JPH0114565B2 - - Google Patents
Info
- Publication number
- JPH0114565B2 JPH0114565B2 JP57132954A JP13295482A JPH0114565B2 JP H0114565 B2 JPH0114565 B2 JP H0114565B2 JP 57132954 A JP57132954 A JP 57132954A JP 13295482 A JP13295482 A JP 13295482A JP H0114565 B2 JPH0114565 B2 JP H0114565B2
- Authority
- JP
- Japan
- Prior art keywords
- modulation
- optical
- light
- gate
- frequency
- 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
Links
- 230000003287 optical effect Effects 0.000 claims description 147
- 238000000034 method Methods 0.000 claims description 31
- 238000002834 transmittance Methods 0.000 claims description 4
- 239000013078 crystal Substances 0.000 description 13
- 230000005540 biological transmission Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Description
【発明の詳細な説明】
本発明は光ゲート用変調方法及びこの変調方法
を適用した光ゲートに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a modulation method for an optical gate and an optical gate to which this modulation method is applied.
光信号の短時間ゲート（光スイツチ）として、
従来一般的には電気光学変調器或いは音響光学変
調器が用いられている。これら変調器を使用する
場合には、これらのゲート幅と同程度の変調用電
気パルス或いは音響パルスが必要となるが、この
ようなパルス幅がnsからpsと短かくかつデユーテ
イ比の小さい電気或いは音響パルスを得ることは
困難若しくは不可能である。これがためこのよう
に短い光ゲートを得ることは難しい。 As a short-time gate (optical switch) for optical signals,
Conventionally, electro-optic modulators or acousto-optic modulators have been generally used. When using these modulators, modulation electrical pulses or acoustic pulses with the same width as these gate widths are required. Obtaining acoustic pulses is difficult or impossible. This makes it difficult to obtain such short optical gates.
他方、最近アメリカにおいて、電気光学効果を
用いて短時間光ゲートを可能とならしめる二つの
理論的方式が提案された。 On the other hand, two theoretical methods have recently been proposed in the United States that make short-term optical gates possible using electro-optic effects.
第一の方式は米国のベル研究所のE.A.J.
Marcatiliが提案した「導波形光方向性結合器に
よる短光パルスゲート」（Applied Optics vol.19
p1468〜1476（1980））である。この第一の方式で
は、光ゲートを、第１図に示すように、電気光学
結晶１の表面附近に２本の光導波路２，３を平行
に設け、これら光導波路上に電極４，５をそれぞ
れ設け、これら電極間に、高周波電源６から高周
波電圧を印加できるように構成している。この場
合、２つの導波路２，３間には弱い結合があり、
また電界無印加時には両導波路の光伝搬速度もほ
ぼ等しくなつている。また導波路長Ｌを選定して
この電界無印加時には一方の導波路２に入射した
光ビームP1が光ゲートの出力部では導波路３に
ほぼ完全に移行し光ビームP3として出力するよ
うになつている。この光ゲートの電極間に電圧を
印加すると、２つの導波路２，３の光伝搬定数に
差異が生じ、このため導波路１から２への光ビー
ムの移行は減少若しくは消滅する。従つて、電極
４，５間に高周波電圧を印加すると、電圧の小さ
な瞬間（１週期に２度生ずる）のみ導波路１より
２へと光ビームの移行が生じることとなるので、
この光ゲートの導波路２に入射した光ビームP1
は電圧の小さい瞬間には導波路３に移行して光ビ
ームP3として出力し、他の時間では移行が起ら
ず、従つて原導波路２から光ビームP4、光信号
P3の補信号として出力し、従つてこの光ゲート
は短時間光ゲートとして作用することができる。
尚、P1，P3，P4のそばにこれら光ビームの強度
を略図的に示してある。 The first method is EAJ of Bell Laboratories in the United States.
"Short optical pulse gate using waveguide optical directional coupler" proposed by Marcatili (Applied Optics vol.19)
p1468-1476 (1980)). In this first method, as shown in FIG. 1, the optical gate is provided with two parallel optical waveguides 2 and 3 near the surface of an electro-optic crystal 1, and electrodes 4 and 5 are placed on these optical waveguides. The configuration is such that a high frequency voltage can be applied between these electrodes from a high frequency power source 6. In this case, there is a weak coupling between the two waveguides 2 and 3,
Furthermore, when no electric field is applied, the light propagation speeds in both waveguides are approximately equal. In addition, the waveguide length L is selected so that when no electric field is applied, the light beam P1 incident on one waveguide 2 almost completely transfers to the waveguide 3 at the output section of the optical gate and is output as the light beam P3 . It's getting old. When a voltage is applied between the electrodes of this optical gate, a difference occurs in the light propagation constants of the two waveguides 2 and 3, so that the transition of the light beam from waveguide 1 to waveguide 2 is reduced or eliminated. Therefore, when a high-frequency voltage is applied between the electrodes 4 and 5, the light beam shifts from waveguide 1 to waveguide 2 only at moments when the voltage is small (occurs twice a week).
The light beam P 1 incident on the waveguide 2 of this optical gate
transfers to the waveguide 3 and outputs it as the optical beam P 3 at the moment when the voltage is small, and no transfer occurs at other times, so that the optical beam P 4 and the optical signal are transferred from the original waveguide 2.
It outputs as a complementary signal of P 3 and thus this light gate can act as a light gate for a short time.
The intensities of these light beams are schematically shown near P 1 , P 3 , and P 4 .
しかしながら、この第一方式による光ゲートで
は、μｍサイズの導波構造が原理的に必要となる
ため、光損傷の観点から高パワーの光を取扱えな
い他、高度な製作技術が要求されるという欠点が
ある。さらにこの第一方式の光ゲートでは高速動
作に不可決な駆動電気信号と光の速度との整合を
とることが困難であるため実際には実現されてい
ない。 However, the optical gate using this first method requires a μm-sized waveguide structure in principle, so it cannot handle high-power light from the viewpoint of optical damage and requires advanced manufacturing technology. There are drawbacks. Furthermore, this first type of optical gate has not been actually realized because it is difficult to match the driving electric signal, which is essential for high-speed operation, with the speed of light.
第二の方式は米国のマサチユセツツ工科大学の
H.A.Haus等が提案した「変調周波数の異なる光
変調器の直列多段接続を利用した光ゲート」
（IEEE Journal of Quantum Electronic vol.1、
QE−16、p870〜873.（1980））である。 The second method is from Masachi University of Technology in the United States.
"Optical gate using series multi-stage connection of optical modulators with different modulation frequencies" proposed by HAHaus et al.
