JPH023522Y2 - - Google Patents
Info
- Publication number
- JPH023522Y2 JPH023522Y2 JP16532183U JP16532183U JPH023522Y2 JP H023522 Y2 JPH023522 Y2 JP H023522Y2 JP 16532183 U JP16532183 U JP 16532183U JP 16532183 U JP16532183 U JP 16532183U JP H023522 Y2 JPH023522 Y2 JP H023522Y2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- optical fiber
- semiconductor laser
- face
- light
- 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 44
- 239000004065 semiconductor Substances 0.000 claims description 33
- 230000003287 optical effect Effects 0.000 claims description 19
- 230000008878 coupling Effects 0.000 claims description 14
- 238000010168 coupling process Methods 0.000 claims description 14
- 238000005859 coupling reaction Methods 0.000 claims description 14
- 230000004907 flux Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 6
- 230000010355 oscillation Effects 0.000 description 5
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Description
【考案の詳細な説明】
本考案は半導体レーザと光フアイバとの結合構
造の改良に関するものである。[Detailed Description of the Invention] The present invention relates to an improvement in the coupling structure between a semiconductor laser and an optical fiber.
従来より半導体レーザと光フアイバとを光学的
に結合する結合構造には第1図に示す如きレンズ
を用いた結合構造がある。この構造は半導体レー
ザ1から出射した光を2個の球面または非球面な
第1のレンズ2および第2のレンズ3により光フ
アイバ4の端面5に集束して入射するようにした
ものである。このような結合構造は半導体レーザ
1からの広がり角の大きい出射光を光フアイバ4
に入射可能なビームに変換するために高い光結合
効率が得られるが、光フアイバ4の端面5からの
反射光が矢印の如く再びレンズ3,2を通つて半
導体レーザ1に戻るため次の如き不具合を生ず
る。即ち半導体レーザ1はそれから出射された光
が光回路の中で反射され再び半導体レーザ1の活
性領域内に帰還されると、レーザの動作が不安定
になることが知られており、例えば電流対光特性
が変化して光出力が変動したり、発振波長が縦モ
ード内で飛び10数Åも変化することがある。この
不具合に対し従来は光路中にアイソレータを挿入
して反射光を遮断している。ところがこのアイソ
レータは甚だ高価であり、また構成が複雑となる
欠点がある。本考案はこの欠点を改良するために
案出されたものである。 Conventionally, as a coupling structure for optically coupling a semiconductor laser and an optical fiber, there is a coupling structure using a lens as shown in FIG. This structure is such that light emitted from a semiconductor laser 1 is focused onto an end face 5 of an optical fiber 4 by two spherical or aspherical first and second lenses 2 and 3. Such a coupling structure connects the emitted light with a large spread angle from the semiconductor laser 1 to the optical fiber 4.
However, since the reflected light from the end face 5 of the optical fiber 4 returns to the semiconductor laser 1 through the lenses 3 and 2 as shown by the arrow, the following happens. This will cause problems. That is, it is known that when the light emitted from the semiconductor laser 1 is reflected in the optical circuit and returned to the active region of the semiconductor laser 1, the operation of the laser becomes unstable. The optical characteristics may change and the optical output may fluctuate, or the oscillation wavelength may jump within the longitudinal mode and change by more than 10 angstroms. Conventionally, to solve this problem, an isolator is inserted into the optical path to block the reflected light. However, this isolator is extremely expensive and has the disadvantage of being complicated in construction. The present invention was devised to improve this drawback.
このため本考案においては、共通の光軸上に半
導体レーザと光フアイバの光入射端面を対向させ
るとともにその中間に第1のレンズと第2のレン
ズを配置してなり、上記半導体レーザは第1のレ
ンズのほぼ焦点位置に配置され、第1のレンズは
半導体レーザの発光指向角にもとづく出射光を集
束してほぼ平行光束とする大きさを有し、上記第
2のレンズには一方の面の曲率半径が3±0.5mm
の平凸レンズを用い、該第2のレンズは第1のレ
ンズからのほぼ平行光束を光フアイバの光入射端
面に集光入射せしめるように集光し、上記光フア
イバの光入射端面は第2のレンズにより集光され
た焦点位置に配置され、光フアイバの光入射端面
は光フアイバの中心軸に対して垂直に形成され該
端面を共通の光軸の直交面に対して2度乃至4度
の角度傾斜せしめて配置したことを特徴とするも
のである。 Therefore, in the present invention, the light incident end faces of the semiconductor laser and the optical fiber are arranged to face each other on a common optical axis, and a first lens and a second lens are arranged between them, and the semiconductor laser The first lens has a size that focuses the emitted light based on the emission direction angle of the semiconductor laser into a substantially parallel beam, and the second lens has one surface. The radius of curvature is 3±0.5mm
A plano-convex lens is used, the second lens condenses the substantially parallel light beam from the first lens so as to make it convergently enter the light incidence end face of the optical fiber, and the light incidence end face of the optical fiber is connected to the second lens. The light incident end face of the optical fiber is formed perpendicular to the central axis of the optical fiber, and the end face is set at an angle of 2 to 4 degrees with respect to a plane perpendicular to the common optical axis. It is characterized by being arranged at an angle.
