JPH0522209B2 - - Google Patents

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Publication number
JPH0522209B2
JPH0522209B2 JP57033162A JP3316282A JPH0522209B2 JP H0522209 B2 JPH0522209 B2 JP H0522209B2 JP 57033162 A JP57033162 A JP 57033162A JP 3316282 A JP3316282 A JP 3316282A JP H0522209 B2 JPH0522209 B2 JP H0522209B2
Authority
JP
Japan
Prior art keywords
waveguides
waveguide
coupled
directional coupler
dielectric
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.)
Expired - Lifetime
Application number
JP57033162A
Other languages
Japanese (ja)
Other versions
JPS57161706A (en
Inventor
Ungaa Hansuugeoruku
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AA ENU TEE NATSUHARIHITENTEHINIIKU GmbH
Original Assignee
AA ENU TEE NATSUHARIHITENTEHINIIKU GmbH
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 AA ENU TEE NATSUHARIHITENTEHINIIKU GmbH filed Critical AA ENU TEE NATSUHARIHITENTEHINIIKU GmbH
Publication of JPS57161706A publication Critical patent/JPS57161706A/en
Publication of JPH0522209B2 publication Critical patent/JPH0522209B2/ja
Granted legal-status Critical Current

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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
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29331—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by evanescent wave coupling
    • G02B6/29332—Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency
    • 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
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2821—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals
    • 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
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29395—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device configurable, e.g. tunable or reconfigurable
    • 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
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B2006/2865—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers couplers of the 3x3 type

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Integrated Circuits (AREA)

Description

【発明の詳細な説明】 本発明は、相互に結合すべき、有利には平行に
延在する２つの導波体から成る選択方向性結合器
に関する。DETAILED DESCRIPTION OF THE INVENTION The invention relates to a selective directional coupler consisting of two waveguides, preferably extending in parallel, to be coupled to each other.

結合度が出力結合すべき電磁振動の周波数乃至
波長に依存する方向性結合器は、例えば同一の伝
送媒体を周波数多重で複数のチヤンネルで利用す
る搬送周波通信伝送において必要とされる。典型
的な使用例として、１本のグラスフアイバ上を光
信号を用いて波長分割多重において行なう同時送
受信がある。この場合一方の方向においては、そ
れとは逆の方向におけるのとは別の波長でもつて
伝送される。この種のフアイバ区間の端部または
中継器において、第１図に示すように選択方向性
結合器を介して波長λ0において送信され、またそ
れと逆の方向で別の波長λeにおいて受信される。 Directional couplers whose degree of coupling depends on the frequency or wavelength of electromagnetic oscillations to be coupled out are required, for example, in carrier frequency communication transmission in which the same transmission medium is used in a plurality of channels by frequency multiplexing. A typical example of use is simultaneous transmission and reception using optical signals over a single glass fiber in wavelength division multiplexing. In this case, in one direction it is also transmitted at a different wavelength than in the opposite direction. At the end or repeater of a fiber section of this type, a signal is transmitted at a wavelength λ 0 via a selective directional coupler, as shown in FIG. 1, and received in the opposite direction at another wavelength λ e . .

方向性結合器の選択性は、λ0における全送信出
力をフアイバ内に供給しかつλeにおける全到来入
力を受信機に送信するのに役立つ。方向性結合器
の選択性は更に、その方向作用によつて促進され
て近端漏話を低減し、その結果高い送信出力であ
つても受信機には殆んど障害とならない僅かな漏
話しか達しない。 The selectivity of the directional coupler helps to provide all transmit power at λ 0 into the fiber and transmit all incoming input at λ e to the receiver. The selectivity of the directional coupler is further facilitated by its directional action to reduce near-end crosstalk, so that even at high transmit powers, only a small amount of crosstalk can be reached with little disturbance to the receiver. do not.

この送受信用２重通信装置の別の利点は、この
使用に対する単一モードフアイバから受信される
基本波が任意の偏光を有することができることで
ある。というのは基本波は実際結合しないで選択
方向性結合器を通過するからである。 Another advantage of this dual transmit/receive communication device is that the fundamental wave received from the single mode fiber for this use can have any polarization. This is because the fundamental wave passes through the selective directional coupler without actually combining.

本発明の課題は、冒頭に述べた形式の選択方向
結合器において、簡単な方法で実現できる選択方
向結合器を提供することである。 The object of the invention is to provide a selective direction coupler of the type mentioned at the outset, which can be implemented in a simple manner.

このことは、特許請求の範囲に記載の特徴によ
り解決される。 This is solved by the features described in the claims.

