JPS6360432A - Waveguide light phase modulator - Google Patents
Waveguide light phase modulatorInfo
- Publication number
- JPS6360432A JPS6360432A JP20268586A JP20268586A JPS6360432A JP S6360432 A JPS6360432 A JP S6360432A JP 20268586 A JP20268586 A JP 20268586A JP 20268586 A JP20268586 A JP 20268586A JP S6360432 A JPS6360432 A JP S6360432A
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- phase
- waveguide
- phase modulator
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- phases
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- 230000005684 electric field Effects 0.000 abstract description 5
- 230000007257 malfunction Effects 0.000 abstract description 3
- 239000002131 composite material Substances 0.000 abstract 1
- 230000000644 propagated effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
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- 238000003786 synthesis reaction Methods 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
〔概 要〕
本発明は、プッシュプル形の導波路光変調器において、
誤動作のない正確な位相変調を可能にするため、各導波
路中の光の位相が互いに同じ大きさでかつ逆符号となる
ような電圧であって、出力光の位相(上記の各位相の合
成位相)が反転するところの前後の電圧で駆動するよう
にしたことにより、上記出力光を2つの位相状態間で不
連続に変化させ、その間の中途半端な状態を除去できる
ようにしたものである。[Detailed Description of the Invention] [Summary] The present invention provides a push-pull type waveguide optical modulator that includes:
In order to enable accurate phase modulation without malfunction, a voltage is applied so that the phases of the light in each waveguide have the same magnitude and opposite signs, and the phase of the output light (synthesis of the above phases) is applied. By driving with voltages before and after the point where the phase) is reversed, the output light can be changed discontinuously between the two phase states, and the half-finished state in between can be removed. .
本発明は、プッシュプル形の導波路光変調器を利用して
位相変調を行なう導波路光位相変調器に関する。The present invention relates to a waveguide optical phase modulator that performs phase modulation using a push-pull type waveguide optical modulator.
従来の導波路光位相変調器の構成を第6図に示す。この
位相変調器は、直線導波路部1を挟んだ両側に1対の電
極2.3を設けた構成である。位相変調は、電極2.3
間に所定の電圧を印加して直線導波路部1に電界をかけ
、電気光学効果により屈折率を変化させることで、出力
光にrOJと「π」の2値の位相変化を与えることによ
って行っている。The configuration of a conventional waveguide optical phase modulator is shown in FIG. This phase modulator has a configuration in which a pair of electrodes 2.3 are provided on both sides of the linear waveguide section 1. Phase modulation is performed using electrodes 2.3
This is done by applying a predetermined voltage between them to apply an electric field to the linear waveguide section 1, changing the refractive index by the electro-optic effect, and giving the output light a binary phase change of rOJ and "π". ing.
上記従来の位相変調器では、上記出力光の位相がそれぞ
れ「0」、「π」となるために必要な電圧を■。(=0
)、Vルとすれば、第4図(C1に示すように電圧を■
。から■□まで変化さ、せると、直線導波路部lの屈折
率は印加される電圧の大きさに応じて連続的に変化する
ので、出力光の位相も「O」から「π」まで連続的に変
化してしまう。In the conventional phase modulator described above, the voltage required for the phase of the output light to be "0" and "π", respectively, is . (=0
), V le, as shown in Figure 4 (C1), the voltage is
. When the refractive index of the linear waveguide section l changes continuously according to the magnitude of the applied voltage, the phase of the output light also changes continuously from "O" to "π". It changes.
すなわち、位相情報としてはrOJと「π」だけが必要
であるにもかかわらず、その間の中途半端な位相までも
が含まれてしまう。このように出力光に中途半端な位相
情報が含まれると、情報の読取り時の判断に誤りが生じ
、間違った情報が伝えられてしまう。In other words, even though only rOJ and "π" are required as phase information, even intermediate phases between them are included. If the output light contains half-finished phase information in this way, errors will occur in the judgment when reading information, and incorrect information will be transmitted.