(IEEE Journal of Quantum Electronic vol.1,
QE-16, p870-873. (1980)).
この第二方式による光ゲートはそれぞれほぼ等
しい変調振幅を有しているが、変調周波数が2N-1
ω0（但しＮ＝１、２、３……）というように順次
に倍、倍と異なる光強度変調器を多段に直列に配
置して成るものである。この第二方式の光ゲート
の作用について説明する。 The optical gates according to the second method each have approximately the same modulation amplitude, but the modulation frequency is 2 N-1.
It is constructed by arranging multiple stages of different light intensity modulators in series such as ω 0 (where N=1, 2, 3, . . . ), which are sequentially doubled and doubled. The operation of this second type of optical gate will be explained.
今、変調以外に損失のない電気光学変調器では
２偏波間或いは２つの光波間の光学位相差をθ
（ｔ）とすると、光透過強度Ｔ（ｔ）は
Ｔ（ｔ）＝cos2θ（ｔ）／２（又はsin2θ（ｔ）／２）
(1)
θ（ｔ）＝θ0＋Δθsin（2πft） (2)
で表わせる。ここにおいて、θ0はバイアス位相で
あり、Δθは変調位相振幅、ｆは変調周波数であ
り、ｔは時間である。今、θ0＝０（又はπの整数
倍）と設定すると、(1)式は
Ｔ（ｔ）＝cos2（Δθ（ｔ）／２sin（2πft）） (3)
となる。ここにおいて、さらにΔθ＝π（ラジア
ン）とし、ｆ＝2p-1・f0（ｐ＝１、２、……Ｍ；f0
＝基本変調周波数）とすると、(3)式より
Tp（ｔ）＝cos2（π／２sin（2pπf0t）） (4)
（ｐ＝１、……、Ｍ）
となる。この(4)式において、ｐ＝１、２及び３と
した３つの電気光学変調器をこの順序で直列に配
置した場合のそれぞれの電気光学変調器自身の光
透過強度すなわち変調特性T1,2,3（ｔ）と、最終段
から出力される光の合成光透過強度すなわち合成
変調特性Ttpt（ｔ）とをそれぞれ第２図ａ〜ｄに
示す。第２図ａは１段目の変調特性T1（ｔ）＝
cos2（π／２sin2πf0t）を示しその変調周波数はf0で
あり、第２図ｂは２段目の変調特性T2（ｔ）＝
cos2（π／２sin4πf0t）を示しその変調周波数は2f0で
あり、第２図Ｃは３段目の変調特性T3（ｔ）＝
cos2（π／２sin8πf0t）を示しその変調周波数は4f0で
ある。そして第２図ｄは１、２、３段の合成変調
特性Ttpt（ｔ）＝T1（ｔ）・T2（ｔ）・T3（ｔ）を表わ
しており、これらの説明及び第３図ａ〜ｄから明
らかなように、この光ゲート最終出力は、t0、
t1、t2、t3……の時刻に最大ピークを有する幅狭
のパルス状出力となる。従つて、このような電気
光学変調器を順次にＭ段（但しｐ＝１、２、……
Ｍ）直列に配置した場合には、Ｍ段の透過光ゲー
トの周期は最も長い周期を有する第１段目の変調
器（ｐ＝１）によつて定まりその周期は１／2f0とな
り、透過ゲートの幅は最も高速の変調器（ｐ＝
Ｍ）で定まり、それは約１／３×2Mf0となる。その
結果、一般の構成では得ることができないような
デユーテイ比の小さいパルス光ゲートを得ること
が可能となる。 Now, in an electro-optic modulator that has no loss other than modulation, the optical phase difference between two polarized waves or two light waves is θ.
(t), the light transmission intensity T(t) is T(t) = cos 2 θ(t)/2 (or sin 2 θ(t)/2)
(1) It can be expressed as θ(t)=θ 0 +Δθsin(2πft) (2) Here, θ 0 is the bias phase, Δθ is the modulation phase amplitude, f is the modulation frequency, and t is the time. Now, if θ 0 =0 (or an integral multiple of π), equation (1) becomes T(t)=cos 2 (Δθ(t)/2sin(2πft)) (3). Here, we further set Δθ=π (radian), and f=2 p-1・f 0 (p=1, 2,...M; f 0
= basic modulation frequency), then from equation (3), Tp(t)=cos 2 (π/2sin(2 p πf 0 t)) (4) (p=1, . . . , M). In this equation (4), when three electro-optic modulators with p=1, 2, and 3 are arranged in series in this order, the light transmission intensity of each electro-optic modulator itself, that is, the modulation characteristic T 1,2 ,3 (t) and the combined light transmission intensity of the light output from the final stage, that is, the combined modulation characteristic T tpt (t), are shown in FIGS. 2a to 2d, respectively. Figure 2a shows the first stage modulation characteristic T 1 (t)=
cos 2 (π/2sin2πf 0 t), and its modulation frequency is f 0 , and Fig. 2b shows the second stage modulation characteristic T 2 (t) =
cos 2 (π/2sin4πf 0 t), and its modulation frequency is 2f 0 , and Figure 2C shows the third stage modulation characteristic T 3 (t)=
cos 2 (π/2sin8πf 0 t), and its modulation frequency is 4f 0 . Figure 2 d shows the composite modulation characteristics T tpt (t) = T 1 (t)・T 2 (t)・T 3 (t) for the 1st, 2nd, and 3rd stages, and these explanations and the third As is clear from figures a to d, the final output of this optical gate is t 0 ,
A narrow pulse-like output having maximum peaks at times t 1 , t 2 , t 3 . . . Therefore, such electro-optic modulators are sequentially arranged in M stages (where p=1, 2, . . .
M) When arranged in series, the period of the M stage transmitted light gate is determined by the first stage modulator (p = 1) which has the longest period, and the period is 1/2f 0 , The gate width is determined by the fastest modulator (p=
M), which is approximately 1/3×2 M f 0 . As a result, it becomes possible to obtain a pulsed light gate with a small duty ratio that cannot be obtained with a general configuration.
