JP7060474B2 - Optical modulators, optical transmitters, optical demodulators, optical receivers and optical communication systems - Google Patents

Optical modulators, optical transmitters, optical demodulators, optical receivers and optical communication systems Download PDF

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JP7060474B2
JP7060474B2 JP2018152914A JP2018152914A JP7060474B2 JP 7060474 B2 JP7060474 B2 JP 7060474B2 JP 2018152914 A JP2018152914 A JP 2018152914A JP 2018152914 A JP2018152914 A JP 2018152914A JP 7060474 B2 JP7060474 B2 JP 7060474B2
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昇太 石村
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  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
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Description

本発明は、光変復調技術に関する。 The present invention relates to a photomodulation / demodulation technique.

非特許文献１及び２は、偏波多重ＱＰＳＫ信号を生成する光変調器を開示している。図１は、非特許文献１及び２が開示する偏波多重ＱＰＳＫ信号を生成する光変調器の構成図である。Ｘ偏波の連続光は、分岐部５で分岐され、それぞれ、図２に示すＱＰＳＫ光変調部６に入力される。上側のＱＰＳＫ光変調部６は、データ列Ｘで連続光をＱＰＳＫ変調し、Ｘ偏波のＱＰＳＫ信号を合波部８に出力する。下側のＱＰＳＫ光変調部６は、データ列Ｙで連続光をＱＰＳＫ変調し、Ｘ偏波のＱＰＳＫ信号を偏波回転部７に出力する。偏波回転部７は、Ｘ偏波のＱＰＳＫ信号の偏波を回転させ、Ｘ偏波と直交するＹ偏波のＱＰＳＫ信号を合波部８に出力する。合波部８は、Ｘ偏波のＱＰＳＫ信号とＹ偏波のＱＰＳＫ信号を合波し、偏波多重ＱＰＳＫ信号を出力する。 Non-Patent Documents 1 and 2 disclose an optical modulator that produces a polarization-multiplexed QPSK signal. FIG. 1 is a configuration diagram of an optical modulator that generates a polarization-multiplexed QPSK signal disclosed in Non-Patent Documents 1 and 2. The X-polarized continuous light is branched at the branching section 5 and is input to the QPSK optical modulation section 6 shown in FIG. 2, respectively. The upper QPSK optical modulation unit 6 QPSK-modulates continuous light in the data string X, and outputs the X-polarized QPSK signal to the combine unit 8. The lower QPSK optical modulation unit 6 QPSK-modulates continuous light in the data string Y and outputs an X-polarized QPSK signal to the polarization rotating unit 7. The polarization rotating unit 7 rotates the polarization of the X-polarized QPSK signal, and outputs the Y-polarized QPSK signal orthogonal to the X-polarized wave to the combiner 8. The combined wave unit 8 combines the X-polarized QPSK signal and the Y-polarized QPSK signal, and outputs a polarized wave multiplex QPSK signal.

図２は、図１のＱＰＳＫ変調部６の構成図である。分岐部６０は、入力される連続光を２分岐して、それぞれ、分岐部６１Ｉ及び６１Ｑに出力する。分岐部６１Ｉは、入力される連続光を２分岐して、光位相調整部６２Ｉ及び６３Ｉに出力する。光位相調整部６２Ｉ及び６３Ｉには、データ列に応じた電圧（以下、バイアス）が印加される。光位相調整部６２Ｉ及び６３Ｉが出力する光の位相は、それぞれ、印加されるバイアスに応じて調整される。合波部６４Ｉは、光位相調整部６２Ｉ及び６３Ｉが出力する光を合波して出力する。ここで、ＱＰＳＫ変調部６は、光位相調整部６２Ｉ及び６３Ｉから出力される光の位相が、基準位相を中心に対称となる様に制御する。例えば、基準位相は、複素平面における実軸（Ｉ軸）の方向に対応する位相である。したがって、合波部６４Ｉが出力する合波光は、印加されるバイアスに応じて複素平面の実軸上を移動（振幅が変動）する信号になる。 FIG. 2 is a block diagram of the QPSK modulation unit 6 of FIG. The branching unit 60 branches the input continuous light into two and outputs the input continuous light to the branching units 61I and 61Q, respectively. The branching unit 61I branches the input continuous light into two and outputs the input continuous light to the optical phase adjusting units 62I and 63I. A voltage (hereinafter, bias) corresponding to the data string is applied to the optical phase adjusting units 62I and 63I. The phases of the light output by the optical phase adjusting units 62I and 63I are adjusted according to the applied bias, respectively. The combined wave unit 64I combines and outputs the light output by the optical phase adjusting units 62I and 63I. Here, the QPSK modulation unit 6 controls so that the phases of the light output from the optical phase adjusting units 62I and 63I are symmetrical with respect to the reference phase. For example, the reference phase is a phase corresponding to the direction of the real axis (I axis) in the complex plane. Therefore, the combined wave light output by the combined wave unit 64I becomes a signal that moves (amplitude fluctuates) on the real axis of the complex plane according to the applied bias.

