WO2009104337A1 - Lens component for optical communication - Google Patents

Lens component for optical communication Download PDF

Info

Publication number
WO2009104337A1
WO2009104337A1 PCT/JP2008/073120 JP2008073120W WO2009104337A1 WO 2009104337 A1 WO2009104337 A1 WO 2009104337A1 JP 2008073120 W JP2008073120 W JP 2008073120W WO 2009104337 A1 WO2009104337 A1 WO 2009104337A1
Authority
WO
WIPO (PCT)
Prior art keywords
condensing lens
optical
lens
light
optical communication
Prior art date
Application number
PCT/JP2008/073120
Other languages
French (fr)
Japanese (ja)
Inventor
宏和 田中
宣夫 中村
聖志 泉
Original Assignee
日本電気硝子株式会社
住友金属鉱山株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電気硝子株式会社, 住友金属鉱山株式会社 filed Critical 日本電気硝子株式会社
Publication of WO2009104337A1 publication Critical patent/WO2009104337A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features
    • 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
    • H01L31/02325—Optical elements or arrangements associated with the device the optical elements not being integrated nor being directly associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/58—Optical field-shaping elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings
    • H01S5/02208—Mountings; Housings characterised by the shape of the housings
    • H01S5/02212—Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings
    • H01S5/02208—Mountings; Housings characterised by the shape of the housings
    • H01S5/02216—Butterfly-type, i.e. with electrode pins extending horizontally from the housings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings
    • H01S5/0225—Out-coupling of light
    • H01S5/02251—Out-coupling of light using optical fibres

