JP2016045256A - Polarized wave multiplexer and optical transmitter using the same - Google Patents

Polarized wave multiplexer and optical transmitter using the same Download PDF

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JP2016045256A
JP2016045256A JP2014167966A JP2014167966A JP2016045256A JP 2016045256 A JP2016045256 A JP 2016045256A JP 2014167966 A JP2014167966 A JP 2014167966A JP 2014167966 A JP2014167966 A JP 2014167966A JP 2016045256 A JP2016045256 A JP 2016045256A
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義弘 小木曽
Yoshihiro Ogiso
義弘 小木曽
慈 金澤
Shigeru Kanazawa
慈 金澤
泰彦 中西
Yasuhiko Nakanishi
泰彦 中西
博正 田野辺
Hiromasa Tanobe
博正 田野辺
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Nippon Telegraph and Telephone Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a polarized wave multiplexer for realizing a compact, inexpensive PDM-QPSK transmitter by reducing the number of times the optical axis is adjusted, as compared with a conventional configuration, and cutting back unnecessary optical lenses, and an optical transmitter using the polarized wave multiplexer.SOLUTION: The polarized wave multiplexer according to the present invention is characterized in being provided with: first and second light-receiving elements; and a polarized wave separation unit on which first and second lights including first and second polarized lights that are mutually orthogonal approximately linear polarized lights are incident, and which transmits the first polarized light of the first light and outputs it to the first light-receiving element, and changes the optical path of the second polarized light of the second light and outputs it to the second light-receiving element, the polarized wave separation unit combining the second polarized light of the first light and the first polarized light of the second light by changing the optical path of the second polarized light of the first light and transmitting the first polarized light of the second light, and outputting the combined light.SELECTED DRAWING: Figure 2

Description

本発明は、偏波合波器及びそれを用いた光送信器に関する。   The present invention relates to a polarization multiplexer and an optical transmitter using the same.

インターネットとブロードバンドサービスの普及により、急増するデータトラフィックを収容する光ネットワークの大容量化・経済化がこれまで以上に求められている。大容量かつ長距離伝送を行うためには、光雑音耐性を維持しつつ光の周波数利用効率を上げることが重要な課題となる。このような方法として、光の波としての位相情報を利用するＤＰＳＫ（Differential Phase Shift Keying）やＤＱＰＳＫ（Differential Quadrature Phase Shift Keying）、さらには光の偏波及び強度情報を利用したＰＤＭ−ＱＰＳＫ（Polarization Division Multiplexed-QPSK）、ＰＤＭ−１６ＱＡＭ（Quadrature Amplitude Modulation）といった多値変調方式が提案されている。   With the widespread use of the Internet and broadband services, there is an ever-increasing demand for larger capacity and more economical optical networks that accommodate rapidly increasing data traffic. In order to perform large-capacity and long-distance transmission, it is important to increase the frequency utilization efficiency of light while maintaining optical noise resistance. As such a method, DPSK (Differential Phase Shift Keying) and DQPSK (Differential Quadrature Phase Shift Keying) using phase information as a wave of light, and PDM-QPSK (Polarization using optical polarization and intensity information) are used. Multi-level modulation schemes such as Division Multiplexed-QPSK and PDM-16QAM (Quadrature Amplitude Modulation) have been proposed.

多値光変調素子の代表的な構成例としては、ＩＱ変調器およびＰＤＭ−ＱＰＳＫ変調器が挙げられる。ＩＱ変調器は直交変調器とも呼ばれ、位相が直交する光電界成分（Ｉチャネル、Ｑチャネル）を独立して生成可能な変調器である。より具体的には、ＩＱ変調器は、マッハツェンダ（ＭＺ：Ｍａｃｈ−Ｚｅｈｎｄｅｒ）変調器を並列接続した特殊な構成をとる。ＰＤＭ−ＱＰＳＫ変調器は、偏波直交多重多値デジタル信号の変調方式で、互いに直交するそれぞれの偏波に対して、変調された４つの光位相（０°、９０°、１８０°、２７０°）に、それぞれ２ビットのデータを割り当てることができる。   Typical configuration examples of the multi-level light modulation element include an IQ modulator and a PDM-QPSK modulator. The IQ modulator is also called a quadrature modulator, and is a modulator that can independently generate optical electric field components (I channel and Q channel) having orthogonal phases. More specifically, the IQ modulator has a special configuration in which Mach-Zehnder (MZ) modulators are connected in parallel. The PDM-QPSK modulator is a polarization orthogonal multiplex multilevel digital signal modulation scheme, and four modulated optical phases (0 °, 90 °, 180 °, 270 °) with respect to respective orthogonal polarizations. ) Can each be assigned 2-bit data.

図１（ａ）にＰＤＭ−ＱＰＳＫ送信器の従来例を示す。図１（ａ）には、２つのＩＱ変調器１１及び１２を含むＰＤＭ−ＱＰＳＫ変調器１０と、光学レンズ２１〜２４と、２連の偏波ビームスプリッタ（ＰＢＳ）３０と、ＩＱ変調器１１及び１２からそれぞれ出力された偏波光を制御モニタする受光素子４１及び４２と、バルクの半波長板５０と、を備えたＰＤＭ−ＱＰＳＫ送信器１が示されている。２つのＩＱ変調器１１及び１２は、Ｉチャネル用ＭＺ変調器１３及びＱチャネル用ＭＺ変調器１４が並列に集積され、Ｉチャネル用ＭＺ変調器１３及びＱチャネル用ＭＺ変調器１４の出力側に調整用電極１５が集積されている。   FIG. 1A shows a conventional example of a PDM-QPSK transmitter. FIG. 1A shows a PDM-QPSK modulator 10 including two IQ modulators 11 and 12, optical lenses 21 to 24, two polarization beam splitters (PBS) 30, and an IQ modulator 11. 1 and 2 show a PDM-QPSK transmitter 1 including light receiving elements 41 and 42 for controlling and monitoring polarized light respectively output from and 12 and a bulk half-wave plate 50. In the two IQ modulators 11 and 12, an I-channel MZ modulator 13 and a Q-channel MZ modulator 14 are integrated in parallel, and are connected to the output side of the I-channel MZ modulator 13 and the Q-channel MZ modulator 14, respectively. The adjustment electrode 15 is integrated.

ＩＱ変調器１１から出力された光のうちの主信号は光学レンズ２２及び半波長板５０を介してＰＢＳ３０に入射し、主信号の逆相成分のモニタ光は光学レンズ２１を介して受光素子４１に入力される。ＩＱ変調器１２から出力された光のうちの主信号は光学レンズ２３を介してＰＢＳ３０に入射し、主信号の逆相成分のモニタ光は光学レンズ２４を介して受光素子４２に入力される。   The main signal out of the light output from the IQ modulator 11 enters the PBS 30 via the optical lens 22 and the half-wave plate 50, and the monitor light of the reverse phase component of the main signal is received by the light receiving element 41 via the optical lens 21. Is input. Of the light output from the IQ modulator 12, the main signal is incident on the PBS 30 via the optical lens 23, and the monitor light of the antiphase component of the main signal is input to the light receiving element 42 via the optical lens 24.

