JPH02236507A - Wide band optical fiber coupler - Google Patents
Wide band optical fiber couplerInfo
- Publication number
- JPH02236507A JPH02236507A JP5623089A JP5623089A JPH02236507A JP H02236507 A JPH02236507 A JP H02236507A JP 5623089 A JP5623089 A JP 5623089A JP 5623089 A JP5623089 A JP 5623089A JP H02236507 A JPH02236507 A JP H02236507A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- optical
- fiber coupler
- coupler
- broadband
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 108
- 230000010287 polarization Effects 0.000 claims abstract description 4
- 238000005253 cladding Methods 0.000 claims description 14
- 238000005530 etching Methods 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 abstract description 50
- 230000008878 coupling Effects 0.000 abstract description 20
- 238000010168 coupling process Methods 0.000 abstract description 20
- 238000005859 coupling reaction Methods 0.000 abstract description 20
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 230000003313 weakening effect Effects 0.000 abstract description 3
- 238000003466 welding Methods 0.000 abstract 2
- 238000006243 chemical reaction Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 5
- 230000004927 fusion Effects 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000007526 fusion splicing Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Classifications
-
- 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
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
- G02B6/2821—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals
- G02B6/2843—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals the couplers having polarisation maintaining or holding properties
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Abstract
Description
【発明の詳細な説明】
く産業上の利用分舒〉
本発明は光通信システム等に於いて光信号の分岐や結合
に用いられる光ファイバカップラに関するもので、特に
光分岐比の波長依存性の少ない広帯域光ファイバカップ
ラに関するものである。[Detailed Description of the Invention] Industrial Applications The present invention relates to an optical fiber coupler used for branching and coupling optical signals in optical communication systems, etc., and particularly relates to an optical fiber coupler used for branching and coupling optical signals in optical communication systems. The present invention relates to a low-bandwidth optical fiber coupler.
く従来の技術とその課題〉
近年、光信号伝送技術の進歩により、多種の光通信シス
テムが提案され、また実用化が図られている。これらを
背景として、1つの光伝送路を伝搬する1種類以上の光
信号を複数の伝送路に分岐したり、あるいは複数の伝送
路より伝搬してきた1種類以上の光信号を結合し重畳す
るという要求が急激に増加している。2. Background Art and its Problems In recent years, with the advancement of optical signal transmission technology, various types of optical communication systems have been proposed and put into practical use. Against this background, it is possible to split one or more types of optical signals propagating through one optical transmission line into multiple transmission lines, or to combine and superimpose one or more types of optical signals propagated through multiple transmission lines. Demand is increasing rapidly.
この働きをする部品の1つが光ファイバカップラである
。この光ファイバカップラは、低損失で、光の伝送路で
ある光ファイバとの接続性に優れる。また、安価である
という要求を満たす必要があり、そのための光ファイバ
カップラの製造法はいくつか考えられているが、融着・
延伸による方法が最も生産性に優れており、今後も急激
な価格の低下が期待されている。One of the components that performs this function is an optical fiber coupler. This optical fiber coupler has low loss and excellent connectivity with optical fibers that are light transmission lines. In addition, it is necessary to satisfy the demand for low cost, and several methods of manufacturing optical fiber couplers have been considered for this purpose, but
The stretching method has the highest productivity, and the price is expected to continue to drop rapidly in the future.
光ファイバカップラの製造に当っては、従来より同一外
径の光ファイバとおしの融看・延伸によって作られてお
り、この同一外径とおしの対称性光ファイバカップラの
光分岐比としては第9図(alに示すように光信号の波
長により0%〜100%の間を周期的に変化するという
特質がある。Conventionally, optical fiber couplers have been manufactured by combining and stretching optical fibers with the same outer diameter and a diameter, and the optical branching ratio of this symmetrical optical fiber coupler with the same outer diameter and diameter is shown in Figure 9. (As shown in al, there is a characteristic that it changes periodically between 0% and 100% depending on the wavelength of the optical signal.
