CN1315790A - 梳状分波方法 - Google Patents

梳状分波方法 Download PDF

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CN1315790A
CN1315790A CN00114440.5A CN00114440A CN1315790A CN 1315790 A CN1315790 A CN 1315790A CN 00114440 A CN00114440 A CN 00114440A CN 1315790 A CN1315790 A CN 1315790A
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beam splitter
polarizing beam
light
output
phase delay
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CN1133084C (zh
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罗勇
方罗珍
刘水华
马琨
许远忠
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Accelink Technologies Co Ltd
Wuhan Research Institute of Posts and Telecommunications Co Ltd
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WUHAN INST OF POSTS AND TELECOMMUNICATIONS SCIENCE MINISTRY OF INFORMATION IND
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29302—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means based on birefringence or polarisation, e.g. wavelength dependent birefringence, polarisation interferometers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/288—Filters employing polarising elements, e.g. Lyot or Solc filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G02B6/29386—Interleaving or deinterleaving, i.e. separating or mixing subsets of optical signals, e.g. combining even and odd channels into a single optical signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/06—Polarisation multiplex systems

Abstract

本发明提供一种光纤通信中梳状分波方法,它主要包括三芯准直器和梯形棱镜组成的输入输出器、偏振分光器、双折射晶体滤波器,至反射式平行光偏振分光器,使光返再次经过上述双折射晶体滤波器滤波、λ/2相位延迟、PMD补偿、偏振分光器至输出,使输入与输出在滤波器的同一侧。反射式平行光偏振分光器可以通过直角棱镜或平面反射镜两种方式使光返回。本发明采用一级滤波器实现两级滤波效果,提高信道隔离度,缩小了体积。

