JP3835592B2 - Optical wavelength division multiplexing transmitter - Google Patents

Optical wavelength division multiplexing transmitter Download PDF

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Publication number
JP3835592B2
JP3835592B2 JP2001179167A JP2001179167A JP3835592B2 JP 3835592 B2 JP3835592 B2 JP 3835592B2 JP 2001179167 A JP2001179167 A JP 2001179167A JP 2001179167 A JP2001179167 A JP 2001179167A JP 3835592 B2 JP3835592 B2 JP 3835592B2
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wavelength
light
optical
modulation
light source
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JP2002374207A (en
Inventor
昇 高知尾
克寛 荒谷
淳一 可児
勝美 岩月
光啓 手島
正満 藤原
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Nippon Telegraph and Telephone Corp
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Nippon Telegraph and Telephone Corp
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Priority to JP2001179167A priority Critical patent/JP3835592B2/en
Priority to US10/163,849 priority patent/US7127168B2/en
Priority to CA002389974A priority patent/CA2389974C/en
Priority to EP02291444A priority patent/EP1267510B1/en
Priority to DE60222719T priority patent/DE60222719T2/en
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Description

【０００１】
【発明の属する技術分野】
本発明は、多波長一括発生光源から出力される多波長光を分波し、その各波長光を複数の光変調器でそれぞれ変調し、その変調信号光を波長多重して送信する光波長多重送信器に関する。特に、多波長一括発生光源の信頼性向上を図った光波長多重送信器に関する。
【０００２】
【従来の技術】
近年の伝送容量増大の要求に応えるために、１本の光ファイバ伝送路で異なる波長を有する複数の光信号を伝送する波長分割多重（ＷＤＭ）伝送システムの開発が進められている。最近では、多重数が数百チャネル以上といったＷＤＭ伝送システムが報告されており、商用レベルでは160 チャネルのＷＤＭ伝送システムが製品化されている。
【０００３】
図７は、従来の光波長多重送信器の構成例を示す。図において、光波長多重送信器は、それぞれ異なる波長を有する半導体レーザ（ＬＤ）５１−１〜５１−ｎと、各半導体レーザの出力光を送信信号により変調する光変調器５２−１〜５２−ｎと、各変調信号光を波長多重して出力する合波器５３により構成される。
【０００４】
ここで、半導体レーザは、温度変化および注入電流変化により発振波長シフトが生じ、また経時変化に伴って発振波長が変化する性質を有することから、伝送仕様上の波長精度を維持するには波長安定化回路が必要になる。この波長安定化は、個々の半導体レーザに対して実施する必要があるので、波長多重数の増加および波長多重間隔の高密度化に比例して、半導体レーザおよび波長安定化回路が増加し、光波長多重送信器の回路規模が増大する。
【０００５】
これに対して、単一の中心波長を有する光を特定の繰り返し周期を有する電気信号（例えば正弦波）を用いて位相変調および振幅変調を行い、側帯波を発生させることにより複数の中心波長を有する多波長光を一括して発生させる多波長一括発生光源（（特願２０００−２０７４９４）、以下「先願」という。）が出願されている。
【０００６】
図８は、先願の多波長一括発生光源を用いた光波長多重送信器の構成例を示す。図９は、先願の多波長一括発生光源における多波長光発生原理を示す。
【０００７】
図８において、多波長一括発生光源１は、光発生部１０および多波長化変調部２０により構成される。光発生部１０は、単一の中心波長の光を発生する半導体レーザ（ＬＤ）１１を有する。多波長化変調部２０は、光発生部１０の出力光を振幅変調する強度変調器２１および位相変調する位相変調器２２と（各変調器の順番は任意）、各変調器に印加する所定の周期信号（正弦波）を発生する周期信号発生器２３と、周期信号の印加電圧およびバイアス電圧を調整する電圧調整部２４，２５から構成される。なお、多波長化変調部２０は、例えばマッハツェンダ強度変調器を用いて分岐されたパスで位相変調を行い、全体として振幅変調動作させる構成としてもよい。
【０００８】
強度変調器２１および位相変調器２２では、光発生部１０の出力光（連続光）の時間波形の振幅または位相を変調することにより、その出力光の離散光スペクトルの各モードの位相に一定の相関を与える（図９(a))。さらに、その変調波の振幅または位相を変調することにより、離散光スペクトルを周波数軸上で上下側波帯に偏移させる（図９(b))。ここで、周波数偏移量を調節することにより、離散光スペクトルが重なって各モードのパワーレベル偏差を一定に制御することができる（図９(c))。
【０００９】