他方、光分岐比が波長により変化しにくく光分岐比の波
長依存性が少ないいわゆる広帯域光ファイバカップラの
出現も望まれ、この種カップラでは、光信号の分岐に好
適となり光源の波長のばらつきへの対応性や、複数の波
長の分岐への対応性に優れろという長所が生ずる。On the other hand, it is also desired that a so-called broadband optical fiber coupler, in which the optical branching ratio does not easily change depending on the wavelength and the wavelength dependence of the optical branching ratio is small, is also desired. This has the advantage of being excellent in compatibility and compatibility with branching multiple wavelengths.
このような広帯域光ファイバカップラを開示したものと
して国際出願PCT/GB86/00445にて提案さ
れるものがある。すなわち、主に2本の単一モード光フ
ァイバのうち1本を事前に延伸しておき(プリ延伸と称
する)、その後融着することによ9広帯域光ファイバを
得るものであり、1本の単一モード光ファイバの伝搬定
数をプリ延伸により変化させて光結合度の最大値を10
0%未満の特定値にし、その近傍での分岐比の波長平坦
性を利用するものである。第9図(b)はその一例で波
長1.3μmで分岐比50%の広帯域光ファイバカップ
ラの特性であり、第9図ta+の如き対称性光ファイバ
カップラの特性と比較して、分岐比の変化が平坦化する
。Such a broadband optical fiber coupler is disclosed in the international application PCT/GB86/00445. That is, one of the two single mode optical fibers is mainly drawn in advance (referred to as pre-stretching) and then fused to obtain a broadband optical fiber. By changing the propagation constant of single mode optical fiber by pre-stretching, the maximum value of optical coupling degree is 10.
A specific value of less than 0% is set, and the wavelength flatness of the branching ratio in the vicinity thereof is utilized. Figure 9(b) is an example of the characteristics of a broadband optical fiber coupler with a wavelength of 1.3 μm and a branching ratio of 50%. Change flattens out.
しかしながら、このプリ延伸による広帯域光ファイバカ
ップラの作製に当ってlよ、均一なプリ延伸が困難であ
るという欠点がある。However, when producing a broadband optical fiber coupler by this pre-stretching, there is a drawback that uniform pre-stretching is difficult.
すなわち、プリ延伸lこ当って厳密な形状コントロール
換言すれば長さ方向の外径分布のコント四−ルができず
、精度が得られないことから融着時に光ファイバに曲が
りが生ずるなどして分岐比の設定値制御や平坦化の程度
もしくは入射光に対する出射光の過剰損失の抑制が困難
であるという問題がある。翻って、このブリ延伸による
非対称性光ファイバカップラの生産歩留りが非常に低い
という問題がある。In other words, if pre-stretching fails, strict shape control cannot be achieved, in other words, it is not possible to control the outer diameter distribution in the length direction, and as a result of the inability to obtain precision, the optical fiber may bend during fusion. There are problems in that it is difficult to control the set value of the branching ratio, the degree of flattening, or the excessive loss of the output light relative to the input light. On the other hand, there is a problem in that the production yield of asymmetric optical fiber couplers due to this bristle drawing is extremely low.
次に、上述の如き単一モード光ファイバでなく偏波保持
光ファイバに着目した場合、この偏波保持光ファイバカ
ップラの光分岐比は、X偏波,Y偏波の相違によりずれ
が生じるが、第10図に示すように光信号の波長により
0%から100%の間を周期的に変化する特質がある。Next, when focusing on a polarization-maintaining optical fiber instead of the single-mode optical fiber as described above, the optical branching ratio of this polarization-maintaining optical fiber coupler will differ due to the difference between the X and Y polarizations. , as shown in FIG. 10, has the characteristic of periodically changing between 0% and 100% depending on the wavelength of the optical signal.