この第二方式による光ゲートでは電気光学結晶
に導波構造を形成するか否かは本質的な問題では
ないので、第一方式による光ゲートにおいて問題
とされた光パワーの制限及び製作上の困難さはそ
れ程重要ではないが、各段の変調器毎にそれぞれ
異なる周波数の変調駆動電源を個別に用意しなけ
ればならないという重大な欠点がある。さらに、
変調の大きさ（(3)式のΔθ）をπ程度以上に大き
くすると、ゲート波形が崩れてしまうので、この
Δθをそのように大きく選定できず、従つてゲー
ト幅を短かくするためには高い周波数（2M-1f0）
で駆動される変調器が必要となる。例えば、1ps
の光ゲートを得るためには、167GHzで作動する
変調器が必要となる。しかしながら、変調器を高
周波数で駆動するための変調駆動電源の入手は極
めて困難であり、変調器の電気回路的な困難な問
題（例えば電極間浮遊容量）も生じ、さらには前
述したと同様に速度整合も非常に困難となる。こ
の第二方式のゲートもこのような欠点を有するた
め未だ実用化に至つていない。 In the second type of optical gate, it is not an essential issue whether or not to form a waveguide structure in the electro-optic crystal, so the optical power limitation and manufacturing difficulties that were problems in the first type of optical gate are not essential. Although the frequency is not so important, there is a serious drawback in that modulation drive power supplies with different frequencies must be individually prepared for each stage of modulators. moreover,
If the magnitude of modulation (Δθ in equation (3)) is increased beyond about π, the gate waveform will collapse, so this Δθ cannot be selected so large. Therefore, in order to shorten the gate width, High frequency (2 M-1 f 0 )
A modulator driven by For example, 1ps
To obtain an optical gate of , a modulator operating at 167 GHz is required. However, it is extremely difficult to obtain a modulation drive power source to drive the modulator at a high frequency, and difficult problems with the electrical circuit of the modulator (for example, stray capacitance between electrodes) arise, and furthermore, as mentioned above, Speed matching also becomes very difficult. This second type of gate also has these drawbacks, so it has not yet been put into practical use.
本発明の目的は上述した従来提案されている光
ゲート変調方式とは全く異なる方式の光ゲート変
調方法を提供することにある。 An object of the present invention is to provide an optical gate modulation method that is completely different from the conventionally proposed optical gate modulation methods described above.
さらに本発明の目的は、光ゲートを入手が容易
な単一の変調駆動電源を利用して簡単な構成とし
得る光ゲート変調方法を提供することにある。 A further object of the present invention is to provide an optical gate modulation method that allows the optical gate to have a simple configuration by using a single modulation drive power source that is easily available.
さらに本発明の目的は大きなパワーの光を取扱
つたり集積小形化を図ること等の適応性に優れる
と共にピコ秒（10-12秒）にまで及ぶ超高速動作
が可能な高速光ゲートを得ることができるように
した光ゲート変調方法を提供することにある。 A further object of the present invention is to obtain a high-speed optical gate that has excellent adaptability such as handling high-power light and achieving miniaturization, and is capable of ultra-high-speed operation up to picoseconds (10 -12 seconds). An object of the present invention is to provide an optical gate modulation method that enables the following.
本発明のさらに他の目的は光ゲートの総合変調
透過波形を多様に制御できる光ゲート変調方法を
提供することにある。 Still another object of the present invention is to provide an optical gate modulation method that can control the overall modulated transmission waveform of the optical gate in various ways.
本発明のさらに他の目的はこの光ゲート変調方
法を適用した光ゲートを提供することにある。 Still another object of the present invention is to provide an optical gate to which this optical gate modulation method is applied.
これらの目的を達成するために、本発明光ゲー
ト変調方法は、光透過度を光ビーム断面内で一様
に制御する光強度変調器を複数段順次に係合させ
て光路中に配置した光ゲートの入射光ビームを強
度変調するにあたり、各段の前記光強度変調器を
共通の変調電圧源からの高周波変調電圧により同
一変調周波数にて駆動するとともに、変調位相振
幅、変調バイアス位相および変調高周波位相の各
変調因子のうち少なくとも一つの変調因子をそれ
ぞれ異ならせて各段の前記光強度変調器に互いに
異なる変調特性をそれぞれ与えることを特徴とす
る。 In order to achieve these objectives, the optical gate modulation method of the present invention involves sequentially engaging multiple stages of light intensity modulators that uniformly control the light transmittance within the cross section of the light beam, thereby controlling the light gate modulation method. To intensity-modulate the light beam incident on the gate, the light intensity modulators in each stage are driven at the same modulation frequency by a high-frequency modulation voltage from a common modulation voltage source, and the modulation phase amplitude, modulation bias phase, and modulation high frequency are The present invention is characterized in that at least one modulation factor among the phase modulation factors is made different to give different modulation characteristics to the light intensity modulators in each stage.
また、本発明光ゲート変調方法の好適例は、各
段の前記光強度変調器における変調バイアス位相
をすべて０またはπ（ラジアン）の整数倍とする
とともに、ｊ＝１、２、……、Ｎとしたｊ番目の
前記光強度変調器における変調位相振幅をπ×
2j-1（ラジアン）にほぼ等しく設定することを特
徴とする。 Further, in a preferable example of the optical gate modulation method of the present invention, the modulation bias phase in the optical intensity modulator of each stage is all 0 or an integral multiple of π (radian), and j=1, 2, ..., N The modulation phase amplitude in the j-th optical intensity modulator is π×
2 j-1 (radians).
さらに上述の目的を達成するために、本発明光
ゲートは、順次に係合させて光路中に配置すると
ともに互いに異なる変調特性をそれぞれ与えた光
透過度を光ビーム断面内で一様にそれぞれ制御す
る複数段の光強度変調器と、それらの光強度変調
器を同一変調周波数にて共通に駆動する高周波変
調電圧を発生させる単一の変調電圧源とを備え、
前記高周波変調電圧における変調位相振幅、変調
バイヤス位相および変調高周波位相の各変調因子
のうち少なくとも一つの変調因子をそれぞれ異な
らせることにより、前記複数段の光強度変調器に
それぞれ与える変調特性を互いに異ならせるよう
に構成したことを特徴とする。 Furthermore, in order to achieve the above-mentioned object, the light gates of the present invention are sequentially engaged and disposed in the optical path, and the light transmittances of the light gates each having different modulation characteristics are controlled uniformly within the cross section of the light beam. A single modulation voltage source that generates a high frequency modulation voltage that commonly drives the optical intensity modulators at the same modulation frequency,
By making at least one of the modulation factors of modulation phase amplitude, modulation bias phase, and modulation high frequency phase different in the high frequency modulation voltage, the modulation characteristics given to each of the plurality of stages of optical intensity modulators can be made different from each other. It is characterized by being configured so that it can be
以下、図面につき本発明の実施例につき説明す
る。 Embodiments of the present invention will be described below with reference to the drawings.
先ず、本発明の原理から説明する。 First, the principle of the present invention will be explained.