Definitions

  • the present invention relates to an optical communication lens component having a condensing lens for optically coupling an optical element having at least one of a light emitting function and a light receiving function to an optical fiber.
  • An optical communication lens component in which a condensing lens is fixed to a sleeve-shaped or cap-shaped metal holder with sealing glass (for example, Patent Document 1 below).
  • This condensing lens performs at least one of the function of condensing the light emitted from the light emitting element onto the optical fiber and the function of condensing the light emitted from the optical fiber onto the light receiving element. Glass made into a spherical shape is widely used.
  • an optical glass lens (refractive index of about 1.5 to 1.8), which has been widely used as a condensing lens, is conventionally used as an optical element and an optical fiber.
  • the degree of coupling varies depending on the radius of curvature of the optical glass lens, but the coupling efficiency may be obtained only about 10 to 20% due to the influence of spherical aberration.
  • the refractive index of the optical glass lens is small for light in the optical communication wavelength band (1260 to 1675 nm) which is currently mainstream in FTTH, intercity, or international long-distance optical communication, and its value is increased. Even if it tries, it originates in about 2.0 being a limit.
  • the optical element in the condensing lens integrated with the optical element, the optical element is configured to realize the photoelectric conversion function or the electro-optical conversion function of the optical element.
  • the semiconductor needs to be a p-type or n-type semiconductor doped with impurities. For this reason, the doped impurities diffuse into the condensing lens portion. As a result, very large absorption derived from impurities occurs in the above optical communication wavelength band, and the coupling efficiency may be greatly reduced.
  • the present invention provides a technique for improving the optical coupling efficiency between an optical element having at least one of a light emitting function and a light receiving function and an optical fiber as much as possible. As an objective.
  • the present invention provides a light having a condensing lens that optically couples an optical element having at least one of a light emitting function and a light receiving function with an optical fiber.
  • the condensing lens is made of a group III-V compound semiconductor or a group II-VI compound semiconductor separate from the optical element, and a part or all of light in a wavelength band of 1260 to 1675 nm.
  • it is characterized by an internal transmittance of 90% or more and a refractive index of 2.1 to 4.5.
  • the condensing lens is formed of a group III-V compound semiconductor or a group II-VI compound semiconductor separate from the optical element (light receiving element, light emitting element, or light receiving / emitting element). Therefore, there is no need to actively dope impurities into the condensing lens as in the case where the condensing lens and the optical element are integrated. Therefore, the internal transmittance for part or all of the light in the wavelength band of 1260 to 1675 nm, which is the mainstream for optical communication, can be 90% or more.
  • the condensing lens from a III-V group compound semiconductor or a II-VI group compound semiconductor in this way, it is much more difficult than an optical glass lens that has been widely used as a condensing lens.
  • High refractive index can be realized. Specifically, the refractive index for part or all of the light in the wavelength band of 1260 to 1675 nm can be set to 2.1 to 4.5.
  • the condensing lens can reliably increase the optical coupling efficiency between the optical element and the optical fiber, It is possible to realize good optical communication with little loss.
  • the condensing lens described above preferably has an internal transmittance of 95% or more, and more preferably 99% or more with respect to a part or all of light in the wavelength band of 1260 to 1675 nm. Further, the condensing lens has an internal transmittance for all light in this wavelength band, rather than having an internal transmittance of 90% or more for a part of light in the wavelength band of 1260 to 1675 nm. It is preferably 90% or more. In this case, the condensing lens reduces light absorption with respect to all light in the wavelength band of 1260 to 1675 nm, and therefore can be applied to optical communication lens components used for light of different wavelengths. It becomes possible.
  • the condensing lens is preferably made of gallium phosphide (GaP) which is a III-V group compound semiconductor, and an impurity concentration thereof is preferably 1.0 ⁇ 10 16 / cm 3 or less.
  • GaP gallium phosphide
  • the coupling efficiency of the optical coupling between the optical element having at least one of the function of emitting light and the function of receiving light and the optical fiber is improved. It can certainly be increased.
  • FIG. 1 It is a figure which shows the state which integrated the optical communication lens component which concerns on embodiment of this invention, and optically combined the optical element and the optical fiber. It is a figure which shows the modification of the lens component for optical communications which concerns on this embodiment. It is a figure which shows the change of the internal transmittance with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on Example 1 of this invention. It is a figure which shows the change of the internal transmittance with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on the comparative example 1. FIG. It is a figure which shows the change of the refractive index with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on Example 1 of this invention.
  • FIG. 1 is a diagram schematically showing a state in which an optical communication lens component according to the first embodiment of the present invention is incorporated and an optical element and an optical fiber are optically coupled.
  • This optical communication lens component 1 includes a covered cylindrical cap 2 and a condensing lens 3 fixed to a lid portion 2 a of the cap 2.
  • the optical communication lens component 1 is fixed to a stem 5 on which the optical element 4 is mounted, and the optical element 4 and the optical fiber 6 are optically coupled by the condensing lens 3.
  • the cap 2 has a through hole 2a1 at the center of the lid 2a and a flange 2c extending radially outward at the bottom of the tube 2b.
  • the condensing lens 3 is fixed to the through hole 2a1 of the lid portion 2a by the low melting point glass 7.
  • the condensing lens 3 is obtained by processing a group III-V compound semiconductor or a group II-VI compound semiconductor into a spherical shape, and has an internal transmittance of 99% or more for all light in the wavelength band of 1260 to 1675 nm.
  • the refractive index is 2.1 to 4.5.
  • the III-V compound semiconductor is a general term for compound semiconductors composed of Group III aluminum, gallium, indium, and the like, and Group V nitrogen, phosphorus, arsenic, antimony, and the like.
  • the II-VI group compound semiconductor is a general term for compound semiconductors consisting of Group II magnesium, zinc, cadmium, mercury, etc. and Group VI oxygen, sulfur, selenium, tellurium, etc. Specifically, for example, Zinc oxide, zinc selenide, zinc sulfide, gadmium sulfide, cadmium telluride and the like.
  • the condensing lens 3 is made of gallium phosphide, which belongs to the III-V group compound semiconductor and is controlled to have an impurity concentration of 1.0 ⁇ 10 16 / cm 3 or less. .
  • gallium phosphide is adopted as a material for the condensing lens 3 in the optical communication wavelength band (1260 to 1675 nm) which is currently mainstream in FTTH, intercity, or international long-distance optical communication.
  • the refractive index of phosphide is about 3.04 to 3.10.
  • the refractive index of general optical glass about 1.5 to 1.8
  • the refractive index of ultra high refractive index optical glass about 2.0. This is because a very high value is exhibited as compared with FIG.
  • the degree of spherical aberration is proportional to the cube of the aperture of the condenser lens 3. That is, the influence of spherical aberration becomes more significant as the incident angle to the condensing lens 3 increases. Therefore, in order to reduce spherical aberration with a single lens, it is advantageous to select a material having a higher refractive index if the focal length is the same. That is, if the material has a high refractive index, the curvature of the condensing lens 3 can be reduced and the incident angle can be reduced, so that the influence of spherical aberration can be reduced.
  • the gallium phosphor belonging to the III-V compound semiconductor is used. Fido is adopted.
  • the reason why the impurity concentration of gallium phosphide is managed as described above is to realize the above-described internal transmittance characteristics in the optical communication wavelength band (1260 to 1675 nm). More specifically, in order to prevent a situation where an impurity level due to impurities is formed in a band gap of a semiconductor and laser light used for optical communication is absorbed by the condensing lens 3, impurities (for example, silicon ) Concentration is managed within the above numerical range. Even when a III-V group compound semiconductor or II-VI group compound semiconductor other than gallium phosphide is used as the material of the condensing lens 3, the impurity concentration can be controlled to the same level as the undoped state. is important.
  • the undoped state here does not contain impurities that are actively doped when manufacturing n-type or p-type semiconductors, but contains impurities such as trace amounts of contamination that are inevitably mixed. It means to allow.
  • the transmittance characteristic obtained by managing the impurities of the condensing lens 3 is obtained by configuring the optical element 4 and the condensing lens 3 separately as shown in FIG. Realized for the first time. That is, when the condensing lens 3 and the optical element 4 such as a light emitting element (LD) are integrated, impurities diffuse from the p-type or n-type semiconductor constituting the optical element 4 to the condensing lens portion. This is because the transmittance may be significantly reduced.
  • LD light emitting element
  • an antireflection film (not shown) is formed on the surface of the condensing lens 3 so that the reflected light from the surface of the condensing lens 3 does not affect the optical communication (for example, the reflectance per one surface). 0.5% or less).
  • the condensing lens 3 is formed of gallium phosphide separate from the optical element 4, the condensing lens 3 and There is no need to actively dope impurities into the condensing lens 3 as in the case where the optical element 4 is integrated. Therefore, the internal transmittance of the condensing lens 3 with respect to all light in the wavelength band of 1260 to 1675 nm, which is the mainstream in optical communication, can be 90% or more.
  • the condensing lens 3 from gallium phosphide in this way, it is possible to realize a very high refractive index as compared with an optical glass lens widely used as a condensing lens. Specifically, the refractive index for all light in the wavelength band of 1260 to 1675 nm can be set to 2.1 to 4.5.
  • the internal transmittance of the condensing lens 3 is 90% or more
  • light absorption is reduced, and light loss due to passing through the condensing lens 3 can be reliably reduced.
  • the refractive index of the condensing lens 3 is within the above numerical range
  • the problem of spherical aberration that occurs when the condensing lens 3 is made of optical glass can be reliably solved. Therefore, when the internal transmittance and refractive index of the condensing lens 3 are within the above numerical ranges, the optical coupling efficiency between the optical element 4 and the optical fiber 6 is reliably increased by the condensing lens 3. Therefore, it is possible to realize good optical communication with little loss.
  • the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist of the present invention.
  • the optical communication lens component 1 in which the condensing lens 3 is fixed to the covered cylindrical cap 2 with the low melting point glass 7 has been described.
  • the lens 3 may be fixed to the butterfly package 8 with an adhesive (not shown) or low melting point glass.
  • the positioning lens 3 and the optical fiber 6 have a high degree of freedom in positioning when mounted and fixed, but may be easily displaced.
  • a V-groove or the like may be formed in advance in the butterfly package 8 at a position where the condensing lens 3 and the optical fiber 6 are to be mounted. Furthermore, a structure in which at least one between the optical element 4 and the condensing lens 3 or between the condensing lens 3 and the optical fiber 6 is filled with an adhesive or low-melting glass may be used.
  • a spherical lens is exemplified as the condensing lens 3.
  • the light traveling direction is changed to a target direction by refraction, such as a hemispherical shape, a drum shape, a rod shape, or a cylinder shape. Any shape can be used.
  • Example 1 of the present invention a spherical condensing lens 3 having a diameter of 2.0 mm formed from gallium phosphide having an impurity concentration controlled to 1.0 ⁇ 10 16 / cm 3 or less was manufactured.
  • the condensing lens 3 is manufactured by manufacturing a gallium phosphide single crystal ingot having an impurity concentration controlled to 1.0 ⁇ 10 16 / cm 3 or less by a liquid-sealed Czochralski method.
  • the ingot was manufactured by processing into a spherical shape (diameter 2.0 mm) by mechanical polishing.
  • Example 1 the change of the internal transmittance with respect to the wavelength of the condensing lens 3 according to Example 1 was measured. The result is shown in FIG.
  • Comparative Example 1 a spherical condensing lens having a diameter of 2.0 mm formed from gallium phosphide having an impurity (silicon) concentration of 4.0 ⁇ 10 17 / cm 3 was manufactured, and similarly, the internal wavelength was adjusted. The change in transmittance was measured. The result is shown in FIG.
  • the condensing lens 3 includes an optical communication wavelength band (1260 to 1675 nm) that is currently mainstream in FTTH, intercity, or international long-distance optical communication.
  • the internal transmittance is 99% or more, and no light absorption that affects the transmission characteristics is observed.
  • the energy gap E g at 300K gallium Foz sulfide is 2.26 eV (about is converted into the wavelength of light 549 nm)
  • the energy separation E 0 ⁇ 1C - ⁇ 15V
  • the light about 446 nm corresponds to the absorption band in the internal transmittance in the figure.
  • the optical communication wavelength band (1260 to 1675 nm) is very large as shown in FIG. Absorption is observed, and the internal transmittance in this wavelength band is about 5 to 20%.
  • the condensing lens 3 according to Example 1 in which the impurity concentration is controlled within the above numerical range is more internal than the condensing lens according to Comparative Example 1 in the optical communication wavelength band. It can be recognized that the transmittance is greatly improved.
  • the condensing lens 3 has a refractive index of 3.00 or more in the wavelength band of 1750 nm or less, and 3.04 to 3 in the optical communication wavelength band (1260 to 1675 nm). There are about 10.
  • the refractive index of the condensing lens 3 is very high compared to general optical glass (refractive index of about 1.5 to 1.8) and ultrahigh refractive optical glass (refractive index of about 2.0). Therefore, by incorporating the condensing lens 3 in the optical communication lens component 1 and using it for optical coupling between the optical element 4 and the optical fiber 6 as shown in FIG. It can be greatly reduced.
  • the condensing lens 3 according to the first embodiment is incorporated in the optical communication lens component 1 shown in FIG. 1, and the distance between the condensing lens 3 and the optical element 4, the condensing lens 3 and the light.
  • the coupling efficiency at various imaging magnifications was measured.
  • FIG. 1 As Comparative Example 2, a spherical condensing lens having a diameter of 2.0 mm made of general optical glass (refractive index of about 1.5 to 1.8) was manufactured, and the coupling efficiency was measured. At that time, the imaging magnification was set to an imaging magnification at which the maximum coupling efficiency was obtained. The result is shown in FIG.
  • a Fabry-Perot laser (a kind of edge-emitting laser that emits light in a direction parallel to the semiconductor substrate) is used as the optical element 4, and the oscillation wavelength is 1310 nm and the output is 10 mW. Respectively.
  • the condensing lens 3 according to Example 1 is compared with the condensing lens made of general optical glass (refractive index of about 1.5 to 1.8) according to Comparative Example 2. It can be recognized that the coupling efficiency is greatly improved.