そして、最も一般的な3dBカップラにおいては、光分
岐比が波長により最も急激となるため、光源波長のばら
つきや波長の温度変化により光分岐比が大幅に変化して
しまう。したがって、一つの偏波保持光ファイバカップ
ラで複数種類の光源に対応することは不可能である。In the most common 3 dB coupler, the optical branching ratio becomes most rapid depending on the wavelength, so the optical branching ratio changes significantly due to variations in the light source wavelength or temperature changes in the wavelength. Therefore, it is impossible for one polarization-maintaining optical fiber coupler to support multiple types of light sources.
この結果、偏波保持光ファイバカップラにおいても広帯
域光ファイバカップラが望まれているが、今まで広帯域
化を実現した偏波保持光ファイバカップラは存在しない
。As a result, a broadband optical fiber coupler is desired for polarization-maintaining optical fiber couplers as well, but to date, there has been no polarization-maintaining optical fiber coupler that has achieved a wide band.
そこで、本発明は、上述の問題に鑑み、単一モード光フ
ァイバカップラにあって歩留りを向上きせると共に、偏
波保持光ファイバカップラにあって広帯域化を始めて実
現させた広帯域光ファイバカップラの提供を目的とする
。SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention aims to provide a broadband optical fiber coupler that improves the yield of a single mode optical fiber coupler and is the first to realize a broadband polarization maintaining optical fiber coupler. purpose.
く課題を解決するための手段〉
上述の目的を達成する本発明の基本思想は、クラッドの
外径が互いに異なる光ファイバを融着し延伸させてカッ
プラを得ることにある。Means for Solving the Problems> The basic idea of the present invention for achieving the above object is to obtain a coupler by fusing and stretching optical fibers whose claddings have different outer diameters.
く作 用〉
クラッド外径が異なるので必然的に光結合部の形状が高
精度で特定されることになり、非対称構造の広帯域カッ
プラを、単一モード光ファイバにあってはプリ延伸なく
、均一かつ高精度に得ることができる。Since the outer diameters of the claddings are different, the shape of the optical coupling part must be specified with high precision, making it possible to use broadband couplers with an asymmetric structure uniformly without pre-stretching for single-mode optical fibers. and can be obtained with high precision.
く実 施 例〉
ここで、第1図ないし第8図を参照して本発明の実施例
を+a明する。なお、第1図ないし第5図は単一モード
光ファイバカップラの例を示し、第6図ないし第8図は
偏波保持光ファイバカップラの例を示す。Embodiments Here, embodiments of the present invention will be explained with reference to FIGS. 1 to 8. Note that FIGS. 1 to 5 show examples of single-mode optical fiber couplers, and FIGS. 6 to 8 show examples of polarization-maintaining optical fiber couplers.
(実施例1)
比屈折率差Δ=0.3%,カットオフ波長1.20μm
,クラッド外径1 2 5 μmと110μmの2本の
単一モード光ファイバによって、光ファイバカップラを
作製した。(Example 1) Relative refractive index difference Δ=0.3%, cutoff wavelength 1.20 μm
An optical fiber coupler was fabricated using two single mode optical fibers with cladding outer diameters of 125 μm and 110 μm.
すなわち、この2本の単一モード光ファイバの光結合部
に該当する部分を、互いに酸水素バーナによね融着(弱
融着)し、続いて火力を弱めてバーナを光ファイバの長
さ方向に振りながら融着部付近を波長1.3μmと1.
55μmでの光結合度のピークが同等になるまで延伸し
て光結合部を作製した。In other words, the parts of these two single mode optical fibers that correspond to the optical coupling part are fused together (weakly fused) using an oxyhydrogen burner, and then the burner is heated in the longitudinal direction of the optical fibers by weakening the heating power. Wavelengths of 1.3 μm and 1.5 μm were applied near the fused portion while shaking the area.
An optical coupling part was produced by stretching until the peak of the optical coupling degree at 55 μm became the same.
第1図は作製された光結合部の断面を示し、la,lb
は単一モード光ファイバ、2m,2bはそれらのコア、
3a,3bばクラッドである。Figure 1 shows a cross section of the optical coupling section that was fabricated, with la, lb
are single mode optical fibers, 2m and 2b are their cores,
3a and 3b are cladding.