分岐部６１Ｑ、光位相調整部６２Ｑ及び６３Ｑ並びに合波部６４Ｑでの処理も、分岐部６１Ｉ、光位相調整部６２Ｉ及び６３Ｉ並びに合波部６４Ｉでの上述した処理と同様である。したがって、合波部６４Ｑが出力する合波光は、印加されるバイアスに応じて複素平面の実軸上を移動する信号になる。合波部６４Ｑが出力する合波光は、位相調整部６５において、その位相が９０度回転される。したがって、位相調整部６５が出力する合波光は、印加されるバイアスに応じて複素平面の虚軸（Ｑ軸）上を移動する信号になる。合波部６６は、合波部６４Ｉが出力する合波光と、位相調整部６５が出力する合波光を合波する。したがって、光位相調整部６２Ｉ及び６３Ｉと、光位相調整部６２Ｑ及び６３Ｑに印加するバイアスをデータ列に応じて調整することで、合波部６６が出力する合波光は、ＱＰＳＫ信号になる。 The processing in the branch portion 61Q, the optical phase adjustment units 62Q and 63Q, and the combine unit 64Q is the same as the above-mentioned processing in the branch unit 61I, the optical phase adjustment units 62I and 63I, and the combine unit 64I. Therefore, the combined wave light output by the combined wave unit 64Q becomes a signal that moves on the real axis of the complex plane according to the applied bias. The phase of the combined wave light output by the combined wave unit 64Q is rotated by 90 degrees in the phase adjusting unit 65. Therefore, the combined wave light output by the phase adjusting unit 65 becomes a signal that moves on the imaginary axis (Q axis) of the complex plane according to the applied bias. The combine unit 66 combines the combined light output by the combined unit 64I and the combined light output by the phase adjusting unit 65. Therefore, by adjusting the bias applied to the optical phase adjusting units 62I and 63I and the optical phase adjusting units 62Q and 63Q according to the data string, the combined light output by the combined unit 66 becomes a QPSK signal.

Ｐ．Ｄｏｎｇ，ｅｔ ａｌ．，"１１２－Ｇｂ/ｓ ｍｏｎｏｌｉｔｈｉｃ ＰＤＭ－ＱＰＳＫ ｍｏｄｕｌａｔｏｒ ｉｎ ｓｉｌｉｃｏｎ"，Ｏｐｔ．Ｅｘｐｒｅｓｓ ２０，Ｂ６２４－Ｂ６２９，２０１２年P. Dong, et al. , "112-Gb / s monolithic PDM-QPSK modulator in silicon", Opt. Express 20, B624-B629, 2012 Ｅ．Ｙａｍａｄａ ｅｔ ａｌ．，"１１２－Ｇｂ/ｓ ＩｎＰ ＤＰ－ＱＰＳＫ Ｍｏｄｕｌａｔｏｒ Ｉｎｔｅｇｒａｔｅｄ ｗｉｔｈ ａ Ｓｉｌｉｃａ－ＰＬＣ Ｐｏｌａｒｉｚａｔｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎｇ Ｃｉｒｃｕｉｔ"，ｉｎ Ｎａｔｉｏｎａｌ Ｆｉｂｅｒ Ｏｐｔｉｃ Ｅｎｇｉｎｅｅｒｓ Ｃｏｎｆｅｒｅｎｃｅ，ＯＳＡ Ｔｅｃｈｎｉｃａｌ Ｄｉｇｅｓｔ（Ｏｐｔｉｃａl Ｓｏｃｉｅｔｙ ｏｆ Ａｍｅｒｉｃａ），ｐａｐｅｒ ＰＤＰ５Ａ．９，２０１２年E. Yamada et al. , "112-Gb / s InP DP-QPSK Modulator Integrated with a Silica-PLC Multiplexing Circuit", in National Fiber Optica Engine 9, 2012

しかしながら、非特許文献１及び２の構成は複雑であり、また、複数回の光の分岐や合波による損失が大きくなる。 However, the configurations of Non-Patent Documents 1 and 2 are complicated, and the loss due to a plurality of light branches and combined waves becomes large.

本発明は、簡易な構成で、偏波多重変調信号を処理する技術を提供するものである。 The present invention provides a technique for processing a polarization multiplex modulation signal with a simple configuration.