以下、添付図面に基づいて本考案の実施例につ
き詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
第2図は本考案による半導体レーザと光フアイ
バの結合構造を示す図である。同図において、1
は半導体レーザ、2および3は球面または非球面
の第1および第2のレンズ、4は光フアイバをそ
れぞれ示す。 FIG. 2 is a diagram showing a coupling structure of a semiconductor laser and an optical fiber according to the present invention. In the same figure, 1
2 and 3 are spherical or aspherical first and second lenses, and 4 is an optical fiber, respectively.
第2図において、共通の光軸7上に半導体レー
ザ1と光フアイバ4の光入射端面5を対向させ、
その中間に第1のレンズ2を半導体レーザ1側と
し第2のレンズ3を光フアイバ4側として配置す
る。半導体レーザ1は第1のレンズ2のほぼ焦点
位置に配置し、第1のレンズ2は半導体レーザ1
の出射光を集束してほぼ平行光束とする大きさを
有する。第2のレンズ3は曲率半径が3mm±0.5
mmの平凸レンズであつて第1のレンズ2からのほ
ぼ平行な光束を光フアイバ4の光入射端面5に集
光入射させる。そうして、光フアイバ4の光入射
端面5は第2のレンズ3により集光される第2の
レンズ3のほぼ焦点位置に配置される。光フアイ
バ4の光入射端面5は光フアイバ4の中心軸6に
対して垂直に形成し、この端面5を共通の光軸7
の直交面に対して2度乃至4度の角度傾斜せしめ
て配置する。つまり光フアイバ4の中心軸6は共
通の光軸7に対して同角度傾斜されることにな
る。なお本考案で、ほぼとは次の用語と一致する
意味と近傍とを含む範囲を示す。例えばほぼ焦点
位置は焦点位置とその近傍を含むことを意味す
る。 In FIG. 2, the semiconductor laser 1 and the light incident end face 5 of the optical fiber 4 are arranged to face each other on a common optical axis 7,
In between, the first lens 2 is placed on the semiconductor laser 1 side and the second lens 3 is placed on the optical fiber 4 side. The semiconductor laser 1 is placed approximately at the focal point of the first lens 2, and the first lens 2
It has a size that converges the emitted light into a substantially parallel beam. The second lens 3 has a radius of curvature of 3mm±0.5
The substantially parallel light beam from the first lens 2, which is a plano-convex lens of mm in diameter, is condensed and incident on the light incident end surface 5 of the optical fiber 4. In this way, the light incident end face 5 of the optical fiber 4 is placed approximately at the focal point of the second lens 3 where the light is focused by the second lens 3. A light incident end face 5 of the optical fiber 4 is formed perpendicular to the central axis 6 of the optical fiber 4, and this end face 5 is aligned with a common optical axis 7.
It is arranged so as to be inclined at an angle of 2 to 4 degrees with respect to the orthogonal plane. In other words, the central axes 6 of the optical fibers 4 are inclined at the same angle with respect to the common optical axis 7. In the present invention, "approximately" refers to a range that includes the meaning and vicinity of the following terms. For example, "approximately the focal point position" means to include the focal point position and its vicinity.