そして、光結合部を石英ガラス基板に固定し、金属ケー
スに収納して広帯域光ファイバカップラとした。The optical coupling part was then fixed to a quartz glass substrate and housed in a metal case to form a broadband optical fiber coupler.
この光ファイバカップラ全体を第2図に示し、la,l
bは単一モード光ファイバ14は光結合部、5は石英ガ
ラス基板、6ば金属ケースである。The entire optical fiber coupler is shown in Figure 2, with la, l
5 is a quartz glass substrate, and 6 is a metal case.
このようにして形成した広帯域光ファイバカップラの過
剰損失は0.2dBと低損失であった。このことは、ク
ラッド外径を125μm,110μmの如く互いに異な
る光ファイバを用いることによ咋、従来のようなブリ延
伸よりも外径の制御性が格段に向上し、形状不均一化が
抑えられ、融着による光ファイバの変形が少なく、これ
に起因する損失増加が抑えられるためと考えられる。The broadband optical fiber coupler thus formed had a low excess loss of 0.2 dB. This means that by using optical fibers with different cladding outer diameters, such as 125 μm and 110 μm, the controllability of the outer diameter is much better than in conventional bristle drawing, and non-uniformity in shape can be suppressed. This is thought to be because the optical fiber is less deformed due to fusion splicing, and the increase in loss caused by this is suppressed.
第3図に、この実施例の広帯域光ファイバカップラの光
分岐比の波長依存性を示す。光分岐比は波長1.2〜1
.6μmで20±3%以内であり、分岐比波長依存性が
平坦化されていることが判る。この際の分岐比のm御性
は従来のブリ延伸による場合では歩留りが数10%と悪
いのに比し、本実施例では80%以上と格段に向上した
。FIG. 3 shows the wavelength dependence of the optical branching ratio of the broadband optical fiber coupler of this example. Optical branching ratio is wavelength 1.2-1
.. It is within 20±3% at 6 μm, and it can be seen that the wavelength dependence of the branching ratio is flattened. The controllability of the branching ratio in this case was significantly improved to 80% or more in this example, compared to the poor yield of several tens of percent in the case of conventional bristle drawing.
(実施例2)
比屈折率差Δ=0.3%,カットオフ波長が1420μ
m,外径が125μmの単一モード光ファイバを用いて
光ファイバヵップラを作製した。(Example 2) Specific refractive index difference Δ=0.3%, cutoff wavelength 1420μ
An optical fiber coupler was fabricated using a single mode optical fiber with an outer diameter of 125 μm.
ここでは、1本の光ファイバの一部(長さ約3傭)を沸
酸に約2分間浸漬し、この光ファイバの外径を120μ
mにエッチングした後、実施例1と同様の工程で広帯域
光ファイバカップラを作製した。Here, a part of one optical fiber (approximately 3 centimeters long) is immersed in hydrochloric acid for about 2 minutes, and the outer diameter of this optical fiber is 120 μm.
After etching, a broadband optical fiber coupler was manufactured using the same steps as in Example 1.
この広帯域光ファイバヵップラの光結合部の断面を第4
図に示しており、1cば外径125μmの単一モード光
ファイバ、ldは外径120μmの単一モード光ファイ
バ、2c,2dはそれらのコア,3c,3dはクラッド
である。The cross section of the optical coupling part of this broadband optical fiber coupler is
As shown in the figure, 1c is a single mode optical fiber with an outer diameter of 125 μm, ld is a single mode optical fiber with an outer diameter of 120 μm, 2c and 2d are their cores, and 3c and 3d are claddings.
こうして得られた広帯域光ファイバカップラの過剰損失
は0.25dBと低損失であった。The broadband optical fiber coupler thus obtained had a low excess loss of 0.25 dB.
