A1 WO2023238279 A1 WO 2023238279A1 JP 2022023117 W JP2022023117 W JP 2022023117W WO 2023238279 A1 WO2023238279 A1 WO 2023238279A1
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WIPO (PCT)
Prior art keywords
circular
light
photodiode
radial
light receiving
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PCT/JP2022/023117
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French (fr)
Japanese (ja)
Inventor
尚友 磯村
悦司 大村
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株式会社京都セミコンダクター
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Application filed by 株式会社京都セミコンダクター filed Critical 株式会社京都セミコンダクター
Priority to JP2023544122A priority Critical patent/JP7412834B1/en
Priority to PCT/JP2022/023117 priority patent/WO2023238279A1/en
Publication of WO2023238279A1 publication Critical patent/WO2023238279A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device

Definitions

  • the present invention relates to an optical power supply converter that converts light input through an optical fiber cable into electric power and supplies the converted electric power.
  • optical power supply converters are used that receive light transmitted to electronic devices via optical fiber cables, generate photocurrent through photoelectric conversion, and supply power.
  • the optical power supply converter has a semiconductor light receiving element for photoelectric conversion.
  • the output voltage of this semiconductor photodetector is usually less than 1V.
  • an optical power supply converter with a high output voltage is used.
  • Patent Document 1 it is possible to increase the output voltage by dividing the circular light-receiving portion of a semiconductor light-receiving element into a plurality of sector-shaped photodiodes by an isolation groove and connecting these in series.
  • the output voltage of a semiconductor light-receiving element composed of a plurality of divided photodiodes connected in series increases as the number of photodiodes increases.
  • the output current is smaller than when it is not divided, and becomes smaller as the number of divisions increases.
  • this output current is limited by the photodiode with the least photocurrent generated by photoelectric conversion. Therefore, in order to make the photocurrents of the plurality of photodiodes equal to each other, the circular light receiving section is equally divided so that the plurality of photodiodes have the same shape and the same area.
  • a plurality of linear isolation grooves with a constant width are formed radially in the radial direction from the center of the circular light receiving area. Concentrate near the center. The larger the number of divisions of the circular light-receiving section, that is, the more isolation grooves there are, the closer the adjacent isolation grooves are, so that a plurality of isolation grooves are connected in the width direction at positions separated from the center of the circular light-receiving section. This makes them continuous in the circumferential direction. Since photoelectric conversion cannot be performed in the isolation groove, the more the number of divisions of the circular light-receiving area is, the more isolation grooves are formed in the circumferential direction near the center of the circular light-receiving area. becomes larger.
  • the intensity distribution of the light input through the optical fiber cable is generally a Gaussian distribution, and the light intensity decreases as the distance from the optical axis increases. This is the intensity distribution. Therefore, by allowing the optical axis of this light to pass through the center of the circular light receiving section perpendicularly to the circular light receiving section, the plurality of photodiodes of the circular light receiving section can receive the light evenly.
  • the circular light receiving section is divided into a circular photodiode and a plurality of photodiodes arranged in the circumferential direction around the circular photodiode as in Patent Document 2, the portion with high light intensity near the optical axis is also photoelectrically converted, and the number of divisions is reduced.
  • the output voltage can be increased by increasing the output voltage.
  • the diameter of the circular photodiode decreases, and the radial isolation grooves become closer to each other on the outside. so that they overlap.
  • an object of the present invention is to provide a light-fed converter with improved output by improving the utilization efficiency of light from an optical fiber cable in a circular light-receiving section divided in order to increase the output voltage.
  • the optical power feeding converter of the invention according to claim 1 is an optical power feeding converter that converts incident light input from an optical fiber cable into a photocurrent by a semiconductor light receiving element and outputs the photocurrent, wherein the semiconductor light receiving element includes a circular light receiving part,
  • the circular light-receiving section includes a circular photodiode divided by a plurality of annular isolation grooves concentric with the circular light-receiving section, and one or more annular photodiodes, and a circular light-receiving section located outside the circular photodiode.
  • It has a plurality of radial photodiodes divided by a plurality of radial isolation grooves formed radially with respect to the center, and the circular photodiode, the annular photodiode, and the radial photodiode are configured to absorb the incident light.
  • the light receiving areas are respectively set so that the amount of light received is equal to each other based on the intensity distribution, and the circular photodiode, the annular photodiode, and the plurality of radial photodiodes are connected in series by a plurality of conductive members. It is characterized by
  • the circular light receiving part of the semiconductor light receiving element is divided by a plurality of annular isolation grooves and a plurality of radial isolation grooves, and is divided into a circular photodiode, one or more annular photodiodes, and a plurality of radial photodiodes. A diode is formed. These plurality of photodiodes are connected in series.
  • the light-receiving areas of the circular photodiode, annular photodiode, and radial photodiode of this circular light-receiving section are set so that the amount of light received is equal to each other based on the light intensity distribution of the incident light input from the optical fiber cable. are set respectively.
  • the central part of the circular light receiving section where the light intensity of the incident light is high can be converted into photocurrent, improving the light utilization efficiency in the circular light receiving section, thereby improving the output of the optical power supply converter. can be done.
  • the optical power feeding converter of the invention according to claim 2 is characterized in that in the invention according to claim 1, the plurality of radial isolation grooves are formed rotationally symmetrically with respect to a central axis passing through the center of the circular light receiving section. It is said that According to the above configuration, since the outer side of the annular photodiode is equally divided in the circumferential direction by the radial isolation grooves formed in a rotationally symmetrical manner, it is possible to easily equalize the light receiving areas of the plurality of radial photodiodes. can. Furthermore, the incident light input from the optical fiber cable has a light intensity distribution that is rotationally symmetrical with respect to the optical axis.
  • the optical axis of the incident light passes through the center of the circular light receiving part perpendicularly to the circular light receiving part, that is, the optical axis of the incident light is made to coincide with the central axis of the circular light receiving part.
  • the amount of light received by each photodiode of the circular light receiving section can be made equal to each other. Therefore, variations in the photocurrents generated by the plurality of photodiodes included in the circular light receiving section are suppressed, and a decrease in the output of the optical power supply converter can be suppressed.
  • optically-fed converter of the present invention it is possible to improve the efficiency of using light from the optical fiber cable in the divided circular light-receiving section to increase the output voltage, thereby improving the output of the optically-fed converter.
  • FIG. 1 is a perspective view of an optical power supply converter according to Example 1 of the present invention.
  • FIG. 2 is an explanatory diagram of light incident on a semiconductor light-receiving element included in the optical power feeding converter of FIG. 1.
  • FIG. 3 is a plan view of the semiconductor light receiving element of FIG. 2 viewed from the light incident side. 4 is a sectional view taken along the line IV-IV in FIG. 3.
  • FIG. 2 is a light intensity distribution diagram of light input via an optical fiber cable.
  • 7 is a graph showing an example of the diameter of a circular photodiode and the outer diameter of an annular photodiode depending on the number of divisions of a circular light receiving section.
  • FIG. 7 is a graph showing a comparative example of output according to the division mode of the circular light-receiving section.
  • FIG. 7 is a diagram showing another example of division of the circular light receiving section.
  • FIG. 3 is a plan view of a back-illuminated semiconductor device according to Example 2 of the present invention, viewed from the light incident side. 10 is a sectional view taken along line XX in FIG. 9. FIG.
  • the optical power supply converter 1 converts light (incident light) L input via, for example, a single mode optical fiber cable OC into a photocurrent, and supplies this photocurrent to the outside. It has a pair of output terminal parts 2a and 2b for.
  • the base 3 equipped with a pair of output terminals 2a and 2b includes a semiconductor light receiving element 10 for generating a photocurrent by photoelectric conversion from received light, and a semiconductor light receiving element 10 for protecting and shielding the semiconductor light receiving element 10.
  • the covers 5 are fixed to each other by, for example, adhesive.
  • a pair of electrodes 10a, 10b of the semiconductor light receiving element 10 are connected to wiring portions 3a, 3b connected to corresponding output terminal portions 2a, 2b, for example, by conductive wires 11a, 11b.
  • the optical fiber cable OC is inserted into the insertion hole 5a passing through the cover 5, and fixed so that its output end E is spaced a predetermined distance from the semiconductor light receiving element 10.
  • the cover 5 may be equipped with a positioning mechanism for the output end E of the optical fiber cable OC.
  • the light L input through the optical fiber cable OC is infrared light with a wavelength of, for example, about 1.5 ⁇ m.
  • This light L is a conical beam whose irradiation range expands as it advances after being emitted from the output end E.
  • the semiconductor light receiving element 10 has a circular light receiving section 12 that generates a photocurrent from the light L through photoelectric conversion.
  • the optical axis OA of the light L emitted from the output end E passes through the center C of the circular light receiving section 12 perpendicularly to the circular light receiving section 12, that is, the optical axis OA and the central axis of the circular light receiving section 12 coincide.
  • the output end E is positioned so that the output end E is positioned as shown in FIG.
  • the circular light-receiving section 12 includes, for example, a circular PIN-type photodiode provided with a light absorption layer, which is divided into a plurality of photodiodes by an isolation groove of a constant width, and these plurality of photodiodes are connected in series. is connected to and formed. Note that since no photocurrent is generated in the isolation groove, it is preferable to reduce the area of the isolation groove in the area of the circular light receiving section 12 in order to increase the output.
  • a circular photodiode 14a is formed in the center of the circular light receiving section 12 by a first annular isolation groove 13a concentric with the circular light receiving section 12. Further, between the first annular isolation groove 13a and the second annular isolation groove 13b which is concentric with the circular light receiving part 12 and has a diameter larger than the first annular isolation groove 13a, an annular photodiode 14b is provided. It is formed.
  • a plurality of grooves (in this case, 30 A straight radial isolation groove 15 is formed.
  • These plurality of radial isolation grooves 15 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12, and equally divide the outside of the annular photodiode 14b in the circumferential direction.
  • the annular isolation groove 13b and the outer circumferential isolation groove 13n are connected. Note that in FIG. 3, some of the symbols of the radial isolation grooves 15 are omitted.
  • a plurality of (30 in this case) radial photodiodes 16 are formed by a plurality of radial isolation grooves 15 on the outside of the annular photodiode 14b. These radial photodiodes 16 are arranged in the circumferential direction so as to surround the annular photodiode 14b.