図１（ｂ）にＭＺ変調器の構成を示す。図１（ｂ）には、入力用導波路６１と、入力用導波路６１を伝搬する光を２本のアーム導波路６２に分岐するための１入力２出力の分波器６３と、アーム導波路２を伝搬する光を合波するための２入力１出力の合波器６４と、出力導波路６５と、２本のアーム導波路６２にそれぞれ設けられた変調用電極６６とを含むＭＺ変調器が示されている。ＭＺ変調器は通常、差動信号（２つの変調用電極６の一方に「１」信号を印加した場合、他方には「０」信号を印加する）で動作をする。２本のアーム導波路６２を伝搬する光が合波器６４によって合波され、光の位相がそろっていれば強め合い、位相が反転していれば弱め合うことで、ＭＺ変調器は光変調器として動作する。   FIG. 1B shows the configuration of the MZ modulator. FIG. 1B shows an input waveguide 61, a 1-input 2-output duplexer 63 for branching light propagating through the input waveguide 61 into two arm waveguides 62, an arm waveguide, and the like. MZ modulation including a two-input one-output multiplexer 64 for multiplexing light propagating through the waveguide 2, an output waveguide 65, and modulation electrodes 66 respectively provided on the two arm waveguides 62. A vessel is shown. The MZ modulator normally operates with a differential signal (when a “1” signal is applied to one of the two modulation electrodes 6, a “0” signal is applied to the other). The light propagating through the two arm waveguides 62 is multiplexed by the multiplexer 64. If the phases of the light are aligned, they are strengthened, and if the phases are inverted, they are weakened. Operates as a vessel.

図１（ｃ）にＭＺ変調器の別の構成を示す。図１（ｃ）に示すＭＺ変調器では、２入力１出力の合波器６４でなく２入力２出力の合波器６７を用いている。２入力２出力の合波器６７を用いることで、主信号を導波する出力用導波路６９で光が強め合う場合、他方の出力用導波路では弱め合うことになる。つまり、他方の出力用導波路で主信号の逆相成分が得られることになり、この他方の出力用導波路を、信号光をモニタするためのモニタ用導波路６８として用いることができる（例えば特許文献１参照）。   FIG. 1C shows another configuration of the MZ modulator. The MZ modulator shown in FIG. 1C uses a 2-input 2-output multiplexer 67 instead of a 2-input 1-output multiplexer 64. By using the 2-input 2-output multiplexer 67, when light is intensified in the output waveguide 69 that guides the main signal, it is weakened in the other output waveguide. That is, the opposite phase component of the main signal can be obtained by the other output waveguide, and the other output waveguide can be used as the monitor waveguide 68 for monitoring the signal light (for example, Patent Document 1).

図１（ａ）に示されるＩＱ変調器１１及び１２は、２つのＭＺ変調器を合波器と分波器で結合したものである。言い換えると、ＭＺ変調器（子ＭＺとも言う）をアーム導波路とする大きなＭＺ変調器（親ＭＺとも言う）とみることができる。つまり、親ＭＺの合波器を２入力２出力の合波器にすることで、主信号と主信号の逆相成分のモニタ光とを得ることができる。このモニタ光は、主にＩＱ変調における位相の直交性を制御するために用いられている。通常、モニタ光は、ＭＺ光干渉によって生じた主信号の逆相成分を２×２のマルチモードカプラ及び光導波路を介して素子端面から取り出すことによって取り出される。この逆相成分を用いることで、原理的な光の過剰損失を増加させることなく光信号をモニタすることができる。   IQ modulators 11 and 12 shown in FIG. 1A are two MZ modulators combined by a multiplexer and a demultiplexer. In other words, it can be regarded as a large MZ modulator (also referred to as a parent MZ) having an MZ modulator (also referred to as a child MZ) as an arm waveguide. That is, the main signal and the monitor light of the opposite phase component of the main signal can be obtained by making the multiplexer of the parent MZ a 2-input 2-output multiplexer. This monitor light is mainly used for controlling phase orthogonality in IQ modulation. Normally, the monitor light is extracted by extracting the anti-phase component of the main signal generated by the MZ optical interference from the element end face through the 2 × 2 multimode coupler and the optical waveguide. By using this antiphase component, it is possible to monitor the optical signal without increasing the excessive light loss in principle.

２つのＩＱ変調器１１及び１２からの出力光は、光学レンズ２１乃至２４によってそれぞれ集光（もしくはコリメート光に変換）される。入力光の偏光面をＴＥ直線偏光とすると、出力光（主信号）はいずれもＴＥ偏光となる。ＩＱ変調器１１及び１２からの２つの主信号のうちの一方を半波長板５０（λ／２波長板）に通すと、ＴＥ偏光はＴＭ偏光に変換される。入力光がＴＭ偏光の場合は、半波長板５０により、ＴＭ偏光がＴＥ偏光に変換される。   Output lights from the two IQ modulators 11 and 12 are condensed (or converted into collimated light) by the optical lenses 21 to 24, respectively. If the polarization plane of the input light is TE linearly polarized light, the output light (main signal) will be TE polarized light. When one of the two main signals from the IQ modulators 11 and 12 is passed through the half-wave plate 50 (λ / 2 wave plate), the TE-polarized light is converted into TM-polarized light. When the input light is TM polarized light, the TM polarized light is converted into TE polarized light by the half-wave plate 50.

図１（ｄ）は、ＰＢＳの構成を例示する。図１（ｄ）に示されるように、ＰＢＳは、例えば４５°直角プリズムの斜面に誘電体偏光膜をコーティングして接着したキューブ状ものであり、ＴＥ偏光を直進させるとともに、ＴＭ偏光の進行方向を９０°曲げる機能を有する。図１（ｄ）に示すＰＢＳを、図１（ａ）に示すように２つ組み合わせて「２連のＰＢＳ」３０とすることで、２つの主信号を偏波多重合成することができる。このように偏波多重合成されて生成された信号がＰＤＭ−ＱＰＳＫ送信器の出力信号となる。   FIG. 1D illustrates the configuration of the PBS. As shown in FIG. 1D, the PBS is, for example, a cube having a dielectric polarizing film coated and bonded to the slope of a 45 ° right-angle prism. The TE polarized light travels straight and the traveling direction of TM polarized light. Has a function of bending 90 °. By combining two PBSs shown in FIG. 1 (d) as shown in FIG. 1 (a) into a “double PBS” 30, it is possible to synthesize two main signals by polarization multiplexing. A signal generated by polarization multiplexing and combining in this way becomes an output signal of the PDM-QPSK transmitter.