本発明の一態様によると、光変調器は、直線偏波である第１偏波の連続光の位相を第１データに基づく第１位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、前記第１変調光を円偏波の第２変調光に変換する変換手段と、前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を第２データに基づく第２位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、を備えていることを特徴とする。 According to one aspect of the present invention, the optical modulator modulates the phase of the continuous light of the first polarization, which is linear polarization, by the first phase manipulation amount based on the first data, and the first modulated light. The first modulation means for outputting the above, the conversion means for converting the first modulation light into the second modulation light of circular polarization, the component of the first polarization of the second modulation light, and the first polarization. Is a second modulation means that modulates the phases of the components of the second polarization orthogonal to each other so as to fluctuate in opposite directions by the amount of the second phase manipulation based on the second data, and outputs the third modulated light. It is characterized by having.

本発明によると、簡易な構成で、偏波多重変調信号を処理することができる。 According to the present invention, it is possible to process a polarization multiplex modulation signal with a simple configuration.

非特許文献に記載の光変調器の構成図。The block diagram of the optical modulator described in a non-patent document. 図１のＱＰＳＫ変調部の構成図。The block diagram of the QPSK modulation part of FIG. 一実施形態による光変調器の構成図。The block diagram of the optical modulator according to one Embodiment. 一実施形態による光変調器の各部が出力する変調信号の説明図。Explanatory drawing of the modulation signal output by each part of the optical modulator according to one Embodiment. 一実施形態による光復調器の構成図。The block diagram of the optical demodulator according to one Embodiment. 一実施形態による光変調器の構成図。The block diagram of the optical modulator according to one Embodiment.

以下、本発明の例示的な実施形態について図面を参照して説明する。なお、以下の実施形態は例示であり、本発明を実施形態の内容に限定するものではない。また、以下の各図においては、実施形態の説明に必要ではない構成要素については図から省略する。 Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples, and the present invention is not limited to the contents of the embodiments. Further, in each of the following figures, components not necessary for the description of the embodiment will be omitted from the drawings.

＜第一実施形態＞
図３は、本実施形態による光変調器の構成図である。なお、本実施形態では、Ｘ偏波とＹ偏波それぞれの変調方式をＱＰＳＫとする。つまり、Ｘ偏波とＹ偏波それぞれにおいて１シンボルで２ビットのデータを搬送するものとする。しかしながら、本発明は、ＰＳＫ、８ＰＳＫ等、他の多値度の変調方式に対しても同様に適用できる。光位相調整部１０には、Ｘ偏波の連続光が入力される。また、変換部１３には、データ列Ｘが入力される。変換部１３は、データ列Ｘの連続する２ビットの値に応じた位相操作量ＶＸを出力する。光位相調整部１０は、Ｘ偏波の連続光の位相を、位相操作量ＶＸだけ変化させ、Ｘ偏波の変調光３１を出力する。光位相調整部１０は、電気光学効果などを利用した位相変調器であり、例えば、図２の光位相調整部６２Ｉ等と同じ構成を使用することができる。例えば、位相操作量ＶＸが０の場合、Ｘ偏波の変調光３１が、図４（Ａ）の座標４１で示す信号になるものとする。この場合、位相操作量ＶＸを増加させると、Ｘ偏波の変調光３１の位相は、図４の点線で示す様な経路で変化する。なお、図４の黒丸は、データ列Ｘの連続する２ビットの値に対応するＱＰＳＫ信号のシンボルの位相を示している。Ｘ偏波の変調光３１の位相が、データ列の連続する２ビットの値に応じた図４（Ａ）の黒丸で示す位相となる様に、変換部３１が位相操作量ＶＸを決定することで、光位相調整部１０はＱＰＳＫ変調を行う。Ｘ偏波の変調光３１は、以下のジョーンズベクトルで表される。 <First Embodiment>
FIG. 3 is a configuration diagram of an optical modulator according to the present embodiment. In this embodiment, the modulation method for each of the X polarization and the Y polarization is QPSK. That is, it is assumed that two bits of data are carried by one symbol in each of the X polarization and the Y polarization. However, the present invention can be similarly applied to other multi-value modulation schemes such as PSK and 8PSK. Continuous light of X polarization is input to the optical phase adjusting unit 10. Further, the data string X is input to the conversion unit 13. The conversion unit 13 outputs a phase manipulated variable V X corresponding to the value of two consecutive bits of the data string X. The optical phase adjusting unit 10 changes the phase of the continuous light of X polarization by the phase manipulation amount VX, and outputs the modulated light 31 of X polarization. The optical phase adjusting unit 10 is a phase modulator using an electro-optical effect or the like, and for example, the same configuration as the optical phase adjusting unit 62I in FIG. 2 can be used. For example, when the phase manipulated variable V X is 0, it is assumed that the modulated light 31 of the X polarization becomes the signal shown by the coordinates 41 in FIG. 4 (A). In this case, when the phase manipulation amount V X is increased, the phase of the X-polarized modulation light 31 changes in the path as shown by the dotted line in FIG. The black circle in FIG. 4 indicates the phase of the symbol of the QPSK signal corresponding to the continuous 2-bit value of the data string X. The conversion unit 31 determines the phase manipulation amount V X so that the phase of the X-polarized modulation light 31 becomes the phase indicated by the black circle in FIG. 4A corresponding to the value of two consecutive bits of the data string. As a result, the optical phase adjustment unit 10 performs QPSK modulation. The X-polarized modulated light 31 is represented by the following Jones vector.