  • the circular, annular, and radial photodiodes formed by dividing the circular light receiving section 12 may be referred to as PD without distinction. Note that in FIG. 3, some of the symbols of the radial photodiodes 16 are omitted.
  • Each PD (circular photodiode 14a, annular photodiode 14b, and radial photodiode 16) of the circular light receiving section 12 is an n-type semiconductor layer stacked on a semi-insulating semiconductor substrate 20, as shown in FIG. 4, for example. 21, a light absorption layer 22, and a p-type semiconductor layer 23.
  • the semiconductor substrate 20 is, for example, an InP substrate
  • the n-type semiconductor layer 21 is, for example, an n-InP layer
  • the light absorption layer 22 is, for example, an InGaAs layer
  • the p-type semiconductor layer 23 is, for example, a p-InP layer.
  • the circular light receiving section 12 is not limited to this, and the circular light receiving section 12 is not limited to the PIN type. Note that the thicknesses of the n-type semiconductor layer 21, the light absorption layer 22, and the p-type semiconductor layer 23 can be set as appropriate, and are often formed to a thickness of about 0.5 to 10 ⁇ m.
  • the isolation grooves include an n-type semiconductor layer 21, a light absorption layer 22, and a p-type semiconductor layer 23. It is formed by selectively etching the semiconductor substrate 20 on which are stacked layers from the p-type semiconductor layer 23 side until the semiconductor substrate 20 is reached. This forms a plurality of electrically isolated PDs. Note that the sidewalls of the isolation groove may be inclined such that, for example, the width becomes narrower toward the semiconductor substrate 20 side.
  • Each of the plurality of PDs has a through hole 17 that penetrates the p-type semiconductor layer 23 and the light absorption layer 22 and reaches the n-type semiconductor layer 21.
  • An insulating protective film 24 is formed to cover the surfaces of the plurality of PDs and the inner walls of the through holes 17 of these PDs, and to fill the isolation grooves.
  • the protective film 24 preferably has an anti-reflection function for the incident light L, but an anti-reflection film not shown may be formed.
  • each PD the protective film 24 on the p-type semiconductor layer 23 and inside the through-hole 17 is partially removed, and the n-type semiconductor layer 21 is exposed at the p-type semiconductor layer 23 and the bottom of the through-hole 17.
  • a plurality of PDs in series using a plurality of conductive members 25 one exposed p-type semiconductor layer 23 is placed between adjacent PDs via an isolation groove. and the other n-type semiconductor layer 21 are connected by a conductive member 25. Note that in FIG. 3, some of the symbols of the plurality of conductive members 25 are omitted.
  • the conductive member 25 is formed by selectively depositing a metal laminated film using, for example, a lift-off method.
  • the metal laminated film is composed of an adhesion layer such as titanium or chromium, and a low resistivity layer such as gold, silver, or aluminum. Since the isolation groove is filled with the protective film 24 and the step difference is reduced, the formation of the conductive member 25 is facilitated.
  • conductive members 25 are provided, for example, for connecting the electrode 10a and the circular photodiode 14a and for connecting the annular photodiode 14b and the radial photodiode 16, respectively. is formed so that the incident light L is not blocked. Since the conductive members 25 connecting adjacent radial photodiodes 16 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12, each radial photodiode 16 is shielded by the conductive member 25. It is preferable that the amounts of light emitted are equal.
  • the isolation groove is filled with the protective film 24 and there is no step, a plurality of conductive members 25 can be easily formed.
  • the isolation groove may be filled with the protective film 24 by making the level difference small to the extent that the conductive member 25 can be formed.
  • an anode electrode connected to the p-type semiconductor layer 23 and a cathode electrode connected to the n-type semiconductor layer 21 are formed in each PD, and one anode electrode is connected to the other between adjacent PDs in the same manner as described above. It may be connected to the cathode electrode by a conductive member 25.
  • a conductive wire containing gold as a main component may be used as the conductive member 25.
  • the optical power supply converter 1 equipped with the semiconductor light receiving element 10 for photoelectrically converting light input via the optical fiber cable OC can supply power at a high voltage.
  • the light L emitted from the output end E of the optical fiber cable OC spreads into a conical shape with an apex angle ⁇ (full angle) of 14 degrees, for example, as shown in FIGS. 2 and 5, and enters the circular light receiving portion 12.
  • the light intensity distribution of this light L is a Gaussian distribution, and the light intensity decreases as the distance from the optical axis OA increases, and the light intensity distribution becomes rotationally symmetrical with respect to the optical axis OA.
  • the circular photodiode 14a, the annular photodiode 14b, and the radial photodiode 16 The light-receiving area of each is set.
  • the circular photodiode 14a that receives high-intensity light has a small area
  • the radial photodiode 16 that receives low-intensity light has a larger area than the circular photodiode 14a and the annular photodiode 14b.
  • the light receiving area is such that, for example, the light intensity incident on the outermost portion of the circular light receiving section 12 is 1/ e2 of the light intensity incident on the center C (approximately 90% of the light L is irradiated onto the circular light receiving section 12). ), the amount of light received by each PD is set to be equal to each other.
  • the photocurrent that each PD can generate varies depending on the number of PDs that the circular light receiving section 12 has. Therefore, when the light receiving area is set so that the photocurrent generated by each PD is equal based on the light intensity distribution, the diameter and circle of the circular photodiode 14a are determined according to the number of PDs that the circular light receiving section 12 has. The outer diameter of the annular photodiode 14b is set.
  • An example of setting the diameter D1 of the circular photodiode 14a and the outer diameter D2 of the annular photodiode 14b is shown in FIG.
  • the diameter D1 of the circular photodiode 14a is 230 ⁇ m.
  • the outer diameter D2 of the annular photodiode 14b is set to 340 ⁇ m.
  • the circular light receiving section 12 is divided into 32 PDs and has one circular photodiode 14a, one annular photodiode 14b, and 30 radial photodiodes 16 (see FIG.
  • the circular photodiode The diameter D1 of the diode 14a is set to 126 ⁇ m, and the outer diameter D2 of the annular photodiode 14b is set to 179 ⁇ m. Note that the diameter D0 of the circular light receiving section 12, the number of PDs, and the width of the isolation groove can be set as appropriate.
  • the circular light receiving section is radially divided into 30 equal parts by a plurality of linear isolation grooves extending radially from the center of the circular light receiving section.
  • an ineffective region where photoelectric conversion cannot be performed is formed near the center of the circular light receiving section 12 where a plurality of isolation grooves are concentrated, and the relative output is 0.89.
  • the utilization efficiency of light incident on the circular light receiving section 12 is 11% lower than in pattern #1, and there is a large waste of light input.
  • pattern #3 a circular photodiode with a diameter of 128 ⁇ m is provided concentrically with the circular photodiode at the center of the circular photodiode, and 30 radial photodiodes are provided by dividing the circumference of the circular photodiode into 30 equal parts.
  • the circular photodiode reduces the ineffective area compared to pattern #2, and the relative output of pattern #3 is 0.93.
  • Pattern #3 has improved utilization efficiency of light incident on the circular light receiving section 12 compared to pattern #2.
  • pattern #4 which corresponds to the circular light receiving section 12 in FIG. 3, a circular photodiode with a diameter of 126 ⁇ m and an annular photodiode with an outer diameter of 179 ⁇ m are provided in the center of the circular light receiving section concentrically with the circular light receiving section. , the outside of the annular photodiode is divided into 30 equal parts to provide 30 radial photodiodes.
  • an ineffective region that should be formed by concentration of isolation grooves outside the circular photodiode is not formed by the annular photodiode. Therefore, the relative output of pattern #4 is 0.97, and the output can be made larger than patterns #2 and #3. Therefore, in pattern #4, the utilization efficiency of light incident on the circular light receiving portion 12 is improved compared to pattern #3, and the wasted light input is reduced compared to patterns #2 and #3.
  • the outer diameter D2 of the annular photodiode 14b becomes smaller, so that a plurality of radial isolation grooves 15 are concentrated near the annular photodiode 14b. I come to do it. Therefore, on the outside of the annular photodiode 14b, not only the second annular isolation groove 13b but also a plurality of radial isolation grooves 15 are connected in the width direction, and are connected in the circumferential direction. A region will be formed.
  • the circular light receiving section 12 has a second circular isolation groove 13b and a third circular isolation groove on the outside of the circular photodiode 14b.
  • a second annular photodiode 14c may be formed between the photodiodes 13c and 13c.
  • the photocurrents generated by the plurality of PDs (circular photodiode 14a, two annular photodiodes 14b, 14c, and plurality of radial photodiodes 16) of the circular light receiving section 12 are input so that they are equal to each other.
  • the light receiving area of each PD is set based on the light intensity distribution of the light L.
  • the circular light receiving section 12 may include three or more annular photodiodes. Note that in FIG. 8, some of the symbols of the radial isolation grooves 15 and the symbols of the radial photodiodes 16 are omitted.
  • the plurality of PDs of the circular light receiving section 12 are connected in series by the plurality of conductive members 25.
  • the circular photodiode and one or more annular photodiodes prevent the formation of an ineffective area and utilize the light incident on the circular light-receiving section 12. Efficiency can be increased.
  • the optical power supply converter 1 can be configured using a back-illuminated semiconductor light-receiving element 10A as shown in FIGS. 9 and 10 instead of the semiconductor light-receiving element 10.
  • the back-illuminated semiconductor light-receiving device 10A has a structure in which a part of the semiconductor light-receiving device 10 is modified, and parts common to the semiconductor light-receiving device 10 are designated by the same reference numerals, and a description thereof will be omitted.
  • the semiconductor substrate 20 of the semiconductor light receiving element 10A is formed of a material that is transparent to incident light, and transmits the incident light L without absorbing it.
  • an InP substrate is transparent to infrared light having a wavelength of approximately 1 ⁇ m or more.
  • an antireflection film 26 for suppressing reflection of the light L is formed on the light L incident surface (back surface) of the semiconductor substrate 20.
  • the circular light receiving section 12 is divided by isolation grooves as described above, and has a plurality of PDs (a circular photodiode 14a, an annular photodiode 14b, and a plurality of radial photodiodes 16).
  • the light receiving areas of the plurality of PDs are set based on the light intensity distribution of the incident light L so that the amount of light received is equal to each other.
  • These plurality of PDs each include an anode electrode 27 connected to the p-type semiconductor layer 23 and a cathode electrode 28 connected to the n-type semiconductor layer 21. Note that in FIG. 9, some of the symbols of the radial photodiodes 16 are omitted.
