JPH11133364A - Waveguide type optical variable attenuator - Google Patents
Waveguide type optical variable attenuatorInfo
- Publication number
- JPH11133364A JPH11133364A JP29861497A JP29861497A JPH11133364A JP H11133364 A JPH11133364 A JP H11133364A JP 29861497 A JP29861497 A JP 29861497A JP 29861497 A JP29861497 A JP 29861497A JP H11133364 A JPH11133364 A JP H11133364A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- waveguide
- mach
- zehnder
- coupler
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は光減衰量を任意に変
えることが出来る導波路型の光可変減衰器に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type variable optical attenuator capable of arbitrarily changing the amount of optical attenuation.
【０００２】[0002]
【従来の技術】近年、光ファイバ通信システムにおいて
は、光情報の分配のために多数の光分岐回路が用いられ
ている。また、減衰した光を増幅するため光ファイバア
ンプを用いた光直接増幅器が多数使われている。前記光
分岐回路の分岐バラツキを補償するため、あるいは前記
光直接増幅器において、入力レベル変動がそのまま出力
段へ現れないよう変動を補償する回路として図１１
（ａ），（ｂ）に示す各種の光減衰器が開発されてい
る。2. Description of the Related Art In recent years, in an optical fiber communication system, a large number of optical branch circuits are used for distributing optical information. Also, many optical direct amplifiers using an optical fiber amplifier are used to amplify the attenuated light. FIG. 11 shows a circuit for compensating for variations in the branching of the optical branching circuit or for compensating for variations in the optical direct amplifier so that variations in the input level do not appear in the output stage.
Various optical attenuators shown in (a) and (b) have been developed.
【０００３】図１１（ａ）は減衰板を回転させることに
よって入射光が異なる減衰率の減衰板を通過することで
減衰率を可変に出来る可変減衰器、図１１（ｂ）は一定
の減衰量を与える固定減衰器である。図において、１は
連続減衰板、２はステップ減衰板、３は減衰膜、４はロ
ッドレンズ、５は光ファイバである。FIG. 11 (a) shows a variable attenuator in which incident light passes through an attenuating plate having a different attenuating rate by rotating the attenuating plate to make the attenuation rate variable. FIG. 11 (b) shows a constant attenuating amount. Is a fixed attenuator. In the figure, 1 is a continuous attenuation plate, 2 is a step attenuation plate, 3 is an attenuation film, 4 is a rod lens, and 5 is an optical fiber.
【０００４】すなわち、図１１（ａ）に示すように、連
続減衰板１は円盤状減衰板よりなり、円周部が円周に沿
って漸次減衰率が変化するように形成されており、減衰
板１を矢印方向に回転させることによって入射光が異な
る減衰率の減衰板１を通過することで減衰率を可変に出
来る。また、ステップ減衰板２は円盤状減衰板よりな
り、円周部には減衰率を異ならせた複数の光通過窓２０
１，２０２，２０３，……が形成されており、減衰板１
を回転させることによって入射光が異なる減衰率の光通
過窓２０１，２０２，２０３，……を通過することで減
衰率を可変に出来る。また、固定減衰器は図１１（ｂ）
に示すように、減衰膜３が形成されたロッドレンズ４の
両端に光ファイバ５を連結することにより、光ファイバ
５からの入射光がロッドレンズ４を通過することで一定
の減衰量を与えることが出来る。That is, as shown in FIG. 11 (a), a continuous damping plate 1 is formed of a disc-shaped damping plate, and a circumferential portion is formed so that a damping rate changes gradually along the circumference. By rotating the plate 1 in the direction of the arrow, the incident light passes through the attenuation plates 1 having different attenuation ratios, thereby making the attenuation ratio variable. The step attenuating plate 2 is formed of a disc-shaped attenuating plate, and a plurality of light passing windows 20 having different attenuation rates are provided on the circumference.
Are formed, and the attenuation plate 1
Is rotated, the incident light passes through the light passing windows 201, 202, 203,... Having different attenuation rates, so that the attenuation rate can be varied. The fixed attenuator is shown in FIG.
As shown in (1), by connecting the optical fibers 5 to both ends of the rod lens 4 on which the attenuation film 3 is formed, the incident light from the optical fiber 5 passes through the rod lens 4 to give a constant attenuation. Can be done.
【０００５】しかしながら、従来の可変減衰器では、機
械的に減衰量を制御するため高速の制御が困難であると
ともに、可動部分を有するため信頼性の点で問題であ
る。さらに、減衰板などのバルク部品を使用するため、
小型化が困難であるという問題があった。一方、固定減
衰器は小型で、高信頼な部品であるが、一定の減衰率し
か与えられないので、光ファイバ通信システムに採用す
る際の柔軟性に欠ける点が問題であった。However, in the conventional variable attenuator, high-speed control is difficult because the amount of attenuation is mechanically controlled, and there is a problem in terms of reliability because it has movable parts. Furthermore, because bulk components such as damping plates are used,
There was a problem that miniaturization was difficult. On the other hand, although the fixed attenuator is a small and highly reliable component, it has a problem that it lacks flexibility when employed in an optical fiber communication system because it can give only a constant attenuation rate.