上記のような従来の構成では、変調素子から受光素子及びＰＢＳに光を集光させる光学レンズは少なくとも３個ないし４個用いられる。   In the conventional configuration as described above, at least three to four optical lenses for condensing light from the modulation element to the light receiving element and the PBS are used.

特開平１１−４４８６７号公報Japanese Patent Laid-Open No. 11-44867

しかしながら、図１（ａ）に示すような従来構成では、２つのＩＱ変調器１１及び１２が４つの出力光（２つの主信号と２つのモニタ光）を出射し、そのうち２つの主信号をＰＢＳ３０に出力し、２つのモニタ光を受光素子４１及び４２に出力する。そのため、２つの主信号と２つのモニタ光についてそれぞれ光軸の調整をしなければならず、光軸の調整は必ずしも容易ではないことから、ＰＤＭ−ＱＰＳＫ送信器の作製が困難であるという問題があった。また、従来構成では、光学レンズ２０は少なくとも３個ないしは４個以上必要となり、実装コスト・実装面積の増大が懸念される。   However, in the conventional configuration as shown in FIG. 1A, the two IQ modulators 11 and 12 emit four output lights (two main signals and two monitor lights), of which two main signals are sent to the PBS 30. The two monitor lights are output to the light receiving elements 41 and 42. Therefore, the optical axes must be adjusted for the two main signals and the two monitor lights, respectively. Since the adjustment of the optical axes is not always easy, there is a problem that it is difficult to manufacture a PDM-QPSK transmitter. there were. Further, in the conventional configuration, at least three or four or more optical lenses 20 are necessary, and there is a concern about an increase in mounting cost and mounting area.

本発明は、このような問題に鑑みてなされたものであって、従来構成と比較して光軸の調整回数を少なくし、且つ不要な光学レンズを削減することで、小型・安価なＰＤＭ−ＱＰＳＫ送信器を実現するための偏波合波器及びそれを用いた光送信器を提供することを目的とする。   The present invention has been made in view of such problems, and can reduce the number of optical axis adjustments compared to the conventional configuration and reduce unnecessary optical lenses, thereby reducing the size and cost of the PDM-. An object of the present invention is to provide a polarization multiplexer for realizing a QPSK transmitter and an optical transmitter using the same.

従来、ＩＱ変調器を構成していたＭＺ変調器に代わり、偏波変調器を用いてＩＱ変調することで、変調信号光とその逆相光との偏光状態が直交する性質を応用することとした。すなわち、従来構成のようにＩチャネル導波路とＱチャネル導波路との合波部として２入力２出力の合波部を用いてモニタ用導波路を設けずに、本発明では、２入力１出力の合波部を用いて主信号用導波路のみにＩＱ変調光を出力し、後段に偏波分離素子を設けることで逆相信号光をモニタ信号として受信することを可能としている。   Applying the property that the polarization state of the modulated signal light and its opposite phase light are orthogonal by performing IQ modulation using a polarization modulator instead of the conventional MZ modulator constituting the IQ modulator; did. That is, the present invention does not provide a monitoring waveguide using a 2-input 2-output combining section as a combining section of an I-channel waveguide and a Q-channel waveguide as in the conventional configuration. By using this combining unit, IQ modulated light is output only to the main signal waveguide, and a polarization separation element is provided in the subsequent stage, so that the opposite phase signal light can be received as a monitor signal.

そこで、請求項１に記載の偏波合波器は、第１の受光素子と、第２の受光素子と、互いに直交する略直線偏光である第１の偏光及び第２の偏光を含む第１の光及び第２の光が入射され、前記第１の光の第１の偏光を透過して前記第１の受光素子に出力し、前記第２の光の第２の偏光の光路を変更して前記第２の受光素子に出力する偏波分離部であって、前記第１の光の第２の偏光の光路を変更し、前記第２の光の第１の偏光を透過することによって、前記第１の光の第２の偏光と前記第２の光の第１の偏光とを合波して出力する偏波分離部と、を備えたことを特徴とする。   Therefore, the polarization multiplexer according to claim 1 includes a first light receiving element, a second light receiving element, and a first polarization and a second polarization that are substantially linearly polarized light orthogonal to each other. Light and second light are incident, transmit the first polarized light of the first light and output to the first light receiving element, and change the optical path of the second polarized light of the second light. A polarization separation unit that outputs to the second light receiving element, changing the optical path of the second polarization of the first light, and transmitting the first polarization of the second light, A polarization separation unit configured to multiplex and output the second polarized light of the first light and the first polarized light of the second light;

請求項２に記載の偏波合波器は、請求項１に記載の偏波合波器であって、前記偏波分離部は、前記第１の光が入射されて、前記第１の光の第１の偏光を透過して出力し、前記第１の光の第２の偏光の光路を変更して出力する第１の偏波分離カプラと、前記第２の光と前記第１の偏波分離カプラから出力された前記第１の光の第２の偏光が入射されて、前記第２の光の第２の偏光の光路と前記第１の偏波分離カプラから出力された前記第１の光の第２の偏光の光路とを変更して出力し、前記第２の光の第１の偏光を透過して出力する第２の偏波分離カプラと、を含むことを特徴とする。   The polarization multiplexer according to claim 2 is the polarization multiplexer according to claim 1, wherein the polarization separation unit receives the first light and receives the first light. A first polarization splitting coupler that transmits and outputs the first polarized light, changes the optical path of the second polarized light of the first light, and outputs the second polarized light and the first polarized light. The second polarization of the first light output from the wave separation coupler is incident, and the first polarization output from the first polarization separation coupler and the optical path of the second polarization of the second light. And a second polarization separation coupler that changes and outputs the optical path of the second polarized light of the second light and transmits and outputs the first polarized light of the second light.

請求項３に記載の偏波合波器は、請求項２に記載の偏波合波器であって、前記第１の受光素子は、前記第１の偏波分離カプラにおける前記第１の光の第１の偏光の出力端面に搭載され、前記第２の受光素子は、前記第２の偏波分離カプラにおける前記第２の光の第２の偏光の出力端面に搭載されていることを特徴とする。   The polarization multiplexer according to claim 3 is the polarization multiplexer according to claim 2, wherein the first light receiving element is the first light in the first polarization separation coupler. The second light receiving element is mounted on the output end face of the second polarization of the second light in the second polarization separation coupler. And

請求項４に記載の偏波合波器は、請求項２又は３に記載の偏波合波器であって、前記第１の偏波分離カプラ及び前記第２の偏波分離カプラは、互いに連結されていることを特徴とする。   The polarization multiplexer according to claim 4 is the polarization multiplexer according to claim 2 or 3, wherein the first polarization separation coupler and the second polarization separation coupler are mutually connected. It is connected.

請求項５に記載の偏波合波器は、請求項２乃至４のいずれかに記載の偏波合波器であって、前記第１の偏波分離カプラの前記第１の光の入力端面又は前記第２の偏波分離カプラの前記第２の光の入力端面に設けられた半波長板をさらに備えたことを特徴とする。   The polarization multiplexer according to claim 5 is the polarization multiplexer according to any one of claims 2 to 4, wherein the input end face of the first light of the first polarization separation coupler. Alternatively, a half-wave plate provided on the input end face of the second light of the second polarization separation coupler is further provided.

