JP4489743B2 - Frame synchronization method and optical signal receiving apparatus - Google Patents

Frame synchronization method and optical signal receiving apparatus Download PDF

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JP4489743B2
JP4489743B2 JP2006272671A JP2006272671A JP4489743B2 JP 4489743 B2 JP4489743 B2 JP 4489743B2 JP 2006272671 A JP2006272671 A JP 2006272671A JP 2006272671 A JP2006272671 A JP 2006272671A JP 4489743 B2 JP4489743 B2 JP 4489743B2
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由明 木坂
茂樹 相澤
宮本　　裕
正文 古賀
和人 武井
靖行 遠藤
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Nippon Telegraph and Telephone Corp
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本発明は角度変調された光信号の受信に関する。特に、受信信号から特定のフレーム同期パタンを検索してフレーム同期を確立する技術に関する。   The present invention relates to the reception of angle modulated optical signals. In particular, the present invention relates to a technique for establishing a frame synchronization by searching a specific frame synchronization pattern from a received signal.

角度変調により位相、周波数または偏波面が２値変調された信号光を受信するには、その信号光を強度変調光に変換し、その強度変調光を受光素子により電気信号に変換する。狭帯域のフィルタや特定の偏波面のみを透過する素子を用いることでも強度変調光に変換することはできるが、多くの場合、位相または周波数が変調された信号光を強度変調光に変換するためにはマッハ・ツェンダ干渉計が用いられ、偏波面が変調された信号光を強度変調光に変換するためには偏波コントローラおよび偏波分離器が用いられる。
ＩＴＵ−Ｔ勧告Ｇ．７０９ In order to receive signal light whose phase, frequency, or polarization plane is binary-modulated by angle modulation, the signal light is converted into intensity-modulated light, and the intensity-modulated light is converted into an electrical signal by a light receiving element. Although it can be converted into intensity-modulated light by using a narrow-band filter or an element that transmits only a specific polarization plane, in many cases, signal light whose phase or frequency is modulated is converted into intensity-modulated light. A Mach-Zehnder interferometer is used, and a polarization controller and a polarization separator are used to convert signal light whose polarization plane is modulated into intensity-modulated light.
ITU-T Recommendation G. 709

マッハ・ツェンダ干渉計や偏波コントローラと偏波分離器との組み合わせでは、ひとつの光入力に対して、互いに論理が反転した二つの光が得られる。例えば周波数変調（ＦＳＫ：Frequency Shift Keying）光をマッハ・ツェンダ干渉計に入力すると、２値の一方を表す周波数のときに一方の出力ポートのみに出力光が得られ、２値の他方を表す周波数のときには他方の出力ポートのみに出力光が得られる。また、位相変調のうち前のビットとの位相変化量により変調を行う差動位相偏移変調（ＤＰＳＫ：Differential
Phase Shift Keying）を用いる場合には、マッハ・ツェンダ干渉計により二つの光路で１ビット分の遅延差を与えて干渉させることにより、位相偏移がない場合には一方の出力ポートのみに出力光が得られ、位相偏移がある場合には他方の出力ポートのみに出力光が得られる。偏波変調（ＰｏｌＳＫ：Polarization
Shift Keying）の場合には、偏波コントローラと偏波分離器とを組み合わせることで、二つの偏波状態に対して別々のポートに出力を得ることができる。どのような条件でどちらのポートに出力されるかは、あらかじめ設定される。 With a combination of a Mach-Zehnder interferometer, a polarization controller and a polarization separator, two lights whose logics are inverted with respect to one light input can be obtained. For example, when frequency modulated (FSK) light is input to a Mach-Zehnder interferometer, output light is obtained only at one output port at a frequency representing one of the binary values, and a frequency representing the other of the binary values. In this case, output light is obtained only at the other output port. Also, differential phase shift keying (DPSK: Differential modulation) that modulates according to the amount of phase change from the previous bit in phase modulation.
When Phase Shift Keying is used, the Mach-Zehnder interferometer causes interference by giving a 1-bit delay difference between the two optical paths, and when there is no phase shift, the output light is output only to one output port. When there is a phase shift, output light is obtained only at the other output port. Polarization modulation (PolSK: Polarization)
In the case of (Shift Keying), by combining a polarization controller and a polarization separator, outputs can be obtained at different ports for two polarization states. Which port is used for output to which port is set in advance.

しかし、設定によっては、出力状態が二つのポートで反転し、受信信号の論理が反転する可能性がある。その場合、受信信号から特定のフレーム同期パタンを検索してフレーム同期を確立しようとしても、そのようなパタンは検出できず、フレーム同期を確立できないことになる。   However, depending on the setting, the output state may be inverted at the two ports, and the logic of the received signal may be inverted. In that case, even if an attempt is made to establish a frame synchronization by searching for a specific frame synchronization pattern from the received signal, such a pattern cannot be detected and the frame synchronization cannot be established.