【０００６】[0006]
【発明が解決しようとする課題】本発明は上記の事情に
鑑みてなされたもので、可動部分がないため信頼性が高
く、小型で製作性が良い導波路型光可変減衰器を提供す
ることを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a waveguide-type variable optical attenuator which has high reliability because of no moving parts, and which is small and has good manufacturability. With the goal.
【０００７】[0007]
【課題を解決するための手段】上記目的を達成するため
に本発明の導波路型光可変減衰器は、光導波路が１／２
波長板を介して連結された複数のマッハツェンダ光干渉
計回路と、前記マッハツェンダ光干渉計回路の光導波路
に設けられたヒータ電極とを具備することを特徴とする
ものである。In order to achieve the above object, a waveguide type optical variable attenuator according to the present invention comprises an optical waveguide having a half optical waveguide.
The Mach-Zehnder optical interferometer circuit includes a plurality of Mach-Zehnder optical interferometer circuits connected via a wavelength plate, and a heater electrode provided in an optical waveguide of the Mach-Zehnder optical interferometer circuit.
【０００８】また本発明は、上記導波路型光可変減衰器
おいて、光導波路の光強度を監視するモニター導波路を
設けたことを特徴とするものである。また本発明は、上
記導波路型光可変減衰器おいて、光導波路として、石英
系光導波路を設けたことを特徴とするものである。The present invention is also characterized in that in the above-mentioned waveguide type optical variable attenuator, a monitor waveguide for monitoring the light intensity of the optical waveguide is provided. According to the present invention, in the above-mentioned waveguide type optical variable attenuator, a silica-based optical waveguide is provided as the optical waveguide.
【０００９】[0009]
【発明の実施の形態】以下図面を参照して本発明の実施
の形態例を詳細に説明する。図１は本発明の一実施形態
例に係る導波路型光可変減衰器の構成説明図である。図
において、６は入力導波路、７は出力導波路、８は連結
導波路、９は１／２波長板、１０，１１はヒータ電極、
１２，１３，１４，１５は３ｄＢカプラ、１６，１７，
１８，１９はアーム導波路、２０は１段目のマッハツェ
ンダ光干渉計回路、２１は２段目のマッハツェンダ干渉
計回路である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of a waveguide-type variable optical attenuator according to an embodiment of the present invention. In the figure, 6 is an input waveguide, 7 is an output waveguide, 8 is a connection waveguide, 9 is a half-wave plate, 10 and 11 are heater electrodes,
12, 13, 14, 15 are 3 dB couplers, 16, 17,
Reference numerals 18 and 19 denote arm waveguides, reference numeral 20 denotes a first-stage Mach-Zehnder interferometer circuit, and reference numeral 21 denotes a second-stage Mach-Zehnder interferometer circuit.
【００１０】すなわち、入力導波路６は３ｄＢカプラ１
２によりアーム導波路１６，１７に結合される。このア
ーム導波路１６，１７にはそれぞれヒータ電極１０が設
けられる。前記アーム導波路１６，１７は３ｄＢカプラ
１３により連結導波路８に結合され、この連結導波路８
は３ｄＢカプラ１４によりアーム導波路１８，１９に結
合される。このアーム導波路１８，１９にはそれぞれヒ
ータ電極１１が設けられる。前記アーム導波路１８，１
９は３ｄＢカプラ１５により出力導波路７に結合され
る。前記入力導波路６、ヒータ電極１０、３ｄＢカプラ
１２，１３、アーム導波路１６，１７より１段目のマッ
ハツェンダ光干渉計回路２０が構成され、前記出力導波
路７、連結導波路８、ヒータ電極１１、３ｄＢカプラ１
４，１５、アーム導波路１８，１９より２段目のマッハ
ツェンダ光干渉計回路２１が構成される。前記１段目の
マッハツェンダ光干渉計回路２０と２段目のマッハツェ
ンダ光干渉計回路２１が１／２波長板９を介して連結さ
れて導波路型光可変減衰器が構成される。That is, the input waveguide 6 is a 3 dB coupler 1
2 couples to the arm waveguides 16 and 17. Each of the arm waveguides 16 and 17 is provided with a heater electrode 10. The arm waveguides 16 and 17 are coupled to the connection waveguide 8 by a 3 dB coupler 13, and the connection waveguide 8
Are coupled to the arm waveguides 18 and 19 by a 3 dB coupler 14. Each of the arm waveguides 18 and 19 is provided with a heater electrode 11. The arm waveguides 18, 1
9 is coupled to the output waveguide 7 by a 3 dB coupler 15. The input waveguide 6, the heater electrodes 10, 3 dB couplers 12, 13, and the arm waveguides 16, 17 constitute a first stage Mach-Zehnder optical interferometer circuit 20, and the output waveguide 7, the coupling waveguide 8, the heater electrode 11, 3dB coupler 1
The Mach-Zehnder optical interferometer circuit 21 of the second stage is composed of the arm waveguides 4 and 15 and the arm waveguides 18 and 19. The first-stage Mach-Zehnder optical interferometer circuit 20 and the second-stage Mach-Zehnder optical interferometer circuit 21 are connected via a half-wave plate 9 to form a waveguide-type variable optical attenuator.