今、複数例の光強度変調器がＮ個光路中に順次
に直列に配置されていて光ゲートが構成されてい
るとする。ｊ番目一段の光強度変調器の各変調因
子、すなわちバイアス位相をθ0jとし、変調位相
振幅をΔθjとし、変調高周波位相をαjとすると、
ｊ番目の光強度変調器の光透過強度Tj（ｔ）は(3)
式より
Tj（ｔ）＝cos2〔θ0j＋Δθj・sin（2πft＋
αj）／２〕(5)
（但しｊ＝１、２、……Ｎとする）
となる。この(5)式の右辺の〔 〕の中がπ（ラジ
アン）の整数倍（０を含む）となる時間ｔの近傍
でTj（ｔ）〜１となり、透過強度にピークが現わ
れる。このピークの幅すなわちゲート幅は変調位
相振幅Δθjが大きい程短かくなるが、これと同時
に一周期中に現われるピークの数も増加してしま
い、従つて一段のみの光強度変調器では良質の短
時間ゲートは得られない。 Now, it is assumed that a plurality of N light intensity modulators are sequentially arranged in series in an optical path to form an optical gate. If each modulation factor of the j-th first-stage optical intensity modulator, that is, the bias phase, is θ 0j , the modulation phase amplitude is Δθ j , and the modulation high frequency phase is α j ,
The light transmission intensity T j (t) of the j-th light intensity modulator is (3)
From the formula, T j (t) = cos 2 [θ 0j + Δθ j・sin (2πft+
α j )/2](5) (However, j=1, 2,...N). In the vicinity of time t when the value in brackets on the right side of equation (5) becomes an integral multiple (including 0) of π (radians), T j (t) becomes 1, and a peak appears in the transmitted intensity. The width of this peak, that is, the gate width, becomes shorter as the modulation phase amplitude Δθ j becomes larger, but at the same time, the number of peaks that appear in one cycle also increases. Gates are not available for a short period of time.
一方、変調特性すなわち光透過強度Tj（ｔ）の
異なる光強度変調器を例えばＮ個直列に光路中に
配置した光ゲートの全体の光透過強度Ttpt（ｔ）
は
Ttpt（ｔ）＝T1（ｔ）×T2（ｔ）×……TN（ｔ） (6)
で与えられる。従つて、光強度変調器の各々に対
し共通の同一の駆動変調周波数を与えても、変調
因子である変調位相振幅Δθj、変調バイアス位相
θ0j、変調高周波位相αjを各光強度変調器のそれ
ぞれに対し個別的に適当に選定することによつ
て、これら光強度変調器に対しそれぞれ異なる変
調特性を与え、これら変調特性の合成によつて光
ゲートから短時間光ゲート波形やその他種々の形
状の光ゲート波形のような単体の光強度変調器で
は得られない変調特性、変調波形を得ることがで
きる。 On the other hand, the total light transmission intensity T tpt (t) of an optical gate in which, for example, N light intensity modulators having different modulation characteristics, that is, light transmission intensity T j (t) are arranged in series in the optical path.
is given by T tpt (t)=T 1 (t)×T 2 (t)×...T N (t) (6). Therefore, even if the same common driving modulation frequency is given to each of the optical intensity modulators, the modulation factors, such as the modulation phase amplitude Δθ j , modulation bias phase θ 0j , and modulation high frequency phase α j , are different from each optical intensity modulator. By individually and appropriately selecting each of these, different modulation characteristics are given to these optical intensity modulators, and by combining these modulation characteristics, it is possible to generate short-time optical gate waveforms from optical gates and other various types. Modulation characteristics and modulation waveforms such as shaped optical gate waveforms that cannot be obtained with a single optical intensity modulator can be obtained.
本発明はこのような原理に基づくものであり、
全ての光強度変調器に対し単一の周波数駆動源か
ら同一の比較的低い変調周波数を共通に与えると
共に各光強度変調器毎にそれぞれの変調因子を適
当に選定し、よつて光ゲート全体の合成のすなわ
ち総合変調特性を所要のものとするようになして
いる。尚、前述の変調周波数は全ての光強度変調
器に対し共通に変えることもできる。 The present invention is based on such a principle,
The same relatively low modulation frequency is commonly applied to all optical intensity modulators from a single frequency driving source, and each modulation factor is appropriately selected for each optical intensity modulator. The synthesis, that is, the overall modulation characteristics are made as required. Note that the above-mentioned modulation frequency can also be changed commonly for all optical intensity modulators.
第３図は本発明による光ゲート変調方法による
変調特性の計算に基づく一例を示す線図であつ
て、縦軸に透過光強度T1（ｔ）、T2（ｔ）、T3
（ｔ）、Ttpt（ｔ）を夫々とり、横軸にｆ・ｔをそ
れぞれとつている。この場合には光ゲートを３段
構成とし、各段の光強度変調器の変調特性すなわ
ち光透過強度Tj（ｔ）（但しｊ＝１、２、３）の
波形と、総合変調特性すなわち総合透過強度Ttpt
（ｔ）＝T1（ｔ）×T2（ｔ）×T3（ｔ）波形を順次に
第３図ａ〜ｄに示してある。尚、この場合、バイ
アス位相θ0j＝０及び変調高周波位相αj＝０と選
定しかつ変調位相振幅Δθj＝π×2j-1（ｊ＝１、
２、３）としている。この第３図に示す計算例か
ら、この３段構成の光ゲートのゲート幅は一周期
の３〜４％程度と非常に短かくなり、このことか
らデユーテイ比の小さな光パルスゲートが得られ
ることがわかる。 FIG. 3 is a diagram showing an example based on calculation of modulation characteristics by the optical gate modulation method according to the present invention, in which the vertical axis represents transmitted light intensities T 1 (t), T 2 (t), T 3
(t) and T tpt (t), respectively, and f and t are respectively plotted on the horizontal axis. In this case, the optical gate is configured in three stages, and the modulation characteristics of the optical intensity modulator of each stage, that is, the waveform of the light transmission intensity T j (t) (where j = 1, 2, 3), and the overall modulation characteristic, that is, the overall Transmission intensity T tpt
(t)=T 1 (t)×T 2 (t)×T 3 (t) The waveforms are sequentially shown in FIGS. 3a to 3d. In this case, the bias phase θ 0j =0 and the modulation high frequency phase α j =0 are selected, and the modulation phase amplitude Δθ j =π×2 j-1 (j=1,
2, 3). From the calculation example shown in Fig. 3, the gate width of this three-stage optical gate is very short, about 3 to 4% of one period, and from this, an optical pulse gate with a small duty ratio can be obtained. I understand.
次に第４図を参照して本発明の変調方法を適用
した光ゲートの基本的構成につき説明する。 Next, the basic structure of an optical gate to which the modulation method of the present invention is applied will be explained with reference to FIG.