本発明は、このような課題を解決し、受信信号の論理が反転していてもフレーム同期を確立することのできるフレーム同期方法および光信号受信装置を提供することを目的とする。   An object of the present invention is to solve such problems and to provide a frame synchronization method and an optical signal receiving apparatus capable of establishing frame synchronization even when the logic of the received signal is inverted.

本発明の第一の観点によると、位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換し、この二つの強度変調光の少なくとも一方を電気信号に変換し、この電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する方法において、前記特定のフレーム同期パタンを検出できない場合には逆論理でフレーム同期パタンを検索することを特徴とするフレーム同期方法が提供される。   According to the first aspect of the present invention, signal light whose phase, frequency, or plane of polarization is binary-modulated is converted into two intensity-modulated lights whose logics are inverted, and at least one of the two intensity-modulated lights is electrically converted. In the method of converting to a signal and searching for a specific frame synchronization pattern from the electrical signal to establish frame synchronization, if the specific frame synchronization pattern cannot be detected, the frame synchronization pattern is searched using inverse logic. A frame synchronization method is provided.

逆論理でフレーム同期パタンを検索するには、前記電気信号の論理を反転させるか、前記電気信号から前記特定のフレーム同期パタンと逆論理のパタンを検索するか、あるいは、前記二つの強度変調光の論理を互いに反転させる。   In order to retrieve the frame synchronization pattern by the reverse logic, the logic of the electric signal is inverted, the pattern of the reverse logic to the specific frame synchronization pattern is searched from the electric signal, or the two intensity-modulated light beams Invert the logic of each other.

前記電気信号の論理を反転させる場合、前記電気信号とその論理を反転させた信号とで並列に前記特定のフレーム同期パタンを検索することもできる。   When the logic of the electrical signal is inverted, the specific frame synchronization pattern can be searched in parallel with the electrical signal and the signal with the inverted logic.

前記信号光がＤＰＳＫ光あるいはＦＳＫ光である場合には、マッハ・ツェンダ干渉計により強度変調光に変換することができる。前記信号光がＰｏｌＳＫ光である場合には、偏波コントローラおよび偏波分離器（ＰＢＳ：Polarization Beam Splitter）により強度変調光に変換することができる。   When the signal light is DPSK light or FSK light, it can be converted into intensity-modulated light by a Mach-Zehnder interferometer. When the signal light is PolSK light, it can be converted into intensity-modulated light by a polarization controller and a polarization beam splitter (PBS).

本発明の別の観点によると、位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、この光電気変換手段の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立するフレーム同期回路とを備えた構成において、前記フレーム同期回路においてフレーム同期が取れない場合には前記光電気変換手段から出力されて前記フレーム同期回路に入力される電気信号の論理を反転させる手段を備えたことを特徴とする光信号受信装置が提供される。   According to another aspect of the present invention, the modulation conversion means for converting the signal light whose phase, frequency, or plane of polarization is binary-modulated into two intensity-modulated lights whose logics are inverted from each other, and the modulation conversion means obtained by the modulation conversion means Photoelectric conversion means for converting at least one of the two intensity-modulated lights into an electric signal; and a frame synchronization circuit for searching for a specific frame synchronization pattern from the electric signal output from the photoelectric conversion means and establishing frame synchronization. The frame synchronization circuit further comprises means for inverting the logic of the electrical signal output from the photoelectric conversion means and input to the frame synchronization circuit when frame synchronization cannot be achieved in the frame synchronization circuit. An optical signal receiving apparatus is provided.

本発明のさらに別の観点によると、位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、この光電気変換手段の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する第一のフレーム同期回路とを備えた構成において、前記光電気変換手段の出力する電気信号の論理を反転させる論理反転回路と、この論理反転回路の出力から前記特定のフレーム同期パタンを検索してフレーム同期を確立する第二のフレーム同期手段と、前記第一のフレーム同期回路と前記第二のフレーム同期回路とのそれぞれのフレーム同期結果にしたがって、フレーム同期が確立した側の論理の電気信号を受信信号として選択する手段とを備えたことを特徴とする光信号受信装置が提供される。   According to still another aspect of the present invention, modulation conversion means for converting signal light whose phase, frequency, or polarization plane is binary-modulated into two intensity-modulated lights whose logics are inverted from each other, and obtained by the modulation conversion means. A photoelectric conversion means for converting at least one of the two intensity-modulated lights into an electric signal, and a first frame for establishing a frame synchronization by searching for a specific frame synchronization pattern from the electric signal output from the photoelectric conversion means. In a configuration including a synchronization circuit, a logic inversion circuit for inverting the logic of an electric signal output from the photoelectric conversion means, and frame synchronization is established by searching for the specific frame synchronization pattern from the output of the logic inversion circuit. According to the respective frame synchronization results of the second frame synchronization means, the first frame synchronization circuit and the second frame synchronization circuit. Optical signal receiving apparatus characterized by comprising a means for selecting the logic of the electrical signal on the side over beam synchronization has been established as a reception signal.

