JPH0261009B2 - - Google Patents
Info
- Publication number
- JPH0261009B2 JPH0261009B2 JP55117897A JP11789780A JPH0261009B2 JP H0261009 B2 JPH0261009 B2 JP H0261009B2 JP 55117897 A JP55117897 A JP 55117897A JP 11789780 A JP11789780 A JP 11789780A JP H0261009 B2 JPH0261009 B2 JP H0261009B2
- Authority
- JP
- Japan
- Prior art keywords
- quarter
- wave plate
- optical isolator
- holder
- 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 - Lifetime
Links
- 230000003287 optical effect Effects 0.000 claims description 24
- 239000004065 semiconductor Substances 0.000 claims description 4
- 230000008602 contraction Effects 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 4
- 230000010365 information processing Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/008—Mountings, adjusting means, or light-tight connections, for optical elements with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Head (AREA)
- Lasers (AREA)
Description
【発明の詳細な説明】
本発明は磁気デイスク等の記録媒体に畜積され
た記録情報を光学的に再生する光学的情報処理装
置等に使用される光アイソレータに関し、特に、
半導体レーザを光学系に組み込んだ光学的情報処
理装置等に使用される光アイソレータの１／４波
長板の固定及び調整技術に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical isolator used in an optical information processing device that optically reproduces recorded information stored on a recording medium such as a magnetic disk, and in particular,
The present invention relates to a technique for fixing and adjusting a quarter-wave plate of an optical isolator used in optical information processing devices incorporating a semiconductor laser into an optical system.
第１図及び第２図は従来の光学的情報処理装置
の光アイソレータを示す構成図である。光アイソ
レータは偏光ビームスプリツタ１または偏光板２
と１／４波長板３とを組み合わせることにより構
成される。この構成によりレーザダイオード４か
ら出力された光はコリメートレンズ５によりコリ
メートされた後、偏光ビームスプリツタ１または
偏光板２により直線偏光となつて１／４波長板３
に入射され、１／４波長板で円偏光となつて後に
続く光学系へと導かれる。後に続く光学系からの
反射光は１／４波長板３を通過して先の場合に対
し直角方向に偏光した直線偏光となる為、偏光ビ
ームスプリツタ１、または偏光板２によりその進
行が阻止され、従つて光源であるレーザダイオー
ド４には戻らなくなる。 1 and 2 are configuration diagrams showing an optical isolator of a conventional optical information processing device. The optical isolator is a polarizing beam splitter 1 or a polarizing plate 2.
and a quarter wavelength plate 3 in combination. With this configuration, the light output from the laser diode 4 is collimated by the collimating lens 5, and then converted into linearly polarized light by the polarizing beam splitter 1 or the polarizing plate 2, and then sent to the quarter-wave plate 3.
The light is incident on the 1/4 wavelength plate, becomes circularly polarized light, and is guided to the subsequent optical system. The reflected light from the subsequent optical system passes through the 1/4 wavelength plate 3 and becomes linearly polarized light that is polarized at right angles to the previous case, so its progress is blocked by the polarizing beam splitter 1 or the polarizing plate 2. Therefore, the light does not return to the laser diode 4, which is the light source.
しかしながらレーザダイオード４は周知の如く
温度によりその発信波長が変化する性質を有して
いる。光の波長が変化すると１／４波長板３と波
長とのマツチングが崩れるため、１／４波長板３
を通つた後の光が円偏光とならず、楕円偏光とな
り、光アイソレータとしての機能が充分でなくな
り、レーザダイオード４に反射帰還光が入射され
る結果となる。レーザダイオード４に反射光が入
射されるとレーザダイオード４は不安定となり、
Ｓ／Ｎ比の低下を招き、光学装置の性能は大きく
低下する。 However, as is well known, the laser diode 4 has the property that its emission wavelength changes depending on the temperature. When the wavelength of light changes, the matching between the 1/4 wavelength plate 3 and the wavelength breaks down, so the 1/4 wavelength plate 3
The light after passing through the laser diode 4 does not become circularly polarized light but becomes elliptically polarized light, and the function as an optical isolator becomes insufficient, resulting in reflected feedback light being incident on the laser diode 4. When reflected light enters the laser diode 4, the laser diode 4 becomes unstable.
This results in a decrease in the S/N ratio, and the performance of the optical device is greatly degraded.
本発明は上記問題点に鑑み、１／４波長板の固
定に技術的手段を駆使することにより、温度変化
に起因する反射帰還光の光源への入射を防止した
新規有用な光アイソレータを提供することを目的
とするものである。 In view of the above problems, the present invention provides a new and useful optical isolator that prevents reflected feedback light caused by temperature changes from entering the light source by making full use of technical means to fix the quarter-wave plate. The purpose is to
以下、本発明を実施例に従つて図面を参照しな
がら詳細に説明する。 Hereinafter, the present invention will be described in detail according to embodiments with reference to the drawings.
第３図は本発明の一実施例である光アイソレー
タの構成図である。 FIG. 3 is a block diagram of an optical isolator which is an embodiment of the present invention.
