JP2004023295A

JP2004023295A - Wavelength multiplex optical transmission apparatus

Info

Publication number: JP2004023295A
Application number: JP2002173235A
Authority: JP
Inventors: Muneyasu Ooura; 大浦　崇靖
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-06-13
Filing date: 2002-06-13
Publication date: 2004-01-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength multiplex optical transmission apparatus that suppresses crosstalk to other channels occurring in applying power without the need for providing an additional optical output interruption device. <P>SOLUTION: The wavelength multiplex optical transmission apparatus is provided with: a start-up sequence control section 5 that controls an optical output variable control section 4 by using an optical output control signal to adjust the level of modulation light to the minimum value of an optical output variable control range, and controls the optical output variable control section 4 by using the optical output control signal to adjust the level of the modulation light to a desired value of the optical output variable control range when receiving a wavelength locking completion signal; and a wavelength monitor control section 6 that monitors the wavelength of continuous light, controls an ATC (Automatic Temperature Control) circuit 2 so as to lock the monitored wavelength within an assigned wavelength region and informs the start-up sequence control section 5 about the wavelength lock completion signal when the monitored wavelength is locked within an assigned wavelength band. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、波長多重（ＷＤＭ）するための光主信号を送信する波長多重光送信装置に係るものである。
【０００２】
【従来の技術】
波長多重光伝送システムでは、チャンネル毎に異なる波長の光主信号が重畳される。使用できる全波長帯域はデバイス性能の観点から制限があるため、光主信号の数を多くして伝送容量を大きくするためには、光主信号の波長間隔をできるだけ小さくすることが必要となる。ところが、波長間隔を小さくしてくと、あるチャンネルの連続光の波長が不安定になった場合に、他の波長チャンネルに対してクロストークによる悪影響が生じる。
【０００３】
図９は従来の波長多重光送信装置の構成を示す図である。
図９において、１０１はＬＤ（レーザダイオード）、１０２はＡＴＣ回路（自動温度制御回路）、１０３は光変調器、１０４は光出力可変制御部である。
【０００４】
次に動作について説明する。
あるチャンネルに割当てられた波長帯域の連続光がＬＤ１０１から出力すると、この連続光は、電気主信号に応じて光変調器１０３で変調された後、光出力可変制御部１０４でレベル調整され、光主信号として出力する。ＡＴＣ回路１０２はＬＤ１０１の素子温度を制御して連続光の波長を設定波長に安定化させる働きをしている。つまり、次の図１０に示すように、ＬＤ１０１から出力する連続光の波長はＬＤ１０１の素子温度に依存するので、ＡＴＣ回路１０２を設けている。
【０００５】
図１０はＬＤ１０１における連続光の波長と素子温度との関係を示す図であり、横軸はＬＤ１０１の素子温度、縦軸は連続光の波長である。
図１０から分かるように、電源投入時には、ある設定波長に相当する温度に素子温度が到達するまで、ＬＤ１０１から出力する連続光の波長はそのチャンネルに割当てられた波長帯域から外れている。したがって、図９の波長多重光送信装置は、電源投入時に連続光の波長が不安定となって、冒頭で述べた通り、他のチャンネルへ悪影響を与えてしまうことになる。
【０００６】
この問題を解決するために、特開平１１−３４０９１９号公報に開示された波長多重光送信装置には、電源供給のＯＮ／ＯＦＦに関する電源アラームおよび波長アラームのいずれか一方を受けたときに光出力を遮断するデバイスが設けられている。しかしながら、この従来の波長多重光送信装置の場合、光出力を遮断するだけのために、光出力遮断用のデバイスを新たに設けることは構成的・コスト的に不利である。
【０００７】
【発明が解決しようとする課題】
従来の波長多重光送信装置は以上のように構成されているので、電源投入時に、ある設定波長に相当する温度にＬＤの素子温度が到達するまで、他のチャンネルに対してクロストークが生じてしまうという課題があった。
【０００８】
また、従来の波長多重光送信装置は、光出力を遮断するだけのために、光出力遮断用のデバイスを新たに必要とするため、構成的・コスト的に不利になってしまうと言う課題があった。
【０００９】
この発明は上記のような課題を解決するためになされたもので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制可能な波長多重光送信装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
この発明に係る波長多重光送信装置は、電源が投入されると、光出力可変制御手段を制御して、光出力可変制御範囲の最小値に変調光をレベル調整するとともに、波長引込み完了信号が通知されると、光出力可変制御手段を制御して、光出力可変制御範囲の所望の値に変調光をレベル調整する立上げ順序制御手段と、連続光の波長をモニタし、モニタした波長が割当て波長帯域内に引込まれるように、自動温度制御手段を制御するとともに、モニタした波長が割当て波長帯域内に引込まれると、立上げ順序制御手段へ波長引込み完了信号を通知する波長監視制御手段とを備えるようにしたものである。
【００１１】
この発明に係る波長多重光送信装置は、電源が投入されると、光変調手段に対する電気主信号をＯＦＦに切り替えるとともに、立上げ順序制御手段へ波長引込み完了信号が通知されると、光変調手段に対する電気主信号をＯＮに切り替える主信号ＯＮ／ＯＦＦ制御手段と、電源が投入されると、光変調手段を最大消光状態に切り替えるとともに、立上げ順序制御手段へ波長引込み完了信号が通知されると、光変調手段をノーマル状態に切り替える変調手段バイアス制御手段とを備えるようにしたものである。
【００１２】
この発明に係る波長多重光送信装置は、レーザ手段の後方から出力される連続光の波長を波長監視制御手段がモニタするようにしたものである。
【００１３】
この発明に係る波長多重光送信装置は、レーザ手段の前方から光変調手段へ出力される連続光を光変調手段と波長監視制御手段とへ分岐する光分岐手段を備え、光分岐手段で分岐された連続光の波長を波長監視制御手段がモニタするようにしたものである。
【００１４】
この発明に係る波長多重光送信装置は、自動温度制御手段の設定温度とレーザ手段の素子温度との誤差を波長監視制御手段がモニタして、モニタした波長の割当て波長帯域内に対する引込みを波長監視制御手段が推定するようにしたものである。
【００１５】