このことは1方の光ファイバをエッチングすることによ
り、従来のようなブリ延伸よりも外径の均一性が向上し
、エッチング部の長さがプリ延伸部より格段に長くする
ことが可能であり、融着部の外径変化がないため、融着
による光ファイバの変形が少なく、これ《ζ起因する損
失増加が抑えられるためと考えられる。This means that by etching one optical fiber, the uniformity of the outer diameter is improved compared to conventional pre-stretching, and the length of the etched part can be made much longer than the pre-stretched part. This is thought to be because there is no change in the outer diameter of the fused portion, so there is little deformation of the optical fiber due to fusion, and the increase in loss due to this <<ζ> is suppressed.
第5図に、この実施例の広帯域光ファイバカップラの光
分岐比の波長依存性を示す。光分岐比波長依存性は波長
1.2〜1.5μmの範囲内で50±4%以内と平坦化
されていることが判る。この際の分岐比のIIIII御
性:ま従来のプリ延伸による場合に比し向上し、歩留り
は70%以上であった。FIG. 5 shows the wavelength dependence of the optical branching ratio of the broadband optical fiber coupler of this example. It can be seen that the wavelength dependence of the optical branching ratio is flat within 50±4% within the wavelength range of 1.2 to 1.5 μm. In this case, the control of the branching ratio was improved compared to the case of conventional pre-stretching, and the yield was 70% or more.
以上述べたように、実施例1,2では、分岐特性の広帯
域化をプリ延伸によらず、クラッド外径の異なる光ファ
イバを用いるか、または1方の光ファイバを事前にエッ
チングすることにより、外径の制御性を格段に向上させ
、光ファイバカップラ製造性を従来になく向上させるこ
とができた。As described above, in Examples 1 and 2, the branching characteristics were broadened not by pre-stretching, but by using optical fibers with different cladding outer diameters, or by etching one of the optical fibers in advance. We were able to significantly improve the controllability of the outer diameter and improve the productivity of optical fiber couplers like never before.
なお、本実施例では、光分岐比を20%又は50%に設
定した場合を示したが、結合部作成時の融着・延伸条件
を変えることにより所望の分岐比を得ることができる。Although the present example shows the case where the optical branching ratio is set to 20% or 50%, a desired branching ratio can be obtained by changing the fusion/stretching conditions when creating the joint.
(実施例3)
カップラを構成する偏波保持光ファイバの断面を第6図
に示す。この図において、lla,1lbがコア、1
2 a, 1 2 bがクラッド、13a,13bが
応力付与部である。両方とも比屈折率差Δ−0.24%
、コア径6.5μm1応力付与部径41μm、応力付与
部のボロン濃度15moj%で同一であるが、クラツド
外径のみ異なり、12aが125μm,12bが120
μmである。(Example 3) FIG. 6 shows a cross section of a polarization-maintaining optical fiber constituting a coupler. In this figure, lla, 1lb are cores, 1
2 a and 1 2 b are clads, and 13 a and 13 b are stress applying parts. Both relative refractive index difference Δ-0.24%
, the core diameter is 6.5 μm, the stress applying part diameter is 41 μm, and the boron concentration in the stress applying part is 15 moj%, but only the outer diameter of the cladding is different, 12a is 125 μm, 12b is 120 μm.
It is μm.
作製に当っては、この2本の光ファイバを互いに平行に
位置合わせし、各々の光ファイバの応力付与部13a,
13bにより形成される主軸面が互いに平行で、かつ2
つのコア11a,llbにより形成されろ面に対して垂
直となるように揃えた状態で酸水素バーナにより融着し
(弱融着)、続いて火力を弱めてバーナを光ファイバの
長さ方向に振りながら融着部付近を、X偏波で波長1.
3μmと1.55μmでの光結合度のピークが同等にな
るまで延伸して光結合部を作製した。In manufacturing, these two optical fibers are aligned parallel to each other, and the stress applying portions 13a,
13b are parallel to each other, and 2
The two cores 11a and llb are aligned perpendicular to the fiber surface and are fused using an oxyhydrogen burner (weak fusion), then the burner is moved in the length direction of the optical fiber by weakening the heating power. While shaking the area near the fused part, use X-polarized wave with a wavelength of 1.