第４図において、１０−１〜１０−Ｎは光ゲー
トを構成するため光路中に順次に直列に配置させ
たＮ（Ｎ２）個の光強度変調器であり、これら
変調器を個別の変調用結晶を用いて或いは１個の
共通の結晶に個別的に形成してもよい。この光ゲ
ートの一段目の変調器１０−１の左側から入射し
た入射光１３をＮ段日の右側から出射するように
なしている。尚、１４は出射光を示す。１２は変
調駆動電源で最大でも数十ＧHz程度の周波数であ
り、この駆動電源で個々の変調器１０−１〜１０
−Ｎを全て同一の変調周波数で駆動する。そして
前述した様に各段の変調器の変調特性は異ならし
め、そのため変調因子すなわち変調バイアス位
相、変調位相振幅及び変調高周波位相を変調器毎
にそれぞれ設定している。この変調バイアス位相
は光の位相であり例えば既知の内部的、外部的な
光学的又は電気光学的手段により設定できる。ま
た変調位相振幅を変化させるには、例えば、各段
へ供給する変調器電力若しくは電圧を調整する方
法の他、各段の変調電極の長さを変えること等に
より、各段の変調感度を変化させる方法及びこれ
ら方法を組合わせる方法等がある。また変調高周
波位相を変化させるには、例えば、高周波位相シ
フタを変調高周波駆動電源と各変調器間に設けた
り各変調器間の高周波線路長とか光路長とかを調
整して高周波位相シフタの代用とすることもでき
る。そこで第４図に示す基本構成例では、変調器
の各段に対する変調バイアス位相及び各段に対す
る印加電力若しくは電圧或いは各段の変調感度を
光ゲート全体の総合変調特性が所要の特性となる
ように種々の値に設定されており、各段の変調器
１０−１〜１０−Ｎと駆動電源１２との間にそれ
ぞれ対応する高周波位相シフタ１５−１，１５−
２，１５−３，……，１５−（Ｎ−１），１５−Ｎ
を設け、この位相シフタによつて各変調器毎に光
及び変調用高周波の走行時間の差によつて生ずる
変調タイミングのずれを個別的に補正したり、或
いは、この変調タイミングを積極的にずらすよう
にして光ゲートのゲート波形を所要の波形に制御
するようになしている。 In Fig. 4, 10-1 to 10-N are N (N2) light intensity modulators arranged in series in the optical path to form an optical gate, and these modulators are used for individual modulation. They may be formed individually using crystals or in one common crystal. The incident light 13 entering from the left side of the first stage modulator 10-1 of this optical gate is emitted from the right side of the Nth stage modulator 10-1. Note that 14 indicates the emitted light. Reference numeral 12 denotes a modulation drive power source, which has a frequency of several tens of GHz at most, and uses this drive power source to operate the individual modulators 10-1 to 10.
-N are all driven at the same modulation frequency. As described above, the modulation characteristics of the modulators at each stage are different, and therefore the modulation factors, that is, the modulation bias phase, modulation phase amplitude, and modulation high frequency phase are set for each modulator. This modulation bias phase is an optical phase and can be set, for example, by known internal or external optical or electro-optic means. To change the modulation phase amplitude, for example, in addition to adjusting the modulator power or voltage supplied to each stage, the modulation sensitivity of each stage can be changed by changing the length of the modulation electrode in each stage. There are methods to do this, methods to combine these methods, etc. In addition, in order to change the modulation high frequency phase, for example, a high frequency phase shifter can be installed between the modulation high frequency drive power source and each modulator, or the high frequency line length or optical path length between each modulator can be adjusted to replace the high frequency phase shifter. You can also. Therefore, in the basic configuration example shown in Fig. 4, the modulation bias phase for each stage of the modulator, the applied power or voltage for each stage, or the modulation sensitivity of each stage are set so that the overall modulation characteristics of the entire optical gate have the required characteristics. High frequency phase shifters 15-1 and 15- are set to various values and correspond to each other between the modulators 10-1 to 10-N of each stage and the drive power source 12.
2,15-3,...,15-(N-1),15-N
This phase shifter can be used to individually correct the deviation in the modulation timing caused by the difference in the transit time of the light and the modulation high frequency wave for each modulator, or to actively shift the modulation timing. In this way, the gate waveform of the optical gate is controlled to a required waveform.
上述した第４図の基本構成例からもわかる様
に、光ゲートを構成するところの光路中に順次に
直列に配置された各段の光強度変調器の変調位相
振幅、変調バイアス位相及び変調高周波位相を任
意に選定して異ならしめて各段の変調器の変調特
性を異ならしめ、よつて光ゲート全体の総合変調
特性（変調波形も含む）を多様に選択できるとと
なる。 As can be seen from the basic configuration example shown in FIG. 4 mentioned above, the modulation phase amplitude, modulation bias phase, and modulation high frequency of each stage of optical intensity modulators arranged sequentially in series in the optical path constituting the optical gate. By arbitrarily selecting and making the phases different, the modulation characteristics of the modulators at each stage are made to differ, and thus the overall modulation characteristics (including the modulation waveform) of the entire optical gate can be selected in a variety of ways.
次に第５図及び第６図を用いて本発明光ゲート
及びその変調方法の具体例につき説明する。尚、
いずれの実施例も光強度変調器を３段とした場合
につき説明する。 Next, a specific example of the optical gate of the present invention and its modulation method will be explained using FIGS. 5 and 6. still,
In each of the embodiments, a case will be described in which the optical intensity modulator is provided in three stages.