なお、光発生部１０は、図１０に示すように、互いに異なる中心波長の光を発生するｎ個の半導体レーザ（ＬＤ）１１−１〜１１−ｎを備え、合波器１２で各レーザ光を合波して出力光とする構成としてもよい。この場合には、多波長化変調部２０で各中心波長に対して側帯波が発生し、さらに広帯域にわたって多波長光を一括発生させることができる。
【００１０】
このような先願の多波長一括発生光源を用いて光波長多重送信器を構成する場合には、図８に示すように、多波長光を各波長にスペクトルスライスする分波器３１を有する光変調部３を用いる。光変調部３では、分波器３１で分波された各波長光を光変調器３２−１〜３２−ｎで送信信号により変調し、合波器３３で各変調信号光を波長多重して出力する。
【００１１】
【発明が解決しようとする課題】
先願の多波長一括発生光源１を用いる図８の光波長多重送信器は、単体の半導体レーザをチャネル数分だけ用意する図７の光波長多重送信器の構成に比べて、装置規模の縮小とともにチャネル当たりの光源コストの低減が可能である。しかし、１つの多波長一括発生光源１から多波長光を一括発生させる構成であるために、その元となる１つの多波長一括発生光源１が故障すると、多波長光のすべてが停止することになる。例えば、多波長一括発生光源１の多波長化変調部２０が故障すると、一括発生する各チャネル対応の多波長光が同時に停止し、それを用いて伝送される莫大な情報がすべて伝送できなくなる。
【００１２】
本発明は、先願の多波長一括発生光源を用いて多波長光を発生させ、その多波長光を分波し、その各波長光を複数の光変調器でそれぞれ変調し、その変調信号光を波長多重して出力する光波長多重送信器において、多波長一括発生光源の冗長構成により信頼性向上を図ることができる光波長多重送信器を提供することを目的とする。
【００１３】
【課題を解決するための手段】
本発明の光波長多重送信器は、先願の多波長一括発生光源１（光発生部１０および多波長化変調部２０）を複数備え、その１つを選択して光変調部３に接続する構成（請求項１）と、先願の多波長一括発生光源１の多波長化変調部２０を複数備え、その１つを選択して光変調部３に接続する構成（請求項４）に大きく分けられる。
【００１４】
さらに、本発明の光波長多重送信器では、請求項１の冗長構成によって多波長一括発生光源１の信頼性が向上したことにより、複数の光変調部３を備え、多波長一括発生光源１から出力される多波長光を各光変調部３に分配する構成とし、多波長一括発生光源１を複数のＷＤＭ伝送システムで共有することを可能とする（請求項２）。
【００１５】
また、本発明の光波長多重送信器では、請求項４の冗長構成により多波長一括発生光源１の多波長化変調部２０の信頼性が向上したことにより、複数の光変調部３を備え、多波長化変調部２０から出力される多波長光を各光変調部３に分配する構成とし、多波長化変調部２０を複数のＷＤＭ伝送システムで共有することを可能とする（請求項５）。
【００１６】
さらに、本発明の光波長多重送信器は、複数Ｍ個の光変調部３に対してそれより多い複数Ｎ個（Ｎ＞Ｍ）の多波長一括発生光源１または多波長光化変調部２０を備え、Ｎ×Ｍ光スイッチを用いて多波長一括発生光源１または多波長化変調部２０と光変調部３をそれぞれ１対１に接続するとともに、いずれかの多波長一括発生光源１または多波長化変調部２０に故障が発生したときに、予備の多波長一括発生光源１または多波長化変調部２０への切り換えが可能な構成とする（請求項３、請求項６）。
【００１７】
【発明の実施の形態】
＜第１の実施形態：請求項１＞
図１は、本発明の光波長多重送信器の第１の実施形態を示す。
【００１８】
図において、本実施形態の光波長多重送信器は、２つの多波長一括発生光源１−１，１−２を備え、光スイッチ４１でその一方の多波長光を選択して光変調部３に接続する。多波長一括発生光源１−１，１−２は、図８または図１０に示す先願の多波長一括発生光源１と同様の構成であり、光発生部１０および多波長化変調部２０から構成される。光変調部３も図８に示すものと同様の構成である。
【００１９】
光スイッチ４１は、選択している一方の多波長一括発生光源から出力される多波長光に異常が発生した場合に、自動または手動で他方の多波長一括発生光源の方へ切り換える。これにより、光変調部３に対する多波長光の安定的な供給が実現する。
【００２０】
＜第２の実施形態：請求項２＞
図２は、本発明の光波長多重送信器の第２の実施形態を示す。
図において、本実施形態の光波長多重送信器は、第１の実施形態と同様に多波長一括発生光源１−１，１−２の二重化により多波長光の安定供給を実現させ、その多波長光を光スターカプラ４２を介して複数Ｍ個の光変調部３−１〜３−Ｍに分配する。これにより、複数Ｍ個の光波長多重送信器を備えたことと実質的に等価になる。すなわち、複数Ｍ個のＷＤＭ伝送システムの各光多波長光源送信器として、二重化された多波長一括発生光源１−１，１−２を共有することができ、より経済的なシステム構成が可能となる。
【００２１】
＜第３の実施形態：請求項３＞
図３は、本発明の光波長多重送信器の第３の実施形態を示す。
図において、本実施形態の光波長多重送信器は、複数Ｍ個の光変調部３−１〜３−Ｍに対して、それより多い複数Ｎ個（Ｎ＞Ｍ）の多波長一括発生光源１−１〜１−Ｎを備える。Ｍ個の多波長一括発生光源１−１〜１−Ｍと光変調部３−１〜３−Ｍは、Ｎ×Ｍ光スイッチ４３を介してそれぞれ１対１に接続される。多波長一括発生光源１−１〜１−Ｎは、図８または図１０に示す先願の多波長一括発生光源１と同様の構成であり、光発生部１０および多波長化変調部２０から構成される。光変調部３−１〜３−Ｍも図８に示すものと同様の構成である。これにより、複数Ｍ個の光波長多重送信器を備えたことと実質的に等価になる。
【００２２】
Ｎ×Ｍ光スイッチ４３は、例えば多波長一括発生光源１−１に故障が発生したときに、予備の多波長一括発生光源１−Ｎと光変調部３−１との接続に切り換える。Ｎ×Ｍ光スイッチ４３は任意の接続が可能であり、例えばＮ＝Ｍ＋２の場合には、任意の２つの多波長一括発生光源の故障に対して予備に切り換えることができ、多波長光の安定的な供給を実現することができる。
【００２３】
＜第４の実施形態：請求項４＞