Figure 0007060474000001
Figure 0007060474000001

１／４波長板（ＱＷＰ）１１は、Ｘ偏波の変調光３１を円偏波の変調光３２に変換する。図４（Ｂ）及び（Ｃ）は、それぞれ、円偏波の変調光３２のＸ偏波成分と、Ｙ偏波成分とを示している。Ｘ偏波の変調光３１の座標４１は、図４（Ｂ）に示す様に、円偏波の変調光２２のＸ偏波成分においては同じ座標位置になるが、図４（Ｃ）に示す様に、円偏波の変調光３２のＹ偏波成分においては位相が９０度だけ回転する。円偏波の変調光３２は、以下のジョーンズベクトルで表される。 The 1/4 wave plate (QWP) 11 converts the X-polarized modulation light 31 into the circularly polarized modulated light 32. 4 (B) and 4 (C) show the X-polarized component and the Y-polarized component of the circularly polarized modulated light 32, respectively. As shown in FIG. 4B, the coordinates 41 of the X-polarized modulated light 31 have the same coordinate positions in the X-polarized component of the circularly polarized modulated light 22, but are shown in FIG. 4C. As described above, the phase of the Y polarization component of the circularly polarized light 32 is rotated by 90 degrees. The circularly polarized modulated light 32 is represented by the following Jones vector.

Figure 0007060474000002
なお、Ｘ偏波成分及びＹ偏波成分の振幅は、変調光３１の（１／√２）になるが、説明を簡略化するため、以下の総ての説明において、振幅の倍率については省略する。
Figure 0007060474000002
 The amplitude of the X-polarization component and the Y-polarization component is (1 / √2) of the modulated light 31, but for the sake of simplicity, the amplitude magnification is omitted in all the following explanations. do.

変換部１４には、データ列Ｙが入力される。変換部１４は、データ列Ｙの連続する２ビットの値に応じた位相操作量ＶＹを出力する。光位相調整部１２のハードウェア構成は、光位相調整部１０と同様である。しかしながら、光位相調整部１２には円偏波の変調光３２が入力されるため、光位相調整部１２は、位相操作量ＶＹに基づきＸ偏波成分とＹ偏波成分の相対位相を制御することになる。光位相調整部１２が出力する円偏波の変調光３３は、以下のジョーンズベクトルで表される。 The data string Y is input to the conversion unit 14. The conversion unit 14 outputs a phase manipulated variable V Y corresponding to the value of two consecutive bits of the data string Y. The hardware configuration of the optical phase adjusting unit 12 is the same as that of the optical phase adjusting unit 10. However, since the circularly polarized wave modulated light 32 is input to the optical phase adjusting unit 12, the optical phase adjusting unit 12 controls the relative phase of the X polarization component and the Y polarization component based on the phase manipulation amount V Y. Will be done. The circularly polarized wave modulated light 33 output by the optical phase adjusting unit 12 is represented by the following Jones vector.

Figure 0007060474000003
Figure 0007060474000003

本実施形態による光送信機は、図３に示す光変調器を有し、円偏波の変調光３３を光伝送路に出力する。 The optical transmitter according to the present embodiment has the optical modulator shown in FIG. 3, and outputs the circularly polarized modulated light 33 to the optical transmission line.

図５は、本実施形態による光受信機が有する光復調器の構成図である。受信部２０には、光送信機が送信した円偏波の変調光３３が入力される。受信部２０は、通常のコヒーレント光受信機と同様に、円偏波の変調光３３のＸ偏波成分とＹ偏波成分それぞれを検出し、円偏波の変調光３３のＸ偏波成分とＹ偏波成分を示す電気信号３４及び３５を出力する。電気信号３４が示す複素平面上の座標をＲｘとし、電気信号３５が示す複素平面上の座標をＲｙとすると、 FIG. 5 is a configuration diagram of an optical demodulator included in the optical receiver according to the present embodiment. The circularly polarized wave modulated light 33 transmitted by the optical transmitter is input to the receiving unit 20. The receiver 20 detects each of the X-polarized component and the Y-polarized component of the circularly polarized light 33, and sets the X-polarized component of the circularly polarized light 33 as the X-polarized component of the circularly polarized light 33, as in the case of a normal coherent optical receiver. The electric signals 34 and 35 indicating the Y polarization component are output. Let Rx be the coordinates on the complex plane indicated by the electric signal 34, and Ry be the coordinates on the complex plane indicated by the electric signal 35.