本発明は、上記問題点に鑑み、中途半端な位相状態を除
去し、誤動作のない正確な位相変調を可能にする導波路
光位相変調器を提供することを目的とする。SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a waveguide optical phase modulator that eliminates half-finished phase states and enables accurate phase modulation without malfunction.
本発明の導波路光位相変調器は、2つのY分岐導波路部
間に2本の直線導波路部を備え、これらの直線導波路部
のそれぞれに対して電極部を設けたプッシュプル形の導
波路光変調器を利用したものであって、上記の各直線導
波路部中の光の位相が互いに同じ大きさでかつ逆符号と
なるような電圧であって、上記各位相の合成位相が反転
するところの前後の電圧を、上記電極部に対して印加す
るようにしたことを特徴としている。The waveguide optical phase modulator of the present invention is a push-pull type optical phase modulator having two straight waveguide sections between two Y-branch waveguide sections, and an electrode section provided for each of these straight waveguide sections. A waveguide optical modulator is used, and the voltage is such that the phases of the light in each of the linear waveguide sections have the same magnitude and opposite signs, and the combined phase of the above phases is It is characterized in that voltages before and after the point of inversion are applied to the electrode portion.
上述したプッシュプル形の導波路光変調器において、上
記電極部に電圧を印加すれば、上記2つの直線導波路部
内には互いに逆方向の電界が生じる。このような電界の
変化に応じて、上記直線導波路部中の光の位相も互いに
逆方向に変化する。In the push-pull waveguide optical modulator described above, when a voltage is applied to the electrode section, electric fields in opposite directions are generated within the two straight waveguide sections. In accordance with such changes in the electric field, the phases of the lights in the linear waveguide section also change in opposite directions.
そこで、この点を考慮し、上記光の位相が互いに同じ大
きさでかつ逆符号となるような電圧を印加すれば、出力
光の位相(上記各位相のベクトル的に合成された位相)
は、例えばrOJと「π」のいずれか一方の状態にしか
ならない。その上、更に、上記出力光の位相が例えばr
OJと「π」の間で互いに反転するところの前後の電圧
(例えばVo 、 Vc )に上記印加電圧を設定すれ
ば、例えば■。から■1に(もしくはVcからV。に)
上記印加電圧を連続して変化させた場合であっても、出
力光の位相は例えばrOJと「π」の間で不連続に切換
り、確実に2値化された位相情報が送り出される。Therefore, considering this point, if voltages are applied such that the phases of the above-mentioned lights have the same magnitude and opposite signs, the phase of the output light (the phase that is vectorially combined of the above-mentioned phases)
For example, only one of rOJ and "π" can exist. Furthermore, the phase of the output light is, for example, r
For example, if the applied voltage is set to a voltage before and after inversion between OJ and "π" (for example, Vo, Vc), then, for example, ■. to ■1 (or from Vc to V.)
Even when the applied voltage is continuously changed, the phase of the output light is discontinuously switched between, for example, rOJ and "π", and binarized phase information is reliably sent out.
以下、本発明の実施例について、図面を参照しながら説
明する。Embodiments of the present invention will be described below with reference to the drawings.
第1図は、本発明の一実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
本実施例は、2つのY分岐導波路部11.12間に、互
いに等しい長さおよび幅を持つ2本の直線導波路部13
.14を備えるとともに、これらの直線導波路部13.
14上にそれぞれ電極15.16を配置したプッシュプ
ル形の構成である。更に、Y分岐導波路部11.12に
は、その中央付近から分岐側に向って徐々に広くなるよ
うに延びた、各導波路よりも幅が狭くかつ低屈折率の切
り込み領域11a、12aを設けたものである。上記の
各導波路部11〜14は、例えば電気光学結晶であるL
iNb0.のZ板でできた基板10に対し、マスクパタ
ーンを介してTi等を拡散させ−て形成する。In this embodiment, two straight waveguide sections 13 having the same length and width are provided between two Y-branch waveguide sections 11 and 12.