  • the anode electrode 27 of one of the adjacent PDs and the cathode electrode 28 of the other are connected so that the plurality of PDs of the circular light receiving section 12 are connected in series by the plurality of conductive members 4 formed on the base 3. It is fixed to a corresponding conductive member 4 with, for example, conductive paste 6.
  • the optical power supply converter 1 converts the incident light L input from the optical fiber cable OC into a photocurrent using the semiconductor light receiving elements 10 and 10A, and outputs the photocurrent.
  • the semiconductor light-receiving elements 10 and 10A have a circular light-receiving section 12 that generates a photocurrent through photoelectric conversion.
  • the circular light receiving section 12 is divided by at least two annular isolation grooves 13a, 13b concentric with the circular light receiving section 12 and a plurality of radial isolation grooves 15. Thereby, a circular photodiode 14a, at least one annular photodiode 14b, and a plurality of radial photodiodes 16 are formed in the circular light receiving section 12.
  • the circular photodiode 14a, the annular photodiode 14b, and the radial photodiode 16 have light-receiving areas set so that the amount of light received is equal to each other based on the light intensity distribution of the incident light, and the plurality of conductive members 25, 4 are connected in series by.
  • the circular light receiving section 12 in which these photodiodes are connected in series can prevent the output from decreasing due to the photodiode generating a small photocurrent. Therefore, it is possible to prevent a decrease in the output of the optical power supply converter 1 that supplies power to the outside from the semiconductor light receiving elements 10, 10A having the circular light receiving section 12.
  • the plurality of radial isolation grooves 15 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12. Since the outer side of the annular photodiode 14b is equally divided in the circumferential direction of the circular light receiving section 12 by the plurality of radial isolation grooves 15, the light receiving area of the plurality of radial photodiodes 16 can be easily made equal.
  • the incident light input from the optical fiber cable OC has a light intensity distribution that is rotationally symmetrical with respect to the optical axis OA, by making the incident light enter so that the optical axis OA passes through the center C of the circular light receiving part 12,
  • the amount of light received by the photodiode 14a, the annular photodiode 14b, and each radial photodiode 16 can be made equal to each other. Therefore, it is possible to reduce variations in the photocurrents generated by these photodiodes and prevent a decrease in the output of the optical power supply converter 1.

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  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

[Problem] To provide an optical power supply converter that, in a circular light-receiving part that has been divided to increase output voltage, improves the efficiency of utilization of light from an optical fiber cable and improves output. [Solution] An optical power supply converter that coverts light from an optical fiber cable into photoelectric current via a semiconductor light-receiving element (10) and outputs the photoelectric current, wherein: a circular light-receiving part (12) of the semiconductor light-receiving element (10) has at least one annular photodiode (14b) and a circular photodiode (14a) divided by a plurality of annular isolation grooves which are concentric with the circular light-receiving part (12), and a plurality of radial photodiodes (16) divided by a plurality of radial isolation grooves outward of the annular photodiode (14b); and the circular photodiode (14a), the annular photodiode (14b), and the plurality of radial photodiodes (16) have light-receiving areas which are respectively set, on the basis of a light intensity distribution, such that the received light amounts thereof are equal to each other, and are connected in series by a plurality of electrically conductive members (25).

Description

光給電コンバータoptical power converter
　本発明は、光ファイバケーブルを介して入力される光を電力に変換して給電する光給電コンバータに関する。 The present invention relates to an optical power supply converter that converts light input through an optical fiber cable into electric power and supplies the converted electric power.
　給電設備がない遠隔地、給電による微弱な電磁界がノイズとなる環境、防爆を必要とする環境、電気的相互影響がある超高電圧設備内等、特殊な環境では電源ケーブルを介して電子機器類を作動させる電力を供給できない場合がある。そのため、電子機器類の傍まで光ファイバケーブルを介して送られる光を受けて、光電変換によって光電流を生成して給電する光給電コンバータが利用されている。 In special environments, such as remote locations without power supply equipment, environments where weak electromagnetic fields from power supply cause noise, environments that require explosion protection, and inside ultra-high voltage equipment where electrical interactions occur, electronic devices may be connected via power cables. In some cases, it may not be possible to supply power to operate the equipment. For this reason, optical power supply converters are used that receive light transmitted to electronic devices via optical fiber cables, generate photocurrent through photoelectric conversion, and supply power.
　光給電コンバータは光電変換用の半導体受光素子を有する。この半導体受光素子の出力電圧は、通常１Ｖ未満である。光給電コンバータからの給電を受ける機器が高い入力電圧を必要とする場合には、出力電圧を高くした光給電コンバータが利用される。例えば特許文献１のように、半導体受光素子の円形受光部をアイソレーション溝によって複数の扇形のフォトダイオードに分割し、これらを直列に接続することによって出力電圧を高くすることが可能である。 The optical power supply converter has a semiconductor light receiving element for photoelectric conversion. The output voltage of this semiconductor photodetector is usually less than 1V. When a device receiving power from an optical power supply converter requires a high input voltage, an optical power supply converter with a high output voltage is used. For example, as in Patent Document 1, it is possible to increase the output voltage by dividing the circular light-receiving portion of a semiconductor light-receiving element into a plurality of sector-shaped photodiodes by an isolation groove and connecting these in series.
　分割されて直列に接続された複数のフォトダイオードによって構成された半導体受光素子の出力電圧は、フォトダイオードが多いほど高くなる。一方、その出力電流は、分割されない場合よりも小さくなり、分割数が多いほど小さくなる。その上、この出力電流は、光電変換により生成される光電流が最小のフォトダイオードによって制限される。それ故、複数のフォトダイオードの光電流を互いに等しくするために、これら複数のフォトダイオードが同形状且つ同面積となるように円形受光部が等分される。 The output voltage of a semiconductor light-receiving element composed of a plurality of divided photodiodes connected in series increases as the number of photodiodes increases. On the other hand, the output current is smaller than when it is not divided, and becomes smaller as the number of divisions increases. Moreover, this output current is limited by the photodiode with the least photocurrent generated by photoelectric conversion. Therefore, in order to make the photocurrents of the plurality of photodiodes equal to each other, the circular light receiving section is equally divided so that the plurality of photodiodes have the same shape and the same area.
　円形受光部を等分するために、一定幅の直線状の複数のアイソレーション溝が、円形受光部の中心から径方向に放射状に形成されているので、複数のアイソレーション溝が円形受光部の中心近傍に集中する。そして、円形受光部の分割数が多いほど、即ちアイソレーション溝が多いほど、隣り合うアイソレーション溝が近づくので、円形受光部の中心から離隔した位置で複数のアイソレーション溝が夫々幅方向に連なることにより周方向に連なる。アイソレーション溝では光電変換をすることができないので、円形受光部の分割数が多いほど、この円形受光部の中心近傍に複数のアイソレーション溝が周方向に連なって形成される光電変換できない無効領域が大きくなる。 In order to divide the circular light receiving area into equal parts, a plurality of linear isolation grooves with a constant width are formed radially in the radial direction from the center of the circular light receiving area. Concentrate near the center. The larger the number of divisions of the circular light-receiving section, that is, the more isolation grooves there are, the closer the adjacent isolation grooves are, so that a plurality of isolation grooves are connected in the width direction at positions separated from the center of the circular light-receiving section. This makes them continuous in the circumferential direction. Since photoelectric conversion cannot be performed in the isolation groove, the more the number of divisions of the circular light-receiving area is, the more isolation grooves are formed in the circumferential direction near the center of the circular light-receiving area. becomes larger.
　ここで、光ファイバケーブルを介して入力される光の強度分布は、一般的にはガウス分布であり、光軸から離隔するほど光強度が低下すると共に、光軸に対して回転対称状の光強度分布である。それ故、この光の光軸が円形受光部の中心をこの円形受光部に対して垂直に通るように入射させることによって、円形受光部の複数のフォトダイオードが均等に受光することができる。 Here, the intensity distribution of the light input through the optical fiber cable is generally a Gaussian distribution, and the light intensity decreases as the distance from the optical axis increases. This is the intensity distribution. Therefore, by allowing the optical axis of this light to pass through the center of the circular light receiving section perpendicularly to the circular light receiving section, the plurality of photodiodes of the circular light receiving section can receive the light evenly.
　このとき、入射光の光軸近傍の光強度が高い部分が、円形受光部の中心近傍の無効領域に入射して光電流に変換されず無駄になるので、光給電コンバータの出力を大きくすることができない。そこで、特許文献２のように、円形受光部の中央部に円形のフォトダイオードを設け、この円形のフォトダイオードの外周側を放射状のアイソレーション溝によって周方向に分割して複数のフォトダイオードを設け、これらフォトダイオードを直列に接続した光給電コンバータが知られている。 At this time, the high intensity part of the incident light near the optical axis enters the ineffective area near the center of the circular light receiving part and is not converted into photocurrent and is wasted, so the output of the optical power supply converter must be increased. I can't. Therefore, as in Patent Document 2, a circular photodiode is provided in the center of a circular light receiving section, and the outer circumferential side of this circular photodiode is circumferentially divided by radial isolation grooves to provide a plurality of photodiodes. , an optical power supply converter in which these photodiodes are connected in series is known.
米国特許第５３４２４５１号明細書US Patent No. 5,342,451 米国特許出願公開第２０１１／０１０８０８１号明細書US Patent Application Publication No. 2011/0108081
　特許文献２のように円形受光部を円形のフォトダイオードとその周囲の周方向に並ぶ複数のフォトダイオードに分割する場合には、光軸近傍の光強度が高い部分も光電変換され、分割数を増やして出力電圧を高くすることができる。しかし、複数のフォトダイオードで生成される光電流が等しくなるように、円形受光部の分割数が多くなるほど、円形のフォトダイオードの直径が小さくなると共に、その外側において放射状のアイソレーション溝同士が近づいて重なり合うようになる。 When the circular light receiving section is divided into a circular photodiode and a plurality of photodiodes arranged in the circumferential direction around the circular photodiode as in Patent Document 2, the portion with high light intensity near the optical axis is also photoelectrically converted, and the number of divisions is reduced. The output voltage can be increased by increasing the output voltage. However, in order to equalize the photocurrent generated by multiple photodiodes, as the number of divisions of the circular photodiode increases, the diameter of the circular photodiode decreases, and the radial isolation grooves become closer to each other on the outside. so that they overlap.