この使用および類似の使用に対する選択方向性
結合器は、第２図に図示のように構成される。２
つの、連続する導波体１および３は、その間に位
置する導波体部分２を介してＺ＝Ｏ乃至Ｚ＝Ｌの
区間において相互に結合される。 A selective directional coupler for this and similar uses is constructed as shown in FIG. 2
Two successive waveguides 1 and 3 are coupled to each other in the section Z=O to Z=L via a waveguide section 2 located between them.

連続する導波体１および３は、同一の横断面を
有する。計算のためにこゝでは、選択的に相互結
合すべき、導波体１および３における波は同じ位
相定数β1＝β3＝βを有することだけを前提とす
る。実際にはこの条件は、選択結合によつて一方
の導波体から他方の導波体へ全出力が過結合され
るべき周波数0乃至波長λ0に対してのみ満足され
ればよい。 Successive waveguides 1 and 3 have the same cross section. For the purposes of the calculations, it is only assumed here that the waves in waveguides 1 and 3, which are to be selectively coupled together, have the same phase constants β 1 =β 3 =β. In practice, this condition need only be satisfied for frequencies 0 to wavelength λ 0 where the total power is to be overcoupled from one waveguide to the other by selective coupling.

導波体１および３における波の結合は、中間導
波体２が導く波の１つを介して行なわれる。こゝ
では計算のために、次のことを前提とする。即ち
導波体１における波は導波体２におけるこの波
と、導波体３における波が導波体２におけるこの
波と結合するのと同じ強さで結合する。しかし実
際にはこの条件も、周波数0乃至波長λ0に対して
のみ満足するものであればよい。 The coupling of the waves in the waveguides 1 and 3 takes place via one of the waves guided by the intermediate waveguide 2. For calculation purposes, we assume the following: That is, the wave in waveguide 1 couples with this wave in waveguide 2 with the same strength as the wave in waveguide 3 couples with this wave in waveguide 2. However, in reality, this condition only needs to be satisfied from frequency 0 to wavelength λ 0 .

上記の条件下にあつてかつ結合器における損失
を無視できるとき、上記の波の振幅A1，A2およ
びA3に対して、結合された微分方程式の次の系
が生ずる。即ち dA1／dZ＝−jβA1 −jcA2 dA2／dz＝−jcA1 −jβ2A2 −jcA3 dA3／dz＝ −jcA2 −jβA3 その際β2は、中間導波体における結合波２の位
相定数でありかつｃは波１および３とこの結合波
との結合に対する結合係数である。 Under the above conditions and when losses in the coupler can be ignored, for the wave amplitudes A 1 , A 2 and A 3 above, the following system of coupled differential equations arises: That is, dA 1 /dZ=−jβA 1 −jcA 2 dA 2 /dz=−jcA 1 −jβ 2 A 2 −jcA 3 dA 3 /dz= −jcA 2 −jβA 3Then β 2 is is the phase constant of coupled wave 2, and c is the coupling coefficient for the coupling of waves 1 and 3 with this coupled wave.

３つの結合された波から成るこの系は、結合区
間に沿つて互いに無関係に移動する３つの固有波
を有する。これら固有波の位相定数は、βとβ＋
δ＋√2＋22とβ＋δ−√2＋22とであり、そ
の際δ＝（β＝β2）／２は、波１および３並びに
結合波２の位相定数の差の半分を示す。 This system of three coupled waves has three natural waves moving independently of each other along the coupling section. The phase constants of these eigenwaves are β and β+
δ+√ 2 +2 2 and β+δ− √ 2 +2 2 , where δ=(β=β 2 )/2 denotes half the difference in the phase constants of waves 1 and 3 and of the combined wave 2.

波１，２および３の振幅に対する一般解におい
て、固有波は次のように重畳される。 In the general solution for the amplitudes of waves 1, 2 and 3, the eigenwaves are superimposed as follows.

