JPS6216404B2 - - Google Patents
Info
- Publication number
- JPS6216404B2 JPS6216404B2 JP57078724A JP7872482A JPS6216404B2 JP S6216404 B2 JPS6216404 B2 JP S6216404B2 JP 57078724 A JP57078724 A JP 57078724A JP 7872482 A JP7872482 A JP 7872482A JP S6216404 B2 JPS6216404 B2 JP S6216404B2
- Authority
- JP
- Japan
- Prior art keywords
- filter
- optical signal
- optical fiber
- transmission
- optical
- 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.)
- Expired
Links
- 239000013307 optical fiber Substances 0.000 claims description 27
- 230000005540 biological transmission Effects 0.000 claims description 26
- 230000003287 optical effect Effects 0.000 claims description 25
- 230000008878 coupling Effects 0.000 claims description 22
- 238000010168 coupling process Methods 0.000 claims description 22
- 238000005859 coupling reaction Methods 0.000 claims description 22
- 230000002457 bidirectional effect Effects 0.000 claims description 9
- 239000011521 glass Substances 0.000 claims description 4
- 238000010008 shearing Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 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
- G02B6/293—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
- G02B6/29304—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 operating by diffraction, e.g. grating
- G02B6/29305—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 operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
- G02B6/2931—Diffractive element operating in reflection
-
- 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
- G02B6/29346—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 operating by wave or beam interference
- G02B6/29361—Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
- G02B6/2937—In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
Description
【発明の詳細な説明】
この発明は光波長多重双方向伝送に使用する光
分波器に関し、特に波長依存性に鋭いしや遮特性
のものを得ようとするものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical demultiplexer used in optical wavelength division multiplexing bidirectional transmission, and is particularly intended to provide an optical demultiplexer with sharp wavelength dependence and shielding characteristics.
<従来技術>
従来の双方向伝送用光分波器の典型例は第1図
に示すように、伝送路用光フアイバ1、送信用光
フアイバ2、受信用光フアイバ3に結合用レンズ
4a,4b,4cを配置し、送信側、受信側の結
合用レンズ4a,4cの各々の前面にフイルタ5
a,5bを配置した構成となつている。送信用光
フアイバ2よりの波長λ1の送信光信号は結合用
レンズ4aを介してフイルタ5aに入射され、こ
のフイルタ5aを通過し、結合用レンズ4bを介
して伝送路用光フアイバ1に入射される。伝送路
用光フアイバ1より伝送された波長λ2の受信光
信号は結合用レンズ4bを介してフイルタ5aに
入射され、このフイルタ5aで反射され、更にフ
イルタ5bを透過して結合用レンズ4cを介して
受信用光フアイバ3に入射される。<Prior art> As shown in FIG. 1, a typical example of a conventional optical demultiplexer for bidirectional transmission includes a transmission line optical fiber 1, a transmitting optical fiber 2, a receiving optical fiber 3, and a coupling lens 4a, 4b and 4c, and a filter 5 is placed in front of each of the coupling lenses 4a and 4c on the transmitting and receiving sides.
It has a configuration in which a and 5b are arranged. A transmitted optical signal with a wavelength λ 1 from the transmitting optical fiber 2 enters the filter 5a via the coupling lens 4a, passes through this filter 5a, and enters the transmission line optical fiber 1 via the coupling lens 4b. be done. The received optical signal of wavelength λ 2 transmitted from the optical fiber 1 for transmission path is incident on the filter 5a via the coupling lens 4b, reflected by the filter 5a, and further transmitted through the filter 5b to pass through the coupling lens 4c. The signal is input to the receiving optical fiber 3 through the optical fiber.
フイルタ5a,5bは一般に誘電体干渉膜フイ
ルタが使用されるが、石英系光フアイバの最低損
失領域である1.5μm帯におけるしや断特性は
6dB/10nm程度であり、近端漏洩減衰量を60dB
とるためにはこのフイルタを1枚使用した場合、
波長間隔を100nmとる必要がある。またこのフ
イルタを数枚重ねて使用すればしや断特性は改善
されるが、その場合透過損失が増加する。さらに
フイルタを重ねることによりレンズ間距離は大き
くなり、結合系の調整性が悪くなるので、損失増
加が起こる可能性が高い。また第1図に示した構
造では各フアイバ1,2,3に1個ずつレンズ4
b,4a,4cが必要であり構造が複雑になる。 Dielectric interference film filters are generally used for the filters 5a and 5b, but the shearing characteristics in the 1.5 μm band, which is the lowest loss region of silica-based optical fibers, are
It is about 6dB/10nm, and the near-end leakage attenuation is 60dB.