An optical coupling part was produced by stretching until the peaks of the degree of optical coupling at 3 μm and 1.55 μm were the same.
この広帯域幅波保持光ファイバカップラの光結合部の断
面を第7図に示す。図にて、14a,14bはOi波保
持光77イバ、lla,llbはそれらのコア、12a
,12’bはクラッド、13a,’13bは応力付与部
である。FIG. 7 shows a cross section of the optical coupling portion of this broadband wave-maintaining optical fiber coupler. In the figure, 14a and 14b are Oi wave holding light beams 77, lla and llb are their cores, and 12a
, 12'b are claddings, and 13a, '13b are stress applying parts.
そして、この光結合部を石英ガラス基板に固定し、金属
ケースに収納して広帯域偏波保持光ファイバカップラと
し、第2図と同様の構造とした。Then, this optical coupling part was fixed to a quartz glass substrate and housed in a metal case to form a broadband polarization-maintaining optical fiber coupler, with a structure similar to that shown in FIG. 2.
第8図に、この広帯域偏波保持光ファイバカップラの光
分岐比の波長依存性を示す。光分岐比は波長1.2〜1
.6μmの範囲内でX傷波では50±3%理内、Y偏波
では60±3%以内であり、分岐比波長依存性が平坦化
されていることが判る。また、本偏波保持光ファイハカ
ップラ1;EX,Yl波共LC1.2−71.55μm
の波長範囲で、クロストーク20dB,II,t下、過
剰損失は0.8dB以下であった。FIG. 8 shows the wavelength dependence of the optical branching ratio of this broadband polarization-maintaining optical fiber coupler. Optical branching ratio is wavelength 1.2-1
.. Within the range of 6 μm, it is within 50±3% for X-polarized waves and 60±3% for Y-polarized waves, indicating that the wavelength dependence of the branching ratio is flattened. In addition, this polarization-maintaining optical fiber coupler 1; LC for both EX and Yl waves is 1.2-71.55 μm.
In the wavelength range of , the excess loss was less than 0.8 dB under crosstalk of 20 dB, II, t.
(実施例4)
比屈折率差Δ=0.24%、コア径6.5μm1応力付
与部径41μm、応力付与部のポロン濃度15moI%
、外径125μmの偏波保持光ファイバを用いて広帯域
帰波保持光ファイバカップラを作製した。(Example 4) Relative refractive index difference Δ=0.24%, core diameter 6.5 μm 1 stress applying part diameter 41 μm, poron concentration in stress applying part 15 moI%
A broadband return-maintaining optical fiber coupler was fabricated using a polarization-maintaining optical fiber with an outer diameter of 125 μm.
ここで{よ、1本の光ファイバの一部(長さ約3c+T
+)を沸酸に約2分間浸漬し、この光ファイバの外径を
120μmにエッチングした後、実施例3と同様の工程
で広帯域光ファイバカップラを作製した。Here {yo, part of one optical fiber (length about 3c+T
+) was immersed in hydrochloric acid for about 2 minutes, and the outer diameter of this optical fiber was etched to 120 μm, and then a broadband optical fiber coupler was produced in the same process as in Example 3.
この広帯域偏波保持光ファイバカップラはX,Y傷波共
に1、2〜1.55μmの波長範囲で、クロストークー
1 8 ’dB以下、過剰損失は1.0dB以下であっ
た。光分岐比の波長依存性は実施例3と同様な変化を示
し、平坦化されていた。This broadband polarization-maintaining optical fiber coupler had a crosstalk of 18' dB or less and an excess loss of 1.0 dB or less in the wavelength range of 1.2 to 1.55 μm for both X and Y damaged waves. The wavelength dependence of the optical branching ratio showed the same change as in Example 3, and was flattened.