A1＝w1e-j〓z＋w2ｅ−ｊ（β＋δ＋√2＋22）ｚ ＋w3ｅ−ｊ（β＋δ−√2＋22）ｚ A2＝δ＋√δ2＋2c2／ｃw2ｅ−ｊ（β＋δ＋√2＋2
2）ｚ ＋√δ2＋2c2−δ／ｃw3ｅ−ｊ（β＋δ−√δ2
＋2c2 ）ｚ A3＝w1e-j〓z＋w2ｅ−ｊ（β＋δ＋√δ2＋2c2 ）ｚ ＋w3ｅ−ｊ（β＋δ−√δ2＋2c2 ）ｚ ｚ＝０において導波体１の入り口のみが防振さ
れるとき、Ｚ＝０における初期条件はA1＝１お
よびA2＝A3＝０である。この防振において波１
および３は結合器に沿つて次の振幅値を有する。
即ち、 次の２つの限界例は実際の使用に対して特に重
要である。即ち、 １ β2＝β の場合 結合波２は、両方の波１および３と同じ位相定
数を有する。この場合δ＝０であり、かつ振幅値
は次の通りである。即ち、 ｜A1｜＝１／２｜１＋cos（√２cz）｜ ｜A3｜＝１／２｜１−cos（√２cz）｜ 従つて位相同期結合波２において出力は、波１
および３の間で結合区間に沿つて変化する。A 1 =w 1 e -j 〓 z +w 2 e−j (β+δ+√ 2 +2 2 )z +w 3 e−j (β+δ−√ 2 +2 2 )z A 2 =δ+√δ 2 +2c 2 /cw 2 e −j(β+δ+√ 2 +2
2 )z +√δ 2 +2c 2 −δ/cw 3 e−j(β+δ−√ δ 2
+2c 2 )z A 3 =w 1 e -j 〓 z +w 2 e−j (β+δ+√ δ 2 +2c 2 )z +w 3 e−j (β+δ−√ δ 2 +2c 2 )z Waveguide at z=0 When only one entrance is damped, the initial conditions at Z=0 are A 1 =1 and A 2 =A 3 =0. In this vibration isolation wave 1
and 3 have the following amplitude values along the coupler:
That is, The following two limiting cases are of particular importance for practical use. That is, if 1 β 2 =β The combined wave 2 has the same phase constant as both waves 1 and 3. In this case, δ=0 and the amplitude values are as follows. That is, |A 1 |=1/2|1+cos(√2cz)| |A 3 |=1/2|1−cos(√2cz)| Therefore, in phase-locked coupled wave 2, the output is wave 1
and 3 along the coupling interval.

ｚ＝（2m＋１）π／（√２ｃ）（たゞし
ｍ＝０，１，２……）の場合、出力は完全に波３
によつて導かれまたｚ＝2mπ／（√２ｃ）（たゞ
しｍ＝０，１，２……）の場合、出力は完全に波
１によつて導かれる。波１から波３へ完全に出力
変換するために、結合器は最適には、 Ｌ＝π／（√２ｃ） (2) の長さにされる。 In the case of z=(2m+1)π/(√2c) (if m=0, 1, 2...), the output is completely wave 3.
and if z=2mπ/(√2c) (where m=0, 1, 2...), the output is completely guided by wave 1. For complete power conversion from wave 1 to wave 3, the coupler is optimally made to have a length of L=π/(√2c) (2).

２ ｜δ｜≫ｃ の場合 波１から３への完全な出力変換は、即ち位相同
期結合波においてδ＝０に対してのみ可能であ
る。δ≠０に対してはその都度波１の入力の一部
のみが波３に変換される。その上第２の限界例δ
≫ｃにおいては非常に僅かでしかない。即ちこの
条件下では振幅値に対して式(1)から近似的に ｜A1｜１−ｊc2／2〓2sin δz e-j〓z ｜A3｜c2／2〓2sin δz が成立つ。 2 If |δ|≫c A complete power conversion from wave 1 to wave 3 is only possible for δ=0, ie in a phase-locked coupled wave. For δ≠0 only part of the input of wave 1 is converted into wave 3 in each case. Moreover, the second limit example δ
≫It is very small in c. That is, under this condition, approximately from equation (1) for the amplitude value, |A 1 |1−jc 2 /2〓 2 sin δz e -j 〓 z |A 3 |c 2 /2〓 2 sin δz Established.

上記の近似式によれば、最高の場合にも入力の
部分c4／（4δ4）のみが波３に変換される。残り
は主として波１にとどまるが、結合波２にも僅か
な部分が導かれる。しかし波１はこの条件下にお
いて最高の場合でもその入力のc2／δ2の部分しか
損失しない。 According to the above approximation formula, only the part c 4 /(4δ 4 ) of the input is converted into wave 3 in the best case. The remainder remains mainly in wave 1, but a small portion is also guided into coupled wave 2. However, wave 1 loses only a portion of its input c 2 /δ 2 in the best case under these conditions.

ところで所望を選択性を得るために、即ち周波
数0乃至波長λ0においてロスのない出力変換を行
ないかつそれとは異なる所定の周波数においては
出来るだけ僅かな出力しか変換されないようにす
るために、次のような中間導波体を選択すること
ができる。即ちその結合波２が＝0において波
１および３と位相同期であるが、遮断周波数にお
いて十分な位相差を有し、そこで条件｜δ｜≫ｃ
が満たされるようにした中間導波体である。 By the way, in order to obtain the desired selectivity, that is, to perform lossless output conversion from frequency 0 to wavelength λ 0 , and to convert as little output as possible at a predetermined frequency different from that, the following An intermediate waveguide such as That is, the combined wave 2 is phase-locked with waves 1 and 3 at = 0 , but has a sufficient phase difference at the cut-off frequency, so that the condition |δ|≫c
This is an intermediate waveguide that satisfies the following conditions.