If you use one piece of this filter to remove
It is necessary to set a wavelength interval of 100 nm. Further, if several of these filters are stacked and used, the cutting characteristics can be improved, but in this case, the transmission loss increases. Furthermore, by stacking filters, the distance between lenses increases, and the adjustability of the coupling system deteriorates, so there is a high possibility that loss will increase. In addition, in the structure shown in Fig. 1, one lens 4 is provided for each fiber 1, 2, and 3.
b, 4a, and 4c are required, making the structure complicated.
<発明の概要>
この発明は双方向伝送用光分波器において結合
用レンズを1個だけ使用し、なおかつ波長分離素
子としてフイルタと回折格子を併せて使用するこ
とを特徴とし、その目的は簡単な構成で鋭いしや
断特性をもつた双方向伝送用光分波器を実現する
にある。<Summary of the invention> The present invention is characterized in that only one coupling lens is used in an optical demultiplexer for bidirectional transmission, and a filter and a diffraction grating are also used as wavelength separation elements, and its purpose is simple. The object of this invention is to realize an optical demultiplexer for bidirectional transmission with a sharp shearing characteristic with a simple configuration.
<第1実施例>
第2図はこの発明による双方向伝送用光分波器
の一例を示し、第1図と対応する部分には同一符
号を付けてある。この実施例では伝送路用光フア
イバ1、送信用光フアイバ2及び受信用光フアイ
バ3の各一端部は平行とされ、その各一端結合用
レンズ4と対向され、その結合用レンズ4の反射
の面と対向して波長λ1の光信号に対しては反射
し、λ2の光信号に対しては透過する特性を有す
るフイルタ6が配され、更にそのフイルタ6と対
向して回折格子8が配される。この実施例では結
合用レンズを1個だけ使用しており、第1図に示
した従来のものと比較して簡易な構成となつてい
る。<First Embodiment> FIG. 2 shows an example of an optical demultiplexer for bidirectional transmission according to the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals. In this embodiment, one end of each of the transmission path optical fiber 1, the transmission optical fiber 2, and the reception optical fiber 3 is parallel, and each end faces the coupling lens 4, so that the reflection of the coupling lens 4 is prevented. A filter 6 having a characteristic of reflecting an optical signal of wavelength λ 1 and transmitting an optical signal of wavelength λ 2 is disposed facing the surface, and further facing the filter 6 is a diffraction grating 8. Allotted. In this embodiment, only one coupling lens is used, and the structure is simpler than that of the conventional one shown in FIG.
第2図において送信用光フアイバ2より出射し
た波長λ1の光信号は結合用レンズ4を透過後、
フイルタ6により反射され、再び結合用レンズ4
を透過し、伝送路用光フアイバ1に収束する。一
方、伝送路用光フアイバ1より出射された波長λ
2の光信号はレンズ4及びフイルタ6を順次透過
した後回折格子8により回折され、再びフイルタ
6、レンズ4を順次透過して受信用光フアイバ3
に収束する。その際、回折格子8の溝本数及び伝
送路用光フアイバ1、受信用光フアイバ3のコア
径、外径、比屈折率差及びレンズの焦点距離を適
当に選ぶことにより、回折格子8による分波器の
しや断特性は20dB/10nm以上とすることがで
き、λ1,λ2の波長間隔を30nmとれば、近端
漏洩減衰量を60dB以上とることが可能である。
さらに波長λ2の分波光はフイルタ6を2度透過
するため、より大きな漏洩減衰量が得られる。 In FIG. 2, the optical signal of wavelength λ 1 emitted from the transmission optical fiber 2 passes through the coupling lens 4, and then
It is reflected by the filter 6 and passes through the coupling lens 4 again.
and converges on the transmission line optical fiber 1. On the other hand, the wavelength λ emitted from the transmission line optical fiber 1
The optical signal No. 2 passes sequentially through a lens 4 and a filter 6, is diffracted by a diffraction grating 8, passes through a filter 6 and a lens 4 sequentially again, and is sent to a receiving optical fiber 3.
converges to. At that time, by appropriately selecting the number of grooves in the diffraction grating 8, the core diameter, outer diameter, relative refractive index difference, and focal length of the lens of the transmission line optical fiber 1 and receiving optical fiber 3, the diffraction grating 8 can separate the The shearing characteristic of the wave device can be set to 20 dB/10 nm or more, and if the wavelength interval between λ 1 and λ 2 is set to 30 nm, the near-end leakage attenuation can be set to 60 dB or more.