Figure 0007060474000004
である。
Figure 0007060474000004
 Is.

復調部２１は、以下の式（１）で示す演算を行って電気信号３６を出力し、以下の式（２）で示す演算を行って電気信号３７を出力する。 The demodulation unit 21 performs an operation represented by the following equation (1) to output an electric signal 36, and performs an operation represented by the following equation (2) to output an electric signal 37.

Figure 0007060474000005
Figure 0007060474000005

式（１）から明らかな様に、電気信号３６は、位相操作量ＶＸを示し、よって、データ列Ｘの連続する２ビットの値に対応する。同様に、式（２）から明らかな様に、電気信号３７は、位相操作量ＶＹを示し、よって、データ列Ｙの連続する２ビットの値に対応する。判定部２２は、電気信号３６に基づきデータ列Ｘの連続する２ビットの値を判定し、判定部２３は、電気信号３６に基づきデータ列Ｙの連続する２ビットの値を判定する。 As is clear from equation (1), the electrical signal 36 indicates a phase manipulated variable V X and thus corresponds to a continuous 2-bit value of the data sequence X. Similarly, as is clear from equation (2), the electrical signal 37 indicates a phase manipulated variable V Y and thus corresponds to a continuous 2-bit value of the data sequence Y. The determination unit 22 determines the continuous 2-bit value of the data string X based on the electric signal 36, and the determination unit 23 determines the continuous 2-bit value of the data string Y based on the electric signal 36.

以上、本実施形態の光変調器は、図１の分岐部５や合波部６を必要とせず、簡易な構成で、偏波多重された変調信号を生成することができる。また、本実施形態の光復調器は、上記光変調器が生成した偏波多重変調信号を復調することができる。なお、光位相調整部１０及び光位相調整部１２は、上述した構成に限定されず、光信号の位相を調整する任意の構成を光位相調整部１０及び光位相調整部１２として使用することができる。なお、光位相調整部１２としては、Ｘ偏波成分とＹ偏波成分の位相を等価的に互いに逆方向に同じ値だけ変化させるものを使用する。 As described above, the light modulator of the present embodiment does not require the branching portion 5 and the combining portion 6 of FIG. 1, and can generate a modulated signal with polarization multiplexing with a simple configuration. Further, the optical demodulator of the present embodiment can demodulate the polarization multiplex modulation signal generated by the optical modulator. The optical phase adjusting unit 10 and the optical phase adjusting unit 12 are not limited to the above-mentioned configurations, and any configuration for adjusting the phase of the optical signal can be used as the optical phase adjusting unit 10 and the optical phase adjusting unit 12. can. As the optical phase adjusting unit 12, a unit that changes the phases of the X polarization component and the Y polarization component equivalently in opposite directions by the same value is used.

＜第二実施形態＞
第一実施形態では、光受信機において、通常のコヒーレント検出を行った後、式（１）及び式（２）で示す演算を行うことで、光送信機が送信したデータ列Ｘと、データ列Ｙの復調・判定を行っていた。本実施形態では、式（１）及び式（２）の演算を送信側で行うことにより、光受信機においては、図５の復調部２１を不要にし、受信部２０が出力する電気信号３４及び３５に基づき、判定部２２及び２３が、データ列Ｘ及びデータ列Ｙの値を判定する。つまり、本実施形態では、従来の復調器を使用することができる。 <Second embodiment>
In the first embodiment, in the optical receiver, after performing normal coherent detection, the data string X transmitted by the optical transmitter and the data string are performed by performing the operations represented by the equations (1) and (2). The demodulation / judgment of Y was performed. In the present embodiment, by performing the operations of the equations (1) and (2) on the transmitting side, the demodulation unit 21 of FIG. 5 becomes unnecessary in the optical receiver, and the electric signal 34 and the electric signal 34 output by the receiving unit 20 Based on 35, the determination units 22 and 23 determine the values of the data column X and the data column Y. That is, in this embodiment, a conventional demodulator can be used.