光周波数に対しては、これらの要求は導波体と
して誘導体フイルムまたはストリツプを使用する
ことによつて満足される。これら光フイルムまた
はストリツプ導波体は例えば第３図によれば、屈
折率n0の透明な材料に埋込まれる。導波体１およ
び３は、第３図の実施例において同じ横断面およ
び同じ屈折率n1＞n0を有する。中間導波体は、比
較的大きな屈折率n1＞n0を有し、かつその横断面
も選択性要求に応じて導波体１および３の横断面
より大きくなければならない。 For optical frequencies, these requirements are met by using dielectric films or strips as waveguides. These optical films or strip waveguides, for example according to FIG. 3, are embedded in a transparent material with a refractive index n 0 . Waveguides 1 and 3 have the same cross section and the same refractive index n 1 >n 0 in the embodiment of FIG. The intermediate waveguide must have a relatively large refractive index n 1 >n 0 and its cross section must also be larger than the cross section of waveguides 1 and 3, depending on the selectivity requirements.

第４図は分散ダイヤグラムにおいて周波数の関
数として、導波体１および３における基本波並び
に結合波として使用することができる、中間導波
体における波の位相定数βを示す。すべての位相
曲線は、それぞれの遮断周波数においてその始点
を、屈折率n0を有する周囲の媒体における波数に
対する直線n02π／c0上に有する。その際c0は真
空中の光速である。周波数が高くなるに従つて位
相曲線はそれぞれの導波体材料の波数に対する直
線へ漸近する。基本波の位相曲線を除けば中間導
波体のすべての高次の波の位相曲線は導波体１お
よび３における基本波の位相曲線と交差する。従
つてこれらすべての高次の波は導波体１および３
における基本波間の結合波として役立てることが
できる。導波体１および３の基本波−位相曲線と
の交差周波数において、１および３における基本
波間での全出力変換が可能になる。 FIG. 4 shows the phase constant β of the waves in the intermediate waveguide, which can be used as the fundamental wave in waveguides 1 and 3 as well as the combined wave, as a function of frequency in a dispersion diagram. All phase curves have their starting point at their respective cutoff frequency on a straight line n 0 2π/c 0 for the wavenumber in the surrounding medium with index of refraction n 0 . In this case, c 0 is the speed of light in vacuum. As the frequency increases, the phase curve asymptotes to a straight line for the wave number of each waveguide material. Except for the phase curve of the fundamental wave, the phase curves of all higher-order waves in the intermediate waveguides intersect the phase curves of the fundamental wave in waveguides 1 and 3. Therefore all these higher order waves are transmitted through waveguides 1 and 3.
It can be used as a coupling wave between fundamental waves in . At the crossing frequency with the fundamental-phase curves of waveguides 1 and 3, a total power conversion between the fundamentals in 1 and 3 becomes possible.

結合波としてどの波を選択しかつこれに応じて
導波体１および３並びに中間導波体２をどのよう
に形成するかは、結合乃至減結合されるべき周波
数の位置に依存する。これら周波数の間隔が比較
的大きい場合、低次の結合波が選択され、周波数
間隔が比較的小さくかつ相応に選択性が比較的高
い場合比較的高次の結合波が選択される。選択性
は中間導波体における屈折率を高めることによつ
ても、その横断面を拡大することによつても高め
られる。即ち中間導波体における結合波の位相曲
線は、導波体１および３における基本波の位相曲
線と、角度を段々と大きくして交わる。その際こ
れらの波の間の位相差は、曲線の交点におけるδ
＝０から出発して、同期周波数からの周波数のず
れが大きくなるに従つて一段と急速に大きくな
る。 Which waves are selected as coupling waves and how the waveguides 1 and 3 and the intermediate waveguide 2 are formed accordingly depends on the location of the frequencies to be coupled or decoupled. If the frequency spacing is relatively large, a lower-order coupled wave is selected; if the frequency spacing is relatively small and the selectivity is correspondingly relatively high, a higher-order coupled wave is selected. The selectivity can be increased both by increasing the refractive index in the intermediate waveguide and by enlarging its cross section. That is, the phase curve of the coupled wave in the intermediate waveguide intersects the phase curve of the fundamental wave in waveguides 1 and 3 at gradually increasing angles. The phase difference between these waves is then δ at the intersection of the curves
Starting from =0, it increases rapidly as the frequency deviation from the synchronous frequency increases.