偏光板２と１／４波長板３とで光アイソレータ
を構成するとともに１／４波長板３を傾斜させて
保持し、両端の保持部分に棒状の保持具６を装着
して保持具６の一端を片持ち梁として固定点７で
固定する。温度が上昇すると保持具６の膨張によ
り１／４波長板３はより一層傾斜することになり
温度が降下すると保持具６の短縮により１／４波
長板３は直立する方向へ位置変換される。従つ
て、光源に配置されたレーザダイオード４の発振
波長が温度変化により変動しても１／４波長板３
がこの温度変化に対応して傾斜するため、常に波
長とのマツチングが良好な光アイソレータが構成
される。 The polarizing plate 2 and the 1/4 wavelength plate 3 constitute an optical isolator, and the 1/4 wavelength plate 3 is held at an angle, and rod-shaped holders 6 are attached to the holding parts at both ends, and one end of the holder 6 is attached. is fixed at fixed point 7 as a cantilever beam. When the temperature rises, the expansion of the holder 6 causes the 1/4 wavelength plate 3 to tilt further, and when the temperature falls, the holder 6 shortens, causing the 1/4 wavelength plate 3 to be moved to an upright position. Therefore, even if the oscillation wavelength of the laser diode 4 disposed in the light source changes due to temperature changes, the quarter-wave plate 3
is tilted in response to this temperature change, so an optical isolator that always matches the wavelength well is constructed.
光源の温度による波長変化量は半導体レーザの
種類により異なつた値を有するが、調整機構には
１／４波長板３の厚さ、光軸の向き、保持具６の
材料及び固定点７からの長さ、最初に設定する時
の１／４波長板３の傾斜角度等多くのパラメータ
があり、これらの適切な設定により常に充分な機
能を有する光アイソレータを構成することができ
る。また、この構成は極めて簡単であり、広い動
作温度範囲、高いＳ／Ｎ比の要求される光フアイ
バとの結合、ビデオデイスク用光学系として用い
れば非常に有効な技術となる。 The amount of wavelength change due to the temperature of the light source has different values depending on the type of semiconductor laser, but the adjustment mechanism includes the thickness of the quarter-wave plate 3, the direction of the optical axis, the material of the holder 6, and the distance from the fixed point 7. There are many parameters such as the length and the inclination angle of the quarter-wave plate 3 when initially set, and by appropriately setting these parameters, it is possible to construct an optical isolator that always has sufficient functionality. Furthermore, this structure is extremely simple, and it becomes a very effective technique when used as an optical system for a video disk, coupled with an optical fiber that requires a wide operating temperature range and a high S/N ratio.
第１図及び第２図は従来の光アイソレータの構
成を示す構成図である。第３図は本発明の一実施
例を示す光アイソレータの構成図である。
２…偏光板、３…１／４波長板、４…レーザダ
イオード、５…コリメートレンズ、６…保持具、
７…固定点。
FIGS. 1 and 2 are block diagrams showing the structure of a conventional optical isolator. FIG. 3 is a configuration diagram of an optical isolator showing an embodiment of the present invention. 2... Polarizing plate, 3... 1/4 wavelength plate, 4... Laser diode, 5... Collimating lens, 6... Holder,
7...Fixed point.
Claims (1)
ータであつて、前記半導体レーザの出力光を直線
偏光にするための偏光素子と、該偏光素子によつ
て偏光された光を円偏光にするための１／４波長
板とを具備して成る光アイソレータにおいて、 前記１／４波長板の両端をそれぞれ熱膨縮する
保持具端部に連結して前記１／４波長板を保持
し、該保持具の他方端を固定してその熱膨縮方向
を逆方向とすることにより、前記保持具の熱膨縮
に応じて前記１／４波長板を回動させる保持角度
制御機構を備えることを特徴とする光アイソレー
タ。[Scope of Claims] 1. An optical isolator using a semiconductor laser as a light source, comprising a polarizing element for linearly polarizing the output light of the semiconductor laser, and circularly polarizing the light polarized by the polarizing element. In an optical isolator comprising a quarter-wave plate for holding the quarter-wave plate, the quarter-wave plate is held by connecting both ends of the quarter-wave plate to respective ends of a thermally expanding and contracting holder; A holding angle control mechanism is provided that rotates the quarter-wave plate in accordance with thermal expansion and contraction of the holder by fixing the other end of the holder and making the direction of thermal expansion and contraction of the holder opposite. An optical isolator featuring:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55117897A JPS5741610A (en) | 1980-08-26 | 1980-08-26 | Optical device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55117897A JPS5741610A (en) | 1980-08-26 | 1980-08-26 | Optical device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5741610A JPS5741610A (en) | 1982-03-08 |
| JPH0261009B2 true JPH0261009B2 (en) | 1990-12-18 |
Family
ID=14722909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55117897A Granted JPS5741610A (en) | 1980-08-26 | 1980-08-26 | Optical device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5741610A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58101319U (en) * | 1981-12-29 | 1983-07-09 | ソニー株式会社 | Vibration absorption wheel for the head drum of magnetic recording and playback equipment |
| JPS58130316A (en) * | 1982-01-29 | 1983-08-03 | Toyo Commun Equip Co Ltd | Optical isolator |
| JPS61195530U (en) * | 1985-05-29 | 1986-12-05 |
-
1980
- 1980-08-26 JP JP55117897A patent/JPS5741610A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5741610A (en) | 1982-03-08 |
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