図６は、本実施形態による光送信機の構成図である。本実施形態において、変換部１３及び変換部１４には、共に、データ列Ｘ及びデータ列Ｙが入力される。変換部１３は、位相操作量Ｖ´Ｘを、ＶＸ＋ＶＹで求め、変換部１４は、位相操作量Ｖ´Ｙを、ＶＸ－ＶＹで求める。なお、ＶＸ及びＶＹは第一実施形態と同様である。したがって、受信部２０が出力する電気信号３４が示す複素平面上の座標Ｒｘと、電気信号３５が示す複素平面上の座標Ｒｙは以下の様になる。 FIG. 6 is a configuration diagram of an optical transmitter according to the present embodiment. In the present embodiment, the data string X and the data string Y are input to both the conversion unit 13 and the conversion unit 14. The conversion unit 13 obtains the phase manipulated variable V'X by V X + V Y , and the conversion unit 14 obtains the phase manipulated variable V'Y by V X - V Y. Note that V X and V Y are the same as those in the first embodiment. Therefore, the coordinates Rx on the complex plane indicated by the electric signal 34 output by the receiving unit 20 and the coordinates Ry on the complex plane indicated by the electric signal 35 are as follows.

Figure 0007060474000006
Figure 0007060474000006

したがって、判定部２２及び２３は、受信部２０が出力する電気信号３４及び３５に基づき、データ列Ｘ及びデータ列Ｙの値を判定することができる。なお、本実施形態において、変換部１３は、位相操作量Ｖ´Ｘを、ＶＸとＶＹの和で求め、変換部１４は、位相操作量Ｖ´Ｙを、ＶＸとＶＹの差で求めた。しかしながら、変換部１３が、位相操作量Ｖ´Ｘを、ＶＸとＶＹの差で求め、変換部１４が、位相操作量Ｖ´Ｙを、ＶＸとＶＹの和で求める構成とすることもできる。 Therefore, the determination units 22 and 23 can determine the values of the data string X and the data column Y based on the electric signals 34 and 35 output by the reception unit 20. In the present embodiment, the conversion unit 13 obtains the phase manipulated variable V'X by the sum of V X and V Y , and the conversion unit 14 determines the phase manipulated variable V'Y as the difference between V X and V Y. I asked for it. However, the conversion unit 13 obtains the phase manipulated variable V'X by the difference between V X and V Y , and the conversion unit 14 obtains the phase manipulated variable V'Y by the sum of V X and V Y. You can also do it.

１０、１２：光位相調整部、１１：１／４波長板 10, 12: Optical phase adjuster, 11: 1/4 wave plate

Claims (8)