第５図において示すように、誘電体基板Ｓに載
置された誘電体ストリツプから成る選択方向性結
合器の例に基づいて、光波乃至マイクロ波の波長
λとの関係においてどんな寸法を選択できるかに
ついて説明する。屈折率n0＝n1／1.1を有する基
板ｓ上に相互間隔ａ＝ｂにおいて設けられてい
る、屈折率n1＝1.5を有する幅ｂ＝3.5λおよび高
さｈ＝1.75λの２つの平行なストリツプst１およ
びst２から成る簡単な方向性結合器は、ストリツ
プの基本波を結合係数ｃ＝0.002λによつて結合す
る。選択方向性結合器に対して同じ基板上に同じ
ストリツプが選択されかつ中間導波体ZWLに対
してn1より多少大きい屈折率を有する２乃至数倍
幅広のストリツプが選択されるとき、ストリツプ
相互間の間隔をａ＝ｂより多少小さく選択するこ
とによつて、外側のストリツプにおける基本波
と、中間導波体における位相同期の結合波との結
合に対して同じ結合係数に調節される。それから
条件(2)は、Ｌ＝1110λとすれば満たされる。光の
波長に対してはＬはmmのオーダにある。集積され
た光学装置において一層短い結合器ですむように
するためには、ストリツプは更に密にまとめられ
なければならない。結合係数はストリツプの間隔
に指数関数的に依存するので、間隔を僅かに狭く
するだけで結合器は一きよに短縮される。 Based on the example of a selective directional coupler consisting of a dielectric strip placed on a dielectric substrate S as shown in FIG. 5, what dimensions can be selected in relation to the wavelength λ of light waves or microwaves? I will explain about it. Two parallel beams of width b=3.5λ and height h=1.75λ with refractive index n 1 =1.5, provided at mutual spacing a=b on substrate s with refractive index n 0 =n 1 /1.1 A simple directional coupler consisting of strips st1 and st2 couples the fundamental waves of the strips by a coupling coefficient c=0.002λ. When the same strip on the same substrate is selected for the selective directional coupler and a strip two to several times wider with a refractive index somewhat greater than n 1 for the intermediate waveguide ZWL, the strips are By selecting the spacing between a=b to be somewhat smaller than a=b, the same coupling coefficient is set for the coupling of the fundamental wave in the outer strip and the phase-locked combined wave in the intermediate waveguide. Then, condition (2) is satisfied if L=1110λ. For the wavelength of light, L is on the order of mm. In order to require shorter couplers in integrated optical devices, the strips must be packed more closely together. Since the coupling coefficient depends exponentially on the spacing of the strips, even a slight reduction in the spacing will significantly shorten the coupler.

光周波数に対する選択方向性結合器の基板およ
びフイルムまたはストリツプは、石英ガラスまた
は別の珪酸塩ガラスから製造することができる。
フイルムまたはストリツプの屈折率を基板の屈折
率に比べて高くするために、かつ殊に中間導波体
において２つの外側の導波体におけるよりも高い
屈折率が得られるようにするために、石英ガラス
に酸化ゲルマニウムまたは酸化りんをドーピング
することができる。 The substrate and film or strip of the selective directional coupler for optical frequencies can be made from quartz glass or another silicate glass.
In order to increase the refractive index of the film or strip compared to the refractive index of the substrate, and in particular to obtain a higher refractive index in the intermediate waveguide than in the two outer waveguides, quartz is used. The glass can be doped with germanium oxide or phosphorous oxide.

例えば屈折率の低い基板ガラスを使用し、外側
の導波体を、例えばポリウレタンのような透明な
ポリマーから製造しかつ中間導波体を硫化亜鉛か
ら製造すると、一層大きい屈折率の差が得られ
る。光周波数において動作すべきこの種の選択方
向性結合器として、沢山の種々異なつた形式の材
料が考えられるが、結合器損失を僅かに抑えるた
めに、伝送すべき光波長に対して十分に透明であ
るように考慮しなければならない。 Larger refractive index differences can be obtained, for example, by using a substrate glass with a low refractive index, making the outer waveguide from a transparent polymer such as polyurethane, and making the intermediate waveguide from zinc sulphide. . Many different types of materials are conceivable for selective directional couplers of this type to operate at optical frequencies, but they must be sufficiently transparent to the optical wavelengths to be transmitted to keep coupler losses small. must be taken into account.