この発明に係る波長多重光送信装置は、変調光に利得を与え、光主信号として出力する光増幅手段と、光増幅手段に励起光を与えて利得を発生させる励起レーザ手段と、励起レーザ手段に励起電流を与えて励起光を発生させ、電源が投入されると、励起電流を最小値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれると、光増幅手段から所望の値の光主信号が出力されるように、励起電流を制御するレーザ電流制御手段とから光出力可変制御手段が構成されるようにしたものである。
【００１６】
この発明に係る波長多重光送信装置は、変調光に光減衰量を与え、光主信号として出力する光可変減衰手段と、電源が投入されると、光減衰量を最大値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれると、光可変減衰手段から所望の値の光主信号が出力されるように、光減衰量を制御する減衰量制御手段とから光出力可変制御手段が構成されるようにしたものである。
【００１７】
【発明の実施の形態】
以下、この発明の実施の一形態を説明する。
実施の形態１．
図１はこの発明の実施の形態１による波長多重光送信装置の構成を示す図である。
図１において、１はＬＤ（レーザダイオード；レーザ手段）、２はＡＴＣ回路（自動温度制御回路、自動温度制御手段）、３は光変調器（光変調手段）、４は光出力可変制御部（光出力可変制御手段）である。また、図１において、５，６はそれぞれ立上げ順序制御部（立上げ順序制御手段）、波長監視制御部（波長監視制御手段）である。
【００１８】
次に動作について説明する。
電源を投入すると、まず、立上げ順序制御部５は、光出力制御信号を光出力可変制御部４へ通知して、光出力可変制御部４の光出力可変制御範囲を最小値に制御する。
【００１９】
ＬＤ１は前方および後方から連続光を出力している。ＬＤ１の前方から出力した連続光は、電気主信号に応じて光変調器３で変調されて変調光となり、光変調器３から光出力可変制御部４へ入力する。前述したように、このときの光出力可変制御部４の光出力可変制御範囲は最小値に制御されているので、光出力可変制御部４から出力する光主信号は最小レベルになり、電源投入時に生じる他のチャンネルへのクロストークを十分に抑制できる。
【００２０】
一方、ＬＤ１の後方から出力した連続光は、波長監視制御部６へ入力される。波長監視制御部６は、ＬＤ１から出力する連続光の波長をモニタし、モニタした波長と設定波長との誤差が小さくなるように、ＡＴＣ回路２の設定温度を制御する。
【００２１】
そして、波長監視制御部６は、モニタした波長が割当ての波長帯域内に引込まれたときに、立上げ順序制御部５に対して波長引込み完了信号を通知する。波長引込み完了信号が通知された立上げ順序制御部５は、光出力可変制御部４に対する光出力制御信号を解除し、光出力可変制御部４の光出力可変制御範囲を適切な値に制御する。つまり、このときの光出力可変制御部４の光減衰量は適当な値に調整され、光出力可変制御部４へ入力した変調光は所望の値の光主信号となって出力する。
【００２２】
このように、図１の波長多重光送信装置では、立上げ順序制御部５，波長監視制御部６によって光出力可変制御部４の光出力可変制御範囲を調整し、電源投入時に生じる他のチャンネルへのクロストークを抑制している。光出力可変制御部４を使って光を遮断しているので、光出力遮断用のデバイスを新たに設けることなく、クロストークの抑制を可能にしている。
【００２３】
以上のように、この実施の形態１によれば、電源が投入されると、光出力可変制御部４を光出力制御信号で制御して、光出力可変制御範囲の最小値に変調光をレベル調整するとともに、波長引込み完了信号が通知されると、光出力可変制御部４を光出力制御信号で制御して、光出力可変制御範囲の所望の値に変調光をレベル調整する立上げ順序制御部５と、連続光の波長をモニタし、モニタした波長が割当て波長帯域内に引込まれるように、ＡＴＣ回路２を制御するとともに、モニタした波長が割当て波長帯域内に引込まれると、立上げ順序制御部５へ波長引込み完了信号を通知する波長監視制御部６とを備えるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００２４】
また、この実施の形態１によれば、ＬＤ１の後方から出力される連続光の波長を波長監視制御部６がモニタするようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００２５】
実施の形態２．
図２はこの発明の実施の形態２による波長多重光送信装置の構成を示す図である。図１と同一符号は同一または相当する構成要素を表している。
図２において、７は光分岐部（光分岐手段）であり、ＬＤ１の前方から出力した連続光を光変調器３と波長監視制御部６とへ分岐している。
【００２６】
図２の波長多重光送信装置は、ＬＤ１前方から光変調器３へ向かう連続光を光分岐部７で分岐して、波長監視制御部６でＬＤ１の連続光の波長をモニタしている点が図１の場合と異なっている。その他の各構成要素の動作は実施の形態１と同様である。このように、ＬＤ１後方からの連続光の代わりに、ＬＤ１前方からの連続光を使って波長をモニタしても、実施の形態１と同様の効果が得られる。
【００２７】
以上のように、この実施の形態２によれば、ＬＤ１の前方から光変調器３へ出力される連続光を光変調器３と波長監視制御部６とへ分岐する光分岐部７を備え、光分岐部７で分岐された連続光の波長を波長監視制御部６がモニタするようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００２８】
実施の形態３．
図３はこの発明の実施の形態３による波長多重光送信装置の構成を示す図である。図１と同一符号は同一または相当する構成要素を表している。
図３において、８はＬＤ温度制御誤差監視部（波長監視制御手段）であり、設定波長に相当するＡＴＣ回路２の設定温度とＬＤ１の素子温度との誤差をモニタするもので、図１の波長監視制御部６の代わりに設けられている。
【００２９】
図３では、設定波長に相当するＡＴＣ回路２の設定温度とＬＤ１の素子温度との誤差をＬＤ温度制御誤差監視部８でモニタすることにより、ＬＤ１の連続光の波長を間接的にモニタしている。そして、この設定温度と素子温度との誤差が割当ての波長帯域内相当となったときに、立上げ順序制御部５へ波長引込み完了信号を通知する点が図１の場合と異なっている。その他の各構成要素の動作は実施の形態１と同様である。このように、波長監視制御部６でＬＤ１の波長を直接モニタする代わりに、ＡＴＣ回路２の設定温度とＬＤ１の素子温度との誤差をモニタしても、実施の形態１と同様の効果が得られる。
【００３０】
以上のように、この実施の形態３によれば、ＡＴＣ回路２の設定温度とＬＤ１の素子温度との誤差をＬＤ温度制御誤差監視部８がモニタして、モニタした波長の割当て波長帯域内に対する引込みをＬＤ温度制御誤差監視部８が推定して立上げ順序制御部５へ波長引込み完了信号を通知するようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００３１】
実施の形態４．
図４はこの発明の実施の形態４による波長多重光送信装置の構成を示す図である。図１と同一符号は同一または相当する構成要素を表している。
図４において、９は主信号ＯＮ／ＯＦＦ制御部（主信号ＯＮ／ＯＦＦ制御手段）、１０は変調器バイアス制御部（変調手段バイアス制御手段）である。
【００３２】
実施の形態１において、光出力可変制御部４の光出力可変制御範囲が狭く、光出力可変制御部４の最小出力が他の波長チャンネルに対してまだ影響を与える場合には、以下に示すように、光変調器３のバイアス制御と電気主信号のＯＮ／ＯＦＦ制御とを行い、光出力可変制御部４出力の最小値を補助的に下げることで、他の波長チャンネルへの影響を抑止しているのが、この実施の形態４の特徴である。
【００３３】
次に動作について説明する。
電源を投入すると、まず、立上げ順序制御部５は、光出力制御信号を光出力可変制御部４へ通知して、光出力可変制御部４の光出力可変制御範囲を最小値に制御する。同時に、立上げ順序制御部５は、電気主信号をＯＦＦにするように主信号ＯＮ／ＯＦＦ制御部９を制御し、光変調器３を最大消光状態にする最大消光バイアス電圧を光変調器３へ与えるように変調器バイアス制御部１０を制御する。
【００３４】
ＬＤ１は前方および後方から連続光を出力している。ＬＤ１の前方から出力した連続光は光変調器３へ入力される。このとき、主信号ＯＮ／ＯＦＦ制御部９からの変調ＯＮ／ＯＦＦ制御信号により電気主信号はＯＦＦに切り替わっており、同時に、変調器バイアス制御部１０からの変調器バイアス切替え制御信号により光変調器３は最大消光バイアス電圧になっているため、実施の形態１と比較して、光出力可変制御部４へ入力される光のレベルをさらに抑えることができる。このため、他のチャンネルに悪影響を与えないレベルまで、光出力可変制御部４の光出力を下げることが可能となっている。
【００３５】
一方、ＬＤ１の後方から出力した連続光は、波長監視制御部６へ入力される。波長監視制御部６は、ＬＤ１から出力する連続光の波長をモニタし、モニタした波長と設定波長との誤差が小さくなるように、ＡＴＣ回路２の設定温度を制御する。