請求項６に記載の偏波合波器は、請求項１乃至５のいずれかに記載の偏波合波器であって、前記第１の受光素子及び前記第２の受光素子が、それぞれ高周波配線基板上に配置されていることを特徴とする。   The polarization multiplexer according to claim 6 is the polarization multiplexer according to any one of claims 1 to 5, wherein the first light receiving element and the second light receiving element are respectively high frequency. It is arranged on a wiring board.

請求項７に記載の偏波合波器は、請求項１乃至６のいずれかに記載の偏波合波器であって、前記第１の受光素子の受光面は、前記第１の受光素子に入力する前記第１の光の第１の偏光の光軸に対して８０°以上９０°未満の角度に傾けられており、前記第２の受光素子の受光面は、前記第２の受光素子に入力する前記第２の光の第２の偏光の光軸に対して８０°以上９０°未満の角度に傾けられていることを特徴とする。   The polarization multiplexer according to claim 7 is the polarization multiplexer according to any one of claims 1 to 6, wherein a light receiving surface of the first light receiving element is the first light receiving element. The light receiving surface of the second light receiving element is tilted at an angle of 80 ° or more and less than 90 ° with respect to the optical axis of the first polarized light of the first light input to the second light receiving element. It is inclined at an angle of not less than 80 ° and less than 90 ° with respect to the optical axis of the second polarized light of the second light input to.

請求項８に記載の光送信器は、請求項１乃至７のいずれかに記載の偏波合波器と、光変調器であって、第１のＩチャネル光及び第１のＱチャネル光を出力する第１のＩＱ変調部と、第２のＩチャネル光及び第２のＱチャネル光を出力する第２のＩＱ変調部と、前記第１のＩＱ変調部から出力された前記第１のＩチャネル光及び前記第１のＱチャネル光を合波して前記第１の光を出力する２入力１出力の第１の合波部と、前記第２のＩＱ変調部から出力された前記第２のＩチャネル光及び前記第２のＱチャネル光を合波して前記第２の光を出力する２入力１出力の第２の合波部と、を含む光変調器と、前記第１の合波部から出力された前記第１の光をコリメートして前記偏波合波器に出力する第１の光学レンズと、前記第２の合波部から出力された前記第２の光をコリメートして前記偏波合波器に出力する第２の光学レンズと、を備えたことを特徴とする。   An optical transmitter according to claim 8 is the polarization multiplexer according to any one of claims 1 to 7 and an optical modulator, wherein the first I-channel light and the first Q-channel light are transmitted. A first IQ modulator that outputs, a second IQ modulator that outputs a second I-channel light and a second Q-channel light, and the first I output from the first IQ modulator. A first input unit with two inputs and one output for combining the channel light and the first Q channel light to output the first light, and the second output from the second IQ modulation unit An optical modulator comprising: a 2-input 1-output second combining unit that combines the I-channel light and the second Q-channel light to output the second light; and A first optical lens that collimates the first light output from the wave unit and outputs the collimated light to the polarization beam combiner; and an output from the second wave combiner. A second optical lens to be output to the polarization multiplexer collimates the second light has, characterized by comprising a.

本発明によれば、従来構成と比較して光軸の調整回数を少なくし、且つ不要な光学レンズを削減することで、小型・安価なＰＤＭ−ＱＰＳＫ送信器を実現することが可能となる。   According to the present invention, it is possible to realize a small and inexpensive PDM-QPSK transmitter by reducing the number of optical axis adjustments and reducing unnecessary optical lenses as compared with the conventional configuration.

ＰＤＭ−ＱＰＳＫ送信器の従来例を説明するための図である。It is a figure for demonstrating the prior art example of a PDM-QPSK transmitter. 本発明の実施例１に係るＰＤＭ−ＱＰＳＫ送信器を例示する図である。It is a figure which illustrates the PDM-QPSK transmitter which concerns on Example 1 of this invention. 本発明の実施例１に係る偏波合波器を例示する図である。It is a figure which illustrates the polarization beam multiplexer which concerns on Example 1 of this invention. 本発明の実施例２に係るＰＤＭ−ＱＰＳＫ送信器を例示する図である。It is a figure which illustrates the PDM-QPSK transmitter which concerns on Example 2 of this invention. 本発明の実施例２に係る偏波合波器を例示する図である。It is a figure which illustrates the polarization multiplexer which concerns on Example 2 of this invention. 本発明の実施例３に係る偏波合波器を例示する図である。It is a figure which illustrates the polarization multiplexer which concerns on Example 3 of this invention.

（実施例１）
図２は本発明の実施例１に係るＰＤＭ−ＱＰＳＫ送信器を例示する。図２には、第１及び第２のＩＱ変調器１１１及び１１２を含むＰＤＭ−ＱＰＳＫ変調器１１０と、光学レンズ１２１及び１２２と、第１及び第２の偏波分離カプラ１３１及び１３２を含む偏波合波器１３０と、第１及び第２のＩＱ変調器１１１及び１１２からそれぞれ出力された偏波光を受光して制御モニタする第１及び第２の受光素子１４１及び１４２と、を備えたＰＤＭ−ＱＰＳＫ送信器１００が示されている。 (Example 1)
FIG. 2 illustrates a PDM-QPSK transmitter according to Embodiment 1 of the present invention. FIG. 2 shows a PDM-QPSK modulator 110 including first and second IQ modulators 111 and 112, an optical lens 121 and 122, and a polarization including first and second polarization separation couplers 131 and 132. A PDM including a wave multiplexer 130 and first and second light receiving elements 141 and 142 that receive and control-monitor the polarized light output from the first and second IQ modulators 111 and 112, respectively. A QPSK transmitter 100 is shown.

第１及び第２のＩＱ変調器１１１及び１１２は、Ｉチャネル用偏波変調器１１３及びＱチャネル用偏波変調器１１４が並列に集積され、第１及び第２のＩＱ変調器１１１及び１１２のＩチャネル用偏波変調器１１３及びＱチャネル用偏波変調器１１４に対して直列に調整用電極１１５が集積されている。第１及び第２のＩＱ変調器１１１及び１１２は、２入力１出力の第１及び第２の合波部１１６及び１１７をそれぞれ含む。第１及び第２の合波部１１６及び１１７は、Ｉチャネル用偏波変調器１１３で生成されたＩチャネル光とＱチャネル用偏波変調器１１４で生成されたＱチャネル光を合波して、それぞれ第１及び第２のＩＱ変調光Ｌ１及びＬ２を出力する。偏波合波器１３０では、第１及び第２の偏波分離カプラ１３１及び１３２として図３に示すような２つの互いに連結されたＰＢＳを用いることができる。   In the first and second IQ modulators 111 and 112, an I-channel polarization modulator 113 and a Q-channel polarization modulator 114 are integrated in parallel, and the first and second IQ modulators 111 and 112 An adjustment electrode 115 is integrated in series with the I-channel polarization modulator 113 and the Q-channel polarization modulator 114. The first and second IQ modulators 111 and 112 include first and second multiplexers 116 and 117 each having two inputs and one output. The first and second multiplexers 116 and 117 combine the I channel light generated by the I channel polarization modulator 113 and the Q channel light generated by the Q channel polarization modulator 114. , Output first and second IQ modulated lights L1 and L2, respectively. In the polarization multiplexer 130, two mutually connected PBSs as shown in FIG. 3 can be used as the first and second polarization separation couplers 131 and 132.