図４は、本発明の光波長多重送信器の第４の実施形態を示す。
図において、本実施形態の光波長多重送信器は、多波長一括発生光源１として１つの光発生部１０と２つの多波長化変調部２０−１，２０−２を備え、光カプラ４４を介して光発生部１０の出力光を多波長化変調部２０−１，２０−２に分配する。多波長化変調部２０−１，２０−２から出力される多波長光は、光スイッチ４５でその一方が選択されて光変調部３に入力する。光発生部１０および多波長化変調部２０−１，２０−２は、図８または図１０に示す先願の多波長一括発生光源１における光発生部１０および多波長化変調部２０と同様の構成である。光変調部３も図８に示すものと同様の構成である。
【００２４】
光スイッチ４５は、選択している一方の多波長化変調部から出力される多波長光に異常が発生した場合に、自動または手動で他方の多波長化変調部の方へ切り換える。これにより、光変調部３に対して多波長光の安定的な供給が実現する。
【００２５】
＜第５の実施形態：請求項５＞
図５は、本発明の光波長多重送信器の第５の実施形態を示す。
図において、本実施形態の光波長多重送信器は、第４の実施形態と同様に多波長化変調部２０−１，２０−２の二重化により多波長光の安定供給を実現させ、その多波長光を光スターカプラ４６を介して複数Ｍ個の光変調部３−１〜３−Ｍに分配する。これにより、複数Ｍ個の光波長多重送信器を備えたことと実質的に等価になる。すなわち、複数Ｍ個のＷＤＭ伝送システムの各光多波長光源送信器として、二重化された多波長化変調部２０−１，２０−２を共有することができ、より経済的なシステム構成が可能となる。
【００２６】
＜第６の実施形態：請求項６＞
図６は、本発明の光波長多重送信器の第６の実施形態を示す。
図において、本実施形態の光波長多重送信器は、複数Ｍ個の光変調部３−１〜３−Ｍに対して、それより多い複数Ｎ個（Ｎ＞Ｍ）の多波長化変調部２０−１〜２０−Ｎを備える。多波長化変調部２０−１〜２０−Ｎには、光スターカプラ４７を介して光発生部１０の出力光が分配される。Ｍ個の多波長化変調部２０−１〜２０−Ｍと光変調部３−１〜３−Ｍは、Ｎ×Ｍ光スイッチ４８を介してそれぞれ１対１に接続される。光発生部１０および多波長化変調部２０−１〜２０−Ｎは、図８または図１０に示す先願の多波長一括発生光源１の光発生部１０および多波長化変調部２０と同様の構成である。光変調部３−１〜３−Ｍも図８に示すものと同様の構成である。これにより、複数Ｍ個の光波長多重送信器を備えたことと実質的に等価になる。
【００２７】
Ｎ×Ｍ光スイッチ４８は、例えば多波長化変調部２０−１に故障が発生したときに、予備の多波長化変調部２０−Ｎと光変調部３−１との接続に切り換える。Ｎ×Ｍ光スイッチ４８は任意の接続が可能であり、例えばＮ＝Ｍ＋２の場合には、任意の２つの多波長化変調部の故障に対して予備に切り換えることができ、多波長光の安定的な供給を実現することができる。
【００２８】
なお、ここでは光発生部１０を１つとしているが、同様の構成を有する複数ｍ個の光発生部１０−１〜１０−ｍを備え、各光発生部ごとにＮ／ｍ個（Ｎ／ｍは整数）の多波長化発生部に対して出力光を分配し、全体でＮ個の多波長化変調部２０−１〜２０−Ｎに光発生部１０−１〜１０−ｍの出力光を分配するようにしてもよい（図６(b))。
【００２９】
また、上記の第１，第２，第４，第５の実施形態では二重化構成を例としたが、三重化以上の冗長構成をとってもよい。また、上記の第２、第４〜第６の実施形態おいて、光スターカプラまたは光カプラによる分岐損失が大きくなる場合には、光増幅器を用いて光パワーを増幅する構成としてもよい。
【００３０】
【発明の効果】
以上説明したように、本発明は、多波長光を一括発生させる多波長一括発生光源の信頼性を向上させることができるので、多波長一括発生光源の低コスト化の利点を活かした低コストかつ高信頼の光波長多重送信器を実現することができる。
【図面の簡単な説明】
【図１】本発明の光波長多重送信器の第１の実施形態を示す図。
【図２】本発明の光波長多重送信器の第２の実施形態を示す図。
【図３】本発明の光波長多重送信器の第３の実施形態を示す図。
【図４】本発明の光波長多重送信器の第４の実施形態を示す図。
【図５】本発明の光波長多重送信器の第５の実施形態を示す図。
【図６】本発明の光波長多重送信器の第６の実施形態を示す図。
【図７】従来の光波長多重送信器の構成例を示す図。
【図８】先願の多波長一括発生光源を用いた光波長多重送信器の構成例を示す図。
【図９】先願の多波長一括発生光源における多波長光発生原理を示す図。
【図１０】先願の多波長一括発生光源における光発生部１０の他の構成例を示す図。
【符号の説明】
１ 多波長一括発生光源
１０ 光発生部
１１ 半導体レーザ（ＬＤ）
１２ 合波器
２０ 多波長化変調部
２１ 強度変調器
２２ 位相変調器
２３ 周期信号発生器
２４，２５ 電圧調整部
３ 光変調部
３１ 分波器
３２ 光変調器
３３ 合波器
４１，４５ 光スイッチ
４２，４６，４７ 光スターカプラ
４３，４８ Ｎ×Ｍ光スイッチ
４４ 光カプラ
５１ 半導体レーザ（ＬＤ）
５２ 光変調器
５３ 合波器[0001]
BACKGROUND OF THE INVENTION
The present invention demultiplexes multi-wavelength light output from a multi-wavelength collective light source, modulates each wavelength light with a plurality of optical modulators, and wavelength-multiplexes and transmits the modulated signal light. Regarding the transmitter. In particular, the present invention relates to an optical wavelength division multiplex transmitter for improving the reliability of a multi-wavelength collective light source.