【００３６】
そして、波長監視制御部６は、モニタした波長が割当ての波長帯域内に引込まれたときに、立上げ順序制御部５に対して波長引込み完了信号を通知する。波長引込み完了信号が通知された立上げ順序制御部５は、まず光出力可変制御部４に対する光出力制御信号を解除し、光出力可変制御部４の光出力可変制御範囲を所望の値に制御する。
【００３７】
同時に、立上げ順序制御部５は、変調器バイアス制御部１０に対して変調器バイアス切替え制御信号を通知し、光変調器３に与える変調器バイアス電圧を最大消光バイアス電圧（最大消光状態）からノーマルバイアス電圧（通常動作時の電圧、ノーマル状態）に切替えるように、変調器バイアス制御部１０を制御する。変調器バイアス電圧がノーマルバイアス電圧に切替えられると、立上げ順序制御部５は、主信号ＯＮ／ＯＦＦ制御部９に対して変調ＯＮ／ＯＦＦ制御信号を通知し、電気主信号をＯＮに切り換えるように主信号ＯＮ／ＯＦＦ制御部９を制御する。その後、光出力可変制御部４は設定された光出力レベルにまで光出力を調整し立上げ制御を完了する。
【００３８】
以上のように、この実施の形態４によれば、電源が投入されると、光変調器３に対する電気主信号をＯＦＦに切り替えるとともに、立上げ順序制御部５へ波長引き込み完了信号が通知されると、立上げ順序制御部５からの変調ＯＮ／ＯＦＦ制御信号によって、光変調器３に対する電気主信号をＯＮに切り替える主信号ＯＮ／ＯＦＦ制御部９と、電源が投入されると、光変調器３を最大消光バイアス電圧に切り替えるとともに、立上げ順序制御部５へ波長引き込み完了信号が通知されると、立上げ順序制御部５からの変調器バイアス切替え制御信号によって、光変調器３をノーマルバイアス電圧に切り替える変調器バイアス制御部１０とを備えるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークをさらに抑制できるという効果が得られる。
【００３９】
実施の形態５．
図５はこの発明の実施の形態５による波長多重光送信装置の構成を示す図である。図１，図２および図４と同一符号は同一または相当する構成要素を表している。
電源立上げ後の制御方法は実施の形態４と同じであるが、ＬＤ１の前方出力を分岐して波長監視・制御を行っている点で構成が異なる。
【００４０】
図５の波長多重光送信装置は、実施の形態２と実施の形態４とを組み合わせたものであり、ＬＤ１前方から光変調器３へ向かう連続光を光分岐部７で分岐して、波長監視制御部６でＬＤ１の連続光の波長をモニタしている。その他の各構成要素の動作は実施の形態２，４と同様である。このように、ＬＤ１後方からの連続光の代わりに、ＬＤ１後方からの連続光を使って波長をモニタしても、実施の形態４と同様の効果が得られる。
【００４１】
実施の形態６．
図６はこの発明の実施の形態６による波長多重光送信装置の構成を示す図である。図１，図３および図４と同一符号は同一または相当する構成要素を表している。
【００４２】
図６の波長多重光送信装置は、実施の形態３と実施の形態４とを組み合わせたものであり、電源投入後の制御方法は同じであるが、ＬＤ１の連続光の波長を直接監視制御する代わりに、設定波長に相当するＡＴＣ回路２の設定温度とＬＤ１の素子温度のモニタ値との誤差をＬＤ温度制御誤差監視部８で監視することにより波長を間接的に監視し、誤差の値が割当ての波長帯域内相当となったときに、立上げ順序制御部５から光出力可変制御部４へ光出力制御信号の解除を通知する点が異なっている。このようにしても、実施の形態４と同様の効果が得られる。
【００４３】
実施の形態７．
最後に、光出力可変制御部４の構成について説明する。
図７は光出力可変制御部４の第１構成例を示す図である。
図７の光出力可変制御部４において、４１は例えばエルビウムを使った希土類添加光ファイバのＥＤＦ（光増幅手段、光カプラやアイソレータなどの図示は省略）、４２はＥＤＦ４１を励起光によって励起して利得を発生させる励起ＬＤ（励起レーザ手段）、４３は励起光を出力させるための励起電流を励起ＬＤ４２に与えるＬＤ電流制御部（レーザ電流制御手段）である。
【００４４】
電源投入時には、ＬＤ電流制御部４３が励起ＬＤ４２の電流値を最小に制御する。したがって、このとき、不図示の光変調器３からＥＤＦ４１へ入力した変調光はほとんど増幅されなくなるので、他のチャンネルに対する影響を抑制できる。そして、不図示の立上げ順序制御部５からＬＤ電流制御部４３へ光出力制御信号の解除が通知されると、設定された光出力レベルになるように、励起ＬＤ４２の電流値をＬＤ電流制御部４３が制御し、ＥＤＦ４１を通過する変調光に利得が与えられる。
【００４５】
図８は光出力可変制御部４の第２構成例を示す図である。
図８の光出力可変制御部４において、４４は電気信号によって光減衰量が調整される光可変減衰器（光可変減衰手段）、４５は光可変減衰器４４の光減衰量を電気信号によって制御する減衰量制御部（減衰量制御手段）である。
【００４６】
電源投入時には、減衰量制御部４５が光可変減衰器４４の光減衰量を最大に制御する。したがって、不図示の光変調器３から光可変減衰器４４へ入力した変調光は光可変減衰器４４で大きく減衰するので、他のチャンネルに対する影響を抑制できる。そして、不図示の立上げ順序制御部５から減衰量制御部４５へ光出力制御信号の解除が通知されると、設定された光出力レベルになるように、光可変減衰器４４への光減衰量を減衰量制御部４５が所望の値に制御する。
【００４７】
以上のように、この実施の形態７によれば、変調光に利得を与え、光主信号として出力するＥＤＦ４１と、ＥＤＦ４１に励起光を与えて利得を発生させる励起ＬＤ４２と、励起ＬＤ４２に励起電流を与えて励起光を発生させ、電源が投入されると、励起電流を最小値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれて光出力制御信号が通知されると、ＥＤＦ４１から所望の値の光主信号が出力されるように、励起電流を制御するＬＤ電流制御部４３とから光出力可変制御部４が構成されるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００４８】
また、この実施の形態７によれば、変調光に光減衰量を与え、光主信号として出力する光可変減衰器４４と、電源が投入されると、光減衰量を最大値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれて光出力制御信号が通知されると、光可変減衰器４４から所望の値の光主信号が出力されるように、光減衰量を制御する減衰量制御部４５とから光出力可変制御部４が構成されるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００４９】
【発明の効果】
以上のように、この発明によれば、電源が投入されると、光出力可変制御手段を制御して、光出力可変制御範囲の最小値に変調光をレベル調整するとともに、波長引込み完了信号が通知されると、光出力可変制御手段を制御して、光出力可変制御範囲の所望の値に変調光をレベル調整する立上げ順序制御手段と、連続光の波長をモニタし、モニタした波長が割当て波長帯域内に引込まれるように、自動温度制御手段を制御するとともに、モニタした波長が割当て波長帯域内に引込まれると、立上げ順序制御手段へ波長引込み完了信号を通知する波長監視制御手段とを備えるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００５０】
この発明によれば、電源が投入されると、光変調手段に対する電気主信号をＯＦＦに切り替えるとともに、立上げ順序制御手段へ波長引込み完了信号が通知されると、光変調手段に対する電気主信号をＯＮに切り替える主信号ＯＮ／ＯＦＦ制御手段と、電源が投入されると、光変調手段を最大消光状態に切り替えるとともに、立上げ順序制御手段へ波長引込み完了信号が通知されると、光変調手段をノーマル状態に切り替える変調手段バイアス制御手段とを備えるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークをさらに抑制できるという効果が得られる。
【００５１】
この発明によれば、レーザ手段の後方から出力される連続光の波長を波長監視制御手段がモニタするようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００５２】
この発明によれば、レーザ手段の前方から光変調手段へ出力される連続光を光変調手段と波長監視制御手段とへ分岐する光分岐手段を備え、光分岐手段で分岐された連続光の波長を波長監視制御手段がモニタするようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００５３】