【００１１】しかして、光信号は入力導波路６に入力さ
れ、３ｄＢカプラ１２によりアーム導波路１６，１７に
伝送される。前記アーム導波路１６，１７はそれぞれ対
応したヒータ電極１０により加熱されることにより熱光
学効果に起因する位相差を光信号に与える。前記アーム
導波路１６，１７に伝送された光信号は３ｄＢカプラ１
３により連結導波路８に伝送され、３ｄＢカプラ１４に
よりアーム導波路１８，１９に伝送される。前記アーム
導波路１８，１９はそれぞれ対応したヒータ電極１１に
より加熱されることにより熱光学効果に起因する位相差
を光信号に与える。前記アーム導波路１８，１９に伝送
された光信号は３ｄＢカプラ１５により出力導波路７に
伝送され外部に出力される。したがって、ヒータ電極１
０，１１によりアーム導波路１６，１７，１８，１９の
加熱量を変えることにより光信号の位相差を変えること
ができ光減衰量を変えることができる。１段目及び２段
目のマッハツェンダ光干渉計回路２０，２１の光透過係
数η1，η2 は次式によって与えられる。The optical signal is input to the input waveguide 6 and transmitted to the arm waveguides 16 and 17 by the 3 dB coupler 12. The arm waveguides 16 and 17 are heated by the corresponding heater electrodes 10 to give a phase difference caused by a thermo-optic effect to an optical signal. The optical signal transmitted to the arm waveguides 16 and 17 is a 3 dB coupler 1
3 and transmitted to the arm waveguides 18 and 19 by the 3 dB coupler 14. The arm waveguides 18 and 19 are heated by the corresponding heater electrodes 11 to give a phase difference caused by a thermo-optic effect to an optical signal. The optical signals transmitted to the arm waveguides 18 and 19 are transmitted to the output waveguide 7 by the 3 dB coupler 15 and output to the outside. Therefore, the heater electrode 1
By changing the heating amounts of the arm waveguides 16, 17, 18, and 19 according to 0 and 11, the phase difference of the optical signal can be changed and the optical attenuation can be changed. The light transmission coefficients η 1 and η 2 of the first-stage and second-stage Mach-Zehnder optical interferometer circuits 20 and 21 are given by the following equations.
【００１２】[0012]
【数１】 (Equation 1)
【００１３】ここで、φ1 ，φ2 はマッハツェンダ光干
渉計回路２０，２１のアーム導波路１６と１７及び１８
と１９の熱光学効果に起因する位相差、ｓｉｎθ1 ，ｓ
ｉｎθ2 は１段目と２段目のマッハツェンダ光干渉計回
路２０，２１を構成する３ｄＢカプラ１２，１３，１
４，１５の結合率を示す。したがって、導波路型光可変
減衰器全体の透過係数ηはHere, φ 1 and φ 2 are the arm waveguides 16, 17 and 18 of the Mach-Zehnder optical interferometer circuits 20 and 21.
Difference due to the thermo-optic effect of と and 19, sin θ 1 , s
inθ 2 is a 3 dB coupler 12, 13, 1 constituting the first and second stage Mach-Zehnder optical interferometer circuits 20, 21
4 and 15 are shown. Therefore, the transmission coefficient η of the entire waveguide type variable optical attenuator is
【００１４】[0014]
【数２】 となる。(Equation 2) Becomes
【００１５】１段目と２段目のマッハツェンダ光干渉計
回路２０，２１が同一の場合、（３）式から、連結導波
路８に挿入された１／２波長板９の偏波変換効果によっ
て導波路型光可変減衰器全体の透過係数ηはWhen the first and second stages of the Mach-Zehnder optical interferometer circuits 20 and 21 are the same, from the equation (3), the polarization conversion effect of the half-wave plate 9 inserted in the coupling waveguide 8 is used. The transmission coefficient η of the entire waveguide type optical variable attenuator is
【００１６】[0016]
【数３】 となるため、３ｄＢカプラ１２，１３，１４，１５の結
合率の偏波依存性、さらに熱光学効果に起因する位相差
の偏波依存性が解消出来ることが分かる。特に、石英系
光導波路は低損失でかつ光ファイバとの整合性も良好な
特徴を有する一方、Ｓｉ基板からの応力複屈折によって
３ｄＢカプラの結合率等に偏波依存性があるという欠点
を有していたが、本構成によってその問題点を解決する
ことが出来る。(Equation 3) Therefore, it can be understood that the polarization dependence of the coupling ratio of the 3 dB couplers 12, 13, 14, 15 and the polarization dependence of the phase difference caused by the thermo-optic effect can be eliminated. In particular, while the silica-based optical waveguide has features of low loss and good matching with the optical fiber, it has a drawback that the coupling ratio of the 3 dB coupler has polarization dependence due to stress birefringence from the Si substrate. However, this configuration can solve the problem.