ＰＤＭ−ＱＰＳＫ変調器１１０は、４つの偏波変調器を並列に集積することで、２つのＩＱ変調信号をそれぞれ異なる出力導波路から出射させる構成となっている。ＰＤＭ−ＱＰＳＫ変調器１１０への入力偏波はＴＥ偏光又はＴＭ偏光とすることができる。偏波多重伝送させるためには、第１及び第２のＩＱ変調器１１１及び１１２から出力される第１及び第２のＩＱ変調光Ｌ１及びＬ２は、それぞれ直交する偏光状態（一方がＴＥ偏光、他方がＴＭ偏光）で出射されて、偏波合波器１３０に入射する必要がある。そのため、第１及び第２のＩＱ変調光Ｌ１及びＬ２は、それぞれ直交した異なる偏波状態で変調駆動されるように、調整用電極１１５によって第１及び第２のＩＱ変調器１１１及び１１２にバイアス電圧を印加することによりそれぞれの偏波状態に調整されている。   The PDM-QPSK modulator 110 is configured to emit two IQ modulation signals from different output waveguides by integrating four polarization modulators in parallel. The input polarization to the PDM-QPSK modulator 110 can be TE polarization or TM polarization. In order to perform polarization multiplexing transmission, the first and second IQ modulated lights L1 and L2 output from the first and second IQ modulators 111 and 112 are respectively in orthogonal polarization states (one is TE polarized light, It is necessary that the other is emitted as TM polarized light and enters the polarization multiplexer 130. Therefore, the first and second IQ modulated lights L1 and L2 are biased to the first and second IQ modulators 111 and 112 by the adjustment electrode 115 so that they are modulated and driven in different orthogonal polarization states, respectively. Each polarization state is adjusted by applying a voltage.

図３は、実施例１に係る偏波合波器１３０の拡大図である。図３に示すように、第１の偏波分離カプラ１３１には、第１のＩＱ変調光Ｌ１が入射する。第１のＩＱ変調光Ｌ１のうちＴＭ偏波Ｌ１ＴＭは第１の偏波分離カプラ１３１で反射されて第２の偏波分離カプラ１３２に入射し、第１のＩＱ変調光Ｌ１のうちＴＥ偏波Ｌ１ＴＥは第１の偏波分離カプラ１３１を透過して第１の受光素子１４１に入射する。また、第２の偏波分離カプラ１３２には、第１の偏波分離カプラ１３１で反射されたＴＭ偏波Ｌ１ＴＭと第２のＩＱ変調光Ｌ２とが入射する。ＴＭ偏波Ｌ１ＴＭは第２の偏波分離カプラ１３２で反射され、第２のＩＱ変調光Ｌ２のうちＴＥ偏波Ｌ２ＴＥは第２の偏波分離カプラ１３２を透過して、信号光として用いられるようにそれぞれ合波される。第２のＩＱ変調光Ｌ２のうちＴＭ偏波Ｌ２ＴＭは第２の偏波分離カプラ１３２で反射されて第２の受光素子１４２に入射する。第１の受光素子１４１に入射したＴＥ偏波Ｌ１ＴＥ及び第２の受光素子１４２に入射したＴＭ偏波Ｌ２ＴＭは、モニタ光として使用される。 FIG. 3 is an enlarged view of the polarization multiplexer 130 according to the first embodiment. As shown in FIG. 3, the first IQ-modulated light L <b> 1 enters the first polarization separation coupler 131. The TM polarization L1 TM of the first IQ modulated light L1 is reflected by the first polarization separation coupler 131 and enters the second polarization separation coupler 132, and the TE polarization of the first IQ modulation light L1 is TE. The wave L1 TE passes through the first polarization separation coupler 131 and enters the first light receiving element 141. Further, the TM polarization L1 TM reflected by the first polarization separation coupler 131 and the second IQ modulated light L2 are incident on the second polarization separation coupler 132. The TM polarization L1 TM is reflected by the second polarization separation coupler 132, and the TE polarization L2 TE of the second IQ modulated light L2 is transmitted through the second polarization separation coupler 132 and used as signal light. Each is combined. Of the second IQ modulated light L2, TM polarization L2 TM is reflected by the second polarization separation coupler 132 and enters the second light receiving element 142. The TE polarized light L1 TE incident on the first light receiving element 141 and the TM polarized light L2 TM incident on the second light receiving element 142 are used as monitor light.

ここで、図３に示されるように、第１及び第２の受光素子１４１及び１４２は反射防止膜を介して第１及び第２の偏波分離カプラ１３１及び１３２にそれぞれ接着することが望ましい。   Here, as shown in FIG. 3, it is desirable that the first and second light receiving elements 141 and 142 are bonded to the first and second polarization separation couplers 131 and 132, respectively, via an antireflection film.

ＰＤＭ−ＱＰＳＫ変調器１１０は、入力偏波に対して材料屈折率の主軸が４５°傾いた状態で屈折率を変化させる必要があるため、ＰＤＭ−ＱＰＳＫ変調器１１０の材料としては結晶歪みに起因した電気光学効果（ポッケルス効果）を有するものが望ましく、例えばニオブ酸リチウムなどの強誘電体材料やＩｎＰやＧａＡｓなどの化合物半導体材料が望ましい。ニオブ酸リチウムの場合には、例えば、ＸＹ軸面にスライスされた基板上に対してＺ軸方向に変調器を形成し、Ｘ軸方向に電界を印加することで偏波変調を行うことができる。また、化合物半導体の場合には、例えば、［１１０］方向又は［１１０］方向と等価な方向に導波路を形成し、［−１１０］方向又は［−１１０］方向と等価な方向に電界を印加することで偏波変調を行うことができる。   Since the PDM-QPSK modulator 110 needs to change the refractive index in a state where the principal axis of the material refractive index is inclined by 45 ° with respect to the input polarization, the PDM-QPSK modulator 110 is caused by crystal distortion. It is desirable to have an electro-optic effect (Pockels effect), for example, a ferroelectric material such as lithium niobate or a compound semiconductor material such as InP or GaAs. In the case of lithium niobate, for example, polarization modulation can be performed by forming a modulator in the Z-axis direction on the substrate sliced in the XY-axis plane and applying an electric field in the X-axis direction. . In the case of a compound semiconductor, for example, a waveguide is formed in a direction equivalent to the [110] direction or the [110] direction, and an electric field is applied in the direction equivalent to the [−110] direction or the [−110] direction. By doing so, polarization modulation can be performed.