[0002]
[Prior art]
In order to meet the demand for an increase in transmission capacity in recent years, development of a wavelength division multiplexing (WDM) transmission system that transmits a plurality of optical signals having different wavelengths through a single optical fiber transmission line is underway. Recently, a WDM transmission system having a multiplexing number of several hundred channels or more has been reported, and a 160-channel WDM transmission system has been commercialized at a commercial level.
[0003]
FIG. 7 shows a configuration example of a conventional optical wavelength division multiplexing transmitter. In the figure, the optical wavelength multiplexing transmitters include semiconductor lasers (LD) 51-1 to 51-n having different wavelengths, and optical modulators 52-1 to 52- for modulating the output light of each semiconductor laser with a transmission signal. n and a multiplexer 53 for wavelength-multiplexing and outputting each modulated signal light.
[0004]
Here, the semiconductor laser has the property that the oscillation wavelength shifts due to changes in temperature and injection current, and the oscillation wavelength changes with time. Circuit is required. Since this wavelength stabilization needs to be performed for each semiconductor laser, the number of semiconductor lasers and wavelength stabilization circuits increases in proportion to the increase in the number of wavelength multiplexing and the increase in the density of wavelength multiplexing intervals. The circuit scale of the wavelength multiplexing transmitter increases.
[0005]
On the other hand, phase modulation and amplitude modulation of light having a single center wavelength using an electrical signal having a specific repetition period (for example, a sine wave), and generating sideband waves, thereby generating a plurality of center wavelengths. A multi-wavelength collective light source (Japanese Patent Application No. 2000-207494, hereinafter referred to as “prior application”) that collectively generates multi-wavelength light has been filed.
[0006]
FIG. 8 shows a configuration example of an optical wavelength division multiplex transmitter using the multi-wavelength collective light source of the prior application. FIG. 9 shows the principle of multi-wavelength light generation in the prior application multi-wavelength collective light source.
[0007]
In FIG. 8, the multi-wavelength collective light source 1 includes a light generation unit 10 and a multi-wavelength modulation unit 20. The light generation unit 10 includes a semiconductor laser (LD) 11 that generates light having a single center wavelength. The multi-wavelength modulation unit 20 includes an intensity modulator 21 that amplitude-modulates the output light of the light generation unit 10 and a phase modulator 22 that performs phase modulation (the order of each modulator is arbitrary), and a predetermined application applied to each modulator. It comprises a periodic signal generator 23 that generates a periodic signal (sine wave), and voltage adjustment units 24 and 25 that adjust the applied voltage and bias voltage of the periodic signal. Note that the multi-wavelength modulation unit 20 may be configured to perform amplitude modulation operation as a whole by performing phase modulation in a path branched using, for example, a Mach-Zehnder intensity modulator.
[0008]
In the intensity modulator 21 and the phase modulator 22, by modulating the amplitude or phase of the time waveform of the output light (continuous light) of the light generator 10, the phase of each mode of the discrete light spectrum of the output light is constant. Correlation is given (FIG. 9 (a)). Further, by modulating the amplitude or phase of the modulated wave, the discrete light spectrum is shifted to the upper and lower sidebands on the frequency axis (FIG. 9 (b)). Here, by adjusting the frequency shift amount, the discrete light spectra can be overlapped to control the power level deviation of each mode to be constant (FIG. 9 (c)).
[0009]
As shown in FIG. 10, the light generation unit 10 includes n semiconductor lasers (LDs) 11-1 to 11-n that generate lights having different center wavelengths, and each of the laser beams is coupled by the multiplexer 12. May be combined to produce output light. In this case, the multi-wavelength modulation unit 20 can generate sidebands for the respective center wavelengths, and can further generate multi-wavelength light over a wide band.
[0010]
When an optical wavelength multiplex transmitter is configured using such a multi-wavelength collective light source of the prior application, as shown in FIG. 8, light having a demultiplexer 31 that spectrally slices multi-wavelength light into each wavelength. The modulation unit 3 is used. In the optical modulation unit 3, each wavelength light demultiplexed by the demultiplexer 31 is modulated by the transmission signal by the optical modulators 32-1 to 32 -n, and each modulated signal light is wavelength-multiplexed by the multiplexer 33. Output.
[0011]
[Problems to be solved by the invention]
The optical wavelength multiplex transmitter of FIG. 8 using the multi-wavelength collective light source 1 of the prior application is reduced in apparatus scale as compared with the configuration of the optical wavelength multiplex transmitter of FIG. 7 in which a single semiconductor laser is prepared for the number of channels. In addition, the light source cost per channel can be reduced. However, since the multi-wavelength light is generated collectively from one multi-wavelength collective light source 1, if one multi-wavelength collective light source 1 as the source fails, all of the multi-wavelength light is stopped. Become. For example, when the multi-wavelength modulation unit 20 of the multi-wavelength collective light source 1 breaks down, multi-wavelength light corresponding to each channel that is generated all at once stops at the same time, and it is impossible to transmit all of the enormous information that is transmitted using it.
[0012]
The present invention generates multi-wavelength light using a multi-wavelength collective light source of the prior application, demultiplexes the multi-wavelength light, modulates each wavelength light with a plurality of optical modulators, and modulates the signal light. An object of the present invention is to provide an optical wavelength multiplex transmitter that can improve reliability by a redundant configuration of a multi-wavelength simultaneous generation light source.
[0013]
[Means for Solving the Problems]
The optical wavelength division multiplex transmitter of the present invention includes a plurality of multi-wavelength collective light sources 1 (the light generation unit 10 and the multi-wavelength modulation unit 20) of the prior application, and one of them is selected and connected to the optical modulation unit 3. A configuration (Claim 1) and a configuration in which a plurality of multi-wavelength modulation units 20 of the multi-wavelength collective light source 1 of the prior application are provided, and one of them is selected and connected to the light modulation unit 3 (Claim 4). Divided.