第５図に示す光ゲートの実施例では、特定の光
導波路を設けておらず、１個の電気光学結晶２０
の一方の表面上に予定の光路に対応させてそれぞ
れ光路に沿う方向の長さの異なる第１、第２及び
第３変調電極２１，２２，２３を設けると共に、
他方の表面上に共通電極２４を設けて、光路中に
順次に配置された３個の変調感度のそれぞれ異な
る光強度変調器を形成する。これら各変調器に変
調用高調波電圧を与えるため、変調駆動電源２５
を第１変調電極２１と共通電極２４との間に接続
し、さらに第１及び第２変調電極２１及び２２
間、及び第２及び第３変調電極２２及び２３間を
それぞれ高周波線路２６及び２７で接続し、さら
にこの第３変調電極を無反射終端２８を終て共通
電極２４に接続し、よつて電源２５に対しこれら
各電極２１，２２，２３が直列に接続するように
なしている。これら高周波線路２６及び２７の長
さを適当に選定し高周波電圧の伝搬時間や位相の
調整を行ない、光の伝搬に合わせて光と同期させ
ることができるようにする。２９は変調バイアス
位相を変化させるため、電気光学結晶２０の一方
の表面上の、光路に対応する個所に所要に応じて
設けた変調バイアス調整用電極（図中斜線を施し
て示す）であり、この電極２９と共通電極２４と
の間に接続した電源３０からの電圧を調整して光
のバイアス位相を調整できるようになしている。
図中、３１，３２，３３は検光子、３４，３５は
プリズム又は反射鏡等の光学素子である。 In the embodiment of the optical gate shown in FIG. 5, no specific optical waveguide is provided, and only one electro-optic crystal 20
First, second, and third modulation electrodes 21, 22, and 23 having different lengths in the direction along the optical path are provided on one surface of the substrate in correspondence with the planned optical path, and
A common electrode 24 is provided on the other surface to form three light intensity modulators having different modulation sensitivities arranged sequentially in the optical path. In order to provide modulation harmonic voltages to each of these modulators, a modulation drive power supply 25
is connected between the first modulation electrode 21 and the common electrode 24, and the first and second modulation electrodes 21 and 22
and the second and third modulation electrodes 22 and 23 are connected by high-frequency lines 26 and 27, respectively, and the third modulation electrode is connected to the common electrode 24 through the non-reflection termination 28, and thus the power source 25 In contrast, these electrodes 21, 22, and 23 are connected in series. By appropriately selecting the lengths of these high frequency lines 26 and 27 and adjusting the propagation time and phase of the high frequency voltage, it is possible to synchronize with the light according to the propagation of the light. Reference numeral 29 denotes a modulation bias adjustment electrode (shown with diagonal lines in the figure) provided as required at a location corresponding to the optical path on one surface of the electro-optic crystal 20 in order to change the modulation bias phase; By adjusting the voltage from a power source 30 connected between this electrode 29 and the common electrode 24, the bias phase of the light can be adjusted.
In the figure, 31, 32, and 33 are analyzers, and 34, 35 are optical elements such as prisms or reflecting mirrors.
この光ゲートでは入射光３６は図中破線で示す
光路を経て出射光３７として出力される。すなわ
ち入射光３６は第１変調電極２１及び検光子３１
を通じて光強度変調され、次に反射鏡（又はプリ
ズム）３４で反射され、次に第２変調電極２２及
び検光子３２で再度光変調され、続いて再度反射
鏡（又はプリズム）３５で反射された後第３変調
電極２３及び検光子３３で再度光強度変調を受け
て所要の総合変調特性を有する出射光３７として
出力される。この際、所要に応じて電極２９を介
し光のバイアス位相を調整する。４段以上の多段
の場合には、段数に対応した数の変調電極や光学
素子をそれぞれ設けてやればよい。尚、これらの
各電極及び光学素子の配置は設定すべき光路に応
じて任意所望に選定し得る。又、出射光３７の一
部を検出し、その信号を変調バイアス調整用の電
源３０にフイードバツクさせて変調バイアス位相
の制御の温度安定化を図ることもできる。 In this optical gate, incident light 36 is outputted as outgoing light 37 through an optical path indicated by a broken line in the figure. That is, the incident light 36 is transmitted to the first modulating electrode 21 and the analyzer 31.
The light intensity is modulated through the reflector (or prism) 34, the light is modulated again by the second modulation electrode 22 and the analyzer 32, and then reflected again by the reflector (or prism) 35. The light is then subjected to light intensity modulation again by the third modulation electrode 23 and the analyzer 33, and is output as emitted light 37 having the required overall modulation characteristics. At this time, the bias phase of the light is adjusted via the electrode 29 as required. In the case of multiple stages of four or more stages, modulation electrodes and optical elements may be provided in numbers corresponding to the number of stages. Note that the arrangement of each of these electrodes and optical elements can be arbitrarily selected depending on the optical path to be set. It is also possible to detect a part of the emitted light 37 and feed the signal back to the modulation bias adjustment power supply 30 to stabilize the temperature of the modulation bias phase control.
第６図は本発明の光ゲートの他の具体的実施例
を示し、この場合には電気光学結晶４０に所望の
パターンで光導波路４１を設け、この光導波路４
１の、形成されるべき変調器に対応した部分に所
要の電極４２−１，４２−２；４３−１，４３−
２，４４−１，４４−２（図中斜線を施して示
す）を夫々設けて第１、第２及び第３バランスド
ブリツジ形光強度変調器４２，４３及び４４を形
成している。尚、この光導波路に対する電極の位
置は所要に応じ選べばよい。勿論、これら電極の
組はそれぞれ各変調器の設定すべき変調感度に応
じた異なる長さを有している。また図示例では変
調駆動電源４５をそれぞれの変調電極４２−１，
４２−２；４３−１，４３−２；４４−１，４４
−２に対し高周波位相シフタ４６，４７及び４８
を設けて光と変調駆動電圧との同期を行なつてい
る。尚、この高周波位相シフタを用いる代わりに
第５図に示すように各電極間を高周波線路で接続
してもよい。この光ゲートの場合には、入射光４
９は光導波路４１に沿つて実線矢印で示すように
各変調器４２，４３，４４経て進みそれぞれ光強
度変調を受けて所望の総合変調特性（変調波形を
含む）の出射光５０として出力される。 FIG. 6 shows another specific embodiment of the optical gate of the present invention. In this case, an electro-optic crystal 40 is provided with an optical waveguide 41 in a desired pattern.
1, required electrodes 42-1, 42-2; 43-1, 43- in the portion corresponding to the modulator to be formed.
2, 44-1, and 44-2 (shown with diagonal lines in the figure) are provided to form first, second, and third balanced bridge type optical intensity modulators 42, 43, and 44, respectively. Note that the position of the electrode relative to this optical waveguide may be selected as required. Of course, each of these electrode sets has a different length depending on the modulation sensitivity to be set for each modulator. Further, in the illustrated example, the modulation drive power source 45 is connected to each modulation electrode 42-1,
42-2; 43-1, 43-2; 44-1, 44
-2 for high frequency phase shifters 46, 47 and 48
is provided to synchronize the light and the modulated drive voltage. Incidentally, instead of using this high frequency phase shifter, each electrode may be connected with a high frequency line as shown in FIG. In the case of this light gate, the incident light 4
9 passes through each modulator 42, 43, and 44 along the optical waveguide 41 as shown by solid arrows, receives light intensity modulation, and is output as an output light 50 having a desired overall modulation characteristic (including modulation waveform). .