く発明の効果ン
ふ上述べたように、本発明では、光ファイバのブリ延伸
を行なわず、クラッド外形の異なる光ファイバを用いる
か、光ファイバの外形をエッチングにより変化させるた
め、融着、延伸する2本の光ファイバの外径の均一性が
格段に向上するため融着による光ファイバの変形が少な
く、光分岐比の制御性が向上し信頼性高くなり、また損
失増加の原因が抑えられ、分岐特性の再現性が向上して
歩留り良く作られる。Effects of the Invention As mentioned above, in the present invention, optical fibers are not stretched, but instead optical fibers with different cladding shapes are used, or the outer shape of the optical fibers is changed by etching. The uniformity of the outer diameters of the two optical fibers is significantly improved, so there is less deformation of the optical fibers due to fusion, the controllability of the optical branching ratio is improved, and reliability is increased, and the cause of increased loss is suppressed. , the reproducibility of branching characteristics is improved and the yield is high.
更に、本発明では、クラッド外径のみの異なる備波保持
光ファイバを用いるか、片方の偏波保持光ファイバの外
形をエッチングにより変化させるため、クロストークや
過剰損失を増加させることなく、光分岐波長持性の平坦
化が可能となる。Furthermore, in the present invention, polarization-maintaining optical fibers with different cladding outer diameters are used, or the outer shape of one polarization-maintaining optical fiber is changed by etching, so that optical branching can be achieved without increasing crosstalk or excessive loss. It becomes possible to flatten the wavelength property.
第1図は実施例1の広帯域光ファイバカップラの光結合
部の断面図、第2図は、広帯域光ファイバカップラを示
す図、第3図は、実施例1の広帯域光ファイバカップラ
の光分岐比の波長依存性を示す特性図、第4図は実施例
2の広帯域光ファイバカップラの光結合部の断面図、第
5図は、実施例2の広帯域光ファイバカップラの光分岐
比の波長依存性を示す特性図、第6図は実施例3に於て
用いた偏波保持光ファイバの断面図、第7図は実施例3
の広帯域惰波保持光ファイバカップラの光結合部の断画
図、第8図は、実施例3の広帯域側波保持光ファイバカ
ップラの光分岐比の波長依存性を示す特性図、第9図は
従来の対称光ファイバカップラ(alと広帯域光ファイ
バカップラ(b)の光分岐比の波長依存性を示す特性図
、第10図は従来の対称偏波保持光ファイバカップラの
光分岐比の波長依存性を示す特性図である。
図 面 中、
la,lb,lc,ldは単一モード光ファイバ、
2a,2b,2c,2d,lla,llbはコア、
3a,3b,3c,3d,12a,12bはクラッド、
4は光結合部、
5は石英ガラス基板、
6は金属ケース、
13a,13bは応力付与部、
14a,14bl;t飼波保持光ファイバである。Figure 1 is a cross-sectional view of the optical coupling part of the broadband optical fiber coupler of Example 1, Figure 2 is a diagram showing the broadband optical fiber coupler, and Figure 3 is the optical branching ratio of the broadband optical fiber coupler of Example 1. 4 is a cross-sectional view of the optical coupling part of the broadband optical fiber coupler of Example 2. FIG. 5 is a characteristic diagram showing the wavelength dependence of the optical branching ratio of the broadband optical fiber coupler of Example 2. FIG. 6 is a cross-sectional view of the polarization-maintaining optical fiber used in Example 3, and FIG. 7 is a characteristic diagram showing Example 3.
FIG. 8 is a characteristic diagram showing the wavelength dependence of the optical branching ratio of the broadband sidewave-maintaining optical fiber coupler of Example 3, and FIG. A characteristic diagram showing the wavelength dependence of the optical branching ratio of the symmetrical optical fiber coupler (al and broadband optical fiber coupler (b)). Figure 10 shows the wavelength dependence of the optical branching ratio of the conventional symmetrical polarization-maintaining optical fiber coupler. In the drawing, la, lb, lc, and ld are single mode optical fibers, 2a, 2b, 2c, 2d, lla, and llb are cores, and 3a, 3b, 3c, 3d, 12a, and 12b are cladding, 4 is an optical coupling part, 5 is a quartz glass substrate, 6 is a metal case, 13a and 13b are stress applying parts, 14a and 14bl; t are wave-maintaining optical fibers.