Abstract

Efficiency of optically coupling an optical element, which has at least a light emitting function or a light receiving function, with an optical fiber is improved as much as possible. A lens component (1) for optical communication has a condensing lens (3) for optically coupling an optical element (4), which has at least a light emitting function or a light receiving function, with an optical fiber (6). The condensing lens (3) is formed of a gallium phosphide having an impurity concentration of 1.0×1016/cm3 or less, and is permitted to have an internal transmittance of 90% or more to all the light in wavelength bands of 1,260-1,675nm and a refractive index of 2.1-4.5.

Description

光通信用レンズ部品Optical communication lens parts
　本発明は、光を発光する機能又は光を受光する機能の少なくとも一方の機能を有する光素子を、光ファイバと光学的に結合するための集光用レンズを有する光通信用レンズ部品に関する。 The present invention relates to an optical communication lens component having a condensing lens for optically coupling an optical element having at least one of a light emitting function and a light receiving function to an optical fiber.
　光通信用レンズ部品としては、スリーブ状又はキャップ状の金属製ホルダーに、集光用レンズを封着用ガラスによって固着したものが知られている（例えば、下記の特許文献１）。この集光用レンズは、発光素子から出射された光を光ファイバに集光する機能、或いは光ファイバから出射された光を受光素子に集光する機能の少なくとも一方の機能を果たすもので、光学ガラスを球状に加工したものが広く利用されている。 An optical communication lens component is known in which a condensing lens is fixed to a sleeve-shaped or cap-shaped metal holder with sealing glass (for example, Patent Document 1 below). This condensing lens performs at least one of the function of condensing the light emitted from the light emitting element onto the optical fiber and the function of condensing the light emitted from the optical fiber onto the light receiving element. Glass made into a spherical shape is widely used.
　また、近年では、この種の集光用レンズとして、光学ガラス以外のものも提案されるに至っている。具体的には、下記の特許文献２には、発光素子や受光素子等の光素子を構成する半導体物質の一部にレンズ機能を付与して、光素子と集光用レンズを一体化することにより、集光用レンズを光素子と同じ半導体で形成することが提案されている。
特開平３－６８９０６号公報 特開平１０－２４２５０６号公報 In recent years, lenses other than optical glass have been proposed as this type of condensing lens. Specifically, in Patent Document 2 below, a lens function is imparted to a part of a semiconductor material constituting an optical element such as a light emitting element or a light receiving element, and the optical element and the condensing lens are integrated. Therefore, it has been proposed that the condensing lens is formed of the same semiconductor as the optical element.
JP-A-3-68906 Japanese Patent Laid-Open No. 10-242506
　ところで、近年の光通信システムの発展に伴って、例えばＦＴＴＨや都市間、或いは国際長距離光通信では、大容量の情報通信が推進されているのが実情であり、更なる通信効率の向上が要求されている。そして、この通信効率を向上させるには、集光用レンズによって光素子と光ファイバとを光学的に結合する際に生じる損失を低減すること、すなわち、集光用レンズによる光の結合効率を向上させることが重要となる。 By the way, with the recent development of optical communication systems, for example, in FTTH, intercity or international long-distance optical communication, large-capacity information communication is being promoted, and further improvement in communication efficiency is achieved. It is requested. In order to improve the communication efficiency, the loss caused when the optical element and the optical fiber are optically coupled by the condensing lens is reduced, that is, the light coupling efficiency by the condensing lens is improved. Is important.
　しかしながら、上記の特許文献１に開示されているように、従来、集光用レンズとして広く利用されている光学ガラス製レンズ（屈折率１．５～１．８程度）を、光素子と光ファイバの光学結合に用いた場合、光学ガラス製レンズの曲率半径等により程度は異なるが、結合効率は、球面収差の影響を受けて、例えば１０～２０％程度しか得られない場合がある。これは、ＦＴＴＨや都市間、或いは国際長距離光通信で現在主流となっている光通信波長帯域（１２６０～１６７５ｎｍ）の光に対して、光学ガラス製レンズの屈折率が小さく、その値を高めようとしても２．０程度が限界であることに起因する。 However, as disclosed in Patent Document 1 above, an optical glass lens (refractive index of about 1.5 to 1.8), which has been widely used as a condensing lens, is conventionally used as an optical element and an optical fiber. When the optical coupling is used, the degree of coupling varies depending on the radius of curvature of the optical glass lens, but the coupling efficiency may be obtained only about 10 to 20% due to the influence of spherical aberration. This is because the refractive index of the optical glass lens is small for light in the optical communication wavelength band (1260 to 1675 nm) which is currently mainstream in FTTH, intercity, or international long-distance optical communication, and its value is increased. Even if it tries, it originates in about 2.0 being a limit.
　また、上記の特許文献２に開示されているように、光素子と一体となった集光用レンズでは、光素子の光電変換機能、あるいは電光変換機能を実現するために、光素子を構成する半導体を、不純物がドーピングされたｐ型またはｎ型半導体にする必要がある。そのため、ドーピングされた不純物が集光用レンズ部分にも拡散することになる。その結果、上記の光通信波長帯域で不純物に由来する非常に大きな吸収が生じ、結合効率が大幅に低下してしまう場合がある。 Further, as disclosed in the above-mentioned Patent Document 2, in the condensing lens integrated with the optical element, the optical element is configured to realize the photoelectric conversion function or the electro-optical conversion function of the optical element. The semiconductor needs to be a p-type or n-type semiconductor doped with impurities. For this reason, the doped impurities diffuse into the condensing lens portion. As a result, very large absorption derived from impurities occurs in the above optical communication wavelength band, and the coupling efficiency may be greatly reduced.
　本発明は、上記事情に鑑み、光を発光する機能又は光を受光する機能の少なくとも一方の機能を有する光素子と、光ファイバとの光学的な結合効率を可及的に向上させることを技術的課題とする。 In view of the above circumstances, the present invention provides a technique for improving the optical coupling efficiency between an optical element having at least one of a light emitting function and a light receiving function and an optical fiber as much as possible. As an objective.
　上記課題を解決するために創案された本発明は、光を発光する機能又は光を受光する機能の少なくとも一方の機能を有する光素子を光ファイバと光学的に結合する集光用レンズを有する光通信用レンズ部品において、前記集光用レンズが、前記光素子とは別体のIII－V族化合物半導体又はII－VI族化合物半導体からなり、１２６０～１６７５ｎｍの波長帯域の一部又は全部の光に対して、内部透過率が９０％以上で且つ屈折率が２．１～４．５であることに特徴づけられる。 In order to solve the above problems, the present invention provides a light having a condensing lens that optically couples an optical element having at least one of a light emitting function and a light receiving function with an optical fiber. In the communication lens component, the condensing lens is made of a group III-V compound semiconductor or a group II-VI compound semiconductor separate from the optical element, and a part or all of light in a wavelength band of 1260 to 1675 nm. On the other hand, it is characterized by an internal transmittance of 90% or more and a refractive index of 2.1 to 4.5.
　このような構成によれば、集光用レンズが、光素子（受光素子、発光素子、或いは受発光素子）とは別体のIII－V族化合物半導体又はII－VI族化合物半導体から形成されるので、集光用レンズと光素子とを一体化する場合のように、集光用レンズに不純物を積極的にドープする必要がなくなる。そのため、光通信として主流となっている１２６０～１６７５ｎｍの波長帯域の一部又は全部の光に対する内部透過率を９０％以上とすることができる。また、このように集光用レンズをIII－V族化合物半導体又はII－VI族化合物半導体から形成することで、従来、集光用レンズとして広く利用されている光学ガラス製レンズに比べて、非常に高い屈折率を実現することができる。具体的には、１２６０～１６７５ｎｍの波長帯域の一部又は全部の光に対する屈折率を２．１～４．５とすることができる。 According to such a configuration, the condensing lens is formed of a group III-V compound semiconductor or a group II-VI compound semiconductor separate from the optical element (light receiving element, light emitting element, or light receiving / emitting element). Therefore, there is no need to actively dope impurities into the condensing lens as in the case where the condensing lens and the optical element are integrated. Therefore, the internal transmittance for part or all of the light in the wavelength band of 1260 to 1675 nm, which is the mainstream for optical communication, can be 90% or more. Further, by forming the condensing lens from a III-V group compound semiconductor or a II-VI group compound semiconductor in this way, it is much more difficult than an optical glass lens that has been widely used as a condensing lens. High refractive index can be realized. Specifically, the refractive index for part or all of the light in the wavelength band of 1260 to 1675 nm can be set to 2.1 to 4.5.