[0014]
Furthermore, in the optical wavelength division multiplex transmitter of the present invention, the reliability of the multi-wavelength collective light source 1 is improved by the redundant configuration of claim 1. The multi-wavelength light to be output is distributed to each optical modulation section 3, and the multi-wavelength collective light source 1 can be shared by a plurality of WDM transmission systems.
[0015]
Further, in the optical wavelength division multiplex transmitter of the present invention, the reliability of the multi-wavelength modulation unit 20 of the multi-wavelength simultaneous generation light source 1 is improved by the redundant configuration of claim 4, thereby including a plurality of optical modulation units 3, The multi-wavelength light output from the multi-wavelength modulation section 20 is configured to be distributed to each optical modulation section 3, and the multi-wavelength modulation section 20 can be shared by a plurality of WDM transmission systems. .
[0016]
Furthermore, the optical wavelength division multiplex transmitter of the present invention includes a plurality of N (N> M) multi-wavelength collective light sources 1 or multi-wavelength optical modulation units 20 with respect to a plurality of M optical modulation units 3. The multi-wavelength collective light source 1 or the multi-wavelength modulation unit 20 and the optical modulator 3 are connected one-to-one using an N × M optical switch, and any multi-wavelength collective light source 1 or multi-wavelength is connected. When a failure occurs in the optical modulation unit 20, the configuration can be switched to the spare multi-wavelength collective light source 1 or the multi-wavelength modulation unit 20 (claims 3 and 6).
[0017]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment: Claim 1>
FIG. 1 shows a first embodiment of an optical wavelength division multiplex transmitter of the present invention.
[0018]
In the figure, the optical wavelength division multiplex transmitter of the present embodiment includes two multi-wavelength collective light sources 1-1 and 1-2, and selects one of the multi-wavelength light by the optical switch 41 and supplies it to the optical modulation unit 3. Connecting. The multi-wavelength collective light sources 1-1 and 1-2 have the same configuration as the multi-wavelength collective light source 1 of the prior application shown in FIG. Is done. The light modulator 3 has the same configuration as that shown in FIG.
[0019]
When an abnormality occurs in the multi-wavelength light output from one of the selected multi-wavelength collective light sources, the optical switch 41 automatically or manually switches to the other multi-wavelength collective light source. Thereby, stable supply of multi-wavelength light to the light modulation unit 3 is realized.
[0020]
<Second Embodiment: Claim 2>
FIG. 2 shows a second embodiment of the optical wavelength division multiplex transmitter of the present invention.
In the figure, the optical wavelength division multiplex transmitter of the present embodiment realizes stable supply of multi-wavelength light by duplicating the multi-wavelength collective light sources 1-1 and 1-2 as in the first embodiment. The light is distributed to a plurality of M light modulation units 3-1 to 3 -M through the light star coupler 42. This is substantially equivalent to having a plurality of M optical wavelength multiplex transmitters. That is, as each optical multi-wavelength light source transmitter of a plurality of M WDM transmission systems, the duplexed multi-wavelength collective light sources 1-1 and 1-2 can be shared, and a more economical system configuration is possible. Become.
[0021]
<Third Embodiment: Claim 3>
FIG. 3 shows a third embodiment of the optical wavelength division multiplexing transmitter of the present invention.
In the figure, the optical wavelength division multiplex transmitter of the present embodiment includes a plurality of N (N> M) multi-wavelength collective light sources 1 for a plurality of M optical modulation units 3-1 to 3 -M. -1 to 1-N. The M multi-wavelength collective light sources 1-1 to 1 -M and the light modulators 3-1 to 3 -M are connected one-to-one via the N × M optical switch 43. The multi-wavelength collective light sources 1-1 to 1-N have the same configuration as the multi-wavelength collective light source 1 of the prior application shown in FIG. Is done. The light modulators 3-1 to 3-M have the same configuration as that shown in FIG. This is substantially equivalent to having a plurality of M optical wavelength multiplex transmitters.
[0022]
For example, when a failure occurs in the multi-wavelength collective light source 1-1, the N × M optical switch 43 switches to a connection between the standby multi-wavelength collective light source 1-N and the optical modulation unit 3-1. The N × M optical switch 43 can be arbitrarily connected. For example, in the case of N = M + 2, it can be switched to a spare for the failure of any two multi-wavelength light sources, and the stability of the multi-wavelength light can be improved. Supply can be realized.
[0023]
<Fourth Embodiment: Claim 4>
FIG. 4 shows a fourth embodiment of the optical wavelength division multiplex transmitter of the present invention.
In the figure, the optical wavelength division multiplex transmitter of this embodiment includes one light generation unit 10 and two multi-wavelength modulation units 20-1 and 20-2 as the multi-wavelength collective light source 1, via an optical coupler 44. Thus, the output light of the light generation unit 10 is distributed to the multi-wavelength modulation units 20-1 and 20-2. One of the multi-wavelength lights output from the multi-wavelength modulation units 20-1 and 20-2 is selected by the optical switch 45 and input to the optical modulation unit 3. The light generation unit 10 and the multi-wavelength modulation units 20-1 and 20-2 are the same as the light generation unit 10 and the multi-wavelength modulation unit 20 in the multi-wavelength collective light source 1 of the prior application shown in FIG. It is a configuration. The light modulator 3 has the same configuration as that shown in FIG.
[0024]
The optical switch 45 automatically or manually switches to the other multi-wavelength modulation section when an abnormality occurs in the multi-wavelength light output from the selected one multi-wavelength modulation section. As a result, stable supply of multi-wavelength light to the light modulation unit 3 is realized.