本発明のさらに別の観点によると、位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、この光電気変換手段の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する第一のフレーム同期回路とを備えた構成において、前記光電気変換手段の出力する電気信号から前記特定のフレーム同期パタンとは逆論理のパタンを検索してフレーム同期を確立する第二のフレーム同期回路と、前記第一のフレーム同期回路でフレーム同期が確立されたときには前記光電気変換手段の出力する電気信号を受信信号として選択し、前記第二のフレーム同期回路でフレーム同期が確立されたときには前記電気信号の論理を反転させた信号を受信信号として選択する選択手段とを備えたことを特徴とする光信号受信装置が提供される。   According to still another aspect of the present invention, modulation conversion means for converting signal light whose phase, frequency, or polarization plane is binary-modulated into two intensity-modulated lights whose logics are inverted from each other, and obtained by the modulation conversion means. A photoelectric conversion means for converting at least one of the two intensity-modulated lights into an electric signal, and a first frame for establishing a frame synchronization by searching for a specific frame synchronization pattern from the electric signal output from the photoelectric conversion means. In a configuration including a synchronization circuit, a second frame synchronization circuit that establishes frame synchronization by searching a pattern having a logic opposite to that of the specific frame synchronization pattern from an electrical signal output from the photoelectric conversion means, When frame synchronization is established by the first frame synchronization circuit, the electrical signal output from the photoelectric conversion means is selected as a reception signal, and the second frame When the frame synchronization is established in the period circuit optical signal receiving apparatus characterized by comprising a selection means for selecting a signal obtained by inverting the logic of the electrical signal as a reception signal.

本発明のさらに別の観点によると、位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、 この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、この光電気変換手段の出力から特定のフレーム同期パタンを検索してフレーム同期を確立するフレーム同期回路とを備えた構成において、前記フレーム同期回路においてフレーム同期が取れない場合には前記変調変換手段の状態を調整してその出力する二つの強度変調光の論理を入れ替える手段を備えたことを特徴とする光信号受信装置が提供される。   According to still another aspect of the present invention, modulation conversion means for converting signal light whose phase, frequency, or polarization plane is binary-modulated into two intensity-modulated lights whose logics are inverted from each other, and obtained by the modulation conversion means A photoelectric conversion means for converting at least one of the two intensity-modulated lights into an electric signal, and a frame synchronization circuit for searching for a specific frame synchronization pattern from the output of the photoelectric conversion means and establishing frame synchronization. An optical signal receiving device comprising: means for adjusting the state of the modulation conversion means and exchanging the logic of two intensity-modulated lights output when the frame synchronization circuit cannot achieve frame synchronization. An apparatus is provided.

本発明によれば、受信信号の論理が反転している場合でも、逆論理でフレーム同期パタンを検索することで、確実にフレーム同期を確立することができる。   According to the present invention, even when the logic of the received signal is inverted, the frame synchronization can be reliably established by searching the frame synchronization pattern with the reverse logic.

以下、本発明の実施形態について図面を参照して説明する。   Embodiments of the present invention will be described below with reference to the drawings.

図１は本発明第一実施例の光信号受信装置を示すブロック構成図である。この装置は、位相、周波数または偏波面が２値変調された信号光を受信するレシーバ１０と、このレシーバ１０の出力する電気信号を処理する信号処理部２０と、この信号処理部２０の動作を制御する制御回路３０とを備える。信号処理部２０は集積回路として構成され、制御回路３０は、信号処理部２０と同じ集積回路内に、あるいはその外部接続回路として構成される。   FIG. 1 is a block diagram showing an optical signal receiving apparatus according to the first embodiment of the present invention. This apparatus includes a receiver 10 that receives signal light whose phase, frequency, or polarization plane is binary-modulated, a signal processing unit 20 that processes an electrical signal output from the receiver 10, and an operation of the signal processing unit 20. And a control circuit 30 for controlling. The signal processing unit 20 is configured as an integrated circuit, and the control circuit 30 is configured in the same integrated circuit as the signal processing unit 20 or as an external connection circuit thereof.