尚、上述した電気光学結晶や電極材料は従来か
ら電気光学変調器に使用されている結晶や材料を
使用でき、又結晶上への電極の設け方は蒸着、堆
積、貼付けその他一般的方法で行ない得る。さら
に各変調器毎に電気光学結晶を個別的に使用して
もよいし又各変調器を共通の１個の電気光学結晶
に集積化してもよく、後者の場合には光ゲートを
小形化し得ると共に温度特性の安定化を図ること
ができる。 As the electro-optic crystal and electrode material mentioned above, crystals and materials conventionally used in electro-optic modulators can be used, and electrodes can be provided on the crystal by vapor deposition, deposition, pasting, or other general methods. obtain. Furthermore, an electro-optic crystal may be used individually for each modulator, or each modulator may be integrated into a common electro-optic crystal, and in the latter case, the optical gate can be made smaller. At the same time, the temperature characteristics can be stabilized.
又、本発明においては変調周波数駆動電源とし
て１つの電源（マスター）若しくはそれによつて
完全に制御される複数個の同一周波数の電源（ス
レーブ）を用いてもよい。 Further, in the present invention, a single power supply (master) or a plurality of power supplies having the same frequency (slaves) completely controlled by the power supply may be used as the modulation frequency drive power supply.
次に上述した本発明による光ゲート変調方法及
び光ゲートの効果につき説明する。 Next, the effect of the optical gate modulation method and optical gate according to the present invention described above will be explained.
本発明によれば、各光強度変調器に対し共通の
同一の変調周波数を供給するため、入手容易な比
較的低い周波数の唯１個の変調駆動電源を使用で
きることとなり、これがため光ゲートを安価な小
形かつ簡便な構成となし得ると共に各段の光強度
変調器の同期は、位相調整が必要となるが、自動
的に行なうことができる。 According to the present invention, since a common and identical modulation frequency is supplied to each optical intensity modulator, it is possible to use only one modulation drive power source with a relatively low frequency that is easily available, which makes the optical gate inexpensive. The structure can be small and simple, and the synchronization of the optical intensity modulators at each stage can be performed automatically, although phase adjustment is required.
さらに本発明によれば、それぞれ相異なる変調
特性を有する光強度変調器を光路に直列に配置し
ている。従つて、光ゲートの総合変調特性の選択
の幅を広げることができ、よつて所要に応じて多
様に変調波形を制御したり、光二重パルスを発生
させたり、光パルス整形等を行なうことができ
る。さらに、デユーテイ比の小さいピコ秒に及ぶ
短時間光ゲートを得ることができ、さらには単体
の光強度変調器では得られない変調特性や変調波
形を得ることができる。 Further, according to the present invention, optical intensity modulators each having different modulation characteristics are arranged in series in the optical path. Therefore, the range of selection of the overall modulation characteristics of the optical gate can be expanded, and it is therefore possible to control the modulation waveform in various ways, generate optical double pulses, perform optical pulse shaping, etc. as required. can. Furthermore, it is possible to obtain a short-time optical gate of picosecond duration with a small duty ratio, and furthermore, it is possible to obtain modulation characteristics and modulation waveforms that cannot be obtained with a single optical intensity modulator.
さらに、本発明によれば従来提案されているよ
うな超高周波の変調周波数を使用しないので、電
極間容量や光走行効果に起因する不所望な問題が
生じないため、光強度変調器の構成が簡単かつ容
易となる。 Furthermore, according to the present invention, since the ultra-high modulation frequency that has been proposed in the past is not used, undesirable problems caused by interelectrode capacitance and optical transport effects do not occur, and the configuration of the optical intensity modulator is simplified. It becomes simple and easy.
さらに、本発明によれば光信号に対し光導波路
を設ける必然性は全くないので（但し小形化のた
の光導波路を設けることは可能である）、光損傷
の問題の生ずるおそれがなく高パワーの光を取扱
えると共に、高度な製作技術が必要とならず、光
ゲートを容易かつ安価に製造することができる。 Furthermore, according to the present invention, there is no necessity to provide an optical waveguide for optical signals (although it is possible to provide an optical waveguide for miniaturization), so there is no risk of optical damage and high power In addition to being able to handle light, it does not require sophisticated manufacturing technology, and the optical gate can be manufactured easily and at low cost.
本発明により、大出力より小出力までの光信号
の短時間で高速度ゲートを簡便に達成でき、さら
に短光パルス、光クロツクパルス等を発生させた
り、また光信号をピコ秒の時間精度でゲート制御
（サンプリング検出）することが可能となり、従
つて通信、計測、光情報処理、加工、光技術研究
等の多方面で利用できる。 According to the present invention, it is possible to easily achieve high-speed gating of optical signals from high output to small output in a short time, and also to generate short optical pulses, optical clock pulses, etc., and to gate optical signals with picosecond time precision. It becomes possible to control (sampling detection), and therefore, it can be used in many fields such as communication, measurement, optical information processing, processing, and optical technology research.
さらに本発明の適用例としては高速光ゲート、
短光パルス発生器、光サンプリングオツシロスコ
ープ、光波形観測器、光パルス計測器、その他等
がある。 Furthermore, examples of application of the present invention include high-speed optical gates,
There are short optical pulse generators, optical sampling oscilloscopes, optical waveform observation instruments, optical pulse measuring instruments, and others.
第１図は従来提案された光ゲート変調方法の説
明に供する線図、第２図は従来提案された他の光
ゲート変調方法の説明に供する線図、第３図は本
発明の光ゲート変調方法及び光ゲートの原理を説
明するための線図、第４図は本発明による光ゲー
ト変調方法及び光ゲートの基本的構成例を説明す
るための線図、第５図及び第６図は本発明による
光ゲートの具体的実施例をそれぞれ示す線図であ
る。
１０−１〜１０−Ｎ，４２，４３，４４……光
強度変調器、１２，２５，４８……変調周波数駆
動電源、１３，３６，４９……入射光、１４，３
７，５０……出射光、１５−１〜１５−Ｎ，４
６，４７，４８……高周波位相シフタ、２０，４
０……電気光学結晶、２１，２２，２３，４２−
１，４２−２，４３−１，４３−２，４４−１，
４４−２……変調電極、２４……共通電極、２
６，２７……高周波線路、２８……無反射終端、
２９……変調バイアス調整用電極、３０……電
源、３１，３２，３３……検光子、３４，３５…
…プリズム又は反射鏡、４１……光導波路。
FIG. 1 is a diagram for explaining a conventionally proposed optical gate modulation method, FIG. 2 is a diagram for explaining another conventionally proposed optical gate modulation method, and FIG. 3 is a diagram for explaining the optical gate modulation method of the present invention. A diagram for explaining the method and the principle of the optical gate, FIG. 4 is a diagram for explaining the optical gate modulation method according to the present invention and a basic configuration example of the optical gate, and FIGS. FIG. 3 is a diagram illustrating a specific embodiment of a light gate according to the invention; 10-1 to 10-N, 42, 43, 44... Light intensity modulator, 12, 25, 48... Modulation frequency drive power supply, 13, 36, 49... Incident light, 14, 3
7,50...Emission light, 15-1 to 15-N, 4
6, 47, 48...high frequency phase shifter, 20, 4
0...Electro-optic crystal, 21,22,23,42-
1, 42-2, 43-1, 43-2, 44-1,
44-2...Modulation electrode, 24...Common electrode, 2
6, 27...High frequency line, 28...Reflection free termination,
29... Modulation bias adjustment electrode, 30... Power supply, 31, 32, 33... Analyzer, 34, 35...