【００１７】また、導波路型光可変減衰器の光出力は、
３ｄＢカプラの結合率を sin2 θTE＝ sin2 θTM＝０．５ （５） とすれば、（４）式から η＝− cosφTE cosφTM （６） となり、熱光学効果によって誘起される位相差に依存す
る。The optical output of the waveguide type variable optical attenuator is:
If the coupling ratio of 3dB couplers and sin 2 θ TE = sin 2 θ TM = 0.5 (5), η = a (4) - induced by cosφ TE cosφ TM (6), and the thermo-optic effect Depends on the phase difference.
【００１８】したがって、光減衰量はｍｓｅｃオーダの
高速な時間応答特性が得られることが分かる。さらに、
ヒータ電極による熱光学効果を用いているため可動部分
を全く含まず、高い信頼性が期待できる。Therefore, it can be seen that a high-speed time response characteristic of the optical attenuation amount on the order of msec can be obtained. further,
Since the thermo-optic effect of the heater electrode is used, no movable part is included, and high reliability can be expected.
【００１９】さらにまた、平面基板上に形成した導波回
路によって機能を実現しているため小型であり、生産性
が良好であり、他の分波回路等に集積化できるという利
点を有する。Further, since the function is realized by the waveguide circuit formed on the flat substrate, the semiconductor device has the advantages that it is small, has good productivity, and can be integrated with other branching circuits and the like.
【００２０】[0020]
［実施例１］図２は本発明に係る導波路型光可変減衰器
の第１の実施例を示す構成説明図である。図２におい
て、図１と同一構成部分は同一符号をもって表す。すな
わち、６は入力導波路、７は出力導波路、８は連結導波
路、９は１／２波長板、１０，１１はヒータ電極、２
２，２３，２４，２５は方向性結合器型３ｄＢカプラ、
１６，１７，１８，１９はアーム導波路、２０は１段目
のマッハツェンダ光干渉計回路、２１は２段目のマッハ
ツェンダ光干渉計回路である。すなわち、本発明の第１
の実施例は３ｄＢカプラとして方向性結合器型３ｄＢカ
プラ２２，２３，２４，２５を用いた例である。[Embodiment 1] FIG. 2 is a structural explanatory view showing a first embodiment of a waveguide type optical variable attenuator according to the present invention. 2, the same components as those in FIG. 1 are represented by the same reference numerals. That is, 6 is an input waveguide, 7 is an output waveguide, 8 is a connection waveguide, 9 is a half-wave plate, 10 and 11 are heater electrodes, 2
2,23,24,25 are directional coupler type 3dB couplers,
Reference numerals 16, 17, 18, and 19 denote arm waveguides, 20 denotes a first-stage Mach-Zehnder optical interferometer circuit, and 21 denotes a second-stage Mach-Zehnder optical interferometer circuit. That is, the first of the present invention
Is an example in which directional coupler type 3 dB couplers 22, 23, 24 and 25 are used as 3 dB couplers.
【００２１】図３は本発明の第１の実施例に係る方向性
結合器型３ｄＢカプラの一例を示す構成説明図である。
すなわち、一方の光導波路３６と他方の光導波路３７は
一部分が２μｍ間隔に接近して方向性結合器型３ｄＢカ
プラ３８が形成される。しかして、一方の光導波路３６
の入力端から入力された光信号は方向性結合器型３ｄＢ
カプラ３８で結合されてそれぞれの光導波路３６及び光
導波路３７の出力端から出力される。FIG. 3 is an explanatory diagram showing an example of a directional coupler type 3 dB coupler according to the first embodiment of the present invention.
That is, the one optical waveguide 36 and the other optical waveguide 37 are partially close to each other at an interval of 2 μm to form a directional coupler type 3 dB coupler 38. Thus, one of the optical waveguides 36
The optical signal input from the input terminal of the directional coupler type 3dB
The light is coupled by a coupler 38 and output from the output ends of the respective optical waveguides 36 and 37.
【００２２】このような光回路を作製するには次の手順
による。先ず、Ｓｉ基板上に火炎堆積法によってＳｉＯ
2 下部クラッド層を堆積し、次にＴｉＯ2 またはＧｅＯ
2 をドーパントとして添加したＳｉＯ2 ガラスのコア層
を堆積した後に、電気炉で透明ガラス化した。次に、コ
ア層をエッチングして、所定の光導波路を形成し、最後
に、ＳｉＯ2 上部クラッド層を堆積した。作製した光導
波路はコア寸法７×７μｍ、比屈折率差０．７５％とし
た。The following procedure is used to fabricate such an optical circuit. First, a SiO film was formed on a Si substrate by flame deposition.
2 Deposit a lower cladding layer, then TiO 2 or GeO
2 after depositing the core layer of SiO 2 glass doped as a dopant was vitrified in an electric furnace. Next, the core layer was etched to form a predetermined optical waveguide, and finally, a SiO 2 upper clad layer was deposited. The manufactured optical waveguide had a core size of 7 × 7 μm and a relative refractive index difference of 0.75%.