　そのため、円形受光部の分割数が多い場合には、複数の放射状のアイソレーション溝が周方向に連なって、円形のフォトダイオードを囲むように無効領域が形成されてしまう。それ故、光軸近傍の光強度が高い部分の一部が円形のフォトダイオードの外側の無効領域に入射することになり、光ファイバケーブルを介して入力される光を十分に利用することができなかった。 Therefore, when the number of divisions of the circular light-receiving section is large, a plurality of radial isolation grooves are connected in the circumferential direction, and an ineffective area is formed to surround the circular photodiode. Therefore, a portion of the high light intensity near the optical axis will be incident on the ineffective area outside the circular photodiode, making it impossible to fully utilize the light input through the optical fiber cable. There wasn't.
　そこで、本発明は、出力電圧を高くするために分割された円形受光部における光ファイバケーブルからの光の利用効率の向上により、出力を向上させた光給電コンバータを提供することを目的としている。 Therefore, an object of the present invention is to provide a light-fed converter with improved output by improving the utilization efficiency of light from an optical fiber cable in a circular light-receiving section divided in order to increase the output voltage.
　請求項１の発明の光給電コンバータは、光ファイバケーブルから入力される入射光を半導体受光素子により光電流に変換して出力する光給電コンバータにおいて、前記半導体受光素子は円形受光部を備え、前記円形受光部は、この円形受光部と同心の複数の円環状アイソレーション溝によって分割された円形フォトダイオード及び１つ以上の円環状フォトダイオードと、前記円環状フォトダイオードの外側に前記円形受光部の中心に対して放射状に形成された複数の放射状アイソレーション溝によって分割された複数の放射状フォトダイオードを有し、前記円形フォトダイオードと前記円環状フォトダイオードと前記放射状フォトダイオードは、前記入射光の光強度分布に基づいて受光量が互いに等しくなるように受光面積が夫々設定され、前記円形フォトダイオードと前記円環状フォトダイオードと複数の前記放射状フォトダイオードが複数の導電性部材によって直列に接続されたことを特徴としている。 The optical power feeding converter of the invention according to claim 1 is an optical power feeding converter that converts incident light input from an optical fiber cable into a photocurrent by a semiconductor light receiving element and outputs the photocurrent, wherein the semiconductor light receiving element includes a circular light receiving part, The circular light-receiving section includes a circular photodiode divided by a plurality of annular isolation grooves concentric with the circular light-receiving section, and one or more annular photodiodes, and a circular light-receiving section located outside the circular photodiode. It has a plurality of radial photodiodes divided by a plurality of radial isolation grooves formed radially with respect to the center, and the circular photodiode, the annular photodiode, and the radial photodiode are configured to absorb the incident light. The light receiving areas are respectively set so that the amount of light received is equal to each other based on the intensity distribution, and the circular photodiode, the annular photodiode, and the plurality of radial photodiodes are connected in series by a plurality of conductive members. It is characterized by
　上記構成によれば、半導体受光素子の円形受光部は、複数の円環状アイソレーション溝と複数の放射状アイソレーション溝によって分割され、円形フォトダイオードと１つ以上の円環状フォトダイオードと複数の放射状フォトダイオードが形成されている。そして、これら複数のフォトダイオードが直列に接続されている。この円形受光部が有する円形フォトダイオードと、円環状フォトダイオードと、放射状フォトダイオードの受光面積は、光ファイバケーブルから入力される入射光の光強度分布に基づいて、受光量が互いに等しくなるように夫々設定されている。それ故、円形受光部の複数のフォトダイオードで夫々生成される光電流のばらつきが抑制され、これら複数のフォトダイオードが直列に接続された場合に光電流のばらつきに起因する半導体受光素子の出力低下が抑制される。従って、この半導体受光素子を有する光給電コンバータの出力低下が抑制される。そして、円形受光部の分割数が多い場合でも、円形受光部の中央部の円形フォトダイオードと１つ以上の円環状フォトダイオードによって、複数の放射状アイソレーション溝が集中して周方向に連なることを防ぐので、光電流を生成できない無効領域が形成されない。従って、円形受光部の中央部で入射光の光強度が高い部分を光電流に変換することができ、円形受光部における光の利用効率を向上させることができるので、光給電コンバータの出力を向上させることができる。 According to the above configuration, the circular light receiving part of the semiconductor light receiving element is divided by a plurality of annular isolation grooves and a plurality of radial isolation grooves, and is divided into a circular photodiode, one or more annular photodiodes, and a plurality of radial photodiodes. A diode is formed. These plurality of photodiodes are connected in series. The light-receiving areas of the circular photodiode, annular photodiode, and radial photodiode of this circular light-receiving section are set so that the amount of light received is equal to each other based on the light intensity distribution of the incident light input from the optical fiber cable. are set respectively. Therefore, variations in the photocurrent generated by the plurality of photodiodes in the circular light-receiving section are suppressed, and when these plurality of photodiodes are connected in series, the output of the semiconductor light-receiving element is reduced due to variations in the photocurrent. is suppressed. Therefore, a decrease in the output of the optical power supply converter having this semiconductor light-receiving element is suppressed. Even when the circular light-receiving section is divided into a large number of sections, the circular photodiode in the center of the circular light-receiving section and one or more annular photodiodes ensure that a plurality of radial isolation grooves are concentrated and connected in the circumferential direction. This prevents the formation of ineffective regions where photocurrent cannot be generated. Therefore, the central part of the circular light receiving section where the light intensity of the incident light is high can be converted into photocurrent, improving the light utilization efficiency in the circular light receiving section, thereby improving the output of the optical power supply converter. can be done.
　請求項２の発明の光給電コンバータは、請求項１の発明において、複数の前記放射状アイソレーション溝は、前記円形受光部の中心を通る中心軸に対して回転対称状に形成されたことを特徴としている。
　上記構成によれば、円環状フォトダイオードの外側が、回転対称状に形成された放射状アイソレーション溝によって周方向に等分されるので、複数の放射状フォトダイオードの受光面積を容易に等しくすることができる。また、光ファイバケーブルから入力される入射光は光軸に対して回転対称の光強度分布である。それ故、入射光の光軸が円形受光部の中心をこの円形受光部に対して垂直に通るように光を入射させて、即ち入射光の光軸を円形受光部の中心軸と一致させて、円形受光部の各フォトダイオードの受光量を互いに等しくすることができる。従って、円形受光部が有する複数のフォトダイオードで夫々生成される光電流のばらつきが抑制され、光給電コンバータの出力の低下を抑制することができる。 The optical power feeding converter of the invention according to claim 2 is characterized in that in the invention according to claim 1, the plurality of radial isolation grooves are formed rotationally symmetrically with respect to a central axis passing through the center of the circular light receiving section. It is said that
According to the above configuration, since the outer side of the annular photodiode is equally divided in the circumferential direction by the radial isolation grooves formed in a rotationally symmetrical manner, it is possible to easily equalize the light receiving areas of the plurality of radial photodiodes. can. Furthermore, the incident light input from the optical fiber cable has a light intensity distribution that is rotationally symmetrical with respect to the optical axis. Therefore, the optical axis of the incident light passes through the center of the circular light receiving part perpendicularly to the circular light receiving part, that is, the optical axis of the incident light is made to coincide with the central axis of the circular light receiving part. , the amount of light received by each photodiode of the circular light receiving section can be made equal to each other. Therefore, variations in the photocurrents generated by the plurality of photodiodes included in the circular light receiving section are suppressed, and a decrease in the output of the optical power supply converter can be suppressed.
　本発明の光給電コンバータによれば、出力電圧を高くするために分割された円形受光部において、光ファイバケーブルからの光の利用効率を向上させて、光給電コンバータの出力を向上させることができる。 According to the optically-fed converter of the present invention, it is possible to improve the efficiency of using light from the optical fiber cable in the divided circular light-receiving section to increase the output voltage, thereby improving the output of the optically-fed converter. .
本発明の実施例１に係る光給電コンバータの斜視図である。1 is a perspective view of an optical power supply converter according to Example 1 of the present invention. 図１の光給電コンバータが有する半導体受光素子への光の入射の説明図である。FIG. 2 is an explanatory diagram of light incident on a semiconductor light-receiving element included in the optical power feeding converter of FIG. 1. FIG. 図２の半導体受光素子を光の入射側から見た平面図である。FIG. 3 is a plan view of the semiconductor light receiving element of FIG. 2 viewed from the light incident side. 図３のIV－IV線断面図である。4 is a sectional view taken along the line IV-IV in FIG. 3. FIG. 光ファイバケーブルを介して入力される光の光強度分布図である。FIG. 2 is a light intensity distribution diagram of light input via an optical fiber cable. 円形受光部の分割数に応じた円形フォトダイオードの直径と円環状フォトダイオードの外径の例を示すグラフである。7 is a graph showing an example of the diameter of a circular photodiode and the outer diameter of an annular photodiode depending on the number of divisions of a circular light receiving section. 円形受光部の分割態様に応じた出力の比較例を示すグラフである。7 is a graph showing a comparative example of output according to the division mode of the circular light-receiving section. 円形受光部の他の分割例を示す図である。FIG. 7 is a diagram showing another example of division of the circular light receiving section. 本発明の実施例２に係る裏面入射型の半導体素子を光の入射側から見た平面図である。FIG. 3 is a plan view of a back-illuminated semiconductor device according to Example 2 of the present invention, viewed from the light incident side. 図９のX－X線断面図である。10 is a sectional view taken along line XX in FIG. 9. FIG.
　以下、本発明を実施するための形態について実施例に基づいて説明する。 Hereinafter, modes for carrying out the present invention will be described based on examples.