このように半導体レーザと光フアイバを結合す
ると大部分の光は光フアイバ4に入射するが約4
%は端面5より反射される。この反射された反射
光ビーム8は半導体レーザ1の発光面からずれた
所に戻ることになる。1例として第5図に示すよ
うにレンズ2を非球面レンズ、レンズ3を一方の
面の曲率半径が半導体レーザと光フアイバとの光
結合効率を最適とする曲率半径が3±0.5mmの平
凸レンズとし、光源として通常の半導体レーザ
(通常の半導体レーザの発光指向角はチップの活
性層に平行な面内で25〜35度、活性層面と垂直な
面内で35〜45度である。)を、光フアイバ4とし
てマルチモード光フアイバ(開口数:0.2であり、
光フアイバへの入射最大角は11.5゜)をそれぞれ
用い、光学系の位置関係を図の如くにした場合
(この場合、レンズ系はレーザ指向角約45゜以内の
光をレンズ2で受け、レンズ3で光フアイバ入射
可能角以内におさまるように角度変換している。)
の反射光を追跡して第6図の如く位置ずれ量Sと
傾射角θfとの関係を計算により求めるとθf=2゜に
おいては光ビームの中心位置S=6.5μm、θf=3゜
においてはS=8.2μm、θf=4゜においてはS=
8.1μmとなる。現在用いられている半導体レーザ
の活性層9の領域は広い方で15μm程度であるの
で、傾斜角θfを2〜3゜以上とすれば反射光の影響
は大幅に取り除くことができる。 When the semiconductor laser and optical fiber are coupled in this way, most of the light enters the optical fiber 4, but approximately 4
% is reflected from the end face 5. This reflected light beam 8 returns to a position shifted from the light emitting surface of the semiconductor laser 1. As an example, as shown in FIG. 5, lens 2 is an aspherical lens, and lens 3 is a flat lens whose radius of curvature on one surface is 3±0.5 mm, which optimizes the optical coupling efficiency between the semiconductor laser and the optical fiber. A convex lens is used, and a normal semiconductor laser is used as a light source (the emission direction angle of a normal semiconductor laser is 25 to 35 degrees in a plane parallel to the active layer of the chip, and 35 to 45 degrees in a plane perpendicular to the active layer surface). A multimode optical fiber (numerical aperture: 0.2,
The maximum angle of incidence on the optical fiber is 11.5 degrees), and the positional relationship of the optical system is as shown in the figure (in this case, the lens system receives light with a laser directivity angle of about 45 degrees or less with lens 2, 3, the angle is changed so that it falls within the possible angle of incidence of the optical fiber.)
The relationship between the amount of positional deviation S and the angle of inclination θ f is calculated by tracking the reflected light of the beam as shown in Fig. 6. When θ f = 2°, the center position of the light beam S = 6.5 μm, and θ f = At 3°, S = 8.2 μm; at θ f = 4°, S =
It becomes 8.1μm. Since the active layer 9 of currently used semiconductor lasers has a wide area of about 15 μm, the influence of reflected light can be largely eliminated by setting the inclination angle θ f to 2 to 3 degrees or more.
第3図は傾斜角θfが半導体レーザの発振波長λ
に及ぼす影響を実験により求めた結果を示したも
のである。図よりθfが±2゜以内においては波長の
変動が認められるがそれ以上においては安定な発
振を示していることがわかる。また第4図は半導
体レーザと光フアイバの光結合効率ηに及ぼす傾
斜角θfの影響を実験により求めた結果を示したも
のであつて、光結合効率ηはθf=±4゜までは殆ん
ど変動がなく、θf=±5゜になると5%程度の効率
低下となる。 Figure 3 shows that the tilt angle θ f is the oscillation wavelength λ of the semiconductor laser.
This figure shows the results obtained through experiments to determine the effect on The figure shows that wavelength fluctuations are observed when θ f is within ±2°, but stable oscillation is observed above this. Figure 4 shows the experimental results of the influence of the tilt angle θ f on the optical coupling efficiency η between the semiconductor laser and the optical fiber. There is almost no fluctuation, and when θ f =±5°, the efficiency decreases by about 5%.
以上の計算および実験から上述の結合構造にお
ける光フアイバの端面の傾斜角θfは2〜4゜が適当
である。このように光フアイバ端面をレンズの光
軸に対し傾けることにより、その端面から半導体
レーザの活性領域に帰還される反射光を減少せし
めて発振動作の不安定性を除去することができる
のである。 From the above calculations and experiments, an appropriate inclination angle θ f of the end face of the optical fiber in the above-mentioned coupling structure is 2 to 4 degrees. By tilting the end face of the optical fiber with respect to the optical axis of the lens in this manner, it is possible to reduce the reflected light that is returned from the end face to the active region of the semiconductor laser, thereby eliminating instability in the oscillation operation.
以上説明した如く本考案の半導体レーザと光フ
アイバの結合構造は、光フアイバの端面をレンズ
の光軸に対して所定角度以内に傾斜せしめること
により、反射光による光源の不安定性を除くこと
を簡囲に実現可能にしたものである。 As explained above, the semiconductor laser and optical fiber coupling structure of the present invention makes it easy to eliminate the instability of the light source caused by reflected light by tilting the end face of the optical fiber within a predetermined angle with respect to the optical axis of the lens. This has made it possible to implement the project in a similar manner.