[0025]
<Fifth Embodiment: Claim 5>
FIG. 5 shows a fifth embodiment of the optical wavelength division multiplex transmitter of the present invention.
In the figure, the optical wavelength division multiplex transmitter of this embodiment realizes stable supply of multi-wavelength light by duplexing the multi-wavelength modulation units 20-1 and 20-2 as in the fourth embodiment. The light is distributed to a plurality of M light modulation units 3-1 to 3 -M through the light star coupler 46. This is substantially equivalent to having a plurality of M optical wavelength multiplex transmitters. That is, as each optical multi-wavelength light source transmitter of a plurality of M WDM transmission systems, the duplexed multi-wavelength modulation units 20-1 and 20-2 can be shared, and a more economical system configuration is possible. Become.
[0026]
<Sixth Embodiment: Claim 6>
FIG. 6 shows a sixth embodiment of the optical wavelength division multiplex transmitter of the present invention.
In the figure, the optical wavelength division multiplex transmitter of the present embodiment includes a plurality of N (N> M) multi-wavelength modulation units 20 with respect to a plurality of M optical modulation units 3-1 to 3 -M. -1 to 20-N. The output light of the light generation unit 10 is distributed to the multi-wavelength modulation units 20-1 to 20 -N via the optical star coupler 47. The M multi-wavelength modulation units 20-1 to 20 -M and the light modulation units 3-1 to 3 -M are connected one-to-one via the N × M optical switch 48. The light generation unit 10 and the multi-wavelength modulation units 20-1 to 20-N are the same as the light generation unit 10 and the multi-wavelength modulation unit 20 of the multi-wavelength collective light source 1 of the prior application shown in FIG. It is a configuration. The light modulators 3-1 to 3-M have the same configuration as that shown in FIG. This is substantially equivalent to having a plurality of M optical wavelength multiplex transmitters.
[0027]
For example, when a failure occurs in the multi-wavelength modulation unit 20-1, the N × M optical switch 48 switches to a connection between the standby multi-wavelength modulation unit 20-N and the optical modulation unit 3-1. The N × M optical switch 48 can be arbitrarily connected. For example, when N = M + 2, the N × M optical switch 48 can be switched to a spare for the failure of any two multi-wavelength modulation units, thereby stabilizing the multi-wavelength light. Supply can be realized.
[0028]
Here, although one light generating unit 10 is provided, a plurality of m light generating units 10-1 to 10-m having the same configuration are provided, and N / m (N / m) are provided for each light generating unit. m is an integer), the output light is distributed to the multi-wavelength generating units, and the output light of the light generating units 10-1 to 10-m is distributed to N multi-wavelength modulating units 20-1 to 20-N as a whole. May be distributed (FIG. 6B).
[0029]
In the first, second, fourth, and fifth embodiments, the duplex configuration is taken as an example. However, a redundancy configuration that is more than triple is possible. In the second and fourth to sixth embodiments, when the branch loss due to the optical star coupler or the optical coupler increases, the optical power may be amplified using an optical amplifier.
[0030]
【The invention's effect】
As described above, the present invention can improve the reliability of a multi-wavelength collective light source that collectively generates multi-wavelength light. A highly reliable optical wavelength division multiplex transmitter can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of an optical wavelength division multiplex transmitter according to the present invention.
FIG. 2 is a diagram showing a second embodiment of the optical wavelength division multiplex transmitter of the present invention.
FIG. 3 is a diagram showing a third embodiment of the optical wavelength division multiplex transmitter of the present invention.
FIG. 4 is a diagram showing a fourth embodiment of the optical wavelength division multiplex transmitter of the present invention.
FIG. 5 is a diagram showing a fifth embodiment of the optical wavelength division multiplex transmitter of the present invention.
FIG. 6 is a diagram showing a sixth embodiment of the optical wavelength division multiplex transmitter of the present invention.
FIG. 7 is a diagram showing a configuration example of a conventional optical wavelength division multiplex transmitter.
FIG. 8 is a diagram showing a configuration example of an optical wavelength multiplexing transmitter using a multi-wavelength collective light source of a prior application.
FIG. 9 is a diagram showing the principle of multi-wavelength light generation in the multi-wavelength collective light source of the prior application.
FIG. 10 is a diagram showing another configuration example of the light generation unit 10 in the multi-wavelength collective light source of the prior application.