この発明によれば、自動温度制御手段の設定温度とレーザ手段の素子温度との誤差を波長監視制御手段がモニタして、モニタした波長の割当て波長帯域内に対する引込みを波長監視制御手段が推定するようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００５４】
この発明によれば、変調光に利得を与え、光主信号として出力する光増幅手段と、光増幅手段に励起光を与えて利得を発生させる励起レーザ手段と、励起レーザ手段に励起電流を与えて励起光を発生させ、電源が投入されると、励起電流を最小値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれると、光増幅手段から所望の値の光主信号が出力されるように、励起電流を制御するレーザ電流制御手段とから光出力可変制御手段が構成されるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【００５５】
この発明によれば、変調光に光減衰量を与え、光主信号として出力する光可変減衰手段と、電源が投入されると、光減衰量を最大値に制御するとともに、連続光の波長が割当ての波長帯域内に引き込まれると、光可変減衰手段から所望の値の光主信号が出力されるように、光減衰量を制御する減衰量制御手段とから光出力可変制御手段が構成されるようにしたので、光出力遮断用のデバイスを新たに設けることなく、電源投入時に生じる他のチャンネルへのクロストークを抑制できるという効果が得られる。
【図面の簡単な説明】
【図１】この発明の実施の形態１による波長多重光送信装置の構成を示す図である。
【図２】この発明の実施の形態２による波長多重光送信装置の構成を示す図である。
【図３】この発明の実施の形態３による波長多重光送信装置の構成を示す図である。
【図４】この発明の実施の形態４による波長多重光送信装置の構成を示す図である。
【図５】この発明の実施の形態５による波長多重光送信装置の構成を示す図である。
【図６】この発明の実施の形態６による波長多重光送信装置の構成を示す図である。
【図７】光出力可変制御部の第１構成例を示す図である。
【図８】光出力可変制御部の第２構成例を示す図である。
【図９】従来の波長多重光送信装置の構成を示す図である。
【図１０】ＬＤにおける連続光の波長と素子温度との関係を示す図である。
【符号の説明】
１　ＬＤ（レーザダイオード；レーザ手段）、２　ＡＴＣ回路（自動温度制御回路、自動温度制御手段）、３　光変調器（光変調手段）、４　光出力可変制御部（光出力可変制御手段）、５　立上げ順序制御部（立上げ順序制御手段）、６波長監視制御部（波長監視制御手段）、７　光分岐部（光分岐手段）、８　ＬＤ温度制御誤差監視部（波長監視制御手段）、９　主信号ＯＮ／ＯＦＦ制御部（主信号ＯＮ／ＯＦＦ制御手段）、１０　変調器バイアス制御部（変調手段バイアス制御手段）、４１　ＥＤＦ（光増幅手段）、４２　励起ＬＤ（励起レーザ手段）、４３　ＬＤ電流制御部（レーザ電流制御手段）、４４　光可変減衰器（光可変減衰手段）、４５　減衰量制御部（減衰量制御手段）。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wavelength division multiplexing optical transmission device for transmitting an optical main signal for wavelength division multiplexing (WDM).
[0002]
[Prior art]
In a wavelength division multiplexing optical transmission system, an optical main signal having a different wavelength is superimposed on each channel. Since the entire wavelength band that can be used is limited from the viewpoint of device performance, in order to increase the transmission capacity by increasing the number of optical main signals, it is necessary to minimize the wavelength interval of the optical main signals. However, if the wavelength interval is reduced, when the wavelength of continuous light of a certain channel becomes unstable, adverse effects due to crosstalk occur on other wavelength channels.
[0003]
FIG. 9 is a diagram showing a configuration of a conventional wavelength multiplexing optical transmission device.
In FIG. 9, 101 is an LD (laser diode), 102 is an ATC circuit (automatic temperature control circuit), 103 is an optical modulator, and 104 is an optical output variable control unit.
[0004]
Next, the operation will be described.
When continuous light in a wavelength band allocated to a certain channel is output from the LD 101, the continuous light is modulated by the optical modulator 103 in accordance with the electric main signal, and then the level is adjusted by the optical output variable control unit 104. Output as the main signal. The ATC circuit 102 functions to control the element temperature of the LD 101 to stabilize the wavelength of continuous light at a set wavelength. That is, as shown in the following FIG. 10, since the wavelength of the continuous light output from the LD 101 depends on the element temperature of the LD 101, the ATC circuit 102 is provided.
[0005]
FIG. 10 is a diagram showing the relationship between the wavelength of the continuous light and the element temperature in the LD 101. The horizontal axis represents the element temperature of the LD 101, and the vertical axis represents the wavelength of the continuous light.
As can be seen from FIG. 10, when the power is turned on, the wavelength of the continuous light output from the LD 101 is out of the wavelength band assigned to the channel until the element temperature reaches a temperature corresponding to a certain set wavelength. Therefore, in the wavelength-division multiplexed optical transmitter shown in FIG. 9, the wavelength of continuous light becomes unstable when the power is turned on, and as described at the beginning, adversely affects other channels.