第1図は従来の半導体レーザと光フアイバの結
合構造の模式図、第2図は本考案の半導体レーザ
と光フアイバの結合構造を説明するための図、第
3図は半導体レーザの発振波長と光フアイバ端面
の傾斜角との関係を実験により求めた線図、第4
図は半導体レーザと光フアイバとの光結合効率と
光フアイバ端面の傾斜角との関係を実験により求
めた線図、第5図は本考案の実施例のレンズのパ
ラメータ及び光学系の位置関係を示す図、第6図
は反射光と位置ずれ量Sと傾斜角θfの関係を示す
図である。
1…半導体レーザ、2,3…第1、第2レン
ズ、4…光フアイバ、5…光フアイバの端面、6
…光フアイバの中心軸、7…レンズの光軸、8…
反射光ビームの中心軸、9…判導体レーザの活性
層領域。
Fig. 1 is a schematic diagram of a conventional coupling structure of a semiconductor laser and an optical fiber, Fig. 2 is a diagram for explaining the coupling structure of a semiconductor laser and an optical fiber of the present invention, and Fig. 3 shows the oscillation wavelength of the semiconductor laser. Diagram 4 of the relationship between the angle of inclination of the optical fiber end face and the angle of inclination obtained through experiments.
The figure is a diagram of the relationship between the optical coupling efficiency between the semiconductor laser and the optical fiber and the inclination angle of the end face of the optical fiber, which was obtained through experiments. Figure 5 shows the lens parameters and the positional relationship of the optical system in the embodiment of the present invention. The figure shown in FIG. 6 is a diagram showing the relationship between the reflected light, the amount of positional deviation S, and the inclination angle θ f . DESCRIPTION OF SYMBOLS 1... Semiconductor laser, 2, 3... First and second lenses, 4... Optical fiber, 5... End surface of optical fiber, 6
... Central axis of optical fiber, 7... Optical axis of lens, 8...
Central axis of reflected light beam, 9... Active layer region of size conductor laser.
Claims (1)
入射端面を対向させるとともにその中間に第1の
レンズと第2のレンズを配置してなり、上記半導
体レーザは第1のレンズのほぼ焦点位置に配置さ
れ、第1のレンズは半導体レーザの発光指向角に
もとづく出射光を集束してほぼ平行光束とする大
きさを有し、上記第2のレンズには一方の面の曲
率半径が3±0.5mmの平凸レンズを用い、該第2
のレンズは第1のレンズからのほぼ平行な光束を
光フアイバの光入射端面に集光入射せしめるよう
に集光し、上記光フアイバの光入射端面は第2の
レンズにより集光されたほぼ焦点位置に配置さ
れ、光フアイバの光入射端面は光フアイバの中心
軸に対して垂直に形成され該端面を共通の光軸の
直交面に対して2度乃至4度の角度傾斜せしめて
配置したことを特徴とする半導体レーザと光フア
イバの結合構造。 A semiconductor laser and an optical fiber have light incident end faces facing each other on a common optical axis, and a first lens and a second lens are arranged between them, and the semiconductor laser is located approximately at the focal point of the first lens. The first lens has a size that focuses the emitted light based on the emission direction angle of the semiconductor laser into a substantially parallel beam, and the second lens has a radius of curvature of 3±0.5 on one surface. Using a plano-convex lens of mm, the second
The lens condenses the substantially parallel light flux from the first lens so as to make it enter the light incidence end face of the optical fiber, and the light incidence end face of the optical fiber is almost at the focal point of the light condensed by the second lens. The light incident end face of the optical fiber is formed perpendicular to the central axis of the optical fiber, and the end face is inclined at an angle of 2 to 4 degrees with respect to a plane perpendicular to the common optical axis. A semiconductor laser and optical fiber coupling structure featuring:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16532183U JPS5984511U (en) | 1983-10-27 | 1983-10-27 | Coupling structure of semiconductor laser and optical fiber |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16532183U JPS5984511U (en) | 1983-10-27 | 1983-10-27 | Coupling structure of semiconductor laser and optical fiber |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5984511U JPS5984511U (en) | 1984-06-07 |
JPH023522Y2 true JPH023522Y2 (en) | 1990-01-26 |
Family
ID=30362226
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16532183U Granted JPS5984511U (en) | 1983-10-27 | 1983-10-27 | Coupling structure of semiconductor laser and optical fiber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5984511U (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016103912A1 (en) | 2014-12-25 | 2016-06-30 | オリンパス株式会社 | Optical transmission connector device |
-
1983
- 1983-10-27 JP JP16532183U patent/JPS5984511U/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS5984511U (en) | 1984-06-07 |
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