【００２３】図４は本発明の第１の実施例に係る光可変
減衰器のヒータ電流と光減衰量の依存性を示す。同図よ
り、光減衰特性に偏波依存性のないことが分かる。この
結果、偏波依存性がない光可変減衰器を実現できた。FIG. 4 shows the dependence of the heater current and the optical attenuation on the variable optical attenuator according to the first embodiment of the present invention. It can be seen from the figure that the optical attenuation characteristic has no polarization dependence. As a result, an optical variable attenuator having no polarization dependence was realized.
【００２４】［実施例２］図５は本発明に係る導波路型
光可変減衰器の第２の実施例を示す構成説明図である。
図５中、図２と同一部分は同一符号を付してその説明を
省略する。図５において、２６，２７，２８，２９は多
モード干渉型３ｄＢカプラである。すなわち、第２の実
施例では第１の実施例の方向性結合器型３ｄＢカプラ２
２，２３，２４，２５を多モード干渉型３ｄＢカプラ２
６，２７，２８，２９で置き換えた構造とした。[Embodiment 2] FIG. 5 is a structural explanatory view showing a second embodiment of the waveguide type optical variable attenuator according to the present invention.
5, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 5, reference numerals 26, 27, 28, and 29 denote multimode interference type 3 dB couplers. That is, in the second embodiment, the directional coupler type 3 dB coupler 2 of the first embodiment is used.
2, 23, 24, 25 are multimode interference type 3 dB couplers 2
6, 27, 28, 29.
【００２５】図６は多モード干渉型３ｄＢカプラの構造
の一例を示す構成説明図である。すなわち、一方の光導
波路３９と他方の光導波路４０は一部分が接近して形成
され、この光導波路３９と光導波路４０の接近した部分
には幅Ｗ、長さＬの多モード干渉型３ｄＢカプラ４１が
形成される。しかして、一方の光導波路３９の入力端か
ら入力された光信号は多モード干渉型３ｄＢカプラ４１
で結合されてそれぞれの光導波路３９及び光導波路４０
の出力端から出力される。Ｓは多モード干渉型３ｄＢカ
プラ導波路間隔で、９μｍ程度である。したがって、本
発明の第１の実施例の方向性結合器型３ｄＢカプラ３８
では導波路の間隔を２μｍに保つ必要性があるが、本発
明の第２の実施例では多モード干渉型３ｄＢカプラ導波
路間隔Ｓを９μｍ程度と大きくすることが出来る。FIG. 6 is an explanatory diagram showing an example of the structure of a multimode interference type 3 dB coupler. That is, one optical waveguide 39 and the other optical waveguide 40 are partially formed close to each other, and a multimode interference type 3 dB coupler 41 having a width W and a length L is provided at a portion where the optical waveguide 39 and the optical waveguide 40 are close to each other. Is formed. The optical signal input from the input end of one optical waveguide 39 is a multimode interference type 3 dB coupler 41.
And the respective optical waveguides 39 and 40
Is output from the output end of S is a multimode interference type 3 dB coupler waveguide interval, which is about 9 μm. Therefore, the directional coupler type 3 dB coupler 38 according to the first embodiment of the present invention.
In the second embodiment of the present invention, the spacing S of the multimode interference type 3 dB coupler waveguide can be increased to about 9 μm.
【００２６】図７（ａ），（ｂ），（ｃ）は本発明の第
２の実施例に係る構造パラメータに対する多モード干渉
型３ｄＢカプラの結合率依存性の一例を示す特性図であ
り、図７（ａ）は構造パラメータＷと結合率の関係を示
す特性図、図７（ｂ）は構造パラメータＬと結合率の関
係を示す特性図、図７（ｃ）は構造パラメータＳと結合
率の関係を示す特性図である。すなわち、構造パラメー
タＷ，Ｌ，Ｓに対する製造トレランスが平坦なため、製
作性が良好である。この結果、生産性の良好な光可変減
衰器を実現できた。FIGS. 7 (a), 7 (b) and 7 (c) are characteristic diagrams showing an example of the coupling ratio dependence of the multimode interference type 3 dB coupler with respect to the structural parameters according to the second embodiment of the present invention. 7A is a characteristic diagram showing a relationship between the structural parameter W and the coupling ratio, FIG. 7B is a characteristic diagram showing a relationship between the structural parameter L and the coupling ratio, and FIG. 7C is a characteristic diagram showing the structural parameter S and the coupling ratio. FIG. 4 is a characteristic diagram showing the relationship of FIG. That is, since the manufacturing tolerances for the structural parameters W, L, and S are flat, the manufacturability is good. As a result, an optical variable attenuator with good productivity was realized.