図２はＤＰＳＫ光あるいはＦＳＫ光を受信するためのレシーバ１０の構成例を示す。このレシーバ１０はマッハ・ツェンダ干渉計（ＭＺＩ）１１と光電気変換部１２とにより構成される。マッハ・ツェンダ干渉計１１は入力光を分波して光路長差を与えた後に再び合波させて干渉させるものであり、その光路長差がＤＰＳＫ光に対しては１ビットの信号差に、ＦＳＫ光に対しては２値変調の周波数差に対応して設定される。この設定により、変調状態に応じて二つの出力ポートＡ、Ｂのいずれか一方に光が出力され、互いに論理が反転した二つの強度変調光が得られる。光電気変換部１２としては二つの受光素子が直列に接続された平衡型光検出器が用いられ、その二つの受光素子でそれぞれマッハ・ツェンダ干渉計１１の二つのポートＡ、Ｂの出力を受光して、ひとつの電気信号を出力する。光電気変換部１２として単一の受光素子を用い、二つの強度変調光の一方のみを受光する構成とすることもできる。   FIG. 2 shows a configuration example of the receiver 10 for receiving DPSK light or FSK light. The receiver 10 includes a Mach-Zehnder interferometer (MZI) 11 and a photoelectric conversion unit 12. The Mach-Zehnder interferometer 11 demultiplexes the input light to give an optical path length difference, and then multiplexes and interferes again. The optical path length difference is a 1-bit signal difference for DPSK light. For FSK light, it is set corresponding to the frequency difference of binary modulation. With this setting, light is output to one of the two output ports A and B according to the modulation state, and two intensity-modulated lights whose logics are inverted are obtained. The photoelectric converter 12 is a balanced photodetector in which two light receiving elements are connected in series, and the two light receiving elements receive the outputs of the two ports A and B of the Mach-Zehnder interferometer 11, respectively. Then, one electrical signal is output. A single light receiving element may be used as the photoelectric conversion unit 12 to receive only one of the two intensity-modulated lights.

また、図３に示すレシーバはＰｏｌＳＫ光を受信するためのものであり、偏波コントローラ１３と、偏波分離器（ＰＢＳ）１４と、光電気変換部１２とにより構成される。この構成においても、変調状態に応じて二つの出力ポートＡ、Ｂのいずれか一方に光が出力され、互いに論理が反転した二つの強度変調光が得られる。光電気変換部１５としては、図２に示した光電気変換部１２と同等のものが用いられる。   The receiver shown in FIG. 3 is for receiving PolSK light, and includes a polarization controller 13, a polarization separator (PBS) 14, and a photoelectric conversion unit 12. Also in this configuration, light is output to one of the two output ports A and B according to the modulation state, and two intensity-modulated lights whose logics are inverted are obtained. As the photoelectric conversion part 15, the thing equivalent to the photoelectric conversion part 12 shown in FIG. 2 is used.

強度変調方式の光通信システムでは受信信号の論理が反転することはないが、図２または図３に示したレシーバを用いる場合、その設定状況により、受信信号の論理が反転する可能性がある。そのような場合、フレーム同期を確立できないことになる。これを防止するための構成および動作について、再び図１を参照して説明する。   In the intensity modulation optical communication system, the logic of the received signal is not inverted. However, when the receiver shown in FIG. 2 or FIG. 3 is used, the logic of the received signal may be inverted depending on the setting state. In such a case, frame synchronization cannot be established. The configuration and operation for preventing this will be described with reference to FIG. 1 again.

信号処理部２０は、レシーバ１０の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立するフレーム同期回路２０２と、確立したフレーム同期を用いてレシーバ１０から出力された電気信号を処理するフレーム処理回路２０３とを備え、さらに、フレーム同期回路２０２においてフレーム同期が取れない場合に、レシーバ１０から出力されてフレーム同期回路２０２に入力される電気信号の論理を反転させる論理反転回路２０１を備える。   The signal processing unit 20 searches for a specific frame synchronization pattern from the electrical signal output from the receiver 10 to establish frame synchronization, and the electrical signal output from the receiver 10 using the established frame synchronization. And a logic inversion circuit 201 that inverts the logic of an electric signal output from the receiver 10 and input to the frame synchronization circuit 202 when the frame synchronization circuit 202 cannot achieve frame synchronization. Is provided.

制御回路３０は、レシーバ１０の動作状態およびフレーム同期回路２０２のフレーム同期結果を監視し、レシーバ１０のロック異常状態が解消されているにもかかわらずフレーム同期がとれないＯＯＦ（アウト・オブ・フレーム）あるいはＬＯＦ（ロス・オブ・フレーム）のときには、論理反転回路２０１に論理反転の指示を出す。なお、ＯＯＦはフレーム同期パタンが規定回数連続で検出されない状態、ＬＯＦはＯＯＦが規定時間（数ｍｓ）継続した状態を表す。論理反転回路２０１により電気信号の論理を反転してもフレーム同期回路２０２でフレーム同期をとれない場合には、アラームを生成する。また、フレーム同期がとれない場合（ＯＯＦあるいはＬＯＦ）に、一定時間ごとに論理反転を繰り返しても良い。この動作はレシーバ１０のロック状態とは無関係であり、ロック状態通知がなくても動作できる。   The control circuit 30 monitors the operation state of the receiver 10 and the frame synchronization result of the frame synchronization circuit 202, and OOF (out-of-frame) in which frame synchronization is not achieved even though the lock abnormality state of the receiver 10 is eliminated. ) Or LOF (loss of frame), the logic inversion circuit 201 is instructed to invert the logic. OOF represents a state in which the frame synchronization pattern has not been detected for a predetermined number of times, and LOF represents a state in which the OOF has continued for a predetermined time (several ms). If frame synchronization cannot be achieved by the frame synchronization circuit 202 even if the logic of the electrical signal is inverted by the logic inversion circuit 201, an alarm is generated. In addition, when frame synchronization cannot be achieved (OOF or LOF), logic inversion may be repeated at regular intervals. This operation is irrelevant to the locked state of the receiver 10 and can be operated without notification of the locked state.