なお、偏波分離カプラ端面及び受光素子面におけるモニタ光のフレネル反射は、偏波間クロストーク特性を劣化させる要因となるため、反射を最小限に抑え、且つ、受光素子への光結合効率を向上させる必要がある。そこで、第１の偏波分離カプラ１３１を透過したモニタ光の光軸に対する第１の受光素子１４１の受光面の角度が８０°以上９０°未満の角度となるように第１の受光素子１４１を第１の偏波分離カプラ１３１に接着し、及び第２の偏波分離カプラ１３２で反射されたモニタ光の光軸に対する第２の受光素子１４２の受光面の角度が８０°以上９０°未満の角度となるように第２の受光素子１４２を第２の偏波分離カプラ１３２に接着することが望ましい。本実施例では、当該角度を８６°とした。   The Fresnel reflection of the monitor light on the polarization separation coupler end face and the light receiving element surface is a factor that degrades the crosstalk characteristics between the polarizations. Therefore, the reflection is minimized and the optical coupling efficiency to the light receiving element is improved. It is necessary to let Therefore, the first light receiving element 141 is set so that the angle of the light receiving surface of the first light receiving element 141 with respect to the optical axis of the monitor light transmitted through the first polarization splitting coupler 131 is an angle of 80 ° or more and less than 90 °. The angle of the light receiving surface of the second light receiving element 142 with respect to the optical axis of the monitor light bonded to the first polarization separating coupler 131 and reflected by the second polarization separating coupler 132 is not less than 80 ° and less than 90 °. It is desirable to bond the second light receiving element 142 to the second polarization separation coupler 132 so as to have an angle. In this embodiment, the angle is 86 °.

また、上記実施例１では、ＴＭ偏波Ｌ１ＴＭ及びＴＥ偏波Ｌ２ＴＥを信号光として用いた例を示したが、ＴＥ偏波Ｌ１ＴＥ及びＴＭ偏波Ｌ２ＴＭを信号光として用いて構成したとしても本発明の有用性は失われないことは明らかである。 In the first embodiment, the TM polarization L1 TM and the TE polarization L2 TE are used as the signal light. However, the TE polarization L1 TE and the TM polarization L2 TM are used as the signal light. However, it is clear that the usefulness of the present invention is not lost.

以上、本発明によれば、偏波変調後に偏波分離素子を介して分離された一方の光をモニタ光として用いることで、モニタ用導波路の排除及び不要なレンズ実装工数の削減ができるため、作製コスト・モジュールサイズの削減が可能となるとともに、従来構成と比較して光軸の調整回数を少なくすることができる。   As described above, according to the present invention, since one of the lights separated through the polarization separation element after the polarization modulation is used as the monitor light, it is possible to eliminate the monitoring waveguide and reduce unnecessary lens mounting man-hours. The manufacturing cost and module size can be reduced, and the number of adjustments of the optical axis can be reduced as compared with the conventional configuration.

（実施例２）
図４は本発明の実施例２に係るＰＤＭ−ＱＰＳＫ送信器を例示する。図４に示す実施例２に係るＰＤＭ−ＱＰＳＫ送信器２００と実施例１に係るＰＤＭ−ＱＰＳＫ送信器１００との構造上の差異は、第２の偏波分離カプラ１３２の入射端に半波長板２１０を設けた点である。実施例２において、半波長板２１０は、変調器から出射されたＴＥ偏波及びＴＭ偏波をそれぞれ９０°回転（ＴＥ⇔ＴＭ変換）させるために結晶軸を４５°傾けて接着している。 (Example 2)
FIG. 4 illustrates a PDM-QPSK transmitter according to Embodiment 2 of the present invention. The structural difference between the PDM-QPSK transmitter 200 according to the second embodiment shown in FIG. 4 and the PDM-QPSK transmitter 100 according to the first embodiment is that a half-wave plate is formed at the incident end of the second polarization separation coupler 132. 210 is provided. In the second embodiment, the half-wave plate 210 is bonded by tilting the crystal axis by 45 ° in order to rotate the TE polarized light and TM polarized light emitted from the modulator by 90 ° (TE⇔TM conversion).

図５は、実施例２に係る偏波合波器２０１の拡大図である。図５に示されるように、第２のＩＱ変調光Ｌ２は半波長板２１０に入射し、第２のＩＱ変調光Ｌ２のうちＴＭ偏波Ｌ２ＴＭは半波長板２１０によってＴＥ偏波Ｌ２ＴＥ’に変換され、ＴＥ偏波Ｌ２ＴＥは半波長板２１０によってＴＭ偏波Ｌ２ＴＭ’に変換される。実施例２では、ＴＭ偏波Ｌ１ＴＭ及びＴＥ偏波Ｌ２ＴＥ’を第２の偏波分離カプラ１３２で合波して信号光として用い、ＴＥ偏波Ｌ１ＴＥ及びＴＭ偏波Ｌ２ＴＭ’をモニタ光として用いることができる。 FIG. 5 is an enlarged view of the polarization multiplexer 201 according to the second embodiment. As shown in FIG. 5, the second IQ modulated light L2 is incident on the half-wave plate 210, and the TM polarization L2 TM of the second IQ modulated light L2 is TE polarized L2 TE ′ by the half-wave plate 210. The TE polarized wave L2 TE is converted into the TM polarized wave L2 TM ′ by the half-wave plate 210. In the second embodiment, TM polarization L1 TM and TE polarization L2 TE ′ are combined by the second polarization separation coupler 132 and used as signal light, and the TE polarization L1 TE and TM polarization L2 TM ′ are monitored. It can be used as light.

半波長板２１０を設けた目的は、第１及び第２のＩＱ変調器１１１及び１１２の駆動条件を統一するためである。すなわち、実施例１に係るＰＤＭ−ＱＰＳＫ送信器１００では、直交した異なる偏波状態で第１及び第２のＩＱ変調器１１１及び１１２をそれぞれ駆動させる必要があったため、それぞれ電圧値の異なるバイアス電圧を印加する必要があったことに加えて、光変調器側に高い偏波変換効率動作が求められていた。   The purpose of providing the half-wave plate 210 is to unify the driving conditions of the first and second IQ modulators 111 and 112. That is, in the PDM-QPSK transmitter 100 according to the first embodiment, it is necessary to drive the first and second IQ modulators 111 and 112 in different orthogonal polarization states. In addition to the necessity of applying a high polarization conversion efficiency operation on the optical modulator side.