.. 14, and these straight waveguide sections 13.
It has a push-pull configuration with electrodes 15 and 16 arranged on each of the electrodes 14 and 14, respectively. Furthermore, the Y-branch waveguide section 11.12 has cut regions 11a and 12a having a narrower width and lower refractive index than each waveguide, which extend gradually from near the center toward the branch side. It was established. Each of the waveguide sections 11 to 14 described above is made of an electro-optic crystal, for example.
iNb0. A substrate 10 made of a Z plate is formed by diffusing Ti or the like through a mask pattern.
上記プッシュプル形の構成において、電極15.16間
に電圧を印加した場合、直線導波路部13.14内には
、互いに逆方向でかつ大きさの等しい電界が生じる。す
るとこれに応じて、直線導波路部13.14中を伝搬す
る光の位相も、互いに逆符号でかつ同じ大きさとなる。In the push-pull configuration described above, when a voltage is applied between the electrodes 15.16, electric fields of equal magnitude and opposite directions are generated within the straight waveguide section 13.14. Accordingly, the phases of the lights propagating in the straight waveguide sections 13 and 14 also have opposite signs and the same magnitude.
そのため、出力光の位相(すなわち、Y分岐導波路部1
2でベクトル的に合成されて出力された光の位相)は、
「O」と「π」のいずれか1つの状態だけを持ち、中途
半端な位相状態は存在しない。Therefore, the phase of the output light (i.e., Y-branch waveguide section 1
2) is the phase of the light vectorially synthesized and outputted.
It has only one state, "O" or "π", and there is no intermediate phase state.
本実施例では、これらの点を考慮して、第4図falに
示すように、上記出力光の位相が「O」と「π」の間で
互いに反転するところの電圧V、を挟んだ前後の電圧で
あって、しかも最大光出力の得られる2つの電圧■。(
=O)、Vxを設定し、これら2つの電圧■。、VTt
の一方を適宜選択して、電極15.16間に印加するこ
とにより、「O」、「π」の2値の位相情報を送り出す
ようにしている。In this embodiment, taking these points into consideration, as shown in FIG. Two voltages ■ that provide the maximum light output. (
=O), set Vx, and these two voltages■. ,VTt
By appropriately selecting one of these and applying it between the electrodes 15 and 16, binary phase information of "O" and "π" is sent out.
このような電圧■。とV2とを用いて変調するようにし
たことにより、電圧をvoからV&まで(V Nからv
oまで)連続して変化させても、出力光の位相には上述
したようなroJと「π」以外の中途半端な状態が含ま
れず、「O」と「π」との間で不連続に位相を切換える
ことができる。■ Such voltage. By modulating the voltage using
Even if the phase of the output light is changed continuously (up to o), the phase of the output light does not include any intermediate states other than roJ and "π" as described above, and it is discontinuous between "O" and "π". The phase can be switched.
しかも、位相が反転するところ(すなわち電圧が■3と
なったところ)では、光出力がゼロとなるので、−層好
都合である。Furthermore, the optical output becomes zero where the phase is reversed (that is, where the voltage becomes 3), which is advantageous for the negative layer.
また本実施例では、第1図に示したように、Y分岐導波
路部11.12に切り込み領域11a、12aを設けた
ことにより、低損失化をも可能にしている。従来のY分
岐導波路では、分岐時の損失を低減するために、理想的
には第5図に点線で示すように分岐角を非常に小さく
(1°以下)しなければならないが、その製造のための
極めて細いマスクパターンを形成すること等が困難なた
め、実際上は同図に実線で示すように角のとれた形状と
なってしまい、低損失化が実現されていなかった。そこ
で本実施例のように切り込み領域11a、12aを設け
ることにより、従来のような極めて細いマスクパターン
を必要とせず、はぼ設計どおりのY分岐が作成できるよ
うになった。そのため、光の分岐が上記切り込み領域1
1a、12aに沿って徐々に行われるようになり、よっ
て分岐時の低損失化が可能になった。このように低損失
化が実現された位相変調器は、コヒーレント光通信にも
使用できる。Furthermore, in this embodiment, as shown in FIG. 1, cut regions 11a and 12a are provided in the Y-branch waveguide portions 11 and 12, thereby making it possible to reduce the loss. In conventional Y-branch waveguides, in order to reduce loss during branching, ideally the branching angle is very small, as shown by the dotted line in Figure 5.