[0006]
In order to solve this problem, a wavelength division multiplexing optical transmission apparatus disclosed in Japanese Patent Application Laid-Open No. H11-340919 requires an optical output when receiving either a power alarm or a wavelength alarm related to ON / OFF of power supply. A device is provided for shutting off. However, in the case of this conventional wavelength division multiplexing optical transmitter, it is disadvantageous in terms of configuration and cost to newly provide a device for interrupting optical output only to interrupt optical output.
[0007]
[Problems to be solved by the invention]
Since the conventional wavelength division multiplexing optical transmitter is configured as described above, when power is turned on, crosstalk occurs in other channels until the LD element temperature reaches a temperature corresponding to a certain set wavelength. There was a problem of getting it.
[0008]
Further, the conventional wavelength multiplexing optical transmission apparatus requires a new device for shutting down the optical output only to shut off the optical output, which is disadvantageous in terms of configuration and cost. there were.
[0009]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is a wavelength multiplexing optical transmission that can suppress crosstalk to another channel that occurs when power is turned on without newly providing a device for shutting off optical output. It is intended to provide a device.
[0010]
[Means for Solving the Problems]
When the power is turned on, the wavelength division multiplexing optical transmission device according to the present invention controls the optical output variable control means to adjust the level of the modulated light to the minimum value of the optical output variable control range, and outputs the wavelength pull-in completion signal. When notified, the light output variable control means is controlled, the start-up sequence control means for adjusting the level of the modulated light to a desired value of the light output variable control range, and the wavelength of the continuous light is monitored. Wavelength monitoring control for controlling the automatic temperature control means so as to be drawn into the allocated wavelength band, and notifying the start-up sequence control means of a wavelength pull-in completion signal when the monitored wavelength is drawn into the allocated wavelength band. Means.
[0011]
The wavelength-division multiplexing optical transmission device according to the present invention, when the power is turned on, switches off the electric main signal to the optical modulation means, and when the start-up sequence control means is notified of the wavelength pull-in completion signal, the light modulation means A main signal ON / OFF control unit for turning on an electric main signal for ON, and when the power is turned on, the light modulation unit is switched to a maximum extinction state, and a start-up sequence control unit is notified of a wavelength pull-in completion signal. And a modulation means bias control means for switching the light modulation means to a normal state.
[0012]
The wavelength division multiplexing optical transmitting apparatus according to the present invention is such that the wavelength monitoring and control means monitors the wavelength of continuous light output from the rear of the laser means.
[0013]
The wavelength division multiplexing optical transmission device according to the present invention includes an optical branching unit that branches continuous light output from the front of the laser unit to the optical modulation unit to the optical modulation unit and the wavelength monitoring control unit, and is branched by the optical branching unit. The wavelength monitoring and controlling means monitors the wavelength of the continuous light.
[0014]
In the wavelength division multiplexing optical transmitting apparatus according to the present invention, the wavelength monitoring control means monitors an error between the set temperature of the automatic temperature control means and the element temperature of the laser means, and monitors the pull-in of the monitored wavelength within the assigned wavelength band. The control means makes the estimation.
[0015]
A wavelength-division multiplexing optical transmission device according to the present invention provides an optical amplifying means for giving a gain to a modulated light and outputting it as an optical main signal, an exciting laser means for giving an exciting light to the optical amplifying means to generate a gain, and an exciting laser means When the power is turned on, the pumping current is controlled to a minimum value, and when the wavelength of the continuous light is drawn into the allocated wavelength band, the desired light is supplied from the optical amplifying means. The optical output variable control means is constituted by a laser current control means for controlling the excitation current so as to output the optical main signal of the value.
[0016]
The wavelength division multiplexing optical transmission device according to the present invention provides an optical attenuation to the modulated light, and an optical variable attenuation unit that outputs the optical main signal, and when the power is turned on, controls the optical attenuation to a maximum value, When the wavelength of the continuous light is drawn into the assigned wavelength band, the optical output variable control means controls the optical attenuation so that the optical main signal of a desired value is output from the optical variable attenuation means. The means are constituted.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a wavelength division multiplexing optical transmitter according to Embodiment 1 of the present invention.
In FIG. 1, 1 is an LD (laser diode; laser means), 2 is an ATC circuit (automatic temperature control circuit, automatic temperature control means), 3 is an optical modulator (optical modulation means), and 4 is an optical output variable control section ( Optical output variable control means). In FIG. 1, reference numerals 5 and 6 denote a start-up sequence control unit (start-up sequence control unit) and a wavelength monitoring control unit (wavelength monitoring control unit).
[0018]
Next, the operation will be described.
When the power is turned on, first, the startup sequence control unit 5 notifies the light output control signal to the light output variable control unit 4 and controls the light output variable control range of the light output variable control unit 4 to the minimum value.
[0019]
The LD 1 outputs continuous light from the front and the rear. The continuous light output from the front of the LD 1 is modulated by the optical modulator 3 according to the electric main signal to become modulated light, and is input from the optical modulator 3 to the optical output variable control unit 4. As described above, since the light output variable control range of the light output variable control unit 4 at this time is controlled to the minimum value, the optical main signal output from the light output variable control unit 4 becomes the minimum level and the power is turned on. Crosstalk to other channels, which sometimes occurs, can be sufficiently suppressed.
[0020]
On the other hand, the continuous light output from behind the LD 1 is input to the wavelength monitoring control unit 6. The wavelength monitoring controller 6 monitors the wavelength of the continuous light output from the LD 1 and controls the set temperature of the ATC circuit 2 so that the error between the monitored wavelength and the set wavelength is reduced.
[0021]
Then, when the monitored wavelength is pulled into the assigned wavelength band, the wavelength monitoring controller 6 notifies the start-up sequence controller 5 of a wavelength pull-in completion signal. The start-up sequence control unit 5 to which the wavelength pull-in completion signal is notified cancels the optical output control signal to the optical output variable control unit 4 and controls the optical output variable control range of the optical output variable control unit 4 to an appropriate value. . That is, the optical attenuation of the variable optical output controller 4 at this time is adjusted to an appropriate value, and the modulated light input to the variable optical output controller 4 is output as an optical main signal having a desired value.
[0022]
As described above, in the wavelength-division multiplexing optical transmission apparatus of FIG. 1, the start-up sequence control unit 5 and the wavelength monitoring control unit 6 adjust the optical output variable control range of the optical output variable control unit 4 so that other channels generated when the power is turned on. To reduce crosstalk. Since the light is blocked by using the variable light output control unit 4, crosstalk can be suppressed without newly providing a device for blocking light output.
[0023]
As described above, according to the first embodiment, when the power is turned on, the optical output variable control section 4 is controlled by the optical output control signal, and the level of the modulated light is set to the minimum value of the optical output variable control range. In addition to the adjustment, when the wavelength pull-in completion signal is notified, the optical output variable control unit 4 is controlled by the optical output control signal to adjust the level of the modulated light to a desired value in the optical output variable control range. The unit 5 monitors the wavelength of the continuous light, controls the ATC circuit 2 so that the monitored wavelength is drawn into the allocated wavelength band, and stands by when the monitored wavelength is drawn into the allocated wavelength band. The wavelength monitoring and control unit 6 for notifying the raising order control unit 5 of the wavelength pull-in completion signal is provided, so that a crosstalk to another channel that occurs when the power is turned on is provided without newly providing an optical output cutoff device. Suppress The effect of wear can be obtained.