Furthermore, since the demultiplexed light with wavelength λ 2 passes through the filter 6 twice, a larger amount of leakage attenuation can be obtained.
一方、この構造の分波器において、フイルタ6
の波長λ1に対する反射損は0.2dB程度であれば
十分であり、これは透過損が約15dBに相当す
る。従つてλ1,λ2の波長間隔が30nmであれ
ば透過光に対するしや断特性は5dB/10nmで十
分である。この値は、長期信頼性がソフトコート
のものよりも優れているハードコートのフイルタ
を波長1.5μm帯で使用した場合でも十分可能な
値である。 On the other hand, in the duplexer with this structure, the filter 6
It is sufficient that the reflection loss for the wavelength λ 1 is about 0.2 dB, which corresponds to a transmission loss of about 15 dB. Therefore, if the wavelength interval between λ 1 and λ 2 is 30 nm, a shearing characteristic of 5 dB/10 nm for transmitted light is sufficient. This value is sufficiently possible even when a hard-coated filter, which has better long-term reliability than a soft-coated filter, is used in the 1.5 μm wavelength band.
<具体例>
第3図は第2図に示した分波器構成の具体例を
示す。同図においては結合用レンズ4として、両
端の入射・出射端面が互いに平行した平面であ
り、これらの距離が送信光信号波長に対し、ほゞ
焦点距離とされた集束性レンズを用いる。その集
束性レンズとして入射・出射端面が平面である集
束性ロツドレンズを使用し、このレンズ4の一方
の端面には3本の光フアイバ1,2,3の一端を
並置して対接させ、他方の端面にはフイルタ6、
ガラスプリズム10、回折格子8を順次密着して
形成している。その際ガラスプリズム10は回折
格子8を適当な角度に保持して固定するためのも
のである。この構成により結合系の軸ずれ、角度
ずれによる特性劣化が起こりにくい。さらに第4
図は結合用レンズ4の集束性レンズとして、2枚
の平凸レンズ4a,4bを、凸面を対向させて配
置し、セラミツク製パイプ11に収納したものを
用いた構造であり、第3図に示したものと同様に
結合系の軸ずれ、角度ずれが起こりにくい構成と
なつている。<Specific Example> FIG. 3 shows a specific example of the duplexer configuration shown in FIG. 2. In the figure, as the coupling lens 4, a converging lens is used, whose input and output end faces are planes parallel to each other, and whose distance is approximately the focal length with respect to the wavelength of the transmitted optical signal. A focusing rod lens whose input and output end surfaces are flat is used as the focusing lens, and one end of three optical fibers 1, 2, and 3 are juxtaposed and facing each other on one end surface of this lens 4, and the other A filter 6 is installed on the end face of the
A glass prism 10 and a diffraction grating 8 are formed in close contact with each other in this order. At this time, the glass prism 10 is used to hold and fix the diffraction grating 8 at an appropriate angle. With this configuration, characteristic deterioration due to axial or angular misalignment of the coupling system is less likely to occur. Furthermore, the fourth
The figure shows a structure in which two plano-convex lenses 4a and 4b are arranged with their convex surfaces facing each other and housed in a ceramic pipe 11 as the focusing lenses of the coupling lens 4, as shown in FIG. Like the previous model, the structure is such that axis and angle misalignment of the coupling system is unlikely to occur.
<効果>
以上説明したように、この発明の双方向伝送用
光分波器は、波長分離素子として回折格子8とフ
イルタ6とを併せて使用するため、波長間隔を広
くとらずに十分な漏話減衰量が得られる。さらに
結合用レンズ4が1個で簡単な構成となつてお
り、また各素子を密着形成していることから、小
型化、高信頼化の面からも優れている。<Effect> As explained above, since the optical demultiplexer for bidirectional transmission of the present invention uses the diffraction grating 8 and the filter 6 together as wavelength separation elements, sufficient crosstalk can be achieved without widening the wavelength interval. Attenuation amount can be obtained. Furthermore, since it has a simple structure with only one coupling lens 4, and each element is formed in close contact with each other, it is excellent in terms of miniaturization and high reliability.