一方、実施例２に係るＰＤＭ−ＱＰＳＫ送信器２００のように第１及び第２のＩＱ変調器１１１及び１１２の駆動条件（バイナリ駆動する際の基準となる偏光状態）を統一させることで、印加バイアス電圧を統一化することができる。さらに、偏波変換効率が良好でない偏波変調器を用いた場合にも、ある一方の偏波に注目した場合には、偏波分離素子を介して十分な偏波消光比が得られるため、良好なＩＱ変調特性が実現できるメリットがある。   On the other hand, it is applied by unifying the driving conditions (polarization state as a reference when performing binary driving) of the first and second IQ modulators 111 and 112 as in the PDM-QPSK transmitter 200 according to the second embodiment. The bias voltage can be unified. Furthermore, even when a polarization modulator with poor polarization conversion efficiency is used, when focusing on one polarization, a sufficient polarization extinction ratio can be obtained via the polarization separation element. There is an advantage that a good IQ modulation characteristic can be realized.

なお、本実施例２では、光路等長化の観点から第２の偏波分離カプラ１３２の入射端に半波長板２１０を接着させたが、第１の偏波分離カプラ１３１の入射端に半波長板２１０を接着させても問題はないことは明らかである。   In the second embodiment, the half-wave plate 210 is bonded to the incident end of the second polarization separation coupler 132 from the viewpoint of equalizing the optical path, but the half-wave plate 210 is adhered to the incident end of the first polarization separation coupler 131. It is clear that there is no problem even if the wave plate 210 is bonded.

また、実施例２ではＴＭ偏波Ｌ１ＴＭ及びＴＥ偏波Ｌ２ＴＥ’を信号光として用いた例を示したが、ＴＥ偏波Ｌ１ＴＥ及びＴＭ偏波Ｌ２ＴＭ’を信号光として用いて構成したとしても本発明の有用性は失われないことは明らかである。 In the second embodiment, the TM polarization L1 TM and the TE polarization L2 TE ′ are used as the signal light. However, the TE polarization L1 TE and the TM polarization L2 TM ′ are used as the signal light. However, it is clear that the usefulness of the present invention is not lost.

（実施例３）
図６は、実施例３に係る偏波合波器３０１の拡大図である。図５に示されるように、実施例３に係る偏波合波器３０１は、実施例２に係る偏波合波器を、電極３２０が設けられた高周波配線基板３１０上に設けた構成となっている。 (Example 3)
FIG. 6 is an enlarged view of the polarization multiplexer 301 according to the third embodiment. As illustrated in FIG. 5, the polarization multiplexer 301 according to the third embodiment has a configuration in which the polarization multiplexer according to the second embodiment is provided on the high-frequency wiring board 310 on which the electrode 320 is provided. ing.

図１に示した従来構成においては、受光素子４１及び４２を光学レンズ２１及び２４によるコリメート光の受光強度が最大となるところに接着固定し、その後、高周波基板へワイヤーボンディングを行って導通をとる。この場合、受光素子４１及び４２の調芯工程が発生する他、ワイヤーボンディングといった実装工程が増えてしまう。   In the conventional configuration shown in FIG. 1, the light receiving elements 41 and 42 are bonded and fixed at a place where the light receiving intensity of the collimated light by the optical lenses 21 and 24 is maximized, and then wire bonding is performed to the high-frequency substrate to establish conduction. . In this case, the alignment process of the light receiving elements 41 and 42 occurs, and the mounting process such as wire bonding increases.

これに対して、実施例３に係る偏波合波器３０１では、第１及び第２の偏波分離素子１３１及び１３２からの分離光（コリメータ光）をモニタ光とすることから、第１及び第２の偏波分離素子１３１及び１３２にそれぞれ接着させる第１及び第２の受光素子１４１及び１４２の位置は一意に決定されるため、調芯工程は不要となる。第１及び第２の受光素子１４１及び１４２の接着位置が事前に決定されることで、事前に高周波配線板３１０上に第１及び第２の偏波分離素子１３１及び１３２を設けておくことが可能となる。その結果、ワイヤーボンディングを行わなくても、簡易なフリップチップ接続等で事前に個別の実装を行うことができるため、実装歩留りの向上、コスト削減が可能となる。   On the other hand, in the polarization multiplexer 301 according to the third embodiment, the separated light (collimator light) from the first and second polarization separation elements 131 and 132 is used as the monitor light. Since the positions of the first and second light receiving elements 141 and 142 to be bonded to the second polarization separation elements 131 and 132, respectively, are uniquely determined, the alignment process is not necessary. The first and second polarization separation elements 131 and 132 may be provided on the high-frequency wiring board 310 in advance by determining the bonding positions of the first and second light receiving elements 141 and 142 in advance. It becomes possible. As a result, it is possible to perform individual mounting in advance by simple flip chip connection or the like without performing wire bonding, so that it is possible to improve the mounting yield and reduce the cost.

また、上記各実施例では、第１及び第２の偏波分離カプラ１３１及び１３２として２つの連結されたＰＢＳを用いた例を示したが、これに限定されず、２つの別個のＰＢＳを用いて構成してもよい。   In each of the above embodiments, two connected PBSs are used as the first and second polarization separation couplers 131 and 132. However, the present invention is not limited to this, and two separate PBSs are used. May be configured.

ＰＤＭ−ＱＰＳＫ送信器 １、１００、２００
ＰＤＭ−ＱＰＳＫ変調器 １０、１１０
ＩＱ変調器 １１、１２、１１１、１１２
Ｉチャネル用ＭＺ変調器 １３、１１３
Ｑチャネル用ＭＺ変調器 １４、１１４
調整用電極 １５、１１５
光学レンズ ２１〜２４、１２１、１２２
ＰＢＳ ３０
受光素子 ４１、４２、１４１、１４２
半波長板 ５０、２１０
２入力１出力の合波部 １１６、１１７
偏波合波器 １３０、２０１、３０１
偏波分離カプラ １３１、１３２
高周波配線基板 ３１０
電極 ３２０ PDM-QPSK transmitter 1, 100, 200
PDM-QPSK modulator 10, 110
IQ modulator 11, 12, 111, 112
I-channel MZ modulator 13, 113
Q channel MZ modulator 14, 114
Adjustment electrode 15, 115
Optical lenses 21-24, 121, 122
PBS 30
Light receiving element 41, 42, 141, 142
Half-wave plate 50, 210
2-input 1-output multiplexer 116, 117
Polarization multiplexer 130, 201, 301
Polarization separation coupler 131, 132
High frequency wiring board 310
Electrode 320

Claims (8)