電気信号の論理反転に要する時間は高々数マイクロ秒であり、例えば非特許文献１で定義された光伝送ネットワーク（ＯＴＮ）の信号光、すなわち光チャネル伝送ユニットＯＴＵ１、ＯＴＵ２、ＯＴＵ３を受信する場合にも、短時間でフレーム同期を確立することができる。   The time required for logical inversion of the electrical signal is at most several microseconds. For example, when receiving the signal light of the optical transmission network (OTN) defined in Non-Patent Document 1, that is, optical channel transmission units OTU1, OTU2, and OTU3. However, frame synchronization can be established in a short time.

図４は本発明第二実施例のＤＰＳＫ信号受信装置を示すブロック構成図である。   FIG. 4 is a block diagram showing a DPSK signal receiving apparatus according to the second embodiment of the present invention.

この実施例装置は、レシーバ１０と、信号処理部２１と、制御回路３１とを備え、信号処理部２１は、レシーバ１０から出力された電気信号から特定のフレーム同期パタンが検出されたときにフレーム同期を確立する第一のフレーム同期回路２１１と、レシーバ１０から出力された電気信号の論理を反転させる論理反転回路２１２と、この論理反転回路２１２の出力から特定のフレーム同期パタンが検出されたときにフレーム同期を確立する第二のフレーム同期回路２１３と、フレーム同期回路２１１、２１３の一方の出力を選択する選択部２１４と、選択されたデータを処理するフレーム処理回路２１５と備える。   The apparatus according to this embodiment includes a receiver 10, a signal processing unit 21, and a control circuit 31, and the signal processing unit 21 generates a frame when a specific frame synchronization pattern is detected from an electrical signal output from the receiver 10. First frame synchronization circuit 211 that establishes synchronization, logic inversion circuit 212 that inverts the logic of the electrical signal output from the receiver 10, and when a specific frame synchronization pattern is detected from the output of this logic inversion circuit 212 A second frame synchronization circuit 213 for establishing frame synchronization, a selection unit 214 for selecting one output of the frame synchronization circuits 211 and 213, and a frame processing circuit 215 for processing the selected data.

この構成において、フレーム同期回路２１１、２１３は互いに逆論理の電気信号に対して同時にフレーム同期の処理を行う。制御回路３１は、それらのフレーム同期結果を監視し、フレーム同期がとれた側のデータを選択するように選択部２１４に指示し、選択されたデータがフレーム処理回路２１５で処理される。   In this configuration, the frame synchronization circuits 211 and 213 simultaneously perform frame synchronization processing on electrical signals having opposite logics. The control circuit 31 monitors these frame synchronization results, instructs the selection unit 214 to select data on the frame synchronized side, and the selected data is processed by the frame processing circuit 215.

本実施例は、フレーム同期回路が二つ必要となり、また、選択部も必要となる が、最初のフレーム同期パタンで確実にフレーム同期を確立することができる。   In this embodiment, two frame synchronization circuits are required and a selection unit is also required. However, frame synchronization can be reliably established with the first frame synchronization pattern.

図５は本発明第三実施例の光信号受信装置を示すブロック構成図である。この実施例は、電気信号の論理を反転させた信号と反転させていない信号とで並列に同じフレーム同期パタンを検索するのではなく、同じ信号に対して、フレーム同期パタンとその逆論理のパタンとを並列に検索することが第二実施例と異なる。   FIG. 5 is a block diagram showing an optical signal receiving apparatus according to the third embodiment of the present invention. In this embodiment, the same frame synchronization pattern is not searched in parallel between the signal with the logic signal inverted and the signal not inverted, but the frame synchronization pattern and the reverse logic pattern are searched for the same signal. Is different from the second embodiment.