第1図は従来の双方向伝送用光分波器を示す構
造図、第2図はこの発明の双方向伝送用光分波器
の一例を示す構造図、第3図及び第4図はそれぞ
れその具体例を示す図である。
1:伝送路用光フアイバ、2:送信用光フアイ
バ、3:受信用光フアイバ、4:結合用レンズ、
5,6:フイルタ、7:光信号、8:回折格子、
10:ガラスプリズム、11:パイプ。
Fig. 1 is a structural diagram showing a conventional optical demultiplexer for bidirectional transmission, Fig. 2 is a structural diagram showing an example of an optical demultiplexer for bidirectional transmission of the present invention, and Figs. 3 and 4 are respectively It is a figure which shows the specific example. 1: Optical fiber for transmission line, 2: Optical fiber for transmission, 3: Optical fiber for reception, 4: Coupling lens,
5, 6: filter, 7: optical signal, 8: diffraction grating,
10: Glass prism, 11: Pipe.
Claims (1)
バと、 その送信用光フアイバからの送信光信号を反射
し、かつ上記伝送路用光フアイバからの受信光信
号を透過することにより送信光信号と受信光信号
とを分離するフイルタと、 そのフイルタを透過した受信光信号を回折して
上記フイルタを通して上記受信用光フアイバに入
射させる反射型回折格子と、 入射、出射端面が互いに平行した平面であり、
これら両端面間の距離が、上記送信光信号波長に
対してほゞ焦点距離であり、一端面に上記3本の
光フアイバの端面が接続され、他端面に上記フイ
ルタが密着された集束性の結合用レンズと、 その結合レンズに上記フイルタを介して一面が
密着され、他面に上記回折格子が密着されてその
回折格子を上記結合用レンズ端面に対して角度を
もたせて固定しているガラスプリズムとよりなる
双方向伝送用光分波器。[Claims] 1. Three optical fibers for transmission line, transmission, and reception, which reflect a transmitted optical signal from the transmission optical fiber, and reflect a received optical signal from the transmission line optical fiber. a filter that separates a transmitted optical signal and a received optical signal by passing through the filter; a reflective diffraction grating that diffracts the received optical signal that has passed through the filter and makes it enter the receiving optical fiber through the filter; The output end faces are planes parallel to each other,
The distance between these end faces is approximately the focal length with respect to the wavelength of the transmitted optical signal, and the end faces of the three optical fibers are connected to one end face, and the filter is closely attached to the other end face. a coupling lens; one surface of the coupling lens is in close contact with the above-mentioned filter, and the above-mentioned diffraction grating is closely attached to the other surface of the glass, and the diffraction grating is fixed at an angle to the end surface of the coupling lens. An optical demultiplexer for bidirectional transmission consisting of a prism.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7872482A JPS58194011A (en) | 1982-05-10 | 1982-05-10 | Optical demultiplexer of two-way transmission |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7872482A JPS58194011A (en) | 1982-05-10 | 1982-05-10 | Optical demultiplexer of two-way transmission |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS58194011A JPS58194011A (en) | 1983-11-11 |
JPS6216404B2 true JPS6216404B2 (en) | 1987-04-13 |
Family
ID=13669825
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7872482A Granted JPS58194011A (en) | 1982-05-10 | 1982-05-10 | Optical demultiplexer of two-way transmission |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS58194011A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01129211A (en) * | 1987-11-13 | 1989-05-22 | Matsushita Electric Ind Co Ltd | Bidirectional optical tuner |
JPH01142505A (en) * | 1987-11-27 | 1989-06-05 | Matsushita Electric Ind Co Ltd | Bidirectional optical tuner |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5617305A (en) * | 1979-07-20 | 1981-02-19 | Matsushita Electric Ind Co Ltd | Light branching coupler |
JPS5640804A (en) * | 1979-09-13 | 1981-04-17 | Nippon Telegr & Teleph Corp <Ntt> | Optical branching filter |
JPS5882219A (en) * | 1981-11-12 | 1983-05-17 | Nec Corp | Light wavelength demultiplexer |
-
1982
- 1982-05-10 JP JP7872482A patent/JPS58194011A/en active Granted
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5617305A (en) * | 1979-07-20 | 1981-02-19 | Matsushita Electric Ind Co Ltd | Light branching coupler |
JPS5640804A (en) * | 1979-09-13 | 1981-04-17 | Nippon Telegr & Teleph Corp <Ntt> | Optical branching filter |
JPS5882219A (en) * | 1981-11-12 | 1983-05-17 | Nec Corp | Light wavelength demultiplexer |
Also Published As
Publication number | Publication date |
---|---|
JPS58194011A (en) | 1983-11-11 |
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