Claims (3)
より形成される光ファイバカップラにおいて、 クラッドの外径が互いに異なる光ファイバ にて形成することを特徴とする広帯域光ファイバカップ
ラ。(1) An optical fiber coupler formed by fusing and stretching two optical fibers, characterized in that the optical fiber coupler is formed of optical fibers whose claddings have different outer diameters.
より細くしてクラッドの外径を互いに異なる光ファイバ
とした請求項(1)の広帯域光ファイバカップラ。(2) The broadband optical fiber coupler according to claim (1), wherein a part of one optical fiber is thinned by etching to make the optical fibers have different outer diameters of cladding.
求項(1)又は(2)の広帯域光ファイバカップラ。(3) The broadband optical fiber coupler according to claim (1) or (2), wherein the two optical fibers are polarization maintaining optical fibers.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5623089A JPH02236507A (en) | 1989-03-10 | 1989-03-10 | Wide band optical fiber coupler |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5623089A JPH02236507A (en) | 1989-03-10 | 1989-03-10 | Wide band optical fiber coupler |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH02236507A true JPH02236507A (en) | 1990-09-19 |
Family
ID=13021300
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5623089A Pending JPH02236507A (en) | 1989-03-10 | 1989-03-10 | Wide band optical fiber coupler |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH02236507A (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63501527A (en) * | 1985-07-30 | 1988-06-09 | ブリティシュ・テレコミュニケーションズ・パブリック・リミテッド・カンパニ | optical fusion coupler |
-
1989
- 1989-03-10 JP JP5623089A patent/JPH02236507A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63501527A (en) * | 1985-07-30 | 1988-06-09 | ブリティシュ・テレコミュニケーションズ・パブリック・リミテッド・カンパニ | optical fusion coupler |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JPH06235841A (en) | Manufacture of 1xn achromatic coupler, fiber optic coupler and 1xn fiber optic coupler | |
KR20010020930A (en) | Method of manufacturing polarization-maintaining optical fiber coupler | |
JPH0799407B2 (en) | Optical fiber coupler | |
JPS59198419A (en) | Production of fiber-shaped directional coupler | |
JPH02236507A (en) | Wide band optical fiber coupler | |
JPS60154215A (en) | Fiber type directional coupler | |
JPS5937503A (en) | Mode scrambler | |
JP2864520B2 (en) | Optical coupler manufacturing method | |
JP2805533B2 (en) | Fiber fusion type optical branch coupler | |
JP2828251B2 (en) | Optical fiber coupler | |
JP2001051150A (en) | Manufacture of polarization retaining optical fiber coupler | |
JP2848832B2 (en) | Broadband optical fiber coupler | |
JPH0130768B2 (en) | ||
JPH0356907A (en) | Production of polarization maintaining type optical fiber coupler | |
JP2883183B2 (en) | Method and apparatus for manufacturing optical fiber coupler | |
JP3095511B2 (en) | Polarization-maintaining optical fiber coupler | |
JPS5918921A (en) | Fiber type coupler and its manufacture | |
JPH09236721A (en) | Single mode optical fiber and method for enlarging core of single mode optical fiber | |
JP3392275B2 (en) | Broadband optical fiber coupler | |
JPH0519135A (en) | Manufacture of optical fiber coupler | |
JP4102702B2 (en) | Manufacturing method of optical fiber coupler | |
JP2866487B2 (en) | Optical fiber coupler | |
KR102080301B1 (en) | Mode selective coupler, method for coupling optic fiber by using the same and communication means comprising a plurality of mode selective couplers | |
JPS61273509A (en) | Apparatus containing lightwave guiding coupler and manufacture thereof | |
JPH02129609A (en) | Structure for connection part of mode converting element and optical fiber |