すなわち、この実施例装置は、レシーバ１０と、信号処理部２２と、制御回路３２とを備え、信号処理部２２は、レシーバ１０の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する第一のフレーム同期回路２２１と、レシーバ１０の出力する電気信号から特定のフレーム同期パタンとは逆論理のパタンを検索してフレーム同期を確立する第二のフレーム同期回路２２２と、フレーム同期回路２２１でフレーム同期が確立されたときにはレシーバ１０の出力する電気信号を受信信号として選択し、フレーム同期回路２２２でフレーム同期が確立されたときにはレシーバ１０の出力した電気信号の論理を反転させた信号を受信信号として選択する反転回路２２３および選択部２２４と、選択された受信信号を処理するフレーム処理回路２２５と備える。   That is, this embodiment apparatus includes a receiver 10, a signal processing unit 22, and a control circuit 32. The signal processing unit 22 searches for a specific frame synchronization pattern from the electrical signal output from the receiver 10, and performs frame synchronization. A first frame synchronization circuit 221 that establishes frame synchronization, a second frame synchronization circuit 222 that establishes frame synchronization by searching a pattern having a logic opposite to that of a specific frame synchronization pattern from the electrical signal output from the receiver 10, and a frame When frame synchronization is established by the synchronization circuit 221, the electrical signal output from the receiver 10 is selected as a reception signal. When frame synchronization is established by the frame synchronization circuit 222, the logic of the electrical signal output from the receiver 10 is inverted. Inverting circuit 223 and selecting unit 224 for selecting a signal as a received signal, and processing the selected received signal It includes a frame processing circuit 225 that.

この構成において、フレーム同期回路２２１、２２２は同じ電気信号に対して互いに逆論理でフレーム同期処理を行う。制御回路３２は、それらのフレーム同期結果を監視し、フレーム同期がとれた側の論理に対応する受信信号を選択するように選択部２２４に指示し、選択された受信信号がフレーム処理回路２２５で処理される。   In this configuration, the frame synchronization circuits 221 and 222 perform frame synchronization processing with the opposite logic to the same electrical signal. The control circuit 32 monitors the frame synchronization results, instructs the selection unit 224 to select a reception signal corresponding to the logic on the side where the frame synchronization is achieved, and the selected reception signal is received by the frame processing circuit 225. It is processed.

図６は本発明第四実施例の光信号受信装置を示すブロック構成図である。   FIG. 6 is a block diagram showing an optical signal receiving apparatus according to the fourth embodiment of the present invention.

この実施例装置は、レシーバ１０と、信号処理部２３と、制御回路３３とを備え、信号処理部２３は、レシーバ１０の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立するフレーム同期回路２３１と、確立したフレーム同期を用いてレシーバ１０から出力された電気信号を処理するフレーム処理回路２３２とを備える。   The apparatus according to this embodiment includes a receiver 10, a signal processing unit 23, and a control circuit 33. The signal processing unit 23 searches for a specific frame synchronization pattern from the electrical signal output from the receiver 10, and establishes frame synchronization. And a frame processing circuit 232 that processes the electrical signal output from the receiver 10 using the established frame synchronization.

制御回路３３は、レシーバ１０の動作状態およびフレーム同期回路２３１のフレーム同期結果を監視し、レシーバ１０のロック異常状態が解消されているにもかかわらずフレーム同期がとれない場合には、レシーバ１０に論理反転の指示を出し、レシーバ１０の状態を調整してその出力する電気信号の論理を反転させる。論理が反転されてもフレーム同期回路２３１でフレーム同期をとれない場合には、アラームを生成する。   The control circuit 33 monitors the operation state of the receiver 10 and the frame synchronization result of the frame synchronization circuit 231, and if the frame synchronization cannot be achieved even though the lock abnormality state of the receiver 10 has been eliminated, A logic inversion instruction is issued, the state of the receiver 10 is adjusted, and the logic of the output electric signal is inverted. If the frame synchronization circuit 231 cannot achieve frame synchronization even if the logic is inverted, an alarm is generated.

レシーバ１０が安定化するには少々時間がかかり、例えばマッハ・ツェンダ干渉計が安定化するには２０秒近くかかる。このため、論理が反転していた場合、本実施例では短時間でのフレーム同期の確立は望めない。しかし、信号処理部２３として既存の集積回路を用い、制御回路３３による制御方法を変更するだけでよいので、実施が容易である。また、光ネットワークの運用開始時にレシーバ１０の状態を設定しておけば、それ以降は変更する必要がない。   It takes some time for the receiver 10 to stabilize, for example, it takes nearly 20 seconds for the Mach-Zehnder interferometer to stabilize. For this reason, when the logic is inverted, in this embodiment, establishment of frame synchronization in a short time cannot be expected. However, since an existing integrated circuit is used as the signal processing unit 23 and only the control method by the control circuit 33 is changed, the implementation is easy. If the state of the receiver 10 is set at the start of operation of the optical network, it is not necessary to change thereafter.

本発明は、フレーム同期を行う光通信システムで広く利用することができるが、特に、非特許文献１で定義されたＯＴＵ１、ＯＴＵ２あるいはＯＴＵ３の受信に利用して、フレーム同期を確実に確立することができる。   The present invention can be widely used in an optical communication system that performs frame synchronization. In particular, the present invention can be used to receive OTU1, OTU2, or OTU3 defined in Non-Patent Document 1 to reliably establish frame synchronization. Can do.