　図１、図２に示すように、光給電コンバータ１は、例えばシングルモードの光ファイバケーブルＯＣを介して入力される光（入射光）Ｌを光電流に変換し、この光電流を外部に給電するための１対の出力端子部２ａ，２ｂを有する。１対の出力端子部２ａ，２ｂが装備された基台３には、受光した光から光電変換により光電流を生成するための半導体受光素子１０と、この半導体受光素子１０の保護及び遮光のためのカバー５が、例えば接着剤によって夫々固定されている。半導体受光素子１０の１対の電極１０ａ，１０ｂは、対応する出力端子部２ａ，２ｂに接続された配線部３ａ，３ｂに、例えば導電性ワイヤ１１ａ，１１ｂによって接続されている。 As shown in FIGS. 1 and 2, the optical power supply converter 1 converts light (incident light) L input via, for example, a single mode optical fiber cable OC into a photocurrent, and supplies this photocurrent to the outside. It has a pair of output terminal parts 2a and 2b for. The base 3 equipped with a pair of output terminals 2a and 2b includes a semiconductor light receiving element 10 for generating a photocurrent by photoelectric conversion from received light, and a semiconductor light receiving element 10 for protecting and shielding the semiconductor light receiving element 10. The covers 5 are fixed to each other by, for example, adhesive. A pair of electrodes 10a, 10b of the semiconductor light receiving element 10 are connected to wiring portions 3a, 3b connected to corresponding output terminal portions 2a, 2b, for example, by conductive wires 11a, 11b.
　光ファイバケーブルＯＣは、カバー５を貫通する挿入孔５ａに差し込まれ、その出射端Ｅが半導体受光素子１０から所定の距離だけ離隔した位置となるように固定される。光ファイバケーブルＯＣの出射端Ｅの位置決め機構が、カバー５に装備されていてもよい。 The optical fiber cable OC is inserted into the insertion hole 5a passing through the cover 5, and fixed so that its output end E is spaced a predetermined distance from the semiconductor light receiving element 10. The cover 5 may be equipped with a positioning mechanism for the output end E of the optical fiber cable OC.
　光ファイバケーブルＯＣを介して入力される光Ｌは、波長が例えば１．５μｍ程度の赤外光である。この光Ｌは、出射端Ｅから出射された後は、進行するほど照射範囲が広がる円錐状のビームである。半導体受光素子１０は、光電変換によって光Ｌから光電流を生成する円形受光部１２を有する。出射端Ｅから出射される光Ｌの光軸ＯＡが円形受光部１２の中心Ｃをこの円形受光部１２に対して垂直に通るように、即ち光軸ＯＡと円形受光部１２の中心軸が一致するように、出射端Ｅが位置決めされる。 The light L input through the optical fiber cable OC is infrared light with a wavelength of, for example, about 1.5 μm. This light L is a conical beam whose irradiation range expands as it advances after being emitted from the output end E. The semiconductor light receiving element 10 has a circular light receiving section 12 that generates a photocurrent from the light L through photoelectric conversion. The optical axis OA of the light L emitted from the output end E passes through the center C of the circular light receiving section 12 perpendicularly to the circular light receiving section 12, that is, the optical axis OA and the central axis of the circular light receiving section 12 coincide. The output end E is positioned so that the output end E is positioned as shown in FIG.
　図３に示すように、円形受光部１２は、例えば光吸収層を備えた円形のＰＩＮ型フォトダイオードが、一定幅のアイソレーション溝によって複数のフォトダイオードに分割され、これら複数のフォトダイオードが直列に接続されて形成されている。尚、アイソレーション溝では光電流が生成されないので、出力を大きくするために円形受光部１２の面積に占めるアイソレーション溝の面積を小さくすることが好ましい。 As shown in FIG. 3, the circular light-receiving section 12 includes, for example, a circular PIN-type photodiode provided with a light absorption layer, which is divided into a plurality of photodiodes by an isolation groove of a constant width, and these plurality of photodiodes are connected in series. is connected to and formed. Note that since no photocurrent is generated in the isolation groove, it is preferable to reduce the area of the isolation groove in the area of the circular light receiving section 12 in order to increase the output.
　円形受光部１２の中央部には、円形受光部１２と同心の第１円環状アイソレーション溝１３ａによって円形フォトダイオード１４ａが形成されている。また、円形受光部１２と同心且つ直径が第１円環状アイソレーション溝１３ａよりも大きい第２円環状アイソレーション溝１３ｂと第１円環状アイソレーション溝１３ａの間には、円環状フォトダイオード１４ｂが形成されている。 A circular photodiode 14a is formed in the center of the circular light receiving section 12 by a first annular isolation groove 13a concentric with the circular light receiving section 12. Further, between the first annular isolation groove 13a and the second annular isolation groove 13b which is concentric with the circular light receiving part 12 and has a diameter larger than the first annular isolation groove 13a, an annular photodiode 14b is provided. It is formed.
　第２円環状アイソレーション溝１３ｂと、円形受光部１２の外周に沿って形成された外周アイソレーション溝１３ｎとの間には、円形受光部１２の中心Ｃに対して放射状に複数（ここでは３０本）の直線状の放射状アイソレーション溝１５が形成されている。これら複数の放射状アイソレーション溝１５は、円形受光部１２の中心Ｃを通る中心軸に対して回転対称状に形成され、円環状フォトダイオード１４ｂの外側を周方向に等分し、且つ第２円環状アイソレーション溝１３ｂと外周アイソレーション溝１３ｎを接続している。尚、図３では放射状アイソレーション溝１５の符号を一部省略している。 Between the second annular isolation groove 13b and the outer periphery isolation groove 13n formed along the outer periphery of the circular light receiving part 12, a plurality of grooves (in this case, 30 A straight radial isolation groove 15 is formed. These plurality of radial isolation grooves 15 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12, and equally divide the outside of the annular photodiode 14b in the circumferential direction. The annular isolation groove 13b and the outer circumferential isolation groove 13n are connected. Note that in FIG. 3, some of the symbols of the radial isolation grooves 15 are omitted.
　こうして円環状フォトダイオード１４ｂの外側には、複数の放射状アイソレーション溝１５によって複数（ここでは３０個）の放射状フォトダイオード１６が形成されている。これら放射状フォトダイオード１６は、円環状フォトダイオード１４ｂを囲むように周方向に並んでいる。以下では、円形受光部１２が分割されて形成された円形、円環状及び放射状の各フォトダイオードを区別せずにＰＤと記載する場合がある。尚、図３では放射状フォトダイオード１６の符号を一部省略している。 In this way, a plurality of (30 in this case) radial photodiodes 16 are formed by a plurality of radial isolation grooves 15 on the outside of the annular photodiode 14b. These radial photodiodes 16 are arranged in the circumferential direction so as to surround the annular photodiode 14b. Hereinafter, the circular, annular, and radial photodiodes formed by dividing the circular light receiving section 12 may be referred to as PD without distinction. Note that in FIG. 3, some of the symbols of the radial photodiodes 16 are omitted.
　円形受光部１２の各ＰＤ（円形フォトダイオード１４ａ、円環状フォトダイオード１４ｂ、放射状フォトダイオード１６）は、例えば図４に示すように、半絶縁性の半導体基板２０上に積層されたｎ型半導体層２１と光吸収層２２とｐ型半導体層２３を有する。半導体基板２０は例えばＩｎＰ基板であり、ｎ型半導体層２１は例えばｎ－ＩｎＰ層であり、光吸収層２２は例えばＩｎＧａＡｓ層であり、ｐ型半導体層２３は例えばｐ－ＩｎＰ層であるが、これに限定されるものではなく、円形受光部１２はＰＩＮ型に限定されるものではない。尚、ｎ型半導体層２１、光吸収層２２、ｐ型半導体層２３の厚さは適宜設定することができ、０．５～１０μｍ程度の厚さに形成される場合が多い。 Each PD (circular photodiode 14a, annular photodiode 14b, and radial photodiode 16) of the circular light receiving section 12 is an n-type semiconductor layer stacked on a semi-insulating semiconductor substrate 20, as shown in FIG. 4, for example. 21, a light absorption layer 22, and a p-type semiconductor layer 23. The semiconductor substrate 20 is, for example, an InP substrate, the n-type semiconductor layer 21 is, for example, an n-InP layer, the light absorption layer 22 is, for example, an InGaAs layer, and the p-type semiconductor layer 23 is, for example, a p-InP layer. The circular light receiving section 12 is not limited to this, and the circular light receiving section 12 is not limited to the PIN type. Note that the thicknesses of the n-type semiconductor layer 21, the light absorption layer 22, and the p-type semiconductor layer 23 can be set as appropriate, and are often formed to a thickness of about 0.5 to 10 μm.
　アイソレーション溝（第１、第２円環状アイソレーション溝１３ａ，１３ｂ、外周アイソレーション溝１３ｎ、複数の放射状アイソレーション溝１５）は、ｎ型半導体層２１と光吸収層２２とｐ型半導体層２３が積層された半導体基板２０をｐ型半導体層２３側から、半導体基板２０に到達するまで選択的にエッチングすることにより形成される。これにより電気的に分離された複数のＰＤが形成される。尚、アイソレーション溝は、例えば半導体基板２０側ほど幅が狭くなるように側壁が傾斜していてもよい。 The isolation grooves (first and second annular isolation grooves 13a, 13b, outer circumferential isolation groove 13n, and multiple radial isolation grooves 15) include an n-type semiconductor layer 21, a light absorption layer 22, and a p-type semiconductor layer 23. It is formed by selectively etching the semiconductor substrate 20 on which are stacked layers from the p-type semiconductor layer 23 side until the semiconductor substrate 20 is reached. This forms a plurality of electrically isolated PDs. Note that the sidewalls of the isolation groove may be inclined such that, for example, the width becomes narrower toward the semiconductor substrate 20 side.
　複数のＰＤは、ｐ型半導体層２３と光吸収層２２を貫通してｎ型半導体層２１に到達する貫通孔１７を夫々有する。そして、絶縁性の保護膜２４が、複数のＰＤの表面とこれらＰＤの貫通孔１７の内壁を覆い且つアイソレーション溝を埋め込むように形成されている。保護膜２４は、入射する光Ｌの反射防止機能を備えていることが好ましいが、図示外の反射防止膜を形成してもよい。 Each of the plurality of PDs has a through hole 17 that penetrates the p-type semiconductor layer 23 and the light absorption layer 22 and reaches the n-type semiconductor layer 21. An insulating protective film 24 is formed to cover the surfaces of the plurality of PDs and the inner walls of the through holes 17 of these PDs, and to fill the isolation grooves. The protective film 24 preferably has an anti-reflection function for the incident light L, but an anti-reflection film not shown may be formed.