　そして、集光用レンズの内部透過率が、９０％以上となる波長においては、光の吸収は少なくなるため、レンズを通過することによる光の損失を確実に低減することができる。また、集光用レンズの屈折率が、上記数値範囲内にあれば、集光用レンズを光学ガラスで製作した場合に生じる球面収差の問題も確実に解消することができる。したがって、集光用レンズの内部透過率と屈折率を、それぞれ上記数値範囲内にすれば、集光用レンズによって、光素子と光ファイバとの光学的な結合効率を確実に高めることができ、損失の少ない良好な光通信を実現することが可能となる。 And, at a wavelength where the internal transmittance of the condensing lens is 90% or more, light absorption is reduced, so that loss of light due to passing through the lens can be surely reduced. Moreover, if the refractive index of the condensing lens is within the above numerical range, the problem of spherical aberration that occurs when the condensing lens is made of optical glass can be reliably solved. Therefore, if the internal transmittance and refractive index of the condensing lens are within the above numerical ranges, the condensing lens can reliably increase the optical coupling efficiency between the optical element and the optical fiber, It is possible to realize good optical communication with little loss.
　なお、上記の集光用レンズは、１２６０～１６７５ｎｍの波長帯域の一部又は全部の光に対して、内部透過率が９５％以上であることが好ましく、９９％以上であることがより好ましい。また、集光用レンズは、１２６０～１６７５ｎｍの波長帯域の一部の光に対して、内部透過率が９０％以上であるよりも、この波長帯域の全部の光に対して、内部透過率が９０％以上であることが好ましい。この場合、集光用レンズは、１２６０～１６７５ｎｍの波長帯域の全部の光に対して光の吸収が少なくなるため、異なる波長の光に対して使用される光通信用レンズ部品に適用することが可能となる。 The condensing lens described above preferably has an internal transmittance of 95% or more, and more preferably 99% or more with respect to a part or all of light in the wavelength band of 1260 to 1675 nm. Further, the condensing lens has an internal transmittance for all light in this wavelength band, rather than having an internal transmittance of 90% or more for a part of light in the wavelength band of 1260 to 1675 nm. It is preferably 90% or more. In this case, the condensing lens reduces light absorption with respect to all light in the wavelength band of 1260 to 1675 nm, and therefore can be applied to optical communication lens components used for light of different wavelengths. It becomes possible.
　上記の構成において、前記集光用レンズは、III－V族化合物半導体であるガリウムフォスファイド（ＧａＰ）からなり、その不純物濃度が、１．０×１０１６／ｃｍ３以下であることが好ましい。 In the above configuration, the condensing lens is preferably made of gallium phosphide (GaP) which is a III-V group compound semiconductor, and an impurity concentration thereof is preferably 1.0 × 10 16 / cm 3 or less.
　このようにすれば、内部透過率と屈折率との関係が、既述した数値範囲内となる集光用レンズを簡単に製造することができる。また、ガリウムフォスファイドは、比較的安価に製作できることから、低コスト化を図る上でも有利となる。 In this way, it is possible to easily manufacture a condensing lens in which the relationship between the internal transmittance and the refractive index is within the numerical range described above. Further, since gallium phosphide can be manufactured at a relatively low cost, it is advantageous for cost reduction.
　以上のように本発明に係る光通信用レンズ部品によれば、光を発光する機能又は光を受光する機能の少なくとも一方の機能を有する光素子と、光ファイバとの光学的結合の結合効率を確実に高めることができる。 As described above, according to the lens component for optical communication according to the present invention, the coupling efficiency of the optical coupling between the optical element having at least one of the function of emitting light and the function of receiving light and the optical fiber is improved. It can certainly be increased.
本発明の実施形態に係る光通信用レンズ部品を組み込んで、光素子と光ファイバを光学的に結合した状態を示す図である。It is a figure which shows the state which integrated the optical communication lens component which concerns on embodiment of this invention, and optically combined the optical element and the optical fiber. 本実施形態に係る光通信用レンズ部品の変形例を示す図である。It is a figure which shows the modification of the lens component for optical communications which concerns on this embodiment. 本発明の実施例１に係る光通信用レンズ部品（集光用レンズ）の波長に対する内部透過率の変化を示す図である。It is a figure which shows the change of the internal transmittance with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on Example 1 of this invention. 比較例１に係る光通信用レンズ部品（集光用レンズ）の波長に対する内部透過率の変化を示す図である。It is a figure which shows the change of the internal transmittance with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on the comparative example 1. FIG. 本発明の実施例１に係る光通信用レンズ部品（集光用レンズ）の波長に対する屈折率の変化を示す図である。It is a figure which shows the change of the refractive index with respect to the wavelength of the lens component for optical communication (condensing lens) which concerns on Example 1 of this invention. 本発明の実施例１に係る光通信用レンズ部品（集光用レンズ）の結像倍率に対する結合効率の変化を示す図である。It is a figure which shows the change of the coupling efficiency with respect to the imaging magnification of the lens component for optical communication (condensing lens) which concerns on Example 1 of this invention. 比較例２に係る光通信用レンズ部品（集光用レンズ）の屈折率に対する結合効率の変化を示す図である。It is a figure which shows the change of the coupling efficiency with respect to the refractive index of the optical communication lens component (condensing lens) which concerns on the comparative example 2. FIG.
符号の説明Explanation of symbols
１　　　光通信用レンズ部品
２　　　キャップ
２ａ　　蓋部
２ａ１　貫通孔
２ｂ　　筒部
２ｃ　　フランジ部
３　　　集光用レンズ
４　　　光素子
５　　　ステム
６　　　光ファイバ
７　　　低融点ガラス
８　　　バタフライパッケージ DESCRIPTION OF SYMBOLS 1 Optical communication lens component 2 Cap 2a Cover part 2a1 Through-hole 2b Tube part 2c Flange part 3 Condensing lens 4 Optical element 5 Stem 6 Optical fiber 7 Low melting glass 8 Butterfly package
　以下、本発明に係る実施形態を図面に基づいて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１は、本発明の第１の実施形態に係る光通信用レンズ部品を組み込んで、光素子と光ファイバとを光学的に結合した状態を模式的に示す図である。この光通信用レンズ部品１は、有蓋円筒状のキャップ２と、キャップ２の蓋部２ａに固着された集光用レンズ３とを備えている。そして、この光通信用レンズ部品１は、光素子４が搭載されたステム５に固定され、光素子４と光ファイバ６とを集光用レンズ３により光学的に結合するようになっている。 FIG. 1 is a diagram schematically showing a state in which an optical communication lens component according to the first embodiment of the present invention is incorporated and an optical element and an optical fiber are optically coupled. This optical communication lens component 1 includes a covered cylindrical cap 2 and a condensing lens 3 fixed to a lid portion 2 a of the cap 2. The optical communication lens component 1 is fixed to a stem 5 on which the optical element 4 is mounted, and the optical element 4 and the optical fiber 6 are optically coupled by the condensing lens 3.
　詳述すると、キャップ２は、蓋部２ａの中心に貫通孔２ａ１を有すると共に、筒部２ｂの底部に半径方向外方に延出したフランジ部２ｃを有する。この蓋部２ａの貫通孔２ａ１に、集光用レンズ３が低融点ガラス７により固着されている。 More specifically, the cap 2 has a through hole 2a1 at the center of the lid 2a and a flange 2c extending radially outward at the bottom of the tube 2b. The condensing lens 3 is fixed to the through hole 2a1 of the lid portion 2a by the low melting point glass 7.
　集光用レンズ３は、III－V族化合物半導体又はII－VI族化合物半導体を球状に加工したもので、１２６０～１６７５ｎｍの波長帯域の全部の光に対して、内部透過率が９９％以上で且つ屈折率が２．１～４．５となる特性を有している。 The condensing lens 3 is obtained by processing a group III-V compound semiconductor or a group II-VI compound semiconductor into a spherical shape, and has an internal transmittance of 99% or more for all light in the wavelength band of 1260 to 1675 nm. In addition, the refractive index is 2.1 to 4.5.
　ここで、III－V族化合物半導体とは、III族のアルミニウム、ガリウム、インジウムなどと、V族の窒素、リン、ヒ素、アンチモンなどからなる化合物半導体の総称であり、具体的には、例えば、アルミニウムナイトライド、アルミニウムフォスファイド、アルミニウムガリウムアルセナイド、アルミニウムガリウムインジウムフォスファイド、アルミニウムガリウムインジウムナイトライド、ガリウムナイトライド、ガリウムフォスファイド、ガリウムアルセナイド、ガリウムアンチモナイド、ガリウムアルセナイドアンチモナイド、ガリウムインジウムフォスファイド、ガリウムインジウムアルセナイド、ガリウムインジウムアンチモナイド、ガリウムインジウムナイトライド、インジウムフォスファイド、インジウムアルセナイド、インジウムアンチモナイド、インジウムアルセナイドアンチモナイド、ガリウムインジウムアルセナイドアンチモナイド、ガリウムインジウムアルセナイドフォスファイド、ガリウムインジウムナイトライドアルセナイド等が挙げられる。 Here, the III-V compound semiconductor is a general term for compound semiconductors composed of Group III aluminum, gallium, indium, and the like, and Group V nitrogen, phosphorus, arsenic, antimony, and the like. Aluminum nitride, aluminum phosphide, aluminum gallium arsenide, aluminum gallium indium phosphide, aluminum gallium indium nitride, gallium nitride, gallium phosphide, gallium arsenide, gallium antimonide, gallium arsenide antimona Id, gallium indium phosphide, gallium indium arsenide, gallium indium antimonide, gallium indium nitride, indium phosphide, indium arsenide, in Um Anti Mona Id, indium arsenide anti Mona Id, gallium indium arsenide anti Mona Id, gallium indium arsenide phosphate sulfide include indium gallium nitride arsenide and the like.
　また、II－VI族化合物半導体とは、II族のマグネシウム、亜鉛、ガドミウム、水銀などと、VI族の酸素、硫黄、セレン、テルルなどからなる化合物半導体の総称であり、具体的には、例えば、ジンクオキサイド、ジンクセレナイド、ジンクサルファイド、ガドミウムサルファイド、カドミウムテルライド等が挙げられる。 The II-VI group compound semiconductor is a general term for compound semiconductors consisting of Group II magnesium, zinc, cadmium, mercury, etc. and Group VI oxygen, sulfur, selenium, tellurium, etc. Specifically, for example, Zinc oxide, zinc selenide, zinc sulfide, gadmium sulfide, cadmium telluride and the like.