第１の受光素子と、
第２の受光素子と、
互いに直交する略直線偏光である第１の偏光及び第２の偏光を含む第１の光及び第２の光が入射され、前記第１の光の第１の偏光を透過して前記第１の受光素子に出力し、前記第２の光の第２の偏光の光路を変更して前記第２の受光素子に出力する偏波分離部であって、前記第１の光の第２の偏光の光路を変更し、前記第２の光の第１の偏光を透過することによって、前記第１の光の第２の偏光と前記第２の光の第１の偏光とを合波して出力する偏波分離部と、
を備えたことを特徴とする偏波合波器。 A first light receiving element;
A second light receiving element;
The first light and the second light including the first polarization and the second polarization, which are substantially linear polarizations orthogonal to each other, enter, pass through the first polarization of the first light, and transmit the first light. A polarization separation unit that outputs to the light receiving element, changes an optical path of the second polarized light of the second light, and outputs the second polarized light to the second light receiving element, wherein the polarization separating unit outputs the second polarized light of the first light; By changing the optical path and transmitting the first polarized light of the second light, the second polarized light of the first light and the first polarized light of the second light are combined and output. A polarization separation unit;
A polarization multiplexer characterized by comprising: 前記偏波分離部は、
前記第１の光が入射されて、前記第１の光の第１の偏光を透過して出力し、前記第１の光の第２の偏光の光路を変更して出力する第１の偏波分離カプラと、
前記第２の光と前記第１の偏波分離カプラから出力された前記第１の光の第２の偏光が入射されて、前記第２の光の第２の偏光の光路と前記第１の偏波分離カプラから出力された前記第１の光の第２の偏光の光路とを変更して出力し、前記第２の光の第１の偏光を透過して出力する第２の偏波分離カプラと、
を含むことを特徴とする請求項１に記載の偏波合波器。 The polarization separator is
The first polarized light that is incident on the first light, transmits and outputs the first polarized light of the first light, and changes and outputs the second polarized light path of the first light. A separation coupler;
The second light and the second polarization of the first light output from the first polarization separation coupler are incident, and the second polarization optical path of the second light and the first light The second polarization separation that outputs the first polarized light of the second light by changing the optical path of the second polarized light output from the polarization separation coupler and outputs the first polarized light. A coupler,
The polarization multiplexer according to claim 1, comprising: 前記第１の受光素子は、前記第１の偏波分離カプラにおける前記第１の光の第１の偏光の出力端面に搭載され、
前記第２の受光素子は、前記第２の偏波分離カプラにおける前記第２の光の第２の偏光の出力端面に搭載されていることを特徴とする請求項２に記載の偏波合波器。 The first light receiving element is mounted on an output end face of the first polarization of the first light in the first polarization separation coupler,
The polarization multiplexing according to claim 2, wherein the second light receiving element is mounted on an output end face of the second polarization of the second light in the second polarization separation coupler. vessel. 前記第１の偏波分離カプラ及び前記第２の偏波分離カプラは、互いに連結されていることを特徴とする請求項２又は３に記載の偏波合波器。   The polarization multiplexer according to claim 2 or 3, wherein the first polarization separation coupler and the second polarization separation coupler are connected to each other. 前記第１の偏波分離カプラの前記第１の光の入力端面又は前記第２の偏波分離カプラの前記第２の光の入力端面に設けられた半波長板をさらに備えたことを特徴とする請求項２乃至４のいずれかに記載の偏波合波器。   A half-wave plate provided on the input end face of the first light of the first polarization separation coupler or the input end face of the second light of the second polarization separation coupler; The polarization multiplexer according to any one of claims 2 to 4. 前記第１の受光素子及び前記第２の受光素子が、それぞれ高周波配線基板上に配置されていることを特徴とする請求項１乃至５のいずれかに記載の偏波合波器。   6. The polarization multiplexer according to claim 1, wherein the first light receiving element and the second light receiving element are respectively disposed on a high-frequency wiring board. 前記第１の受光素子の受光面は、前記第１の受光素子に入力する前記第１の光の第１の偏光の光軸に対して８０°以上９０°未満の角度に傾けられており、
前記第２の受光素子の受光面は、前記第２の受光素子に入力する前記第２の光の第２の偏光の光軸に対して８０°以上９０°未満の角度に傾けられていることを特徴とする請求項１乃至６のいずれかに記載の偏波合波器。 The light receiving surface of the first light receiving element is inclined at an angle of not less than 80 ° and less than 90 ° with respect to the optical axis of the first polarized light of the first light input to the first light receiving element,
The light receiving surface of the second light receiving element is inclined at an angle of not less than 80 ° and less than 90 ° with respect to the optical axis of the second polarized light of the second light input to the second light receiving element. The polarization multiplexer according to any one of claims 1 to 6. 請求項１乃至７のいずれかに記載の偏波合波器と、
光変調器であって、
第１のＩチャネル光及び第１のＱチャネル光を出力する第１のＩＱ変調部と、
第２のＩチャネル光及び第２のＱチャネル光を出力する第２のＩＱ変調部と、
前記第１のＩＱ変調部から出力された前記第１のＩチャネル光及び前記第１のＱチャネル光を合波して前記第１の光を出力する２入力１出力の第１の合波部と、
前記第２のＩＱ変調部から出力された前記第２のＩチャネル光及び前記第２のＱチャネル光を合波して前記第２の光を出力する２入力１出力の第２の合波部と、
を含む光変調器と、
前記第１の合波部から出力された前記第１の光をコリメートして前記偏波合波器に出力する第１の光学レンズと、
前記第２の合波部から出力された前記第２の光をコリメートして前記偏波合波器に出力する第２の光学レンズと、
を備えたことを特徴とする光送信器。 The polarization multiplexer according to any one of claims 1 to 7,
An optical modulator,
A first IQ modulator that outputs first I channel light and first Q channel light;
A second IQ modulator that outputs second I channel light and second Q channel light;
A 2-input 1-output first combining unit that combines the first I-channel light and the first Q-channel light output from the first IQ modulation unit and outputs the first light. When,
A 2-input 1-output second combining unit that combines the second I-channel light and the second Q-channel light output from the second IQ modulation unit and outputs the second light. When,
An optical modulator comprising:
A first optical lens that collimates the first light output from the first combining unit and outputs the collimated light to the polarization multiplexer;
A second optical lens that collimates the second light output from the second combining unit and outputs the collimated light to the polarization multiplexer;
An optical transmitter comprising:
JP2014167966A 2014-08-20 2014-08-20 Polarized wave multiplexer and optical transmitter using the same Pending JP2016045256A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018040946A (en) * 2016-09-07 2018-03-15 日本電信電話株式会社 Light monitor circuit
JP2019174571A (en) * 2018-03-27 2019-10-10 住友大阪セメント株式会社 Optical modulation device
JP2021184110A (en) * 2017-10-25 2021-12-02 日本電信電話株式会社 Light monitor circuit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018040946A (en) * 2016-09-07 2018-03-15 日本電信電話株式会社 Light monitor circuit
JP2021184110A (en) * 2017-10-25 2021-12-02 日本電信電話株式会社 Light monitor circuit
JP7156472B2 (en) 2017-10-25 2022-10-19 日本電信電話株式会社 Optical monitor circuit
JP2019174571A (en) * 2018-03-27 2019-10-10 住友大阪セメント株式会社 Optical modulation device
JP7135374B2 (en) 2018-03-27 2022-09-13 住友大阪セメント株式会社 light modulator

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