(1° or less), but because it is difficult to form an extremely thin mask pattern for manufacturing, in practice the shape ends up with rounded corners, as shown by the solid line in the figure. , low loss had not been achieved. Therefore, by providing the cut regions 11a and 12a as in this embodiment, it is possible to create a Y-branch as designed without requiring an extremely thin mask pattern as in the conventional method. Therefore, the branching of the light is caused by the above cut area 1.
1a and 12a, thereby making it possible to reduce the loss at the time of branching. A phase modulator that has achieved low loss in this way can also be used for coherent optical communications.
次に、第2図は本発明の他の実施例を示す構成図である
。Next, FIG. 2 is a block diagram showing another embodiment of the present invention.
本実施例は、第1図における互いに等しい長さの直線導
波路部13.14の代わりに、互いに異なる長さの直線
導波路部23.24を設けたものである。このように互
いの長さを変えることにより光学バイアスがかかり、よ
って第4図(b)に示すように電圧■。(≠O)、V=
cで駆動することができる。本実施例でも上記実施例と
同様に、「o」と「π」の2値化された位相情報を送り
出すことができ、中途半端な位相を除去することができ
るとともに、切り込み領域11a、12aにより低損失
化も可能になる。なお、上記直線導波路部23.24の
ように互いの長さを変える代わりに、それらの幅を変え
ることによって光学バイアスをかけるようにしてもよい
。In this embodiment, straight waveguide sections 23.24 of mutually different lengths are provided in place of the straight waveguide sections 13.14 of mutually equal length in FIG. By changing the lengths of each other in this way, an optical bias is applied, resulting in a voltage of 2 as shown in FIG. 4(b). (≠O), V=
It can be driven by c. In this embodiment, as in the above embodiment, it is possible to send out binarized phase information of "o" and "π", and it is possible to remove half-finished phases. It also becomes possible to reduce loss. Note that instead of changing the lengths of each of the linear waveguide sections 23 and 24, the optical bias may be applied by changing their widths.
第3図は、本発明の更に他の実施例を示す構成図である
。本実施例は、基板10′がLtNboxのX板または
Y板からなり、第1図における電極15.16の代わり
に、直線導波路部13.14をそれぞれ両側から挟むよ
うに一対の電極25a、25b;26a、26bを設け
てプッシュプル形の構成としたものである。このような
電極構成においては、一方の電極25a、25b間と他
方の電極26a、26b間とに、互いに逆方向で大きさ
きの等しい電圧であって、出力光を「O」と「π」の2
つの位相状態に切換え得る電圧を印加して、上記各実施
例と同様に駆動すればよい。この場合、一対の電極25
a、25b間及び26a、26b間の各距離を、上述し
た電極15.16間の距離よりも小さくできるので、よ
り低電圧による駆動が可能となる。FIG. 3 is a configuration diagram showing still another embodiment of the present invention. In this embodiment, the substrate 10' consists of an X plate or a Y plate of LtN box, and instead of the electrodes 15 and 16 in FIG. 25b; 26a and 26b are provided to form a push-pull configuration. In such an electrode configuration, voltages of equal magnitude and in opposite directions are applied between one electrode 25a and 25b and the other electrode 26a and 26b, and the output light is divided into "O" and "π". 2
It is sufficient to apply a voltage capable of switching between two phase states and drive in the same manner as in each of the above embodiments. In this case, a pair of electrodes 25
Since each distance between a and 25b and between 26a and 26b can be made smaller than the distance between the electrodes 15 and 16 described above, driving with a lower voltage is possible.