　本実施形態では、集光用レンズ３は、これらのうち、III－V族化合物半導体に属し、不純物濃度が１．０×１０１６／ｃｍ３以下に管理されたガリウムフォスファイドから形成されている。 In the present embodiment, the condensing lens 3 is made of gallium phosphide, which belongs to the III-V group compound semiconductor and is controlled to have an impurity concentration of 1.0 × 10 16 / cm 3 or less. .
　このようにガリウムフォスファイドを集光用レンズ３の材料として採用したのは、ＦＴＴＨや都市間、あるいは国際長距離光通信で現在主流となっている光通信波長帯域（１２６０～１６７５ｎｍ）において、ガリウムフォスファイドの屈折率は３．０４～３．１０程度あり、一般的な光学ガラスの屈折率（１．５～１．８程度）や超高屈折率光学ガラスの屈折率（２．０程度）に比べ、非常に高い値を示すためである。 As described above, gallium phosphide is adopted as a material for the condensing lens 3 in the optical communication wavelength band (1260 to 1675 nm) which is currently mainstream in FTTH, intercity, or international long-distance optical communication. The refractive index of phosphide is about 3.04 to 3.10. The refractive index of general optical glass (about 1.5 to 1.8) and the refractive index of ultra high refractive index optical glass (about 2.0). This is because a very high value is exhibited as compared with FIG.
　一般的に、球面収差の程度は、集光用レンズ３の口径の３乗に比例する。つまり、集光用レンズ３への入射角が大きくなるほど球面収差の影響が著しい。そのため、単レンズで球面収差を低減するためには、焦点距離が同じであるならば、より屈折率が高い材料を選択した方が有利となる。すなわち、屈折率が高い材料であれば、集光用レンズ３の曲率を小さくして入射角を小さくすることができるので、球面収差の影響を低減できる。したがって、屈折率の高い、III－V族化合物半導体又はII－VI族化合物半導体を集光用レンズ３の材質として採用することが好ましく、本実施形態では、III－V族化合物半導体に属するガリウムフォスファイドを採用している。 Generally, the degree of spherical aberration is proportional to the cube of the aperture of the condenser lens 3. That is, the influence of spherical aberration becomes more significant as the incident angle to the condensing lens 3 increases. Therefore, in order to reduce spherical aberration with a single lens, it is advantageous to select a material having a higher refractive index if the focal length is the same. That is, if the material has a high refractive index, the curvature of the condensing lens 3 can be reduced and the incident angle can be reduced, so that the influence of spherical aberration can be reduced. Therefore, it is preferable to employ a III-V compound semiconductor or II-VI compound semiconductor having a high refractive index as the material of the condensing lens 3. In this embodiment, the gallium phosphor belonging to the III-V compound semiconductor is used. Fido is adopted.
　一方、ガリウムフォスファイドの不純物濃度を上記のように管理したのは、上記の光通信波長帯域（１２６０～１６７５ｎｍ）において、上記した内部透過率特性を実現するためである。詳述すると、半導体が有するバンドギャップ中に不純物による不純物準位が形成されて、光通信に用いるレーザ光が集光用レンズ３で吸収されるという事態を防止するために、不純物（例えば、シリコン）濃度を上記数値範囲のように管理している。なお、ガリウムフォスファイド以外のIII－V族化合物半導体、又はII－VI族化合物半導体を集光用レンズ３の材料として採用する場合にも、不純物濃度をアンドープの状態と同程度に管理することが重要である。なお、ここでいうアンドープの状態とは、ｎ型やｐ型半導体を製造する際に積極的にドーピングされる程度の不純物は含有せず、不可避的に混入する微量のコンタミ等の不純物が含有している状態は許容することを意味する。 On the other hand, the reason why the impurity concentration of gallium phosphide is managed as described above is to realize the above-described internal transmittance characteristics in the optical communication wavelength band (1260 to 1675 nm). More specifically, in order to prevent a situation where an impurity level due to impurities is formed in a band gap of a semiconductor and laser light used for optical communication is absorbed by the condensing lens 3, impurities (for example, silicon ) Concentration is managed within the above numerical range. Even when a III-V group compound semiconductor or II-VI group compound semiconductor other than gallium phosphide is used as the material of the condensing lens 3, the impurity concentration can be controlled to the same level as the undoped state. is important. The undoped state here does not contain impurities that are actively doped when manufacturing n-type or p-type semiconductors, but contains impurities such as trace amounts of contamination that are inevitably mixed. It means to allow.
　このような集光用レンズ３の不純物を管理して得られる上記の透過率特性は、図１に示したように、光素子４と、集光用レンズ３とを別体に構成することにより初めて実現できる。すなわち、集光用レンズ３と発光素子（ＬＤ）等の光素子４とを一体化した場合には、光素子４を構成するｐ型又はｎ型半導体から、不純物が集光用レンズ部分に拡散し、透過率が著しく低下するおそれがあるためである。 The transmittance characteristic obtained by managing the impurities of the condensing lens 3 is obtained by configuring the optical element 4 and the condensing lens 3 separately as shown in FIG. Realized for the first time. That is, when the condensing lens 3 and the optical element 4 such as a light emitting element (LD) are integrated, impurities diffuse from the p-type or n-type semiconductor constituting the optical element 4 to the condensing lens portion. This is because the transmittance may be significantly reduced.
　なお、集光用レンズ３の表面には、図示しない反射防止膜が形成されており、集光用レンズ３の表面での反射光が光通信に影響を与えないレベル（例えば、片面当たり反射率０．５％以下）に低減されている。 Note that an antireflection film (not shown) is formed on the surface of the condensing lens 3 so that the reflected light from the surface of the condensing lens 3 does not affect the optical communication (for example, the reflectance per one surface). 0.5% or less).
　以上のような本実施形態に係る光通信用レンズ部品１によれば、集光用レンズ３が、光素子４とは別体のガリウムフォスファイドから形成されているので、集光用レンズ３と光素子４とを一体化する場合のように、集光用レンズ３に不純物を積極的にドープする必要がなくなる。そのため、光通信として主流となっている１２６０～１６７５ｎｍの波長帯域の全部の光に対する集光用レンズ３の内部透過率を９０％以上とすることができる。また、このように集光用レンズ３をガリウムフォスファイドから形成することで、集光用レンズとして広く利用されている光学ガラス製レンズに比べて、非常に高い屈折率を実現することができる。具体的には、１２６０～１６７５ｎｍの波長帯域の全部の光に対する屈折率を２．１～４．５とすることができる。 According to the optical communication lens component 1 according to the present embodiment as described above, since the condensing lens 3 is formed of gallium phosphide separate from the optical element 4, the condensing lens 3 and There is no need to actively dope impurities into the condensing lens 3 as in the case where the optical element 4 is integrated. Therefore, the internal transmittance of the condensing lens 3 with respect to all light in the wavelength band of 1260 to 1675 nm, which is the mainstream in optical communication, can be 90% or more. In addition, by forming the condensing lens 3 from gallium phosphide in this way, it is possible to realize a very high refractive index as compared with an optical glass lens widely used as a condensing lens. Specifically, the refractive index for all light in the wavelength band of 1260 to 1675 nm can be set to 2.1 to 4.5.
　そして、集光用レンズ３の内部透過率が、９０％以上となる波長においては、光の吸収は少なくなり、集光用レンズ３を通過することによる光の損失を確実に低減することができる。また、集光用レンズ３の屈折率が、上記数値範囲内にあれば、集光用レンズ３を光学ガラスで製作した場合に生じる球面収差の問題も確実に解消することができる。したがって、集光用レンズ３の内部透過率と屈折率を、それぞれ上記数値範囲内にすれば、集光用レンズ３によって、光素子４と光ファイバ６との光学的な結合効率を確実に高めることができ、損失の少ない良好な光通信を実現することが可能となる。 Then, at a wavelength at which the internal transmittance of the condensing lens 3 is 90% or more, light absorption is reduced, and light loss due to passing through the condensing lens 3 can be reliably reduced. . In addition, if the refractive index of the condensing lens 3 is within the above numerical range, the problem of spherical aberration that occurs when the condensing lens 3 is made of optical glass can be reliably solved. Therefore, when the internal transmittance and refractive index of the condensing lens 3 are within the above numerical ranges, the optical coupling efficiency between the optical element 4 and the optical fiber 6 is reliably increased by the condensing lens 3. Therefore, it is possible to realize good optical communication with little loss.
　なお、本発明は、上記の実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内において、さらに種々なる形態で実施することができる。例えば、上記の実施形態では、集光用レンズ３を有蓋筒状のキャップ２に低融点ガラス７で固着した形態の光通信用レンズ部品１を説明したが、図２に示すように、集光用レンズ３をバタフライパッケージ８に図示しない接着剤又は低融点ガラスなどで固着した形態であってもよい。また、バタフライパッケージ８内が平らな一平面である場合、集光用レンズ３や光ファイバ６を実装・固定する際の位置決めの自由度が高い反面、容易に位置ずれしてしまう可能性があるため、バタフライパッケージ８内において、集光用レンズ３や光ファイバ６が実装されるべき位置に予めＶ溝などを形成しておいてもよい。さらに、光素子４と集光用レンズ３の間、又は集光用レンズ３と光ファイバ６の間の少なくとも一方に、接着剤又は低融点ガラスを充填した構造であってもよい。 It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, in the above embodiment, the optical communication lens component 1 in which the condensing lens 3 is fixed to the covered cylindrical cap 2 with the low melting point glass 7 has been described. However, as illustrated in FIG. The lens 3 may be fixed to the butterfly package 8 with an adhesive (not shown) or low melting point glass. Further, when the inside of the butterfly package 8 is a flat plane, the positioning lens 3 and the optical fiber 6 have a high degree of freedom in positioning when mounted and fixed, but may be easily displaced. Therefore, a V-groove or the like may be formed in advance in the butterfly package 8 at a position where the condensing lens 3 and the optical fiber 6 are to be mounted. Furthermore, a structure in which at least one between the optical element 4 and the condensing lens 3 or between the condensing lens 3 and the optical fiber 6 is filled with an adhesive or low-melting glass may be used.