[0024]
Further, according to the first embodiment, the wavelength monitoring and control unit 6 monitors the wavelength of the continuous light output from the rear of the LD 1. The effect is obtained that crosstalk to other channels generated at the time of insertion can be suppressed.
[0025]
Embodiment 2 FIG.
FIG. 2 is a diagram showing a configuration of a wavelength division multiplexing optical transmission apparatus according to Embodiment 2 of the present invention. 1 denote the same or corresponding components.
In FIG. 2, reference numeral 7 denotes an optical splitter (optical splitter), which splits continuous light output from the front of the LD 1 to the optical modulator 3 and the wavelength monitoring controller 6.
[0026]
The wavelength division multiplexing optical transmitter shown in FIG. 2 is such that continuous light traveling from the front of the LD 1 to the optical modulator 3 is branched by the optical branching unit 7 and the wavelength of the continuous light of the LD 1 is monitored by the wavelength monitoring control unit 6. This is different from the case of FIG. The operation of each of the other components is the same as in the first embodiment. As described above, even if the wavelength is monitored using the continuous light from the front of the LD 1 instead of the continuous light from the rear of the LD 1, the same effect as in the first embodiment can be obtained.
[0027]
As described above, according to the second embodiment, the optical branching unit 7 that branches continuous light output from the front of the LD 1 to the optical modulator 3 to the optical modulator 3 and the wavelength monitoring control unit 6 is provided. Since the wavelength of the continuous light branched by the optical branching unit 7 is monitored by the wavelength monitoring and controlling unit 6, crosstalk to other channels generated when the power is turned on can be achieved without newly providing a device for shutting off optical output. Is obtained.
[0028]
Embodiment 3 FIG.
FIG. 3 is a diagram showing a configuration of a wavelength division multiplexing optical transmission apparatus according to Embodiment 3 of the present invention. 1 denote the same or corresponding components.
3, reference numeral 8 denotes an LD temperature control error monitoring unit (wavelength monitoring control unit) which monitors an error between the set temperature of the ATC circuit 2 corresponding to the set wavelength and the element temperature of the LD 1. The monitoring control unit 6 is provided instead.
[0029]
In FIG. 3, the error between the set temperature of the ATC circuit 2 corresponding to the set wavelength and the element temperature of the LD 1 is monitored by the LD temperature control error monitoring unit 8 to indirectly monitor the wavelength of the continuous light of the LD 1. I have. The difference from the case of FIG. 1 is that when the error between the set temperature and the element temperature falls within the assigned wavelength band, the start-up sequence control unit 5 is notified of the wavelength pull-in completion signal. The operation of each of the other components is the same as in the first embodiment. As described above, instead of directly monitoring the wavelength of the LD 1 by the wavelength monitoring control unit 6, the same effect as that of the first embodiment can be obtained by monitoring the error between the set temperature of the ATC circuit 2 and the element temperature of the LD 1. It is.
[0030]
As described above, according to the third embodiment, the error between the set temperature of the ATC circuit 2 and the element temperature of the LD 1 is monitored by the LD temperature control error monitoring unit 8, and the monitored wavelength is assigned to the allocated wavelength band. Since the pull-in is estimated by the LD temperature control error monitoring unit 8 and the start-up sequence control unit 5 is notified of the wavelength pull-in completion signal. The effect that the cross talk to the channel of this can be suppressed is acquired.
[0031]
Embodiment 4 FIG.
FIG. 4 is a diagram showing a configuration of a wavelength division multiplexing optical transmission apparatus according to Embodiment 4 of the present invention. 1 denote the same or corresponding components.
In FIG. 4, reference numeral 9 denotes a main signal ON / OFF control unit (main signal ON / OFF control unit), and reference numeral 10 denotes a modulator bias control unit (modulation unit bias control unit).
[0032]
In the first embodiment, when the light output variable control range of the light output variable control unit 4 is narrow and the minimum output of the light output variable control unit 4 still affects other wavelength channels, as shown below. In addition, the bias control of the optical modulator 3 and the ON / OFF control of the electrical main signal are performed, and the minimum value of the output of the variable optical output control unit 4 is reduced to suppress the influence on other wavelength channels. This is the characteristic of the fourth embodiment.
[0033]
Next, the operation will be described.
When the power is turned on, first, the startup sequence control unit 5 notifies the light output control signal to the light output variable control unit 4 and controls the light output variable control range of the light output variable control unit 4 to the minimum value. At the same time, the start-up sequence control unit 5 controls the main signal ON / OFF control unit 9 so as to turn off the electric main signal, and sets the maximum extinction bias voltage that brings the optical modulator 3 into the maximum extinction state. The modulator bias control unit 10 is controlled so as to supply it to
[0034]
The LD 1 outputs continuous light from the front and the rear. Continuous light output from the front of the LD 1 is input to the optical modulator 3. At this time, the electric main signal is switched OFF by the modulation ON / OFF control signal from the main signal ON / OFF control unit 9, and at the same time, the optical modulator is controlled by the modulator bias switching control signal from the modulator bias control unit 10. Since 3 is the maximum extinction bias voltage, the level of light input to the variable optical output control unit 4 can be further suppressed as compared with the first embodiment. Therefore, the light output of the light output variable control unit 4 can be reduced to a level that does not adversely affect other channels.
[0035]
On the other hand, the continuous light output from behind the LD 1 is input to the wavelength monitoring control unit 6. The wavelength monitoring controller 6 monitors the wavelength of the continuous light output from the LD 1 and controls the set temperature of the ATC circuit 2 so that the error between the monitored wavelength and the set wavelength is reduced.
[0036]
Then, when the monitored wavelength is pulled into the assigned wavelength band, the wavelength monitoring controller 6 notifies the start-up sequence controller 5 of a wavelength pull-in completion signal. The start-up sequence control unit 5 to which the wavelength pull-in completion signal is notified first releases the optical output control signal to the optical output variable control unit 4 and controls the optical output variable control range of the optical output variable control unit 4 to a desired value. I do.
[0037]
At the same time, the start-up sequence control unit 5 notifies the modulator bias control unit 10 of a modulator bias switching control signal, and changes the modulator bias voltage applied to the optical modulator 3 from the maximum extinction bias voltage (maximum extinction state). The modulator bias control unit 10 is controlled so as to switch to a normal bias voltage (voltage during normal operation, normal state). When the modulator bias voltage is switched to the normal bias voltage, the start-up sequence control unit 5 notifies the main signal ON / OFF control unit 9 of the modulation ON / OFF control signal and switches the electric main signal to ON. The main signal ON / OFF control section 9 is controlled. Thereafter, the light output variable control section 4 adjusts the light output to the set light output level and completes the start-up control.