本発明の導波路光位相変調器によれば、中途半端な位相
状態を含まない、確実に2値化された位相情報を送り出
すことができるので、情報の読取り時の判断に誤りを生
じることがなくなり、従って非常に正確な位相変調が実
現できる。According to the waveguide optical phase modulator of the present invention, it is possible to reliably send out binarized phase information that does not include any half-finished phase states, so errors in judgment when reading information can be avoided. Therefore, very accurate phase modulation can be achieved.
第1図は本発明の一実施例を示す構成図、第2図は本発
明の他の実施例を示す構成図、第3図は本発明の更に他
の実施例を示す構成図、第4図(at、 (b)、 (
c)はそれぞれ、本発明の一実施例、他の実施例、従来
例における位相変調出力を示す図、
第5図は従来のY分岐導波路を示す構成図、第6図は従
来の導波路光位相変調器を示す構成図である。
11.12・・・Y分岐導波路部、
11a、12a・・・切り込み領域、
13.14・・・直線導波路部、
15.16・・・電極、
23.24・・・直線導波路部、
25a、25bH26a、26b−=電極。
慰tPメ【施シfす
(b)
(C)
イ立イ1弓償−調は1力
第4図
忙禾LylY骨該棒漢跨
第5図
イA〔−リミ/l*三バξJン5−りτLイユ乙才4コ
を咽]呑第6図FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, FIG. 3 is a block diagram showing still another embodiment of the present invention, and FIG. Figure (at, (b), (
c) is a diagram showing the phase modulation output in one embodiment of the present invention, another embodiment, and a conventional example, respectively. FIG. 5 is a configuration diagram showing a conventional Y-branch waveguide, and FIG. 6 is a diagram showing a conventional waveguide. FIG. 2 is a configuration diagram showing an optical phase modulator. 11.12...Y branch waveguide section, 11a, 12a...notch region, 13.14...straight waveguide section, 15.16...electrode, 23.24...straight waveguide section , 25a, 25bH26a, 26b-=electrode. Comfort tP me [use shi fsu (b) (C) I stand A 1 bow redemption - key is 1 force 4 figure busy LylY bone this stick kan straddle figure 5 A [-Rimi/l * 3 B ξ J Figure 6
Claims (1)
線導波路部(13、14;23、24)を備え、該2本
の直線導波路部のそれぞれに対して電極部(15、16
;25a、25b、26a、26b)を設けたプッシュ
プル形の導波路光変調器において、 前記各直線導波路中の光の位相が互いに同じ大きさでか
つ逆符号となるような電圧であって、前記各位相の合成
位相が反転するところの前後の電圧を、前記電極部に対
して印加するようにしたことを特徴とする導波路光位相
変調器。 2)前記Y分岐導波路部は、その中央付近から分岐側に
延びた、各導波路部よりも幅が狭くかつ低屈折率の切り
込み領域(11a、12a)を有することを特徴とする
特許請求の範囲第1項記載の導波路光位相変調器。 3)前記切り込み領域の幅は前記分岐側に向って徐々に
広くなることを特徴とする特許請求の範囲第2項記載の
導波路光位相変調器。 4)前記電極部は前記各直線導波路部上に配置されたそ
れぞれ1つの電極(15、16)からなることを特徴と
する特許請求の範囲第1項乃至第3項のいずれか1つに
記載の導波路光位相変調器。 5)前記電極部は前記各直線導波路部を両側から挟むよ
うに配置されたそれぞれ1対の電極(25a、25b;
26a、26b)からなることを特徴とする特許請求の
範囲第1項乃至第3項のいずれか1つに記載の導波路光
位相変調器。 6)前記合成位相は0とπとの間で互いに反転すること
を特徴とする特許請求の範囲第1項乃至第5項のいずれ
か1つに記載の導波路光位相変調器。 7)前記合成位相の反転するところの電圧で、光出力が
最小となることを特徴とする特許請求の範囲第1項乃至
第6項のいずれか1つに記載の導波路光位相変調器。[Claims] 1) Two straight waveguide parts (13, 14; 23, 24) are provided between two Y-branch waveguide parts (11, 12), and the two straight waveguide parts For each electrode part (15, 16
; 25a, 25b, 26a, 26b), the voltage is such that the phases of the light in each of the linear waveguides have the same magnitude and opposite signs; . A waveguide optical phase modulator, characterized in that voltages before and after the point where the combined phase of the respective phases is reversed are applied to the electrode portion. 2) A patent claim characterized in that the Y-branch waveguide section has a cut region (11a, 12a) having a narrower width and lower refractive index than each waveguide section, extending from the vicinity of the center toward the branch side. The waveguide optical phase modulator according to item 1. 3) The waveguide optical phase modulator according to claim 2, wherein the width of the cut region gradually increases toward the branching side. 4) According to any one of claims 1 to 3, wherein the electrode part consists of one electrode (15, 16) arranged on each of the straight waveguide parts. The described waveguide optical phase modulator. 5) The electrode portions each include a pair of electrodes (25a, 25b;