本発明第一実施例の光信号受信装置を示すブロック構成図。The block block diagram which shows the optical signal receiver of 1st Example of this invention. ＤＰＳＫ光あるいはＦＳＫ光を受信するためのレシーバの構成例を示す図。The figure which shows the structural example of the receiver for receiving DPSK light or FSK light. ＰｏｌＳＫ光を受信するためのレシーバの構成例を示す図。The figure which shows the structural example of the receiver for receiving PolSK light. 本発明第二実施例の光信号受信装置を示すブロック構成図。The block block diagram which shows the optical signal receiver of 2nd Example of this invention. 本発明第三実施例の光信号受信装置を示すブロック構成図。The block block diagram which shows the optical signal receiver of 3rd Example of this invention. 本発明第四実施例の光信号受信装置を示すブロック構成図。The block block diagram which shows the optical signal receiver of 4th Example of this invention.

符号の説明Explanation of symbols

１０ レシーバ
１１ マッハ・ツェンダ干渉計
１２、１５ 光電気変換部
１３ 偏波コントローラ
１４ 偏波分離器
２０、２１、２２、２３ 信号処理部
３０、３１、３２、３３ 制御回路
２０１、２１２、２２３ 論理反転回路
２０２、２１１、２１３、２２１、２２２、２３１ フレーム同期回路
２０３、２１５、２２５、２３２ フレーム処理回路
２１４、２２４ 選択部 DESCRIPTION OF SYMBOLS 10 Receiver 11 Mach-Zehnder interferometer 12, 15 Photoelectric conversion part 13 Polarization controller 14 Polarization separator 20, 21, 22, 23 Signal processing part 30, 31, 32, 33 Control circuit 201, 212, 223 Logic inversion Circuit 202, 211, 213, 221, 222, 231 Frame synchronization circuit 203, 215, 225, 232 Frame processing circuit 214, 224 Selector

Claims (3)

位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換し、
この二つの強度変調光の少なくとも一方を電気信号に変換し、
この電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立し、
前記特定のフレーム同期パタンを検出できない場合には逆論理でフレーム同期パタンを検索する
フレーム同期方法において、
前記電気信号とその論理を反転させた信号とで並列に前記特定のフレーム同期パタンを検索する
ことを特徴とするフレーム同期方法。 The signal light whose phase, frequency or plane of polarization is binary-modulated is converted into two intensity-modulated lights whose logics are reversed from each other,
Convert at least one of these two intensity-modulated lights into an electrical signal,
Search for a specific frame synchronization pattern from this electrical signal to establish frame synchronization ,
In the frame synchronization method of searching for the frame synchronization pattern by reverse logic when the specific frame synchronization pattern cannot be detected ,
A frame synchronization method , wherein the specific frame synchronization pattern is searched in parallel between the electrical signal and a signal obtained by inverting the logic . 位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、
この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、
この光電気変換手段の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する第一のフレーム同期回路と
を備えた光信号受信装置において、
前記光電気変換手段の出力する電気信号の論理を反転させる論理反転回路と、
この論理反転回路の出力から前記特定のフレーム同期パタンを検索してフレーム同期を確立する第二のフレーム同期回路と、
前記第一のフレーム同期回路と前記第二のフレーム同期回路とのそれぞれのフレーム同期結果にしたがって、フレーム同期が確立した側の論理の電気信号を受信信号として選択する手段と
を備えたことを特徴とする光信号受信装置。 Modulation conversion means for converting signal light whose phase, frequency or plane of polarization is binary-modulated into two intensity-modulated lights whose logics are inverted from each other;
Photoelectric conversion means for converting at least one of the two intensity-modulated lights obtained by the modulation conversion means into an electric signal;
In an optical signal receiving apparatus comprising: a first frame synchronization circuit that searches for a specific frame synchronization pattern from an electrical signal output from the photoelectric conversion means and establishes frame synchronization;
A logic inversion circuit for inverting the logic of the electric signal output from the photoelectric conversion means;
A second frame synchronization circuit that establishes frame synchronization by searching for the specific frame synchronization pattern from the output of the logic inversion circuit;
Means for selecting, as a received signal, a logical electrical signal on the side where frame synchronization is established according to the respective frame synchronization results of the first frame synchronization circuit and the second frame synchronization circuit. An optical signal receiver. 位相、周波数または偏波面が２値変調された信号光を互いに論理が反転した二つの強度変調光に変換する変調変換手段と、
この変調変換手段により得られた二つの強度変調光の少なくとも一方を電気信号に変換する光電気変換手段と、
この光電気変換手段の出力する電気信号から特定のフレーム同期パタンを検索してフレーム同期を確立する第一のフレーム同期回路と
を備えた光信号受信装置において、
前記光電気変換手段の出力する電気信号から前記特定のフレーム同期パタンとは逆論理のパタンを検索してフレーム同期を確立する第二のフレーム同期回路と、
前記第一のフレーム同期回路でフレーム同期が確立されたときには前記光電気変換手段の出力する電気信号を受信信号として選択し、前記第二のフレーム同期回路でフレーム同期が確立されたときには前記電気信号の論理を反転させた信号を受信信号として選択する選択手段と
を備えたことを特徴とする光信号受信装置。 Modulation conversion means for converting signal light whose phase, frequency or plane of polarization is binary-modulated into two intensity-modulated lights whose logics are inverted from each other;
Photoelectric conversion means for converting at least one of the two intensity-modulated lights obtained by the modulation conversion means into an electric signal;
In an optical signal receiving apparatus comprising: a first frame synchronization circuit that searches for a specific frame synchronization pattern from an electrical signal output from the photoelectric conversion means and establishes frame synchronization;
A second frame synchronization circuit that establishes frame synchronization by searching a pattern having a logic opposite to that of the specific frame synchronization pattern from an electrical signal output from the photoelectric conversion means;
When frame synchronization is established by the first frame synchronization circuit, the electrical signal output from the photoelectric conversion means is selected as a reception signal, and when frame synchronization is established by the second frame synchronization circuit, the electrical signal is selected. An optical signal receiving apparatus comprising: selecting means for selecting a signal obtained by inverting the logic of the received signal as a received signal.
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Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6224731A (en) * 1985-07-25 1987-02-02 Nippon Telegr & Teleph Corp <Ntt> Single mode optical fiber polarized wave multiplex transmission system
JPH0242329A (en) * 1988-04-14 1990-02-13 Nippon Telegr & Teleph Corp <Ntt> Device for measuring optical frequency modulation characteristic
JPH05153110A (en) * 1991-11-26 1993-06-18 Fujitsu Ltd Frame synchronization detecting circuit
JPH0621891A (en) * 1992-06-30 1994-01-28 Fujitsu Ltd Optical transmitter evaluation device for coherent optical communication
JPH1013342A (en) * 1996-06-27 1998-01-16 Nippon Telegr & Teleph Corp <Ntt> Optical wavelength division multiplex transmitter
JPH1127334A (en) * 1997-06-30 1999-01-29 Kenwood Corp Absolute phase processing synchronization acquisition
JP2001339366A (en) * 2000-05-25 2001-12-07 Nippon Telegr & Teleph Corp <Ntt> Wavelength code division multiplex optical receiver
JP2002344426A (en) * 2001-05-18 2002-11-29 Kansai Electric Power Co Inc:The Transmission/reception method and transmission/reception apparatus for polarization state control signal
WO2005088876A1 (en) * 2004-03-17 2005-09-22 Nippon Telegraph And Telephone Corporation Optical transmission system, optical transmission device and optical reception device of optical transmission system
JP2006217605A (en) * 2005-01-31 2006-08-17 Lucent Technol Inc Optical receiving apparatus and method
JP2006270909A (en) * 2005-02-28 2006-10-05 Fujitsu Ltd Optical signal reception device
JP2006295603A (en) * 2005-04-12 2006-10-26 Mitsubishi Electric Corp Optical receiver
JP2007288702A (en) * 2006-04-20 2007-11-01 Fujitsu Ltd Device and control method for optical signal reception