直線偏波である第１偏波の連続光の位相を第１データに基づく第１位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、
前記第１変調光を円偏波の第２変調光に変換する変換手段と、
前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を第２データに基づく第２位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、
を備えていることを特徴とする光変調器。 A first modulation means that modulates the phase of continuous light of the first polarization, which is linearly polarized, so as to fluctuate by the amount of the first phase manipulation based on the first data, and outputs the first modulated light.
A conversion means for converting the first modulated light into a second modulated light having circular polarization,
The phase of the first polarization component of the second modulated light and the second polarization component orthogonal to the first polarization fluctuate in opposite directions by the second phase manipulation amount based on the second data. A second modulation means that modulates the light so as to output the third modulated light, and
An optical modulator characterized by being equipped with. 第１データに基づく第１位相操作量及び第２データに基づく第２位相操作量から第３位相操作量を判定し、直線偏波である第１偏波の連続光の位相を前記第３位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、
前記第１変調光を円偏波の第２変調光に変換する変換手段と、
前記第１位相操作量及び前記第２位相操作量から第４位相操作量を判定し、前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を前記第４位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、
を備え、
前記第３位相操作量は、前記第１位相操作量と前記第２位相操作量との和又は差であり、前記第３位相操作量が前記第１位相操作量と前記第２位相操作量との和である場合、前記第４位相操作量は、前記第１位相操作量と前記第２位相操作量との差であり、前記第３位相操作量が前記第１位相操作量と前記第２位相操作量との差である場合、前記第４位相操作量は、前記第１位相操作量と前記第２位相操作量との和であることを特徴とする光変調器。 The third phase manipulation amount is determined from the first phase manipulation amount based on the first data and the second phase manipulation amount based on the second data, and the phase of the continuous light of the first polarization which is linear polarization is the phase of the third phase. The first modulation means that is modulated so as to fluctuate by the amount of operation and outputs the first modulated light,
A conversion means for converting the first modulated light into a second modulated light having circular polarization,
The fourth phase manipulated amount is determined from the first phase manipulated amount and the second phase manipulated amount, and the component of the first polarization of the second modulated light and the first polarization are orthogonal to each other in the second polarization. A second modulation means that modulates the phase of the components of the above components in opposite directions by the amount of the fourth phase manipulation and outputs the third modulated light.
Equipped with
The third phase manipulated amount is the sum or difference between the first phase manipulated amount and the second phase manipulated amount, and the third phase manipulated amount is the first phase manipulated amount and the second phase manipulated amount. In the case of the sum of, the fourth phase manipulated amount is the difference between the first phase manipulated amount and the second phase manipulated amount, and the third phase manipulated amount is the first phase manipulated amount and the second phase manipulated amount. When the difference from the phase manipulated amount, the fourth phase manipulated amount is the sum of the first phase manipulated amount and the second phase manipulated amount . 請求項１又は２に記載の光変調器を有することを特徴とする光送信機。 An optical transmitter comprising the light modulator according to claim 1 or 2 . 円偏波である変調光の第１偏波の成分及び前記第１偏波とは直交する第２偏波の成分それぞれをコヒーレント検出して第１電気信号及び第２電気信号を出力する出力手段と、
前記第１電気信号と前記第２電気信号を乗ずることで第３電気信号を生成し、前記第１電気信号を前記第２電気信号で除することで第４電気信号を生成する生成手段と、
前記第３電気信号の位相に基づき第１データを判定し、前記第４電気信号の位相に基づき第２データを判定する判定手段と、
を備え、
前記変調光は、前記第１偏波の連続光の位相を前記第１データに基づく第１位相操作量だけ変動させる様に変調して第１変調光を出力し、前記第１変調光を円偏波の第２変調光に変換し、前記第２変調光の前記第１偏波の成分と前記第２偏波の成分の位相を前記第２データに基づく第２位相操作量だけ互いに逆向きに変動させる様に変調することで生成されたものであることを特徴とする光復調器。 Coherent detection is performed for each of the first polarization component of the modulated light having circular polarization and the second polarization component orthogonal to the first polarization, and the first electric signal and the second electric signal are obtained. Output means to output and
A generation means for generating a third electric signal by multiplying the first electric signal and the second electric signal, and generating a fourth electric signal by dividing the first electric signal by the second electric signal.
A determination means for determining the first data based on the phase of the third electric signal and determining the second data based on the phase of the fourth electric signal.
Equipped with
The modulated light is modulated so that the phase of the continuous light of the first polarization is changed by the amount of the first phase operation based on the first data, the first modulated light is output, and the first modulated light is circular. It is converted into the second modulated light of polarization, and the phases of the first polarization component and the second polarization component of the second modulated light are opposite to each other by the second phase manipulation amount based on the second data. An optical demodulator characterized by being generated by modulation so as to fluctuate to . 請求項４に記載の光復調器を有することを特徴とする光受信機。 An optical receiver comprising the optical demodulator according to claim 4 . 光送信機と光受信機と、を含む光通信システムであって、
前記光送信機は、
直線偏波である第１偏波の連続光の位相を第１データに基づく第１位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、
前記第１変調光を円偏波の第２変調光に変換する変換手段と、
前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を第２データに基づく第２位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、
を備え、
前記光受信機は、
前記第３変調光を受信し、前記第３変調光の前記第１偏波の成分及び前記第２偏波の成分それぞれをコヒーレント検出して第１電気信号及び第２電気信号を出力する出力手段と、
前記第１電気信号と前記第２電気信号を乗ずることで第３電気信号を生成し、前記第１電気信号を前記第２電気信号で除することで第４電気信号を生成する生成手段と、
前記第３電気信号の位相に基づき前記第１データを判定し、前記第４電気信号の位相に基づき前記第２データを判定する判定手段と、
を備えていることを特徴とする光通信システム。 An optical communication system including an optical transmitter and an optical receiver.
The optical transmitter is
A first modulation means that modulates the phase of continuous light of the first polarization, which is linearly polarized, so as to fluctuate by the amount of the first phase manipulation based on the first data, and outputs the first modulated light.
A conversion means for converting the first modulated light into a second modulated light having circular polarization,