26a, 26b), the waveguide optical phase modulator according to any one of claims 1 to 3. 6) The waveguide optical phase modulator according to any one of claims 1 to 5, wherein the combined phases are mutually inverted between 0 and π. 7) The waveguide optical phase modulator according to any one of claims 1 to 6, wherein the optical output is minimized at a voltage at which the combined phase is inverted.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61202685A JPH07107585B2 (en) | 1986-08-30 | 1986-08-30 | Driving method for waveguide optical phase modulator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61202685A JPH07107585B2 (en) | 1986-08-30 | 1986-08-30 | Driving method for waveguide optical phase modulator |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6360432A true JPS6360432A (en) | 1988-03-16 |
JPH07107585B2 JPH07107585B2 (en) | 1995-11-15 |
Family
ID=16461458
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61202685A Expired - Lifetime JPH07107585B2 (en) | 1986-08-30 | 1986-08-30 | Driving method for waveguide optical phase modulator |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07107585B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02196212A (en) * | 1989-01-25 | 1990-08-02 | Fujitsu Ltd | Optical modulator |
JPH0375615A (en) * | 1989-08-18 | 1991-03-29 | Fujitsu Ltd | Phase shift keying system using zehnder type optical modulator |
JP2008542806A (en) * | 2005-05-25 | 2008-11-27 | フォトリヌ テクノロジー | Optical integrated circuit with an optical waveguide forming at least one optical isolation |
CN104471466A (en) * | 2012-07-26 | 2015-03-25 | 富士通光器件株式会社 | Optical modulator and optical transmitter |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55134818A (en) * | 1979-04-03 | 1980-10-21 | Thomson Csf | Luminuous intensity modulator |
JPS6028621A (en) * | 1983-07-27 | 1985-02-13 | Fujitsu Ltd | Optical modulator and optical frequency controller |
-
1986
- 1986-08-30 JP JP61202685A patent/JPH07107585B2/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55134818A (en) * | 1979-04-03 | 1980-10-21 | Thomson Csf | Luminuous intensity modulator |
JPS6028621A (en) * | 1983-07-27 | 1985-02-13 | Fujitsu Ltd | Optical modulator and optical frequency controller |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02196212A (en) * | 1989-01-25 | 1990-08-02 | Fujitsu Ltd | Optical modulator |
JPH0375615A (en) * | 1989-08-18 | 1991-03-29 | Fujitsu Ltd | Phase shift keying system using zehnder type optical modulator |
JP2008542806A (en) * | 2005-05-25 | 2008-11-27 | フォトリヌ テクノロジー | Optical integrated circuit with an optical waveguide forming at least one optical isolation |
CN104471466A (en) * | 2012-07-26 | 2015-03-25 | 富士通光器件株式会社 | Optical modulator and optical transmitter |
Also Published As
Publication number | Publication date |
---|---|
JPH07107585B2 (en) | 1995-11-15 |
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