　また、上記の実施形態では、集光用レンズ３として球形のものを例示したが、半球形、ドラム形、ロッド形、シリンダ形等、屈折作用で光の進行方向を目的とする方向へ変更するものであればいずれの形状でもよい。 In the above embodiment, a spherical lens is exemplified as the condensing lens 3. However, the light traveling direction is changed to a target direction by refraction, such as a hemispherical shape, a drum shape, a rod shape, or a cylinder shape. Any shape can be used.
　本発明の実施例１として、不純物濃度が１．０×１０１６／ｃｍ３以下に管理されたガリウムフォスファイドから形成された直径２．０ｍｍの球状の集光用レンズ３を製造した。なお、この集光用レンズ３は、不純物濃度が１．０×１０１６／ｃｍ３以下に管理されたガリウムフォスファイドの単結晶インゴットを液体封止チョクラルスキー法により製作した後、この単結晶インゴットを機械研磨により球状（直径２．０ｍｍ）に加工することにより製造した。 As Example 1 of the present invention, a spherical condensing lens 3 having a diameter of 2.0 mm formed from gallium phosphide having an impurity concentration controlled to 1.0 × 10 16 / cm 3 or less was manufactured. The condensing lens 3 is manufactured by manufacturing a gallium phosphide single crystal ingot having an impurity concentration controlled to 1.0 × 10 16 / cm 3 or less by a liquid-sealed Czochralski method. The ingot was manufactured by processing into a spherical shape (diameter 2.0 mm) by mechanical polishing.
　まず初めに、実施例１に係る集光用レンズ３の波長に対する内部透過率の変化を測定した。その結果を図３に示す。また、比較例１として、不純物（シリコン）濃度が４．０×１０１７／ｃｍ３のガリウムフォスファイドから形成された直径２．０ｍｍの球状の集光用レンズを製造し、同様に波長に対する内部透過率の変化を測定した。その結果を図４に示す。 First, the change of the internal transmittance with respect to the wavelength of the condensing lens 3 according to Example 1 was measured. The result is shown in FIG. In addition, as Comparative Example 1, a spherical condensing lens having a diameter of 2.0 mm formed from gallium phosphide having an impurity (silicon) concentration of 4.0 × 10 17 / cm 3 was manufactured, and similarly, the internal wavelength was adjusted. The change in transmittance was measured. The result is shown in FIG.
　図３に示すように、実施例１に係る集光用レンズ３は、ＦＴＴＨや都市間、あるいは国際長距離光通信で現在主流となっている光通信波長帯域（１２６０～１６７５ｎｍ）を含む１１００～１７５０ｎｍの波長帯域において、内部透過率が９９％以上となっており、伝送特性に影響を及ぼすような光の吸収は見られない。なお、ガリウムフォスファイドの３００ＫにおけるエネルギーギャップＥｇは２．２６ｅＶ（光の波長に変換すると約５４９ｎｍ）、エネルギーセパレーションＥ０（Γ1Ｃ－Γ１５Ｖ）は２．７８ｅＶ（光の波長に変換すると約４４６ｎｍ）であり、図中の内部透過率における吸収帯に相当する。 As shown in FIG. 3, the condensing lens 3 according to the first embodiment includes an optical communication wavelength band (1260 to 1675 nm) that is currently mainstream in FTTH, intercity, or international long-distance optical communication. In the wavelength band of 1750 nm, the internal transmittance is 99% or more, and no light absorption that affects the transmission characteristics is observed. Note that the energy gap E g at 300K gallium Foz sulfide is 2.26 eV (about is converted into the wavelength of light 549 nm), the energy separation E 0 (Γ 1C -Γ 15V) is is converted into a wavelength of 2.78 eV (the light about 446 nm) and corresponds to the absorption band in the internal transmittance in the figure.
　これに対し、比較例１に係る集光用レンズでは、バンドギャップ中に不純物準位が形成されるため、図４に示すように、上記の光通信波長帯域（１２６０～１６７５ｎｍ）において非常に大きな吸収が見られ、この波長帯域での内部透過率は５～２０％程度となっている。 On the other hand, in the condensing lens according to Comparative Example 1, since impurity levels are formed in the band gap, as shown in FIG. 4, the optical communication wavelength band (1260 to 1675 nm) is very large as shown in FIG. Absorption is observed, and the internal transmittance in this wavelength band is about 5 to 20%.
　したがって、このことからも、不純物濃度が上記数値範囲内に管理された実施例１に係る集光用レンズ３は、比較例１に係る集光用レンズよりも、上記の光通信波長帯域における内部透過率が大幅に改善されていることが認識できる。 Therefore, also from this, the condensing lens 3 according to Example 1 in which the impurity concentration is controlled within the above numerical range is more internal than the condensing lens according to Comparative Example 1 in the optical communication wavelength band. It can be recognized that the transmittance is greatly improved.
　次に、実施例１に係る集光用レンズ３の波長に対する屈折率の変化を測定した。その結果を図５に示す。 Next, the change in the refractive index with respect to the wavelength of the condensing lens 3 according to Example 1 was measured. The result is shown in FIG.
　図５に示すように、集光用レンズ３の屈折率は、１７５０ｎｍ以下の波長帯域において３．００以上であって、上記の光通信波長帯域（１２６０～１６７５ｎｍ）においては３．０４～３．１０程度ある。この集光用レンズ３の屈折率は、一般的な光学ガラス（屈折率１．５～１．８程度）や超高屈折率光学ガラス（屈折率２．０程度）と比較すると非常に高い。そのため、当該集光用レンズ３を、図１に示したように、光通信用レンズ部品１に組み込んで、光素子４と光ファイバ６との光学結合に使用することにより、球面収差の影響を大幅に低減することができる。 As shown in FIG. 5, the condensing lens 3 has a refractive index of 3.00 or more in the wavelength band of 1750 nm or less, and 3.04 to 3 in the optical communication wavelength band (1260 to 1675 nm). There are about 10. The refractive index of the condensing lens 3 is very high compared to general optical glass (refractive index of about 1.5 to 1.8) and ultrahigh refractive optical glass (refractive index of about 2.0). Therefore, by incorporating the condensing lens 3 in the optical communication lens component 1 and using it for optical coupling between the optical element 4 and the optical fiber 6 as shown in FIG. It can be greatly reduced.
　さらに、実施例１に係る集光用レンズ３を、図１に示した光通信用レンズ部品１に組み込むと共に、集光用レンズ３と光素子４との距離や、集光用レンズ３と光ファイバ６との距離を変更することにより、種々の結像倍率における結合効率を測定した。その結果を図６に示す。また、比較例２として、一般的な光学ガラス（屈折率１．５～１．８程度）からなる直径２．０ｍｍの球状の集光用レンズを製造し、結合効率を測定した。その際、結像倍率はそれぞれ最大の結合効率が得られる結像倍率とした。その結果を図７に示す。なお、これら結合効率の測定に際し、光素子４としては、発光素子であるファブリ・ペロレーザ（半導体基板と平行方向に発光する端面発光型レーザの一種）を使用し、発振波長は１３１０ｎｍ、出力は１０ｍＷにそれぞれ設定した。 Further, the condensing lens 3 according to the first embodiment is incorporated in the optical communication lens component 1 shown in FIG. 1, and the distance between the condensing lens 3 and the optical element 4, the condensing lens 3 and the light. By changing the distance to the fiber 6, the coupling efficiency at various imaging magnifications was measured. The result is shown in FIG. As Comparative Example 2, a spherical condensing lens having a diameter of 2.0 mm made of general optical glass (refractive index of about 1.5 to 1.8) was manufactured, and the coupling efficiency was measured. At that time, the imaging magnification was set to an imaging magnification at which the maximum coupling efficiency was obtained. The result is shown in FIG. When measuring these coupling efficiencies, a Fabry-Perot laser (a kind of edge-emitting laser that emits light in a direction parallel to the semiconductor substrate) is used as the optical element 4, and the oscillation wavelength is 1310 nm and the output is 10 mW. Respectively.
　図６に示すように、実施例１に係る集光用レンズ３では、結像倍率が２倍の場合、結合効率は３０％、結像倍率が２．５倍の場合、結合効率は３６％となった。更には結像倍率を２．７倍にすれば、結合効率が３８．５％にまで達する。 As shown in FIG. 6, in the condensing lens 3 according to Example 1, when the imaging magnification is 2, the coupling efficiency is 30%, and when the imaging magnification is 2.5, the coupling efficiency is 36%. It became. Further, when the imaging magnification is increased to 2.7 times, the coupling efficiency reaches 38.5%.
　これに対し、比較例２に係る集光用レンズでは、屈折率が１．４９６の場合、結合効率は９．５％、屈折率が１．７８の場合、結合効率は２０．５％となった。 On the other hand, in the condensing lens according to Comparative Example 2, when the refractive index is 1.496, the coupling efficiency is 9.5%, and when the refractive index is 1.78, the coupling efficiency is 20.5%. It was.
　したがって、このことからも、実施例１に係る集光用レンズ３は、比較例２に係る一般的な光学ガラス（屈折率１．５～１．８程度）からなる集光用レンズに比べ、結合効率が大幅に改善されることが認識できる。 Therefore, also from this, the condensing lens 3 according to Example 1 is compared with the condensing lens made of general optical glass (refractive index of about 1.5 to 1.8) according to Comparative Example 2. It can be recognized that the coupling efficiency is greatly improved.