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6224731A (en) * 1985-07-25 1987-02-02 Nippon Telegr & Teleph Corp <Ntt> Single mode optical fiber polarized wave multiplex transmission system
JPH0242329A (en) * 1988-04-14 1990-02-13 Nippon Telegr & Teleph Corp <Ntt> Device for measuring optical frequency modulation characteristic
JPH05153110A (en) * 1991-11-26 1993-06-18 Fujitsu Ltd Frame synchronization detecting circuit
JPH0621891A (en) * 1992-06-30 1994-01-28 Fujitsu Ltd Optical transmitter evaluation device for coherent optical communication
JPH1013342A (en) * 1996-06-27 1998-01-16 Nippon Telegr & Teleph Corp <Ntt> Optical wavelength division multiplex transmitter
JPH1127334A (en) * 1997-06-30 1999-01-29 Kenwood Corp Absolute phase processing synchronization acquisition
JP2001339366A (en) * 2000-05-25 2001-12-07 Nippon Telegr & Teleph Corp <Ntt> Wavelength code division multiplex optical receiver
JP2002344426A (en) * 2001-05-18 2002-11-29 Kansai Electric Power Co Inc:The Transmission/reception method and transmission/reception apparatus for polarization state control signal
WO2005088876A1 (en) * 2004-03-17 2005-09-22 Nippon Telegraph And Telephone Corporation Optical transmission system, optical transmission device and optical reception device of optical transmission system
JP2006217605A (en) * 2005-01-31 2006-08-17 Lucent Technol Inc Optical receiving apparatus and method
JP2006270909A (en) * 2005-02-28 2006-10-05 Fujitsu Ltd Optical signal reception device
JP2006295603A (en) * 2005-04-12 2006-10-26 Mitsubishi Electric Corp Optical receiver
JP2007288702A (en) * 2006-04-20 2007-11-01 Fujitsu Ltd Device and control method for optical signal reception

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