　各ＰＤにおいて、ｐ型半導体層２３上及び貫通孔１７の内部の保護膜２４が部分的に除去されて、ｐ型半導体層２３及び貫通孔１７底部でｎ型半導体層２１が露出する。そして、図３、図４のように、複数の導電性部材２５によって複数のＰＤを直列に接続するために、アイソレーション溝を介して隣り合うＰＤ間で、露出した一方のｐ型半導体層２３と他方のｎ型半導体層２１とが導電性部材２５によって接続される。尚、図３では複数の導電性部材２５の符号を一部省略している。 In each PD, the protective film 24 on the p-type semiconductor layer 23 and inside the through-hole 17 is partially removed, and the n-type semiconductor layer 21 is exposed at the p-type semiconductor layer 23 and the bottom of the through-hole 17. As shown in FIGS. 3 and 4, in order to connect a plurality of PDs in series using a plurality of conductive members 25, one exposed p-type semiconductor layer 23 is placed between adjacent PDs via an isolation groove. and the other n-type semiconductor layer 21 are connected by a conductive member 25. Note that in FIG. 3, some of the symbols of the plurality of conductive members 25 are omitted.
　導電性部材２５は、例えばリフトオフ法を用いて金属積層膜を選択的に堆積させることによって形成される。金属積層膜は、例えばチタン、クロムのような密着層と、例えば金、銀、アルミニウムのような低抵抗率層によって構成されている。アイソレーション溝は、保護膜２４によって埋め込まれて段差が小さくなっているので、導電性部材２５の形成が容易になる。 The conductive member 25 is formed by selectively depositing a metal laminated film using, for example, a lift-off method. The metal laminated film is composed of an adhesion layer such as titanium or chromium, and a low resistivity layer such as gold, silver, or aluminum. Since the isolation groove is filled with the protective film 24 and the step difference is reduced, the formation of the conductive member 25 is facilitated.
　また、放射状アイソレーション溝１５を埋め込んだ保護膜２４上に、例えば電極１０ａと円形フォトダイオード１４ａとの接続用及び円環状フォトダイオード１４ｂと放射状フォトダイオード１６との接続用の導電性部材２５が夫々形成され、入射する光Ｌが遮られないようにしている。隣り合う放射状フォトダイオード１６を接続する導電性部材２５が円形受光部１２の中心Ｃを通る中心軸に対して回転対称状に形成されることにより、各放射状フォトダイオード１６において導電性部材２５によって遮られる光量が等しくなることが好ましい。 Further, on the protective film 24 in which the radial isolation groove 15 is embedded, conductive members 25 are provided, for example, for connecting the electrode 10a and the circular photodiode 14a and for connecting the annular photodiode 14b and the radial photodiode 16, respectively. is formed so that the incident light L is not blocked. Since the conductive members 25 connecting adjacent radial photodiodes 16 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12, each radial photodiode 16 is shielded by the conductive member 25. It is preferable that the amounts of light emitted are equal.
　アイソレーション溝が保護膜２４によって埋め込まれて段差が無い場合には、複数の導電性部材２５を容易に形成することができる。保護膜２４によるアイソレーション溝の埋め込みは、導電性部材２５を形成できる程度に段差を小さくしていればよい。図示を省略するが、各ＰＤにおいてｐ型半導体層２３に接続するアノード電極とｎ型半導体層２１に接続するカソード電極を形成し、上記と同様に隣り合うＰＤ間で一方のアノード電極を他方のカソード電極に導電性部材２５によって接続してもよい。また、導電性部材２５として例えば金を主成分とする導電性ワイヤを使用してもよい。 If the isolation groove is filled with the protective film 24 and there is no step, a plurality of conductive members 25 can be easily formed. The isolation groove may be filled with the protective film 24 by making the level difference small to the extent that the conductive member 25 can be formed. Although not shown, an anode electrode connected to the p-type semiconductor layer 23 and a cathode electrode connected to the n-type semiconductor layer 21 are formed in each PD, and one anode electrode is connected to the other between adjacent PDs in the same manner as described above. It may be connected to the cathode electrode by a conductive member 25. Further, as the conductive member 25, for example, a conductive wire containing gold as a main component may be used.
　円形受光部１２において、円形フォトダイオード１４ａと円環状フォトダイオード１４ｂと複数の放射状フォトダイオード１６が直列に接続されているので、半導体受光素子１０が出力する光電流は小さくなるが、その出力電圧を高くすることができる。従って、光ファイバケーブルＯＣを介して入力される光を光電変換するために半導体受光素子１０を備えた光給電コンバータ１は、高い電圧で給電することができる。 In the circular light receiving section 12, since the circular photodiode 14a, the annular photodiode 14b, and the plurality of radial photodiodes 16 are connected in series, the photocurrent output by the semiconductor light receiving element 10 is small, but the output voltage is It can be made higher. Therefore, the optical power supply converter 1 equipped with the semiconductor light receiving element 10 for photoelectrically converting light input via the optical fiber cable OC can supply power at a high voltage.
　光ファイバケーブルＯＣの出射端Ｅから出射された光Ｌは、図２、図５のように例えば頂角θ（全角）が１４度の円錐状に広がって円形受光部１２に入射する。この光Ｌの光強度分布はガウス分布であり、光軸ＯＡから離隔するほど光強度が低下すると共に光軸ＯＡに対して回転対称の光強度分布になる。この光強度分布に基づいて、円形受光部１２の各ＰＤが生成する光電流が等しくなるように、即ち受光量が等しくなるように、円形フォトダイオード１４ａと円環状フォトダイオード１４ｂと放射状フォトダイオード１６の受光面積が夫々設定されている。高強度の光を受ける円形フォトダイオード１４ａは面積が小さく、低強度の光を受ける放射状フォトダイオード１６は円形フォトダイオード１４ａ、円環状フォトダイオード１４ｂよりも面積が大きくなる。尚、受光面積は、例えば円形受光部１２の最外周部分に入射する光強度が中心Ｃに入射する光強度の１／ｅ２になる（円形受光部１２に光Ｌの約９０％が照射される）状況において、各ＰＤの受光量が互いに等しくなるように設定される。 The light L emitted from the output end E of the optical fiber cable OC spreads into a conical shape with an apex angle θ (full angle) of 14 degrees, for example, as shown in FIGS. 2 and 5, and enters the circular light receiving portion 12. The light intensity distribution of this light L is a Gaussian distribution, and the light intensity decreases as the distance from the optical axis OA increases, and the light intensity distribution becomes rotationally symmetrical with respect to the optical axis OA. Based on this light intensity distribution, the circular photodiode 14a, the annular photodiode 14b, and the radial photodiode 16 The light-receiving area of each is set. The circular photodiode 14a that receives high-intensity light has a small area, and the radial photodiode 16 that receives low-intensity light has a larger area than the circular photodiode 14a and the annular photodiode 14b. The light receiving area is such that, for example, the light intensity incident on the outermost portion of the circular light receiving section 12 is 1/ e2 of the light intensity incident on the center C (approximately 90% of the light L is irradiated onto the circular light receiving section 12). ), the amount of light received by each PD is set to be equal to each other.
　光入力が一定の場合、円形受光部１２が有するＰＤの個数に応じて、各ＰＤが生成することができる光電流が変動する。それ故、光強度分布に基づいて各ＰＤが生成する光電流が等しくなるように受光面積が設定される際に、円形受光部１２が有するＰＤの個数に応じた円形フォトダイオード１４ａの直径及び円環状フォトダイオード１４ｂの外径が設定される。 When the light input is constant, the photocurrent that each PD can generate varies depending on the number of PDs that the circular light receiving section 12 has. Therefore, when the light receiving area is set so that the photocurrent generated by each PD is equal based on the light intensity distribution, the diameter and circle of the circular photodiode 14a are determined according to the number of PDs that the circular light receiving section 12 has. The outer diameter of the annular photodiode 14b is set.
　例えば直径Ｄ０＝１ｍｍの円形受光部１２が、幅１０μｍのアイソレーション溝によって、１つの円形フォトダイオード１４ａと１つの円環状フォトダイオード１４ｂと複数の放射状フォトダイオード１６に分割される場合について、図６に円形フォトダイオード１４ａの直径Ｄ１と円環状フォトダイオード１４ｂの外径Ｄ２の設定例を示す。 For example, FIG. 6 shows a case where a circular light receiving section 12 with a diameter D0=1 mm is divided into one circular photodiode 14a, one annular photodiode 14b, and a plurality of radial photodiodes 16 by an isolation groove with a width of 10 μm. An example of setting the diameter D1 of the circular photodiode 14a and the outer diameter D2 of the annular photodiode 14b is shown in FIG.
　円形受光部１２が１０個のＰＤに分割されて１つの円形フォトダイオード１４ａと１つの円環状フォトダイオード１４ｂと８個の放射状フォトダイオード１６を有する場合には、円形フォトダイオード１４ａの直径Ｄ１が２３０μｍ、円環状フォトダイオード１４ｂの外径Ｄ２が３４０μｍに設定される。また、円形受光部１２が３２個のＰＤに分割されて１つの円形フォトダイオード１４ａと１つの円環状フォトダイオード１４ｂと３０個の放射状フォトダイオード１６を有する場合（図３参照）には、円形フォトダイオード１４ａの直径Ｄ１が１２６μｍ、円環状フォトダイオード１４ｂの外径Ｄ２が１７９μｍに設定される。尚、円形受光部１２の直径Ｄ０、ＰＤの個数及びアイソレーション溝の幅は、適宜設定することができる。 When the circular light receiving section 12 is divided into 10 PDs and has one circular photodiode 14a, one annular photodiode 14b, and eight radial photodiodes 16, the diameter D1 of the circular photodiode 14a is 230 μm. , the outer diameter D2 of the annular photodiode 14b is set to 340 μm. Further, when the circular light receiving section 12 is divided into 32 PDs and has one circular photodiode 14a, one annular photodiode 14b, and 30 radial photodiodes 16 (see FIG. 3), the circular photodiode The diameter D1 of the diode 14a is set to 126 μm, and the outer diameter D2 of the annular photodiode 14b is set to 179 μm. Note that the diameter D0 of the circular light receiving section 12, the number of PDs, and the width of the isolation groove can be set as appropriate.
