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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