Claims (2)

  1. 　光を発光する機能又は光を受光する機能の少なくとも一方の機能を有する光素子を光ファイバと光学的に結合する集光用レンズを有する光通信用レンズ部品において、
    　前記集光用レンズが、前記光素子とは別体のIII－V族化合物半導体又はII－VI族化合物半導体からなり、１２６０～１６７５ｎｍの波長帯域の一部又は全部の光に対して、内部透過率が９０％以上で且つ屈折率が２．１～４．５であることを特徴とする光通信用レンズ部品。     In an optical communication lens component having a condensing lens that optically couples an optical element having at least one of a function of emitting light or a function of receiving light with an optical fiber,
    The condensing lens is made of a group III-V compound semiconductor or a group II-VI compound semiconductor that is separate from the optical element, and internally transmits a part or all of light in a wavelength band of 1260 to 1675 nm. A lens component for optical communication, characterized by having a refractive index of 90% or more and a refractive index of 2.1 to 4.5.
  2. 　前記集光用レンズが、III－V族化合物半導体であるガリウムフォスファイドからなり、その不純物濃度が、１．０×１０１６／ｃｍ３以下である請求項１に記載の光通信用レンズ部品。 2. The optical communication lens component according to claim 1, wherein the condensing lens is made of gallium phosphide, which is a III-V group compound semiconductor, and an impurity concentration thereof is 1.0 × 10 16 / cm 3 or less.
PCT/JP2008/073120 2008-02-22 2008-12-18 Lens component for optical communication WO2009104337A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008-041845 2008-02-22
JP2008041845A JP2009198908A (en) 2008-02-22 2008-02-22 Lens component for optical communication