The phase of the first polarization component of the second modulated light and the second polarization component orthogonal to the first polarization fluctuate in opposite directions by the second phase manipulation amount based on the second data. A second modulation means that modulates the light so as to output the third modulated light, and
Equipped with
The optical receiver is
Upon receiving the third modulated light, the first polarized wave component and the second polarized wave component of the third modulated light are coherently detected, and the first electric signal and the second electric signal are obtained. Output means to output and
A generation means for generating a third electric signal by multiplying the first electric signal and the second electric signal, and generating a fourth electric signal by dividing the first electric signal by the second electric signal.
A determination means for determining the first data based on the phase of the third electric signal and determining the second data based on the phase of the fourth electric signal.
An optical communication system characterized by being equipped with. 光送信機と光受信機と、を含む光通信システムであって、
前記光送信機は、
第１データに基づく第１位相操作量及び第２データに基づく第２位相操作量から第３位相操作量を判定し、直線偏波である第１偏波の連続光の位相を前記第３位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、
前記第１変調光を円偏波の第２変調光に変換する変換手段と、
前記第１位相操作量及び前記第２位相操作量から第４位相操作量を判定し、前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を前記第４位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、
を備え、
前記光受信機は、
前記第３変調光を受信し、前記第３変調光の前記第１偏波の成分及び前記第２偏波の成分それぞれをコヒーレント検出して第１電気信号及び第２電気信号を出力する出力手段と、
前記第１電気信号の位相に基づき前記第１データを判定し、前記第２電気信号の位相に基づき前記第２データを判定する判定手段と、
を備え、
前記第３位相操作量は、前記第１位相操作量と前記第２位相操作量との和であり、前前記第４位相操作量は、前記第１位相操作量と前記第２位相操作量との差であることを特徴とする光通信システム。 An optical communication system including an optical transmitter and an optical receiver.
The optical transmitter is
The third phase manipulation amount is determined from the first phase manipulation amount based on the first data and the second phase manipulation amount based on the second data, and the phase of the continuous light of the first polarization which is linear polarization is the phase of the third phase. The first modulation means that is modulated so as to fluctuate by the amount of operation and outputs the first modulated light,
A conversion means for converting the first modulated light into a second modulated light having circular polarization,
The fourth phase manipulated amount is determined from the first phase manipulated amount and the second phase manipulated amount, and the component of the first polarization of the second modulated light and the first polarization are orthogonal to each other in the second polarization. A second modulation means that modulates the phase of the components of the above components in opposite directions by the amount of the fourth phase manipulation and outputs the third modulated light.
Equipped with
The optical receiver is
An output means that receives the third modulated light, coherently detects each of the first polarized wave component and the second polarized wave component of the third modulated light, and outputs a first electric signal and a second electric signal. When,
A determination means for determining the first data based on the phase of the first electric signal and determining the second data based on the phase of the second electric signal.
Equipped with
The third phase manipulated variable is the sum of the first phase manipulated variable and the second phase manipulated variable, and the fourth phase manipulated variable is the first phase manipulated variable and the second phase manipulated variable. An optical communication system characterized by the difference between the two . 光送信機と光受信機と、を含む光通信システムであって、
前記光送信機は、
第１データに基づく第１位相操作量及び第２データに基づく第２位相操作量から第３位相操作量を判定し、直線偏波である第１偏波の連続光の位相を前記第３位相操作量だけ変動させる様に変調して第１変調光を出力する第１変調手段と、
前記第１変調光を円偏波の第２変調光に変換する変換手段と、
前記第１位相操作量及び前記第２位相操作量から第４位相操作量を判定し、前記第２変調光の前記第１偏波の成分と前記第１偏波とは直交する第２偏波の成分の位相を前記第４位相操作量だけ互いに逆向きに変動させる様に変調して第３変調光を出力する第２変調手段と、
を備え、
前記光受信機は、
前記第３変調光を受信し、前記第３変調光の前記第１偏波の成分及び前記第２偏波の成分それぞれをコヒーレント検出して第１電気信号及び第２電気信号を出力する出力手段と、
前記第１電気信号の位相に基づき前記第２データを判定し、前記第２電気信号の位相に基づき前記第１データを判定する判定手段と、
を備え、
前記第３位相操作量は、前記第１位相操作量と前記第２位相操作量との差であり、前前記第４位相操作量は、前記第１位相操作量と前記第２位相操作量との和であることを特徴とする光通信システム。 An optical communication system including an optical transmitter and an optical receiver.
The optical transmitter is
The third phase manipulation amount is determined from the first phase manipulation amount based on the first data and the second phase manipulation amount based on the second data, and the phase of the continuous light of the first polarization which is linear polarization is the phase of the third phase. The first modulation means that is modulated so as to fluctuate by the amount of operation and outputs the first modulated light,
A conversion means for converting the first modulated light into a second modulated light having circular polarization,
The fourth phase manipulated amount is determined from the first phase manipulated amount and the second phase manipulated amount, and the component of the first polarization of the second modulated light and the first polarization are orthogonal to each other in the second polarization. A second modulation means that modulates the phase of the components of the above components in opposite directions by the amount of the fourth phase manipulation and outputs the third modulated light.
Equipped with
The optical receiver is
An output means that receives the third modulated light, coherently detects each of the first polarized wave component and the second polarized wave component of the third modulated light, and outputs a first electric signal and a second electric signal. When,
A determination means for determining the second data based on the phase of the first electric signal and determining the first data based on the phase of the second electric signal.
Equipped with
The third phase manipulated variable is the difference between the first phase manipulated variable and the second phase manipulated variable, and the fourth phase manipulated variable is the first phase manipulated variable and the second phase manipulated variable. An optical communication system characterized by being the sum of .
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