Description

梳状分波方法
本发明涉及一种梳状分波方法，属于光通信技术领域。
随着光通信技术的发展，光纤中传输的信息量与日俱增，特别是全光网路的发展，对密集波分复用(DWDM)、光开关等光无源器件的技术提出更高的要求。目前密集波分复用(DWDM)主要采用光栅、光波导、干涉滤波片，双折射滤波等方法，但随着密集波分复用信道间距密集程度的进一步提高，就需要更好的方法来分开信号和合成信号。采用双折射晶体滤波片的分波长器就是其中一种较好的方法。在一般设计的方法中，采用单级滤波的可以减少器件体积，但是使得信道隔离度不高。采用双级滤波的由于需要两个双折射晶体滤波片组，使得结构复杂，体积大，所需器件多，提高了生产成本。
本发明的目的是采用光反射的方法，利用一组双折射滤波片，实现两级滤波的效果，提高两输出信道的隔离度，减少了器件，缩小体积。
本发明的技术方案是：光路主要经过输入器1、偏振分光器2、λ/2相位延迟片4、滤波器5、偏振分光器6至输出，其特征是光经过双折射晶体滤体器5后进入能使输出光反向的反射式平行光偏振分光器6，使光返回再次经过双折射晶体滤波器5、λ/2相位延迟片4、偏振分光器2至输出，光的输入与输出在滤波器的同侧。
上述的梳状分波方法的一种实施例是反射式平行偏振分光器6由偏振分光器6-1和直角棱镜6-2组成，直角棱镜的斜面平行于偏振分光器的相临面。
上述的梳状分波方法的另一种实施例是反射式平行光偏振分光器6由λ/2相位延迟片6-3、6-4对称置于偏振分光器6-1的前侧，偏振分光器6-1的后侧是λ/4相位延迟片6-5，最后是平面反射镜6-2。
上述的梳状分波方法，其特征是光波输入与输出共用一个由三芯准直器和梯形棱镜或三个单芯准直器阵列组成的输入输出器。
上述的梳状分波方法，在偏振分光器2与相位延迟片之间设有PMD偏振模色散补偿器3。
本发明的优点是提供了一种新的方法来实现密集波分复用(DWDM)信号的分开和合并。这种结构的第一个优点是通过反射实现对双折射晶体滤波片组的重复利用，达到双重滤波的效果，提高了器件的信道隔离度、减少了器件、缩小了体积。第二个优点是该结构对输入光没有偏振要求，即与偏振无关。第三个优点是该结构提供了一种补偿偏振模色散(PMD)的方法，消除器件偏振模色散(PMD)对系统的影响。用本方法制作分波长器件可把一束密集波分复用信号光中的奇数列和偶数列信号分别藕合到不同的光纤中，实现把信道间隔变为原来的两倍的目的，相当于实现了信号的解复周。该器件也可把等间距交错的两列信号藕合到同一个光纤中，实现信号的复用。该方法还可以通过对双折射滤波片的改变，实现1×2的反射型高隔离度的光开关、光衰减器、光调制器等器件。
下面对附图进行说明，并进一步说明其工作原理：图1是本发明第一种实施例的结构示意图、图2是图1实施例的俯视光路图、图3是PMD光路侧视图、图4是本发明第二种实施例的结构示意图、图5是图4实施例的俯视光路图、图6是图4中PMD光路侧视图、图7采用准直器阵列实施例结构示意图，图8是准直器阵列的结构示意图。图中1是输入输出部分，1-1是三芯准直器、1-2是梯形棱镜、1-3是三准直器阵列、2是偏振分光器、3是PMD补偿平片、4是λ/2相位延迟波片、5是双折射晶体滤波片组、6是反射式平行光偏振分光器、6-1是偏振分光器、6-2是直角棱镜、6-3、6-4是λ/2相位延迟片、6-5是λ/4相位延迟片、6-7是平面反射镜。
图2中输入光中含有波列-1和波列-2，我们这样定义波列-1、波列-2，其中波列-1是指那些通过双折射晶体滤波片组5后住相改变为[2KⅡ]一系列波长，波列-2是指那些通过双折射晶体滤波片组5后，相位改变为[(2K+1)Ⅱ]一系列波长。光线L101通过偏振分光器2，其中L106B通过玻璃平片3、λ/2相位延迟波片4后其偏振方向与L106A相同，同时L106B与L106A所走光程差得到补偿，即由于偏振分光器2所产生的PMD得到补偿，其补偿原理在后面会详细说明。由于L106A与L106B在后面的光路中有相同的性质，因此只分析其中一种即可。L106通过双折射滤波片组5后，由于波列-1、波列-2的相位变化不一样，所以其偏振方向也不同，在L108中，偏振垂直于纸面的为波列-1，平行于纸面的为波列-2,L108通过偏振分光器6-1把波列-1、波列-2分开为L111和L110,L110、L111通过棱镜6-2后交换位只置，由于偏振态的不同，在偏振分光器6-1的作用下L110向下偏返回为L109、L111垂直通过偏振分光器6-1返回为L107，L107、L109再次通过双折射晶体滤波片组5，达到双重滤波的效果，同时使波列-2的光线L109变为偏振方向与纸面垂直的L105，因此L104、L105、L106具有相同的偏振方向，且处于同一平面，L104、L105通过4、3、2后成为两束与L101平行且处于同一水平面的光。然后耦合到三个单芯准直器阵列1-2或通过一个梯形棱镜1-2的作用耦合到一个三芯准直器1-1中，在实际的制作中为节省空间，可以把梯形棱镜1-2可放在4、5之间。在图5中L201、L206、L208与图3中L101、L106、L108分析相同，L210为波列-2，L211为波列-1,L210、L211通过入/4相位延迟波片6-5，平面反射镜6-2后向位改变λ/2，其偏振方向与原来垂直，让它们分别通过6-3、6-4两个λ/2相位延迟波片，使它们的偏振变得与原来相同，L207为波列-2,L209为波列-1,L207通过双折射滤波片组5后，偏振方向变得与纸面垂直，L209通过双折射滤波片组5后偏振方向不变，因此L104、L105、L106具有相同的偏振方向，且处于同一平面，后面的光路与图3相同。图3是两个实施例通过补偿器3的光路侧视图，它反应了光线经过偏振分光器、PMD补偿器后L106和L206的光路状态及补偿偏振模色散的效果。图7是准直透镜阵列1-3,1-3-1上有固定光纤的V型槽，1-3-2是准直透镜。
图9、10分别为采用三片长度大约为7mm的YV04晶体排列成的双折射晶体滤波片组，在图中两透射峰的距离约为1006HZ。图9为单级滤波的光谱图，图10为两级滤波的光谱图，它们的谱线比较结果如下：
-0.5dB -1.0dB -3.0dB -25.0dB -30.0dB
单级滤波 0.45  0.55  0.76  1.35  1.40
两级滤波 0.37  0.45  0.62  1.15  1.21
本发明的实施例已由上述技术方案及附图说明给出了两种分波长器的实施例，一种是采用直角棱镜为反射主体的方案，一种是以平面反射镜为反射主体的方案。图1是采用棱镜的反射式平行光偏振分光器，出射方向与入射方向相反，但光线处于同一水平面，出射光线的分离距离由双折射晶体决定，与晶体的光轴方向、晶体长度、晶体的双折射率有关，晶体可选择YV04、Ti02、a-BB0、CaC03等。例如采用长度为10mm的YV04晶体时，两出射光的分离距离约为1mm。图4是采用平面反射加入λ/4相位延迟波片的反射式平行光偏振分光器，由于45°光轴方向、λ/4相位延迟的波片的作用，使分离的两偏振光偏振态与原来垂直，若要变回原偏振态可加入45°光轴方向、λ/2相位延迟波片6-3、6-4即可。
本发明采用补偿偏振分光器引起的补偿偏振模色散(PMD)的结构。在偏振分光器中由于O光、E光所走的光程不同，从而引起的补偿偏振模色散(PMD)。在这里通过对光程短的其中一束光的光程进行补偿，这到消除偏振模色散(PMD)的目的。例如对一个7mm长的、光轴方向为45°的YV4偏振分光器所产生的偏振模色散(PMD)进行补，可先计算出O光与E光的光程差约为0.89mm，若采用K9玻璃来补偿，要求玻璃的厚度约为1.78mm。
在该反射型分波长器结构中，通过对双折射滤波片组进行改变，加入电光调制、磁光调制或者其它调制方法，可制作反射型光开关等。例如：当用一片相位延迟可控制的双折射晶体代替滤波片组就完成了光开关的作用。