【００２７】［実施例３］図８は本発明に係る導波路型
光可変減衰器の第３の実施例を示す構成説明図である。
図８中、図２と同一部分は同一符号を付してその説明を
省略する。図８において、３０，３１，３２，３３はＹ
分岐回路である。すなわち、第３の実施例では第１の実
施例の方向性結合器型３ｄＢカプラ２２，２３，２４，
２５をＹ分岐回路３０，３１，３２，３３で置き換えた
構造とした。[Embodiment 3] FIG. 8 is a structural explanatory view showing a third embodiment of the waveguide-type variable optical attenuator according to the present invention.
8, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 8, 30, 31, 32, and 33 are Y
It is a branch circuit. That is, in the third embodiment, the directional coupler type 3 dB couplers 22, 23, 24,
25 is replaced with Y branch circuits 30, 31, 32, and 33.
【００２８】図９は本発明の第３の実施例に係るＹ分岐
回路の一例を示す構成説明図である。すなわち、入力側
の光導波路４２はＹ分岐回路４５で出力側の光導波路４
３と４４に分岐される。しかして、入力側の光導波路４
２の入力端から入力された光信号はＹ分岐回路４５で分
岐されて出力側の光導波路４３，４４のそれぞれの出力
端から出力される。FIG. 9 is an explanatory diagram showing an example of a Y-branch circuit according to a third embodiment of the present invention. That is, the input side optical waveguide 42 is connected to the output side optical waveguide 4 by the Y branch circuit 45.
Branches into 3 and 44. Thus, the input side optical waveguide 4
The optical signal input from the input terminal 2 is branched by the Y branch circuit 45 and output from the output terminals of the optical waveguides 43 and 44 on the output side.
【００２９】本発明の第３の実施例に係るＹ分岐回路で
は波長依存性がないため広帯域な光可変減衰器を実現で
きた。 ［実施例４］図１０は本発明に係る導波路型光可変減衰
器の第４の実施例を示す構成説明図である。図１０中、
図１と同一部分は同一符号を付してその説明を省略す
る。図１０において、３４はパワー分岐用カプラ、３５
はモニター導波路である。すなわち、第４の実施例では
図１の入力導波路６にパワー分岐用カプラ３４を形成し
てモニター導波路３５を設け、このモニター導波路３５
により入力導波路６の光強度を監視する構造とした。本
発明の第４の実施例の構成ではモニター導波路３５を有
することによって、光入力レベルを監視出来るので、よ
り高精度に光可変減衰器を制御できる。In the Y-branch circuit according to the third embodiment of the present invention, since there is no wavelength dependency, a wide-band variable optical attenuator can be realized. [Embodiment 4] FIG. 10 is a structural explanatory view showing a fourth embodiment of the waveguide-type variable optical attenuator according to the present invention. In FIG.
1 are denoted by the same reference numerals and description thereof will be omitted. In FIG. 10, reference numeral 34 denotes a power branching coupler;
Is a monitor waveguide. That is, in the fourth embodiment, a monitor branch 35 is provided by forming a power branching coupler 34 in the input waveguide 6 of FIG.
To monitor the light intensity of the input waveguide 6. In the configuration of the fourth embodiment of the present invention, since the optical input level can be monitored by having the monitor waveguide 35, the optical variable attenuator can be controlled with higher precision.
【００３０】[0030]
【発明の効果】以上説明したように、本発明によれば、
平面基板上に連結した２段のマッハツェンダ光干渉計回
路の連結部に１／２波長板を挿入した構成としたことに
より、信頼性が高く、小型で製作性が良い導波路型光可
変減衰器を提供出来る利点がある。更にまた、導波路型
デバイスであるため、複数の可変減衰器を集積化するこ
とが可能であり、小型化の効果は一層顕著になる。As described above, according to the present invention,
A waveguide-type variable optical attenuator with high reliability, small size and good manufacturability by adopting a configuration in which a half-wave plate is inserted in the connection part of a two-stage Mach-Zehnder optical interferometer circuit connected on a flat substrate There is an advantage that can be provided. Furthermore, since the device is a waveguide device, a plurality of variable attenuators can be integrated, and the effect of miniaturization becomes more remarkable.
【図１】本発明の一実施形態例に係る導波路型光可変減
衰器を示す構成説明図である。FIG. 1 is a configuration explanatory view showing a waveguide type optical variable attenuator according to an embodiment of the present invention.
【図２】本発明の第１の実施例に係る導波路型光可変減
衰器を示す構成説明図である。FIG. 2 is a configuration explanatory view showing a waveguide type optical variable attenuator according to a first example of the present invention.
【図３】本発明の第１の実施例に係る方向性結合器型３
ｄＢカプラの構造の一例を示す構成図である。FIG. 3 shows a directional coupler type 3 according to the first embodiment of the present invention.
It is a block diagram which shows an example of a structure of a dB coupler.
【図４】本発明の第１の実施例に係る導波路型光可変減
衰器のヒータ電流と光減衰量の依存性の一例を示す特性
図である。FIG. 4 is a characteristic diagram showing an example of the dependence of the heater current and the optical attenuation on the waveguide-type optical variable attenuator according to the first embodiment of the present invention.