電磁エネルギーを相互間で選択的に変換すべき
導波体の形態も、中間導波体の形態も、基板中ま
たは基板上における簡単なフイルムまたはストリ
ツプに限定されない場合は、それに代わりリツジ
状および***状導体並びにストリツプを具備した
フイルム導波体が考えられる。第６図は、代表的
な例として、殊に光周波数に対する選択方向性結
合器の断面図を示し、その際２つの外側の導波体
はリツジ状導波体RL１乃至RL２でありかつ中間
導波体としてストリツプを備えたフイルム導波体
FWLが用いられ、このフイルム導波体の基板は
外側のリツジ状導波体も所属する同じ誘電体フイ
ルムによつて形成される。フイルムおよびリツジ
部の屈折率n1は、基板Ｓの屈折率n0より多少大き
くなければならずかつストリツプはn1より更に大
きい屈折率n2を有するべきである。 If neither the form of the waveguides nor the form of the intermediate waveguides to which electromagnetic energy is to be selectively converted between each other is limited to simple films or strips in or on the substrate, ridges and ridges may be used instead. Film waveguides with shaped conductors as well as strips are conceivable. FIG. 6 shows, as a typical example, a sectional view of a selective directional coupler, in particular for optical frequencies, in which the two outer waveguides are ridge-shaped waveguides RL1 and RL2 and an intermediate waveguide. Film waveguide with strip as wave body
A FWL is used, and the substrate of this film waveguide is formed by the same dielectric film to which the outer ridge waveguide also belongs. The refractive index n 1 of the film and the ridge should be somewhat greater than the refractive index n 0 of the substrate S, and the strip should have a refractive index n 2 even greater than n 1 .

マイクロ波に対する選択方向性結合器は、殊に
ミリメートル波を使用するときは、誘電体ストリ
ツプ導波体を用いても構成することはできる。と
いうのは誘電体ストリツプは一層比較的小さな横
断面を有するからである。しかしこれに対し誘電
体イメージ線路および中空導波体も考えられる。
第７図は誘電体イメージ線路から成る選択方向性
結合器の断面図である。その際３つの誘電体イメ
ージ線路BL１、BL２およびBL３は、共通の金
属板Ｐ上に相互に平行に延在している。２つの外
側の誘電体イメージ線路は、同じ寸法の横断面お
よび同じ屈折率を有し、一方中間導波体である内
側の誘電体イメージ線路は、より大きい横断面お
よびn1より大きい屈折率n2も有する。 Selective directional couplers for microwaves can also be constructed using dielectric strip waveguides, especially when using millimeter waves. This is because the dielectric strip has a smaller cross section. However, dielectric image lines and hollow waveguides are also conceivable.
FIG. 7 is a sectional view of a selective directional coupler comprising a dielectric image line. The three dielectric image lines BL1, BL2 and BL3 then extend parallel to each other on a common metal plate P. The two outer dielectric image lines have the same dimension cross-section and the same refractive index, while the inner dielectric image line, which is the intermediate waveguide, has a larger cross-section and a refractive index n greater than n 1 Also has 2 .

第８図は矩形中空導体Ｈ１，Ｈ２，Ｈ３から成
る選択方向性結合器を断面において示す。中間中
空導体は、外側の中空導体と、例えば共通の間隔
に設けた孔列Ｌ１およびＬ２によつて結合され
る。中間中空導体Ｈ２は、外側の中空導体より幅
広の横断面を有しまたは誘電体によつて部分的ま
たは全体が充てんされている。第８図の実施例に
おいて、外側の中空導体より横断面を広くし、同
時に中間中空導体H2に誘電体を充てんするとい
う両方の構成は、選択性を高める作用をする。 FIG. 8 shows in cross section a selective directional coupler consisting of rectangular hollow conductors H1, H2, H3. The intermediate hollow conductor is connected to the outer hollow conductor by, for example, a common spacing of hole rows L1 and L2. The intermediate hollow conductor H2 has a wider cross section than the outer hollow conductor or is partially or completely filled with dielectric material. In the embodiment of FIG. 8, both the configuration of having a wider cross-section than the outer hollow conductor and at the same time filling the intermediate hollow conductor H2 with dielectric material serve to increase the selectivity.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、フアイバー端面に設けられる選択方
向性結合器の作用を説明する図、第２図は第１図
に図示したような目的のために使用される本発明
の選択方向性結合器の構成を説明する図、第３図
は光周波数に対する方向性結合器の実施例の構成
を示す図、第４図は周波数と、導波体１および３
における基本波並びに中間導波体２における結合
波の位相定数βとの関係を示す図、第５図は本発
明の選択方向性結合器の１実施例の断面図、第６
図は光周波数に適した本発明の選択方向性結合器
の１実施例の断面図、第７図は誘電体イメージ線
路から成る本発明の選択方向性結合器の断面図、
第８図は矩形中空導波体から成る本発明の選択方
向性結合器の断面図である。 １，３……結合すべき導波体、２……中間導波
体、st１，st２……ストリツプ導体、ZWL……中
間導波体、Ｓ……誘電体基板、RL１，RL２……
リツジ状導体、FWL……ストリツプを具備した
フイルム導波体、BL１，BL２，BL３……誘電
体イメージ線路、Ｈ１，Ｈ２，Ｈ３……中空導波
体、Ｌ１，Ｌ２……孔、n0，n1，n2……屈折率。 FIG. 1 is a diagram explaining the action of a selective directional coupler provided on the fiber end face, and FIG. 2 is a diagram illustrating the selective directional coupler of the present invention used for the purpose shown in FIG. 3 is a diagram illustrating the configuration of an embodiment of a directional coupler for optical frequencies, and FIG. 4 is a diagram for explaining the frequency and waveguides 1 and 3.
FIG. 5 is a cross-sectional view of one embodiment of the selective directional coupler of the present invention, and FIG.
The figure is a cross-sectional view of one embodiment of the selective directional coupler of the present invention suitable for optical frequencies, and FIG. 7 is a cross-sectional view of the selective directional coupler of the present invention comprising a dielectric image line.
FIG. 8 is a sectional view of a selective directional coupler of the present invention comprising a rectangular hollow waveguide. 1, 3...Waveguide to be coupled, 2...Intermediate waveguide, st1, st2...Strip conductor, ZWL...Intermediate waveguide, S...Dielectric substrate, RL1, RL2...
Rib-shaped conductor, FWL...film waveguide with strip, BL1, BL2, BL3...dielectric image line, H1, H2, H3...hollow waveguide, L1, L2...hole, n 0 , n 1 , n 2 ... refractive index.