[Explanation of symbols]
1 Multi-wavelength collective light source 10 Light generator 11 Semiconductor laser (LD)
12 multiplexer 20 multi-wavelength modulation unit 21 intensity modulator 22 phase modulator 23 periodic signal generators 24 and 25 voltage adjustment unit 3 optical modulator 31 demultiplexer 32 optical modulator 33 multiplexers 41 and 45 optical switch 42, 46, 47 Optical star couplers 43, 48 N × M optical switch 44 Optical coupler 51 Semiconductor laser (LD)
52 optical modulator 53 multiplexer

Claims (6)

単一または複数の中心波長を有する連続光を発生する光発生部と、前記連続光を振幅変調する強度変調器および位相変調する位相変調器と、前記強度変調器および前記位相変調器に印加する所定の周期信号を発生する周期信号発生器を有し、前記連続光を所定の周期信号で振幅変調および位相変調し、前記連続光の離散光スペクトルを周波数軸上で上下側波帯に偏移させ、前記中心波長および前記側帯波からなる多波長光を発生させる多波長化変調部とで構成される多波長一括発生光源と、
前記多波長一括発生光源から出力された多波長光を入力して各波長に分波する分波器と、分波された各波長光を送信信号により変調する複数の光変調器と、各変調信号光を波長多重して出力する合波器とにより構成される光変調部とを備えた光波長多重送信器において、
前記多波長一括発生光源を複数備え、
前記複数の多波長一括発生光源の１つを選択して前記光変調部に接続するとともに、選択された多波長一括発生光源に異常が発生したときに他の多波長一括発生光源に切り換えて前記光変調部に接続する光スイッチを備えたことを特徴とする光波長多重送信器。A light generator for generating a continuous light having a single or plurality of center wavelengths, applying said continuous light and a phase modulator for intensity modulator and phase modulation to amplitude modulation, the intensity modulator and said phase modulator It has a periodic signal generator for generating a predetermined periodic signal, the continuous light amplitude-modulated and phase-modulated in a predetermined cycle signal, shift the upper and lower sidebands of the discrete spectrum of the continuous light on the frequency axis is allowed, and the multi-wavelength generation light source composed of a multi-wavelength modulating section for generating multi-wavelength light consisting of the center wavelength and said sidebands,
A demultiplexer that receives the multi-wavelength light output from the multi-wavelength collective light source and demultiplexes it into each wavelength, a plurality of optical modulators that modulate each demultiplexed light with a transmission signal, and each modulation In an optical wavelength division multiplex transmitter including an optical modulator configured by a multiplexer that wavelength-multiplexes and outputs signal light,
A plurality of the multi-wavelength collective light sources are provided,
One of the plurality of multi-wavelength collective light sources is selected and connected to the light modulation unit, and when an abnormality occurs in the selected multi-wavelength collective light source, the other multi-wavelength collective light source is switched to An optical wavelength division multiplex transmitter comprising an optical switch connected to an optical modulator. 請求項１に記載の光波長多重送信器において、
前記光変調部を複数備え、
前記光スイッチで選択された多波長一括発生光源からの多波長光を複数に分岐して前記複数の光変調部にそれぞれ供給する手段を備えたことを特徴とする光波長多重送信器。The optical wavelength division multiplexing transmitter according to claim 1,
Comprising a plurality of the light modulators;
An optical wavelength division multiplex transmitter comprising means for branching multi-wavelength light from a multi-wavelength collective light source selected by the optical switch into a plurality of light sources and supplying them to the plurality of optical modulators, respectively. 単一または複数の中心波長を有する連続光を発生する光発生部と、前記連続光を振幅変調する強度変調器および位相変調する位相変調器と、前記強度変調器および前記位相変調器に印加する所定の周期信号を発生する周期信号発生器を有し、前記連続光を所定の周期信号で振幅変調および位相変調し、前記連続光の離散光スペクトルを周波数軸上で上下側波帯に偏移させ、前記中心波長および前記側帯波からなる多波長光を発生させる多波長化変調部とで構成される多波長一括発生光源と、
前記多波長一括発生光源から出力された多波長光を入力して各波長に分波する分波器と、分波された各波長光を送信信号により変調する複数の光変調器と、各変調信号光を波長多重して出力する合波器とにより構成される光変調部とを備えた光波長多重送信器において、
前記多波長一括発生光源を複数Ｎ個と、前記光変調部を複数Ｍ個（Ｍ＜Ｎ）とを備え、
前記Ｍ個の多波長一括発生光源と、前記Ｍ個の光変調部をそれぞれ１対１に接続するとともに、いずれかの多波長一括発生光源に故障が発生したときに、（Ｎ−Ｍ）個ある予備の多波長一括発生光源に切り換えて対応する光変調部に接続するＮ×Ｍ光スイッチを備えたことを特徴とする光波長多重送信器。A light generator for generating a continuous light having a single or plurality of center wavelengths, applying said continuous light and a phase modulator for intensity modulator and phase modulation to amplitude modulation, the intensity modulator and said phase modulator It has a periodic signal generator for generating a predetermined periodic signal, the continuous light amplitude-modulated and phase-modulated in a predetermined cycle signal, shift the upper and lower sidebands of the discrete spectrum of the continuous light on the frequency axis is allowed, and the multi-wavelength generation light source composed of a multi-wavelength modulating section for generating multi-wavelength light consisting of the center wavelength and said sidebands,
A demultiplexer that receives the multi-wavelength light output from the multi-wavelength collective light source and demultiplexes it into each wavelength, a plurality of optical modulators that modulate each demultiplexed light with a transmission signal, and each modulation In an optical wavelength division multiplex transmitter including an optical modulator configured by a multiplexer that wavelength-multiplexes and outputs signal light,
A plurality of N multi-wavelength light sources, and a plurality of M light modulators (M <N),
When the M multi-wavelength collective light sources and the M light modulators are connected in a one-to-one relationship and one of the multi-wavelength collective light sources fails, (N−M) An optical wavelength division multiplex transmitter comprising an N × M optical switch connected to a corresponding optical modulation unit by switching to a spare multi-wavelength collective light source. 単一または複数の中心波長を有する連続光を発生する光発生部と、前記連続光を振幅変調する強度変調器および位相変調する位相変調器と、前記強度変調器および前記位相変調器に印加する所定の周期信号を発生する周期信号発生器を有し、前記連続光を所定の周期信号で振幅変調および位相変調し、前記連続光の離散光スペクトルを周波数軸上で上下側波帯に偏移させ、前記中心波長および前記側帯波からなる多波長光を発生させる多波長化変調部とで構成される多波長一括発生光源と、
前記多波長一括発生光源から出力された多波長光を入力して各波長に分波する分波器と、分波された各波長光を送信信号により変調する複数の光変調器と、各変調信号光を波長多重して出力する合波器とにより構成される光変調部とを備えた光波長多重送信器において、
前記多波長一括発生光源は、複数の多波長化変調部と、光発生部の出力光を分岐して各多波長化変調部に供給する手段とを備え、