【図５】本発明の第２の実施例に係る導波路型光可変減
衰器を示す構成説明図である。FIG. 5 is an explanatory diagram illustrating a configuration of a waveguide type optical variable attenuator according to a second embodiment of the present invention.
【図６】本発明の第２の実施例に係る多モード干渉型３
ｄＢカプラの構造の一例を示す構成図である。FIG. 6 shows a multimode interference type 3 according to a second embodiment of the present invention.
It is a block diagram which shows an example of a structure of a dB coupler.
【図７】本発明の第２の実施例に係る構造パラメータに
対する多モード干渉型カプラの結合率依存性の一例を示
す特性図であり、（ａ）構造パラメータＷと結合率の関
係を示す特性図、（ｂ）構造パラメータＬと結合率の関
係を示す特性図、（ｃ）構造パラメータＳと結合率の関
係を示す特性図である。FIG. 7 is a characteristic diagram showing an example of a coupling rate dependency of a multi-mode interference coupler with respect to a structural parameter according to a second embodiment of the present invention, wherein (a) a characteristic showing a relationship between the structural parameter W and the coupling ratio; FIG. 4B is a characteristic diagram showing a relationship between a structural parameter L and a coupling ratio, and FIG. 4C is a characteristic diagram showing a relationship between a structural parameter S and a coupling ratio.
【図８】本発明の第３の実施例に係る導波路型光可変減
衰器を示す構成説明図である。FIG. 8 is a configuration explanatory view showing a waveguide type optical variable attenuator according to a third embodiment of the present invention.
【図９】本発明の第３の実施例に係るＹ分岐回路の構造
の一例を示す構成図である。FIG. 9 is a configuration diagram illustrating an example of a structure of a Y-branch circuit according to a third embodiment of the present invention.
【図１０】本発明の第４の実施例に係る導波路型光可変
減衰器を示す構成説明図である。FIG. 10 is a configuration explanatory view showing a waveguide type optical variable attenuator according to a fourth embodiment of the present invention.
【図１１】従来の光減衰器を示す構成説明図であり、
（ａ）は可変減衰器、（ｂ）は固定減衰器である。FIG. 11 is a configuration explanatory view showing a conventional optical attenuator;
(A) is a variable attenuator, (b) is a fixed attenuator.
１ 連続減衰板 ２ ステップ減衰板 ３ 減衰膜 ４ ロッドレンズ ５ ファイバ ６ 入力導波路 ７ 出力導波路 ８ 連結導波路 ９ １／２波長板 １０，１１ ヒータ電極 １２，１３，１４，１５ ３ｄＢカプラ １６，１７，１８，１９ アーム導波路 ２０ １段目のマッハツェンダ光干渉計回路 ２１ ２段目のマッハツェンダ光干渉計回路 ２２，２３，２４，２５ 方向性結合器型３ｄＢカプ
ラ ２６，２７，２８，２９ 多モード干渉型３ｄＢカプ
ラ ３０，３１，３２，３３ Ｙ分岐回路 ３４ パワー分岐用カプラ ３５ モニター導波路DESCRIPTION OF SYMBOLS 1 Continuous attenuation plate 2 Step attenuation plate 3 Attenuation film 4 Rod lens 5 Fiber 6 Input waveguide 7 Output waveguide 8 Connecting waveguide 9 1/2 wave plate 10, 11 Heater electrode 12, 13, 14, 15 3dB coupler 16, 17, 18, 19 Arm waveguide 20 First stage Mach-Zehnder optical interferometer circuit 21 Second stage Mach-Zehnder optical interferometer circuit 22, 23, 24, 25 Directional coupler type 3 dB coupler 26, 27, 28, 29 Many Mode interference type 3 dB coupler 30, 31, 32, 33 Y branch circuit 34 Power branch coupler 35 Monitor waveguide
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山本 靖 東京都渋谷区桜丘町20番１号 エヌティテ ィエレクトロニクス株式会社内 (72)発明者 河合 武司 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 (72)発明者 古賀 正文 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 (72)発明者 河内 正夫 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasushi Yamamoto 20-1 Sakuragaoka-cho, Shibuya-ku, Tokyo Inside NTT Electronics Corporation (72) Inventor Takeshi Kawai 3-9-1-2 Nishishinjuku, Shinjuku-ku, Tokyo Japan Within Telegraph and Telephone Corporation (72) Masafumi Koga Inventor 3- 19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Within Telegraph and Telephone Corporation (72) Masao Kawachi 3-2-1-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation
Claims (3)
れた複数のマッハツェンダ光干渉計回路と、 前記マッハツェンダ光干渉計回路の光導波路に設けられ
たヒータ電極とを具備することを特徴とする導波路型光
可変減衰器。1. An optical waveguide comprising: a plurality of Mach-Zehnder optical interferometer circuits in which optical waveguides are connected via a half-wave plate; and a heater electrode provided in the optical waveguide of the Mach-Zehnder optical interferometer circuit. A waveguide type optical variable attenuator.
波路を設けたことを特徴とする請求項１記載の導波路型
光可変減衰器。2. The waveguide type optical variable attenuator according to claim 1, further comprising a monitor waveguide for monitoring the light intensity of the optical waveguide.