...prism or reflecting mirror, 41...optical waveguide.
Claims (1)
光強度変調器を複数段順次に係合させて光路中に
配置した光ゲートの入射光ビームを強度変調する
にあたり、各段の前記光強度変調器を共通の変調
電圧源からの高周波変調電圧により同一変調周波
数にて駆動するとともに、変調位相振幅、変調バ
イアス位相および変調高周波位相の各変調因子の
うち少なくとも一つの変調因子をそれぞれ異なら
せて各段の前記光強度変調器に互いに異なる変調
特性をそれぞれ与えることを特徴とする光ゲート
変調方法。 ２ 各段の前記光強度変調器における変調バイア
ス位相をすべて０またはπ（ラジアン）の整数倍
とするとともに、ｊ＝１、２、……、Ｎとしたｊ
番目の前記光強度変調器における変調位相振幅を
π×2j-1（ラジアン）にほぼ等しく設定すること
を特徴とする特許請求の範囲第１項記載の光ゲー
ト変調方法。 ３ 順次に係合させて光路中に配置するとともに
互いに異なる変調特性をそれぞれ与えた光透過度
を光ビーム断面内で一様にそれぞれ制御する複数
段の光強度変調器と、それらの光強度変調器を同
一変調周波数にて共通に駆動する高周波変調電圧
を発生させる単一の変調電圧源とを備え、前記高
周波変調電圧における変調位相振幅、変調バイヤ
ス位相および変調高周波位相の各変調因子のうち
少なくとも一つの変調因子をそれぞれ異ならせる
ことにより、前記複数段の光強度変調器にそれぞ
れ与える変調特性を互いに異ならせるように構成
したことを特徴とする光ゲート。[Claims] 1. In intensity modulating an incident light beam of a light gate placed in an optical path by sequentially engaging a plurality of stages of light intensity modulators that control the light transmittance uniformly within the cross section of the light beam. , the optical intensity modulators in each stage are driven at the same modulation frequency by a high-frequency modulation voltage from a common modulation voltage source, and at least one of the modulation factors of modulation phase amplitude, modulation bias phase, and modulation high-frequency phase is driven. An optical gate modulation method, characterized in that modulation factors are made different to give mutually different modulation characteristics to the optical intensity modulators in each stage. 2 The modulation bias phase in the optical intensity modulator at each stage is all 0 or an integral multiple of π (radian), and j = 1, 2, ..., N.
2. The optical gate modulation method according to claim 1, wherein the modulation phase amplitude in the th optical intensity modulator is set approximately equal to π×2 j−1 (radians). 3. Multiple stages of light intensity modulators that are sequentially engaged and arranged in the optical path, each giving different modulation characteristics, and controlling the light transmittance uniformly within the cross section of the light beam, and their light intensity modulation. a single modulation voltage source that generates a high-frequency modulation voltage that commonly drives the devices at the same modulation frequency; An optical gate characterized in that the modulation characteristics provided to each of the plurality of stages of optical intensity modulators are made to differ from each other by making one modulation factor different from each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13295482A JPS5924827A (en) | 1982-07-31 | 1982-07-31 | Optical gate modulating method and optical gate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13295482A JPS5924827A (en) | 1982-07-31 | 1982-07-31 | Optical gate modulating method and optical gate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5924827A JPS5924827A (en) | 1984-02-08 |
| JPH0114565B2 true JPH0114565B2 (en) | 1989-03-13 |
Family
ID=15093377
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13295482A Granted JPS5924827A (en) | 1982-07-31 | 1982-07-31 | Optical gate modulating method and optical gate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5924827A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6326619A (en) * | 1986-07-21 | 1988-02-04 | Oki Electric Ind Co Ltd | Waveguide type optical wavelength filter |
| JP5173153B2 (en) * | 2006-06-14 | 2013-03-27 | 日本電信電話株式会社 | Electro-optic element |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS497017A (en) * | 1972-05-09 | 1974-01-22 |
-
1982
- 1982-07-31 JP JP13295482A patent/JPS5924827A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS497017A (en) * | 1972-05-09 | 1974-01-22 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5924827A (en) | 1984-02-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4505587A (en) | Picosecond optical sampling | |
| US5339183A (en) | Optical signal transmission device | |
| JP2603437B2 (en) | Periodic domain inversion electro-optic modulator | |
| US5033826A (en) | High temporal resolution optical instrument | |
| US20050213863A1 (en) | Optical modulator | |
| US8737773B2 (en) | Optical control element | |
| CA2088330C (en) | Optical pulse generator | |
| EP0078454A2 (en) | Interferometric multimode fiber optic switch and modulator | |
| US5111326A (en) | Integrated Kerr shutter and fiber laser optical modulation | |
| US6717708B2 (en) | Re-circulating optical pulse generator | |
| US4372643A (en) | Standing-wave, velocity-matched gate | |
| US4381139A (en) | Velocity mismatched modulator | |
| US6643051B1 (en) | Method and system for generating return-to-zero signals | |
| CN115144841A (en) | Large-bandwidth linear frequency modulation signal generation device and method | |
| JPH0114565B2 (en) | ||
| JPH0375848B2 (en) | ||
| CN112019276A (en) | Grouped mode-hopping time domain modulation method and Fourier mode-locked laser | |
| JPH0375847B2 (en) | ||
| JP2006126759A (en) | Light modulator | |
| EP1640788A1 (en) | Method of driving Mach-Zehnder light modulator and light modulating device | |
| JPH02170142A (en) | Waveguide type optical control device and driving method thereof | |
| JPH0593891A (en) | Waveguide type optical modulator and its driving method | |
| US6798558B2 (en) | Optical clock multiplier and method thereof | |
| JP2003228033A (en) | Optical modulator | |
| JPH0814664B2 (en) | Light modulator |