Claims (1)

【特許請求の範囲】 １ 相互に結合すべき、２つの導波体を有する選
択方向性結合器において、前記２つの光導波体
１，３の間に別の光導波体２が配置されており、
該別の光導波体は、その全長にわたつて他の前記
２つの導波体１，３とともに唯一の結合器を形成
しており、前記別の導波体の結合波は所望の結合
周波数0において前記２つの他の導波体１，３に
おける波と位相同期していることを特徴とする選
択方向性結合器。 ２ 結合すべき両導波体１，３は、中間導波体２
とのみ結合されている特許請求の範囲第１項記載
の選択方向性結合器。 ３ 結合すべき両導波体１，３は、誘電体フイル
ムでありかつ該導波体の間に中間導波体２として
の誘電体フイルムが存在する特許請求の範囲第１
項記載の選択方向性結合器。 ４ 結合すべき両導波体１，３は、誘電体ストリ
ツプ導体でありかつ該ストリツプ導体の間に、中
間導波体２としての誘電体フイルムが存在する特
許請求の範囲第１項記載の選択方向性結合器。 ５ 結合すべき両導波体１，３および中間導波体
２は、誘電体ストリツプである特許請求の範囲第
１項記載の選択方向性結合器。 ６ 結合すべき両導波体１，３および誘電体スト
リツプである中間導波体２は、屈折率の低い誘電
体基板上に載置されている特許請求の範囲第５項
記載の選択方向性結合器。 ７ 結合すべき両導波体１，３および誘電体スト
リツプである中間導波体２は、屈折率の低い誘電
体基板内に埋込まれている特許請求の範囲第５項
記載の選択方向性結合器。 ８ 結合すべき両導波体１，３は、誘電体フイル
ム上のリツジから成り、かつ中間導波体２も誘電
体フイルム上のリツジによつて形成される特許請
求の範囲第１項記載の選択方向性結合器。 ９ 結合すべき導波体１，３およびリツジ状導体
としての中間導波体２は該導波体の誘電体フイル
ムとともに屈折率の低い誘電体基板上に載置され
ている特許請求の範囲第８項記載の選択方向性結
合器。 １０ 結合すべき両導波体RL１，RL２は、誘電
体フイルム上のリツジから成りかつ中間導波体
は、ストリツプを具備したフイルム導波体FWL
としてフイルム上のストリツプから形成される特
許請求の範囲第１項記載の選択方向性結合器。 １１ リツジ状導体である結合すべき導波体RL
１，RL２およびストリツプを具備したフイルム
導波体FWLである中間導波体は、該導波体の共
通のフイルムとともに屈折率の比較的低い誘電体
基板Ｓ上に載置されている特許請求の範囲第１０
項記載の選択方向性結合器。 １２ 結合すべき導波体BL１，BL３および中間
導波体BL２は、共通の金属板Ｐ上の誘電体イメ
ージ線路である特許請求の範囲第１項記載の選択
方向性結合器。 １３ 結合間隔は可変である特許請求の範囲第１
項記載の選択方向性結合器。 １４ 誘電体の屈折率は可変である特許請求の範
囲第６項記載の選択方向性結合器。 １５ 結合すべき導波体は中空導波体Ｈ１，Ｈ３
であり、かつ中間導波体も中空導波体Ｈ２であ
り、該中間導波体は共通の隔壁に設けた孔列Ｌ
１，Ｌ２によつて前記導波体Ｈ１，Ｈ３と結合さ
れている特許請求の範囲第１項記載の選択方向性
結合器。 １６ 結合すべき導波体および中間導波体は、矩
形中間導波体である特許請求の範囲第１５項記載
の選択方向性結合器。 １７ 中間導波体Ｈ２は結合器全体に沿つて、該
中間導波体の横断面を少なくとも部分的に充てん
する誘電体挿入物を備えている特許請求の範囲第
１５項記載の選択方向性結合器。[Claims] 1. A selective directional coupler having two waveguides to be coupled to each other, in which another optical waveguide 2 is arranged between the two optical waveguides 1 and 3. ,
Over its entire length, the further optical waveguide forms a unique coupler together with the other two waveguides 1, 3, and the coupled wave of the further waveguide has a desired coupling frequency 0. A selective directional coupler characterized in that it is phase synchronized with the waves in the two other waveguides 1 and 3. 2 Both waveguides 1 and 3 to be combined are intermediate waveguide 2
2. A selective directional coupler according to claim 1, wherein the selective directional coupler is coupled only with: 3. Both waveguides 1 and 3 to be coupled are dielectric films, and a dielectric film as an intermediate waveguide 2 is present between the waveguides.
Selective directional coupler as described in section. 4. The selection according to claim 1, in which both waveguides 1 and 3 to be coupled are dielectric strip conductors, and a dielectric film as intermediate waveguide 2 is present between the strip conductors. Directional coupler. 5. The selective directional coupler according to claim 1, wherein both waveguides 1, 3 and the intermediate waveguide 2 to be coupled are dielectric strips. 6. The selection direction according to claim 5, wherein both waveguides 1 and 3 to be coupled and the intermediate waveguide 2, which is a dielectric strip, are placed on a dielectric substrate with a low refractive index. combiner. 7. The selection direction according to claim 5, wherein both waveguides 1 and 3 to be coupled and the intermediate waveguide 2, which is a dielectric strip, are embedded in a dielectric substrate with a low refractive index. combiner. 