[0038]
As described above, according to the fourth embodiment, when the power is turned on, the electrical main signal for the optical modulator 3 is turned off, and the start-up sequence control unit 5 is notified of the wavelength pull-in completion signal. A main signal ON / OFF control unit 9 for turning on an electric main signal for the optical modulator 3 by a modulation ON / OFF control signal from the start-up sequence control unit 5; 3 is switched to the maximum extinction bias voltage, and when the start-up sequence controller 5 is notified of the wavelength pull-in completion signal, the modulator 3 is switched to the normal bias by the modulator bias switching control signal from the start-up sequence controller 5. Since the modulator bias control unit 10 for switching to voltage is provided, another channel generated when the power is turned on can be provided without newly providing an optical output cutoff device. Effect that can be further suppressed crosstalk to panel.
[0039]
Embodiment 5 FIG.
FIG. 5 is a diagram showing a configuration of a wavelength division multiplexing optical transmission apparatus according to Embodiment 5 of the present invention. 1, 2 and 4 denote the same or corresponding components.
The control method after the power is turned on is the same as that of the fourth embodiment, but differs in that the forward output of the LD 1 is branched to perform wavelength monitoring and control.
[0040]
The wavelength division multiplexing optical transmitting apparatus of FIG. 5 is a combination of the second and fourth embodiments, and a continuous light traveling from the front of the LD 1 to the optical modulator 3 is branched by the optical branching unit 7 to monitor the wavelength. The controller 6 monitors the wavelength of the continuous light of the LD 1. The operation of each of the other components is the same as in the second and fourth embodiments. As described above, even if the wavelength is monitored using continuous light from behind LD1 instead of continuous light from behind LD1, the same effect as in the fourth embodiment can be obtained.
[0041]
Embodiment 6 FIG.
FIG. 6 is a diagram showing a configuration of a wavelength division multiplexing optical transmission apparatus according to Embodiment 6 of the present invention. 1, 3 and 4 denote the same or corresponding components.
[0042]
The wavelength division multiplexing optical transmitting apparatus of FIG. 6 is a combination of the third and fourth embodiments, and the control method after power-on is the same, but directly monitors and controls the wavelength of the continuous light of LD1. Instead, the wavelength is indirectly monitored by monitoring the error between the set temperature of the ATC circuit 2 corresponding to the set wavelength and the monitored value of the element temperature of the LD 1 by the LD temperature control error monitoring unit 8, and the error value is changed. The difference is that the start-up sequence control unit 5 notifies the optical output variable control unit 4 of the release of the optical output control signal when the wavelength is within the assigned wavelength band. Even in this case, the same effect as in the fourth embodiment can be obtained.
[0043]
Embodiment 7 FIG.
Finally, the configuration of the optical output variable control section 4 will be described.
FIG. 7 is a diagram illustrating a first configuration example of the optical output variable control unit 4.
In the optical output variable control unit 4 of FIG. 7, 41 is an EDF of a rare earth-doped optical fiber using, for example, erbium (illustration of an optical amplifier, an optical coupler, an isolator, etc. is omitted). An excitation LD (excitation laser means) 43 for generating a gain is an LD current control unit (laser current control means) for applying an excitation current for outputting excitation light to the excitation LD 42.
[0044]
When the power is turned on, the LD current control unit 43 controls the current value of the excitation LD 42 to a minimum. Therefore, at this time, the modulated light input from the optical modulator 3 (not shown) to the EDF 41 is hardly amplified, so that the influence on other channels can be suppressed. When the start-up sequence control unit 5 (not shown) notifies the LD current control unit 43 of the release of the light output control signal, the current value of the excitation LD 42 is controlled by the LD current control so that the set light output level is achieved. The gain is given to the modulated light passing through the EDF 41 under the control of the unit 43.
[0045]
FIG. 8 is a diagram illustrating a second configuration example of the optical output variable control unit 4.
In the variable optical output controller 4 of FIG. 8, reference numeral 44 denotes an optical variable attenuator (optical variable attenuator) whose optical attenuation is adjusted by an electric signal, and 45 denotes an optical attenuation of the optical variable attenuator 44 by an electric signal. (Attenuation control means).
[0046]
When the power is turned on, the attenuation controller 45 controls the optical attenuation of the variable optical attenuator 44 to the maximum. Therefore, the modulated light input from the optical modulator 3 (not shown) to the variable optical attenuator 44 is greatly attenuated by the variable optical attenuator 44, so that the influence on other channels can be suppressed. Then, when the start-up sequence control unit 5 (not shown) notifies the attenuation control unit 45 of the release of the optical output control signal, the optical attenuation to the optical variable attenuator 44 is adjusted so that the optical output level becomes the set optical output level. The amount is controlled by the attenuation control unit 45 to a desired value.
[0047]
As described above, according to the seventh embodiment, the EDF 41 that applies gain to the modulated light and outputs the modulated light as an optical main signal, the pump LD 42 that supplies the EDF 41 with pump light to generate a gain, and the pump LD 42 When the power is turned on, the excitation current is controlled to the minimum value, and the wavelength of the continuous light is drawn into the assigned wavelength band and the optical output control signal is notified. Since the optical output variable control unit 4 is composed of the LD current control unit 43 that controls the excitation current so that the optical main signal of a desired value is output from the EDF 41, a device for interrupting the optical output is used. The effect of being able to suppress crosstalk to other channels that occurs when the power is turned on can be obtained without newly providing.
[0048]
Further, according to the seventh embodiment, the optical variable attenuator 44 for giving the optical attenuation to the modulated light and outputting it as an optical main signal, and when the power is turned on, controls the optical attenuation to the maximum value and When the wavelength of the continuous light is drawn into the assigned wavelength band and the optical output control signal is notified, the optical attenuation is controlled so that the optical main signal of a desired value is output from the optical variable attenuator 44. Since the variable optical output control unit 4 is constituted by the attenuation control unit 45 and the attenuation control unit 45, the crosstalk to other channels generated when the power is turned on can be suppressed without newly providing a device for shutting off the optical output. The effect is obtained.
[0049]
【The invention's effect】
As described above, according to the present invention, when the power is turned on, the optical output variable control means is controlled to adjust the level of the modulated light to the minimum value of the optical output variable control range, and the wavelength pull-in completion signal is output. When notified, the light output variable control means is controlled, the start-up sequence control means for adjusting the level of the modulated light to a desired value of the light output variable control range, and the wavelength of the continuous light is monitored. Wavelength monitoring control for controlling the automatic temperature control means so as to be drawn into the allocated wavelength band, and notifying the start-up sequence control means of a wavelength pull-in completion signal when the monitored wavelength is drawn into the allocated wavelength band. Therefore, it is possible to obtain an effect that crosstalk to another channel that occurs when the power is turned on can be suppressed without newly providing a device for blocking optical output.
[0050]
According to the present invention, when the power is turned on, the electric main signal to the optical modulator is switched to OFF, and when the start-up sequence controller is notified of the wavelength pull-in completion signal, the electric main signal to the optical modulator is changed. The main signal ON / OFF control means for switching to ON, and when the power is turned on, the light modulation means is switched to the maximum extinction state, and when the start-up sequence control means is notified of the wavelength pull-in completion signal, the light modulation means is turned on. Since the modulation means and the bias control means for switching to the normal state are provided, it is possible to obtain an effect that the crosstalk to another channel which occurs when the power is turned on can be further suppressed without newly providing an optical output cutoff device. .