　図７は、直径Ｄ０＝１ｍｍの円形受光部１２を分割しないパターン＃１の出力（電力）を１とした場合に、分割のパターン別の相対出力を示している。パターン＃２は、円形受光部の中心から径方向に延びる直線状の複数のアイソレーション溝によって円形受光部が放射状に３０等分されている。このパターン＃２は、複数のアイソレーション溝が集中する円形受光部１２の中心近傍に光電変換できない無効領域が形成され、相対出力は０．８９である。つまり、パターン＃２は、パターン＃１と比べて円形受光部１２に入射する光の利用効率が１１％低く、光入力の無駄が大きい。 FIG. 7 shows the relative output for each division pattern, assuming that the output (power) of pattern #1 in which the circular light receiving portion 12 with a diameter D0 = 1 mm is not divided is 1. In pattern #2, the circular light receiving section is radially divided into 30 equal parts by a plurality of linear isolation grooves extending radially from the center of the circular light receiving section. In this pattern #2, an ineffective region where photoelectric conversion cannot be performed is formed near the center of the circular light receiving section 12 where a plurality of isolation grooves are concentrated, and the relative output is 0.89. In other words, in pattern #2, the utilization efficiency of light incident on the circular light receiving section 12 is 11% lower than in pattern #1, and there is a large waste of light input.
　パターン＃３は、円形受光部の中央に円形受光部と同心状に直径が１２８μｍの円形フォトダイオードを設け、円形フォトダイオードの周りを３０等分して３０個の放射状フォトダイオードを設けている。円形フォトダイオードによって無効領域がパターン＃２よりも縮小しており、パターン＃３の相対出力は０．９３である。パターン＃３は、パターン＃２と比べて円形受光部１２に入射する光の利用効率が向上している。 In pattern #3, a circular photodiode with a diameter of 128 μm is provided concentrically with the circular photodiode at the center of the circular photodiode, and 30 radial photodiodes are provided by dividing the circumference of the circular photodiode into 30 equal parts. The circular photodiode reduces the ineffective area compared to pattern #2, and the relative output of pattern #3 is 0.93. Pattern #3 has improved utilization efficiency of light incident on the circular light receiving section 12 compared to pattern #2.
　図３の円形受光部１２に相当するパターン＃４は、円形受光部の中央部に、この円形受光部と同心状に直径が１２６μｍの円形フォトダイオードと外径が１７９μｍの円環状フォトダイオードを設け、円環状フォトダイオードの外側を３０等分して３０個の放射状フォトダイオードを設けている。このパターン＃４は、円形フォトダイオードの外側にアイソレーション溝の集中によって形成されるはずの無効領域が、円環状フォトダイオードによって形成されない。それ故、パターン＃４の相対出力は０．９７になり、パターン＃２，＃３よりも出力を大きくすることができる。従って、パターン＃４は、円形受光部１２に入射する光の利用効率がパターン＃３よりも向上し、無駄になる光入力をパターン＃２，＃３よりも減少させている。 In pattern #4, which corresponds to the circular light receiving section 12 in FIG. 3, a circular photodiode with a diameter of 126 μm and an annular photodiode with an outer diameter of 179 μm are provided in the center of the circular light receiving section concentrically with the circular light receiving section. , the outside of the annular photodiode is divided into 30 equal parts to provide 30 radial photodiodes. In this pattern #4, an ineffective region that should be formed by concentration of isolation grooves outside the circular photodiode is not formed by the annular photodiode. Therefore, the relative output of pattern #4 is 0.97, and the output can be made larger than patterns #2 and #3. Therefore, in pattern #4, the utilization efficiency of light incident on the circular light receiving portion 12 is improved compared to pattern #3, and the wasted light input is reduced compared to patterns #2 and #3.
　図６のように、円形受光部１２が有するＰＤの数が多くなるほど、円環状フォトダイオード１４ｂの外径Ｄ２が小さくなるので、円環状フォトダイオード１４ｂの近傍に複数の放射状アイソレーション溝１５が集中するようになる。そのため、円環状フォトダイオード１４ｂの外側に、第２円環状アイソレーション溝１３ｂだけでなく、複数の放射状アイソレーション溝１５が夫々幅方向に連なることにより周方向に連なって、光電変換できない環状の無効領域が形成されることになる。 As shown in FIG. 6, as the number of PDs included in the circular light receiving section 12 increases, the outer diameter D2 of the annular photodiode 14b becomes smaller, so that a plurality of radial isolation grooves 15 are concentrated near the annular photodiode 14b. I come to do it. Therefore, on the outside of the annular photodiode 14b, not only the second annular isolation groove 13b but also a plurality of radial isolation grooves 15 are connected in the width direction, and are connected in the circumferential direction. A region will be formed.
　このような無効領域の形成を防止するため、例えば図８のように、円形受光部１２は、円環状フォトダイオード１４ｂの外側に、第２円環状アイソレーション溝１３ｂと第３円環状アイソレーション溝１３ｃの間に形成された第２の円環状フォトダイオード１４ｃを有していてもよい。この場合も、円形受光部１２の複数のＰＤ（円形フォトダイオード１４ａ、２つの円環状フォトダイオード１４ｂ，１４ｃ、複数の放射状フォトダイオード１６）が生成する光電流が互いに等しくなるように、入力される光Ｌの光強度分布に基づいて各ＰＤの受光面積が夫々設定される。円形受光部１２は、３個以上の円環状フォトダイオードを有していてもよい。尚、図８では、放射状アイソレーション溝１５の符号及び放射状フォトダイオード１６の符号を一部省略している。 In order to prevent the formation of such an ineffective area, for example, as shown in FIG. 8, the circular light receiving section 12 has a second circular isolation groove 13b and a third circular isolation groove on the outside of the circular photodiode 14b. A second annular photodiode 14c may be formed between the photodiodes 13c and 13c. Also in this case, the photocurrents generated by the plurality of PDs (circular photodiode 14a, two annular photodiodes 14b, 14c, and plurality of radial photodiodes 16) of the circular light receiving section 12 are input so that they are equal to each other. The light receiving area of each PD is set based on the light intensity distribution of the light L. The circular light receiving section 12 may include three or more annular photodiodes. Note that in FIG. 8, some of the symbols of the radial isolation grooves 15 and the symbols of the radial photodiodes 16 are omitted.
　図示を省略するが、円環状フォトダイオードを増加させた場合でも、円形受光部１２の複数のＰＤは、複数の導電性部材２５によって直列に接続される。以上のように、円形受光部１２が有するＰＤの数が多い場合でも、円形フォトダイオードと１つ以上の円環状フォトダイオードによって無効領域の形成を防いで、円形受光部１２に入射する光の利用効率を高くすることができる。 Although not shown, even when the number of annular photodiodes is increased, the plurality of PDs of the circular light receiving section 12 are connected in series by the plurality of conductive members 25. As described above, even when the circular light-receiving section 12 has a large number of PDs, the circular photodiode and one or more annular photodiodes prevent the formation of an ineffective area and utilize the light incident on the circular light-receiving section 12. Efficiency can be increased.
　光給電コンバータ１は、半導体受光素子１０の代わりに、図９、図１０に示すような裏面入射型の半導体受光素子１０Ａを用いて構成することができる。裏面入射型の半導体受光素子１０Ａは、半導体受光素子１０の一部を変更した構造であり、半導体受光素子１０と共通する部分には同じ符号を付して説明を省略する。 The optical power supply converter 1 can be configured using a back-illuminated semiconductor light-receiving element 10A as shown in FIGS. 9 and 10 instead of the semiconductor light-receiving element 10. The back-illuminated semiconductor light-receiving device 10A has a structure in which a part of the semiconductor light-receiving device 10 is modified, and parts common to the semiconductor light-receiving device 10 are designated by the same reference numerals, and a description thereof will be omitted.
　半導体受光素子１０Ａの半導体基板２０は、入射光に対して透明な材料で形成され、入射する光Ｌを吸収せずに透過させる。例えばＩｎＰ基板は、波長が概ね１μｍ以上の赤外光に対して透明である。半導体基板２０の光Ｌの入射面（裏面）には、光Ｌの反射を抑制する反射防止膜２６が形成されていることが好ましい。円形受光部１２は、上記と同様にアイソレーション溝によって分割され、複数のＰＤ（円形フォトダイオード１４ａと円環状フォトダイオード１４ｂと複数の放射状フォトダイオード１６）を有する。 The semiconductor substrate 20 of the semiconductor light receiving element 10A is formed of a material that is transparent to incident light, and transmits the incident light L without absorbing it. For example, an InP substrate is transparent to infrared light having a wavelength of approximately 1 μm or more. Preferably, an antireflection film 26 for suppressing reflection of the light L is formed on the light L incident surface (back surface) of the semiconductor substrate 20. The circular light receiving section 12 is divided by isolation grooves as described above, and has a plurality of PDs (a circular photodiode 14a, an annular photodiode 14b, and a plurality of radial photodiodes 16).
　複数のＰＤは、上記と同様に入射する光Ｌの光強度分布に基づいて、受光量が互いに等しくなるように受光面積が夫々設定されている。これら複数のＰＤは、ｐ型半導体層２３に接続されたアノード電極２７と、ｎ型半導体層２１に接続されたカソード電極２８を夫々備えている。尚、図９では、放射状フォトダイオード１６の符号を一部省略している。 Similarly to the above, the light receiving areas of the plurality of PDs are set based on the light intensity distribution of the incident light L so that the amount of light received is equal to each other. These plurality of PDs each include an anode electrode 27 connected to the p-type semiconductor layer 23 and a cathode electrode 28 connected to the n-type semiconductor layer 21. Note that in FIG. 9, some of the symbols of the radial photodiodes 16 are omitted.
　円形受光部１２の複数のＰＤが基台３に形成された複数の導電性部材４によって直列に接続されるように、隣り合うＰＤのうちの一方のアノード電極２７と他方のカソード電極２８とが対応する導電性部材４に例えば導電性ペースト６によって固定されている。図示を省略するが、この円形受光部１２で生成された光電流を出力端子部２ａ，２ｂから出力するために、直列接続された複数のＰＤの両端の導電性部材４が対応する配線部３ａ，３ｂに接続されている。複数の導電性部材４が円形受光部１２に入射する光Ｌを遮らないので、複数のＰＤ間の光電流のばらつきを一層小さくすることができる。 The anode electrode 27 of one of the adjacent PDs and the cathode electrode 28 of the other are connected so that the plurality of PDs of the circular light receiving section 12 are connected in series by the plurality of conductive members 4 formed on the base 3. It is fixed to a corresponding conductive member 4 with, for example, conductive paste 6. Although not shown, in order to output the photocurrent generated in the circular light receiving section 12 from the output terminal sections 2a and 2b, a wiring section 3a corresponding to the conductive members 4 at both ends of a plurality of PDs connected in series. , 3b. Since the plurality of conductive members 4 do not block the light L incident on the circular light receiving section 12, variations in photocurrent among the plurality of PDs can be further reduced.