8. The waveguides 1 and 3 to be coupled are formed of a ridge on a dielectric film, and the intermediate waveguide 2 is also formed of a ridge on a dielectric film. Selective directional coupler. 9 The waveguides 1 and 3 to be coupled and the intermediate waveguide 2 as a ridge-like conductor are placed on a dielectric substrate with a low refractive index together with the dielectric film of the waveguide. 9. The selective directional coupler according to item 8. 10 The two waveguides RL1, RL2 to be coupled consist of a ridge on a dielectric film and the intermediate waveguide is a film waveguide FWL with a strip.
2. A selective directional coupler as claimed in claim 1, formed from a strip on a film. 11 Waveguide RL to be coupled which is a ridge-shaped conductor
1. The intermediate waveguide, which is a film waveguide FWL with RL2 and a strip, is placed on a dielectric substrate S with a relatively low refractive index together with the common film of the waveguide. Range 10th
Selective directional coupler as described in section. 12. The selective directional coupler according to claim 1, wherein the waveguides BL1, BL3 and the intermediate waveguide BL2 to be coupled are dielectric image lines on a common metal plate P. 13 Claim 1 in which the coupling interval is variable
Selective directional coupler as described in section. 14. The selective directional coupler according to claim 6, wherein the dielectric has a variable refractive index. 15 The waveguides to be coupled are hollow waveguides H1 and H3
, and the intermediate waveguide is also a hollow waveguide H2, and the intermediate waveguide has a hole row L provided in a common partition wall.
2. A selective directional coupler according to claim 1, wherein the selective directional coupler is coupled to the waveguides H1, H3 by means of L1, L2. 16. The selective directional coupler according to claim 15, wherein the waveguide and intermediate waveguide to be coupled are rectangular intermediate waveguides. 17. Selective directional coupling according to claim 15, wherein the intermediate waveguide H2 is provided with a dielectric insert along the entire coupler, which at least partially fills the cross section of the intermediate waveguide. vessel.
JP3316282A 1981-03-07 1982-03-04 Selectively dirctional connector Granted JPS57161706A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19813108742 DE3108742C2 (en) 1981-03-07 1981-03-07 Selective directional coupler

Publications (2)

Publication Number Publication Date
JPS57161706A JPS57161706A (en) 1982-10-05
JPH0522209B2 true JPH0522209B2 (en) 1993-03-26

Family

ID=6126627

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3316282A Granted JPS57161706A (en) 1981-03-07 1982-03-04 Selectively dirctional connector

Country Status (5)

Country Link
JP (1) JPS57161706A (en)
CA (1) CA1185333A (en)
DE (1) DE3108742C2 (en)
FR (1) FR2501383B1 (en)
GB (1) GB2096790B (en)

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Also Published As

Publication number Publication date
GB2096790A (en) 1982-10-20
GB2096790B (en) 1984-08-01
FR2501383B1 (en) 1986-04-04
DE3108742C2 (en) 1985-11-14
JPS57161706A (en) 1982-10-05
CA1185333A (en) 1985-04-09
FR2501383A1 (en) 1982-09-10
DE3108742A1 (en) 1982-09-23

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