たことを特徴とする請求項１又は２記載の導波路型光可
変減衰器。3. The waveguide-type variable optical attenuator according to claim 1, wherein a quartz-based optical waveguide is provided as the optical waveguide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29861497A JP3337629B2 (en) | 1997-10-30 | 1997-10-30 | Waveguide type optical variable attenuator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29861497A JP3337629B2 (en) | 1997-10-30 | 1997-10-30 | Waveguide type optical variable attenuator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11133364A true JPH11133364A (en) | 1999-05-21 |
| JP3337629B2 JP3337629B2 (en) | 2002-10-21 |
Family
ID=17862015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29861497A Expired - Fee Related JP3337629B2 (en) | 1997-10-30 | 1997-10-30 | Waveguide type optical variable attenuator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3337629B2 (en) |
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| JP2001264708A (en) * | 2000-03-14 | 2001-09-26 | Fujitsu Ltd | Optical device with optical waveguide and manufacturing method therefor |
| WO2002054138A3 (en) * | 2001-01-05 | 2003-11-20 | Mtech World Co Ltd | Variable optical attenuator of in-line type and fabrication method thereof |
| JP2005092217A (en) * | 2003-09-17 | 2005-04-07 | Lucent Technol Inc | Tunable dispersion compensator |
| US6952309B1 (en) | 1999-07-09 | 2005-10-04 | Sumitomo Electric Industries, Ltd. | Optical amplifier and optical amplification method |
| JP2006011278A (en) * | 2004-06-29 | 2006-01-12 | Hitachi Cable Ltd | Tandem connection type multicore variable optical attenuator |
| US7155086B2 (en) * | 2000-03-09 | 2006-12-26 | Nippon Telegraph And Telephone Corporation | Optical signal processing device using optical gate |
| US7280713B2 (en) | 2002-05-15 | 2007-10-09 | Fujitsu Limited | Optical modulator, optical waveguide device and acousto-optic tunable filter apparatus |
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| CN114153026A (en) * | 2022-01-24 | 2022-03-08 | 吉林大学 | Mode-insensitive optical power distributor based on Y-branch structure and preparation method thereof |
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1997
- 1997-10-30 JP JP29861497A patent/JP3337629B2/en not_active Expired - Fee Related
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6952309B1 (en) | 1999-07-09 | 2005-10-04 | Sumitomo Electric Industries, Ltd. | Optical amplifier and optical amplification method |
| US7155086B2 (en) * | 2000-03-09 | 2006-12-26 | Nippon Telegraph And Telephone Corporation | Optical signal processing device using optical gate |
| JP2001264708A (en) * | 2000-03-14 | 2001-09-26 | Fujitsu Ltd | Optical device with optical waveguide and manufacturing method therefor |
| WO2002054138A3 (en) * | 2001-01-05 | 2003-11-20 | Mtech World Co Ltd | Variable optical attenuator of in-line type and fabrication method thereof |
| US7340114B2 (en) | 2002-02-07 | 2008-03-04 | Fujitsu Limited | Optical waveguide device and optical modulator |
| US7280713B2 (en) | 2002-05-15 | 2007-10-09 | Fujitsu Limited | Optical modulator, optical waveguide device and acousto-optic tunable filter apparatus |
| US7289703B2 (en) | 2002-05-15 | 2007-10-30 | Fujitsu Limited | Optical modulator, optical waveguide device and acousto-optic tunable filter apparatus |
| US7315676B2 (en) | 2002-05-15 | 2008-01-01 | Fujitsu Limited | Optical modulator, optical waveguide device and acousto-optic tunable filter apparatus |
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| JP2005092217A (en) * | 2003-09-17 | 2005-04-07 | Lucent Technol Inc | Tunable dispersion compensator |
| JP2006011278A (en) * | 2004-06-29 | 2006-01-12 | Hitachi Cable Ltd | Tandem connection type multicore variable optical attenuator |
| JP4506304B2 (en) * | 2004-06-29 | 2010-07-21 | 日立電線株式会社 | Tandem connection type multi-core variable optical attenuator |
| CN103760692A (en) * | 2014-02-25 | 2014-04-30 | 四川飞阳科技有限公司 | Planar optical waveguide variable optical attenuator and adjusting method of planar optical waveguide variable optical attenuator |
| CN109343236A (en) * | 2018-11-28 | 2019-02-15 | 武汉光迅科技股份有限公司 | A kind of adjusting method of optical attenuator and optical attenuator |
| CN114153026A (en) * | 2022-01-24 | 2022-03-08 | 吉林大学 | Mode-insensitive optical power distributor based on Y-branch structure and preparation method thereof |
| CN114153026B (en) * | 2022-01-24 | 2023-09-05 | 吉林大学 | Mode-insensitive optical power distributor based on Y-branch structure and preparation method thereof |
| CN115291323A (en) * | 2022-08-30 | 2022-11-04 | 吉林大学 | Multi-mode optical attenuator based on MZI structure |
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