[0051]
According to the present invention, since the wavelength monitoring and control means monitors the wavelength of continuous light output from the rear of the laser means, other devices that occur when the power is turned on can be provided without newly providing an optical output cutoff device. The effect of suppressing crosstalk to the channel can be obtained.
[0052]
According to the invention, there is provided an optical branching unit for branching continuous light output from the front of the laser unit to the optical modulation unit to the optical modulation unit and the wavelength monitoring control unit, and a wavelength of the continuous light branched by the optical branching unit. Is monitored by the wavelength monitoring and control means, so that the effect of suppressing crosstalk to other channels that occurs when the power is turned on can be obtained without newly providing a device for shutting off optical output.
[0053]
According to the present invention, an error between the set temperature of the automatic temperature control means and the element temperature of the laser means is monitored by the wavelength monitoring control means, and the wavelength monitoring control means estimates the pull-in of the monitored wavelength within the allocated wavelength band. As a result, an effect is obtained that crosstalk to other channels that occurs when the power is turned on can be suppressed without newly providing a device for shutting off optical output.
[0054]
According to the present invention, an optical amplifier for giving a gain to the modulated light and outputting it as an optical main signal, an excitation laser for giving the excitation light to the optical amplifier to generate a gain, and applying an excitation current to the excitation laser When the power is turned on, the pumping current is controlled to a minimum value, and when the wavelength of the continuous light is drawn into the assigned wavelength band, the optical main signal of a desired value is transmitted from the optical amplifying means. And the laser current control means for controlling the excitation current so as to output the light output, so that the light output variable control means is constituted. The effect that the cross talk to the channel of this can be suppressed is acquired.
[0055]
According to the present invention, the optical variable attenuation means for giving an optical attenuation to the modulated light and outputting it as an optical main signal, and when the power is turned on, controls the optical attenuation to a maximum value and reduces the wavelength of the continuous light. An optical output variable control unit is configured by an optical attenuation control unit that controls an optical attenuation amount such that an optical main signal of a desired value is output from the optical variable attenuation unit when the optical main signal is drawn into the allocated wavelength band. As a result, an effect is obtained that crosstalk to other channels that occurs when the power is turned on can be suppressed without newly providing a device for shutting off optical output.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a wavelength division multiplexing optical transmission device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a wavelength division multiplexing optical transmission device according to a second embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a wavelength division multiplexing optical transmission device according to a third embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of a wavelength division multiplexing optical transmission device according to a fourth embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of a wavelength division multiplexing optical transmission device according to a fifth embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of a wavelength division multiplexing optical transmission device according to a sixth embodiment of the present invention.
FIG. 7 is a diagram illustrating a first configuration example of an optical output variable control unit.
FIG. 8 is a diagram illustrating a second configuration example of the optical output variable control unit.
FIG. 9 is a diagram illustrating a configuration of a conventional wavelength division multiplexing optical transmission device.
FIG. 10 is a diagram illustrating a relationship between a wavelength of continuous light and an element temperature in an LD.
[Explanation of symbols]
1 LD (laser diode; laser means), 2 ATC circuit (automatic temperature control circuit, automatic temperature control means), 3 optical modulator (optical modulation means), 4 optical output variable control section (optical output variable control means), 5 Startup sequence control unit (startup sequence control unit), 6 wavelength monitoring control unit (wavelength monitoring control unit), 7 optical branching unit (optical branching unit), 8 LD temperature control error monitoring unit (wavelength monitoring control unit), 9 Main signal ON / OFF control section (main signal ON / OFF control section), 10 modulator bias control section (modulation section bias control section), 41 EDF (optical amplification section), 42 excitation LD (excitation laser section), 43 LD Current control unit (laser current control means), 44 variable optical attenuator (variable light attenuation means), 45 attenuation control unit (attenuation control means).

Claims

Laser means for outputting continuous light, automatic temperature control means for controlling the element temperature of the laser means to a set temperature, and stabilizing the wavelength of the continuous light within an allocated wavelength band, and A light modulating means for modulating continuous light from the laser means and outputting it as modulated light; and a light output variable control for adjusting the level of the modulated light from the light modulating means within the light output variable control range and outputting it as an optical main signal And a wavelength multiplexing optical transmission device comprising:
When the power is turned on, the optical output variable control means is controlled to adjust the level of the modulated light to the minimum value of the optical output variable control range, and when the wavelength pull-in completion signal is notified, the optical output variable control means is controlled. A start-up sequence control unit that controls the control unit and adjusts the level of the modulated light to a desired value of the light output variable control range;
The wavelength of the continuous light is monitored, and the automatic temperature control means is controlled so that the monitored wavelength is drawn into the allocated wavelength band, and the monitored wavelength is drawn into the allocated wavelength band. A wavelength multiplexing optical transmission device comprising: a wavelength monitoring and control unit that notifies the start-up sequence control unit of the wavelength pull-in completion signal.

When the power is turned on, the main electric signal for the light modulating means is turned off, and when the start-up sequence control means is notified of the wavelength pull-in completion signal, the main electric signal for the light modulating means is turned on. Signal ON / OFF control means;
When the power is turned on, the light modulation unit is switched to the maximum extinction state, and when the start-up sequence control unit is notified of the wavelength pull-in completion signal, the modulation unit bias control unit switches the light modulation unit to the normal state. The wavelength division multiplexing optical transmission device according to claim 1, further comprising:

The wavelength monitoring control means includes:
3. The wavelength division multiplexing optical transmission device according to claim 1, wherein the wavelength of the continuous light output from behind the laser means is monitored.

An optical branching unit that branches continuous light output to the optical modulation unit from the front of the laser unit to the optical modulation unit and the wavelength monitoring control unit,
The wavelength monitoring control means,
3. The wavelength division multiplexing optical transmission device according to claim 1, wherein the wavelength of the continuous light branched by the optical branching unit is monitored.

The wavelength monitoring control means includes:
3. The wavelength multiplexing apparatus according to claim 1, wherein an error between a set temperature of the automatic temperature control means and an element temperature of the laser means is monitored, and a pull-in of the monitored wavelength within an assigned wavelength band is estimated. Optical transmitter.

The light output variable control means includes:
Optical amplification means for giving a gain to the modulated light and outputting it as an optical main signal,
Pump laser means for generating the gain by providing pump light to the optical amplification means,
Applying an excitation current to the excitation laser means to generate the excitation light, and when the power is turned on, while controlling the excitation current to a minimum value, when the wavelength of the continuous light is drawn into the assigned wavelength band, 3. The wavelength multiplexing device according to claim 1, further comprising: a laser current control unit that controls the pump current so that a desired value of the optical main signal is output from the optical amplification unit. Optical transmitter.

The light output variable control means includes:
An optical variable attenuating means for giving an optical attenuation to the modulated light and outputting it as an optical main signal;
When the power is turned on, the optical attenuation is controlled to the maximum value, and when the wavelength of the continuous light is drawn into the assigned wavelength band, an optical main signal of a desired value is output from the optical variable attenuation means. 3. The wavelength division multiplexing optical transmission device according to claim 1, further comprising an attenuation control unit for controlling the optical attenuation.