Claims (6)

1、一种梳状分波方法，光路主要经过输入器(1)、λ/2相位延迟器(4)、滤波器(5)、偏振器(6)至输出，其特征是光经过双折射晶体滤体器(5)后进入能使输出光反向的反射式平行光偏振分光器(6)，使光返回再次经过滤波器(5)、λ/2相位延迟器(4)、偏振分光器(2)至输出，光的输入与输出在滤波器的同侧。
2、根据权利要求1所述的梳状分波方法，其特征是反射式平行光偏振分光器(6)由偏振分光器(6-1)和直角棱镜(6-2)组成，直角棱镜的斜面平行于偏振分光器的相临面。
3、根据权利要求1或2所述的梳状分波方法，其特征是反射式平行光偏振分光器(6)由λ/2相位延迟片(6-3)、(6-4)对称置于偏振分光器(6-1)的前侧，偏振分光器(6-1)的后侧是λ/4相位延迟片(6-5)，最后是平面反射镜(6-2)。
4、根据权利要求1或2所述的梳状分波方法，其特征是光波输入与输出共用一个由三芯准直器加梯形棱镜或三准直器阵列组成的输入输出器。
5、根据权利要求1或3所述的梳状分波方法，其特征是光波输入与输出共用一个由三芯准直器加梯形棱镜或三准直器阵列组成的输入输出器。
6、根据权利要求1所述的梳状分波方法，其特征是在偏振分光器2与λ/2相位延迟器4之间设有PMD偏振模色散补偿器3。
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CN100449334C (zh) * 2006-08-14 2009-01-07 上海飞锐光电科技有限公司 三色光等腰梯形合色组合棱镜
WO2012122728A1 (zh) * 2011-03-17 2012-09-20 昂纳信息技术（深圳）有限公司 一种偏振光干涉型的梳状滤波器
CN104201555A (zh) * 2014-09-18 2014-12-10 福建福晶科技股份有限公司 一种偏振无关电光q开关
CN112114400A (zh) * 2019-06-20 2020-12-22 福州高意通讯有限公司 一种光纤环行器
CN112114400B (zh) * 2019-06-20 2023-09-26 福州高意通讯有限公司 一种光纤环行器

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