　上記光給電コンバータ１の作用、効果について説明する。
　光給電コンバータ１は、光ファイバケーブルＯＣから入力される入射光Ｌを半導体受光素子１０，１０Ａにより光電流に変換して出力する。半導体受光素子１０，１０Ａは、光電変換により光電流を生成する円形受光部１２を有する。円形受光部１２は、この円形受光部１２と同心の少なくとも２つの円環状アイソレーション溝１３ａ，１３ｂと複数の放射状アイソレーション溝１５によって分割されている。これにより円形受光部１２には、円形フォトダイオード１４ａと、少なくとも１つの円環状フォトダイオード１４ｂと、複数の放射状フォトダイオード１６が形成されている。これら円形フォトダイオード１４ａと円環状フォトダイオード１４ｂと放射状フォトダイオード１６は、入射光の光強度分布に基づいて受光量が互いに等しくなるように受光面積が夫々設定され、複数の導電性部材２５，４によって直列に接続されている。 The operation and effects of the optical power feeding converter 1 will be explained.
The optical power supply converter 1 converts the incident light L input from the optical fiber cable OC into a photocurrent using the semiconductor light receiving elements 10 and 10A, and outputs the photocurrent. The semiconductor light-receiving elements 10 and 10A have a circular light-receiving section 12 that generates a photocurrent through photoelectric conversion. The circular light receiving section 12 is divided by at least two annular isolation grooves 13a, 13b concentric with the circular light receiving section 12 and a plurality of radial isolation grooves 15. Thereby, a circular photodiode 14a, at least one annular photodiode 14b, and a plurality of radial photodiodes 16 are formed in the circular light receiving section 12. The circular photodiode 14a, the annular photodiode 14b, and the radial photodiode 16 have light-receiving areas set so that the amount of light received is equal to each other based on the light intensity distribution of the incident light, and the plurality of conductive members 25, 4 are connected in series by.
　円形受光部１２が有する複数のフォトダイオードの受光量が互いに等しくなるので、これらフォトダイオードで生成される光電流のばらつきを小さくすることができる。それ故、これらフォトダイオードを直列に接続した円形受光部１２は、生成する光電流が小さいフォトダイオードによる出力の低下を防止することができる。従って、この円形受光部１２を有する半導体受光素子１０，１０Ａから外部に給電する光給電コンバータ１の出力低下を防止することができる。また、円環状及び放射状のアイソレーション溝では光電流が生成されないが、円形受光部１２の中央部に形成された円形フォトダイオード１４ａと円環状フォトダイオード１４ｂによって、入射光の光強度が大きい部分が光電流に変換されずに無駄になることを防止することができる。 Since the amounts of light received by the plurality of photodiodes included in the circular light receiving section 12 are equal to each other, variations in photocurrent generated by these photodiodes can be reduced. Therefore, the circular light receiving section 12 in which these photodiodes are connected in series can prevent the output from decreasing due to the photodiode generating a small photocurrent. Therefore, it is possible to prevent a decrease in the output of the optical power supply converter 1 that supplies power to the outside from the semiconductor light receiving elements 10, 10A having the circular light receiving section 12. Further, although no photocurrent is generated in the annular and radial isolation grooves, the portions where the light intensity of the incident light is high are generated by the circular photodiode 14a and the annular photodiode 14b formed at the center of the circular light receiving section 12. This can prevent the photocurrent from being wasted without being converted into photocurrent.
　複数の放射状アイソレーション溝１５は、円形受光部１２の中心Ｃを通る中心軸に対して回転対称状に形成されている。円環状フォトダイオード１４ｂの外側が複数の放射状アイソレーション溝１５によって円形受光部１２の周方向に等分されるので、複数の放射状フォトダイオード１６の受光面積を容易に等しくすることができる。そして、光ファイバケーブルＯＣから入力される入射光は、光軸ＯＡに対して回転対称の光強度分布なので、その光軸ＯＡが円形受光部１２の中心Ｃを通るように入射させることにより、円形フォトダイオード１４ａと円環状フォトダイオード１４ｂと各放射状フォトダイオード１６とで、受光量を互いに等しくすることができる。従って、これらフォトダイオードで生成される光電流のばらつきを小さくして、光給電コンバータ１の出力の低下を防ぐことができる。 The plurality of radial isolation grooves 15 are formed rotationally symmetrically with respect to the central axis passing through the center C of the circular light receiving section 12. Since the outer side of the annular photodiode 14b is equally divided in the circumferential direction of the circular light receiving section 12 by the plurality of radial isolation grooves 15, the light receiving area of the plurality of radial photodiodes 16 can be easily made equal. Since the incident light input from the optical fiber cable OC has a light intensity distribution that is rotationally symmetrical with respect to the optical axis OA, by making the incident light enter so that the optical axis OA passes through the center C of the circular light receiving part 12, The amount of light received by the photodiode 14a, the annular photodiode 14b, and each radial photodiode 16 can be made equal to each other. Therefore, it is possible to reduce variations in the photocurrents generated by these photodiodes and prevent a decrease in the output of the optical power supply converter 1.
　その他、当業者であれば、本発明の趣旨を逸脱することなく、上記実施形態に種々の変更を付加した形態で実施可能であり、本発明はその種の変更形態も包含するものである。 In addition, those skilled in the art can implement various modifications to the above embodiments without departing from the spirit of the present invention, and the present invention includes such modifications.
１　　：光給電コンバータ
２ａ，２ｂ：出力端子部
３　　：基台
４　　：導電性部材
５　　：カバー
５ａ　：挿入孔
１０，１０Ａ：半導体受光素子
１０ａ，１０ｂ：電極
１１ａ，１１ｂ：導電性ワイヤ
１２　：円形受光部
１３ａ～１３ｃ：第１～第３円環状アイソレーション溝（円環状アイソレーション溝）
１３ｎ：外周アイソレーション溝
１４ａ：円形フォトダイオード
１４ｂ：円環状フォトダイオード
１４ｃ：第２の円環状フォトダイオード
１５　：放射状アイソレーション溝
１６　：放射状フォトダイオード
１７　：貫通孔
２０　：半導体基板
２１　：ｎ型半導体層
２２　：光吸収層
２３　：ｐ型半導体層
２４　：保護膜
２５　：導電性部材
２６　：反射防止膜
２７　：アノード電極
２８　：カソード電極
ＯＣ　：光ファイバケーブル
Ｅ　　：出射端
Ｌ　　：光（入射光） 1: Optical power supply converter 2a, 2b: Output terminal section 3: Base 4: Conductive member 5: Cover 5a: Insertion hole 10, 10A: Semiconductor light receiving element 10a, 10b: Electrode 11a, 11b: Conductive wire 12: Circular Light receiving parts 13a to 13c: first to third annular isolation grooves (annular isolation grooves)
13n: Outer periphery isolation groove 14a: Circular photodiode 14b: Annular photodiode 14c: Second annular photodiode 15: Radial isolation groove 16: Radial photodiode 17: Through hole 20: Semiconductor substrate 21: N-type semiconductor Layer 22: Light absorption layer 23: P-type semiconductor layer 24: Protective film 25: Conductive member 26: Anti-reflection film 27: Anode electrode 28: Cathode electrode OC: Optical fiber cable E: Output end L: Light (incident light)

Claims (2)

  1. 　光ファイバケーブルから入力される入射光を半導体受光素子により光電流に変換して出力する光給電コンバータにおいて、
    　前記半導体受光素子は円形受光部を備え、
    　前記円形受光部は、この円形受光部と同心の複数の円環状アイソレーション溝によって分割された円形フォトダイオード及び１つ以上の円環状フォトダイオードと、前記円環状フォトダイオードの外側に前記円形受光部の中心に対して放射状に形成された複数の放射状アイソレーション溝によって分割された複数の放射状フォトダイオードを有し、
    　前記円形フォトダイオードと前記円環状フォトダイオードと前記放射状フォトダイオードは、前記入射光の光強度分布に基づいて受光量が互いに等しくなるように受光面積が夫々設定され、
    　前記円形フォトダイオードと前記円環状フォトダイオードと複数の前記放射状フォトダイオードが複数の導電性部材によって直列に接続されたことを特徴とする光給電コンバータ。     In an optical power supply converter that converts incident light input from an optical fiber cable into a photocurrent using a semiconductor photodetector and outputs it,
    The semiconductor light-receiving element includes a circular light-receiving section,
    The circular light receiving section includes a circular photodiode divided by a plurality of circular isolation grooves concentric with the circular light receiving section, one or more circular photodiodes, and the circular light receiving section outside the circular photodiode. has a plurality of radial photodiodes divided by a plurality of radial isolation grooves formed radially with respect to the center of the
    The circular photodiode, the annular photodiode, and the radial photodiode each have a light receiving area set so that the amount of light received is equal to each other based on the light intensity distribution of the incident light,
    An optical power supply converter characterized in that the circular photodiode, the annular photodiode, and a plurality of the radial photodiodes are connected in series by a plurality of conductive members.
  2. 　複数の前記放射状フォトダイオードは、前記円形受光部の中心を通る中心軸に対して回転対称状に形成されたことを特徴とする請求項１に記載の光給電コンバータ。 The optical power supply converter according to claim 1, wherein the plurality of radial photodiodes are formed rotationally symmetrically with respect to a central axis passing through the center of the circular light receiving section.
PCT/JP2022/023117 2022-06-08 2022-06-08 Optical power supply converter WO2023238279A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02224375A (en) * 1989-02-27 1990-09-06 Toshiba Corp Solar cell module
US20110108081A1 (en) * 2006-12-20 2011-05-12 Jds Uniphase Corporation Photovoltaic Power Converter
JP2015072251A (en) * 2013-09-04 2015-04-16 カシオ計算機株式会社 Solar panel and clock

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02224375A (en) * 1989-02-27 1990-09-06 Toshiba Corp Solar cell module
US20110108081A1 (en) * 2006-12-20 2011-05-12 Jds Uniphase Corporation Photovoltaic Power Converter
JP2015072251A (en) * 2013-09-04 2015-04-16 カシオ計算機株式会社 Solar panel and clock

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JPWO2023238279A1 (en) 2023-12-14

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