Publications (1)

Publication Number Publication Date
WO2009104337A1 true WO2009104337A1 (en) 2009-08-27

Family

ID=40985229

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2008/073120 WO2009104337A1 (en) 2008-02-22 2008-12-18 Lens component for optical communication

Country Status (2)

Country Link
JP (1) JP2009198908A (en)
WO (1) WO2009104337A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016101417A1 (en) * 2014-12-25 2016-06-30 昂纳信息技术（深圳）有限公司 Laser packaging structure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150065721A (en) * 2012-09-11 2015-06-15 퀀텀 일렉트로 아프투 시스템즈 에스디엔.비에이치디. Method and apparatus for optical coupling and opto-electronic conversion

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6178177A (en) * 1984-09-25 1986-04-21 Nec Corp Manufacture of monolithic lens
JPS61138904A (en) * 1984-12-12 1986-06-26 Mitsubishi Electric Corp Optical coupling device
JPS61138905A (en) * 1984-12-12 1986-06-26 Mitsubishi Electric Corp Optical coupling device
JPS61145876A (en) * 1984-12-20 1986-07-03 Mitsubishi Electric Corp Package for light emitting device
JPH0194309A (en) * 1987-10-07 1989-04-13 Mitsubishi Electric Corp Laser diode module incorporating isolator
JPH04307976A (en) * 1991-04-05 1992-10-30 Nec Corp Array optical semiconductor device
JPH11271572A (en) * 1998-03-24 1999-10-08 Hitachi Ltd Optical coupling system, optical module, and optical transmission system
JPH11344648A (en) * 1998-05-07 1999-12-14 Trw Inc Fiber/waveguide-mirror-lens alignment device
JP2004085861A (en) * 2002-08-27 2004-03-18 Oki Electric Ind Co Ltd Optical device for wavelength division multiplex communication and manufacturing method therefor
JP2004354999A (en) * 2003-05-28 2004-12-16 Samsung Electronics Co Ltd Optical coupling lens system and its manufacturing method

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6178177A (en) * 1984-09-25 1986-04-21 Nec Corp Manufacture of monolithic lens
JPS61138904A (en) * 1984-12-12 1986-06-26 Mitsubishi Electric Corp Optical coupling device
JPS61138905A (en) * 1984-12-12 1986-06-26 Mitsubishi Electric Corp Optical coupling device
JPS61145876A (en) * 1984-12-20 1986-07-03 Mitsubishi Electric Corp Package for light emitting device
JPH0194309A (en) * 1987-10-07 1989-04-13 Mitsubishi Electric Corp Laser diode module incorporating isolator
JPH04307976A (en) * 1991-04-05 1992-10-30 Nec Corp Array optical semiconductor device
JPH11271572A (en) * 1998-03-24 1999-10-08 Hitachi Ltd Optical coupling system, optical module, and optical transmission system
JPH11344648A (en) * 1998-05-07 1999-12-14 Trw Inc Fiber/waveguide-mirror-lens alignment device
JP2004085861A (en) * 2002-08-27 2004-03-18 Oki Electric Ind Co Ltd Optical device for wavelength division multiplex communication and manufacturing method therefor
JP2004354999A (en) * 2003-05-28 2004-12-16 Samsung Electronics Co Ltd Optical coupling lens system and its manufacturing method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016101417A1 (en) * 2014-12-25 2016-06-30 昂纳信息技术（深圳）有限公司 Laser packaging structure

Also Published As

Publication number Publication date
JP2009198908A (en) 2009-09-03

Similar Documents

Publication Publication Date Title
US11454808B2 (en) Metalens and optical apparatus including the same
US20200264343A1 (en) Multilayered meta lens and optical apparatus including the same
EP0872747B1 (en) Optical module
US6411639B1 (en) Semiconductor laser module with an external resonator including a band-pass filter and reflective element
US7439533B2 (en) Optical module and optical communication device
EP3322109B1 (en) Optical transmission module, optical transceiver, and optical communication system including same
US20210367398A1 (en) Optical module
WO2009104337A1 (en) Lens component for optical communication
RU2506616C1 (en) High-speed infrared lens
US7589915B2 (en) Optical element, optical module holder including optical element, optical module, and optical connector
US20160087398A1 (en) Semiconductor light-receiving element
US7266139B2 (en) Optical semiconductor device module and bidirectional module
US20230011341A1 (en) Light-Receiving Device
US20040051956A1 (en) Collimating lens
US7218813B2 (en) Optical communication system
US11456574B2 (en) External-cavity semiconductor laser
JP3689644B2 (en) Bidirectional optical communication device and bidirectional optical communication device
KR100488337B1 (en) Rotational asymmetric aspheric lens
JP2005024617A (en) Optical transmitter
US10958036B2 (en) Semiconductor light-emitting device and optical device
JP2568506B2 (en) Semiconductor light receiving device
EP3588564A1 (en) Solid-state photodetector
US20240118454A1 (en) Meta-surface optical element
CN210222306U (en) Light receiving device capable of improving saturation performance
WO2023286165A1 (en) Light receiving device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08872574

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08872574

Country of ref document: EP

Kind code of ref document: A1