前記多波長化変調部の１つを選択して前記光変調部に接続するとともに、選択された多波長化変調部に異常が発生したときに他の多波長化変調部に切り換えて前記光変調部に接続する光スイッチを備えたことを特徴とする光波長多重送信器。A light generator for generating a continuous light having a single or plurality of center wavelengths, applying said continuous light and a phase modulator for intensity modulator and phase modulation to amplitude modulation, the intensity modulator and said phase modulator It has a periodic signal generator for generating a predetermined periodic signal, the continuous light amplitude-modulated and phase-modulated in a predetermined cycle signal, shift the upper and lower sidebands of the discrete spectrum of the continuous light on the frequency axis is allowed, and the multi-wavelength generation light source composed of a multi-wavelength modulating section for generating multi-wavelength light consisting of the center wavelength and said sidebands,
A demultiplexer that receives the multi-wavelength light output from the multi-wavelength collective light source and demultiplexes it into each wavelength, a plurality of optical modulators that modulate each demultiplexed light with a transmission signal, and each modulation In an optical wavelength division multiplex transmitter including an optical modulator configured by a multiplexer that wavelength-multiplexes and outputs signal light,
The multi-wavelength batch generation light source includes a plurality of multi-wavelength modulation units, and means for branching the output light of the light generation unit and supplying each of the multi-wavelength modulation units,
One of the multi-wavelength modulation units is selected and connected to the optical modulation unit, and when an abnormality occurs in the selected multi-wavelength modulation unit, the optical modulation is switched to another multi-wavelength modulation unit An optical wavelength division multiplex transmitter comprising an optical switch connected to the unit. 請求項４に記載の光波長多重送信器において、
前記光変調部を複数備え、
前記光スイッチで選択された多波長化変調部からの多波長光を複数に分岐して前記複数の光変調部にそれぞれ供給する手段を備えたことを特徴とする光波長多重送信器。The optical wavelength division multiplexing transmitter according to claim 4,
Comprising a plurality of the light modulators;
An optical wavelength division multiplex transmitter comprising means for branching multi-wavelength light from a multi-wavelength modulation unit selected by the optical switch into a plurality of light and supplying the light to each of the plurality of optical modulation units. 単一または複数の中心波長を有する連続光を発生する光発生部と、前記連続光を振幅変調する強度変調器および位相変調する位相変調器と、前記強度変調器および前記位相変調器に印加する所定の周期信号を発生する周期信号発生器を有し、前記連続光を所定の周期信号で振幅変調および位相変調し、前記連続光の離散光スペクトルを周波数軸上で上下側波帯に偏移させ、前記中心波長および前記側帯波からなる多波長光を発生させる多波長化変調部とで構成される多波長一括発生光源と、
前記多波長一括発生光源から出力された多波長光を入力して各波長に分波する分波器と、分波された各波長光を送信信号により変調する複数の光変調器と、各変調信号光を波長多重して出力する合波器とにより構成される光変調部とを備えた光波長多重送信器において、
前記多波長一括発生光源は、複数Ｎ個の多波長化変調部と、１または複数の光発生部の出力光を分岐して各多波長化変調部に供給する手段とを備え、
前記光変調部を複数Ｍ個（Ｍ＜Ｎ）備え、
前記Ｍ個の多波長化変調部と、前記Ｍ個の光変調部をそれぞれ１対１に接続するとともに、いずれかの多波長化変調部に故障が発生したときに、（Ｎ−Ｍ）個ある予備の多波長化変調部に切り換えて対応する光変調部に接続するＮ×Ｍ光スイッチを備えたことを特徴とする光波長多重送信器。A light generator for generating a continuous light having a single or plurality of center wavelengths, applying said continuous light and a phase modulator for intensity modulator and phase modulation to amplitude modulation, the intensity modulator and said phase modulator It has a periodic signal generator for generating a predetermined periodic signal, the continuous light amplitude-modulated and phase-modulated in a predetermined cycle signal, shift the upper and lower sidebands of the discrete spectrum of the continuous light on the frequency axis is allowed, and the multi-wavelength generation light source composed of a multi-wavelength modulating section for generating multi-wavelength light consisting of the center wavelength and said sidebands,
A demultiplexer that receives the multi-wavelength light output from the multi-wavelength collective light source and demultiplexes it into each wavelength, a plurality of optical modulators that modulate each demultiplexed light with a transmission signal, and each modulation In an optical wavelength division multiplex transmitter including an optical modulator configured by a multiplexer that wavelength-multiplexes and outputs signal light,
The multi-wavelength collective light source includes a plurality of N multi-wavelength modulation units and means for branching the output light of one or a plurality of light generation units and supplying the branched light to each multi-wavelength modulation unit,
A plurality of M light modulation units (M <N),
The M number of multi-wavelength modulation units and the M number of optical modulation units are connected one-to-one, and when a failure occurs in any of the multi-wavelength modulation units, (N−M) An optical wavelength division multiplex transmitter comprising an N × M optical switch connected to a corresponding optical modulation unit by switching to a spare multi-wavelength modulation unit.
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EP02291444A EP1267510B1 (en) 2001-06-13 2002-06-11 Multi-wavelength optical modulation circuit and wavelength-division multiplexed optical signal transmitter
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KR100698766B1 (en) 2005-09-07 2007-03-23 한국과학기술원 Apparatus for Monitoring Failure Positions in Wavelength Division Multiplexing-Passive Optical Networks and Wavelength Division Multiplexing-Passive Optical Network Systems Having the Apparatus
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US8571410B2 (en) 2006-10-11 2013-10-29 Novera Optics, Inc. Mutual wavelength locking in WDM-PONS
US8170418B2 (en) * 2008-03-28 2012-05-01 Nortel Networks Limited Protected light source for multiple wavelength division multiplexed passive optical networks (WDM-PONS)
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