JP2000241779A - Optical integrated circuit with tunable phase difference - Google Patents
Optical integrated circuit with tunable phase differenceInfo
- Publication number
- JP2000241779A JP2000241779A JP11046861A JP4686199A JP2000241779A JP 2000241779 A JP2000241779 A JP 2000241779A JP 11046861 A JP11046861 A JP 11046861A JP 4686199 A JP4686199 A JP 4686199A JP 2000241779 A JP2000241779 A JP 2000241779A
- Authority
- JP
- Japan
- Prior art keywords
- light
- phase difference
- titanium
- optical waveguide
- 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.)
- Withdrawn
Links
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光学素子に関し、
特に所望の位相差を得るための光集積回路に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element,
In particular, the present invention relates to an optical integrated circuit for obtaining a desired phase difference.
【０００２】[0002]
【従来の技術】従来、円偏光または楕円偏光などの出射
光束を必要とする場合、直線偏光の入射光束を１／４波
長板などの波長板を通過させることで、所望の偏波状態
を得ていた。2. Description of the Related Art Conventionally, when an outgoing light beam such as a circularly polarized light or an elliptically polarized light is required, a desired polarized state can be obtained by passing an incident light beam of a linearly polarized light through a wave plate such as a quarter wave plate. I was
【０００３】波長板は、図３に示すように、互いに直交
する光学的固有軸を有する複屈折性媒質すなわち複屈折
結晶型波長板２１または負荷応力により複屈折を誘起せ
しめたプラスチックを、光の通過方向につき一定の厚さ
Ｔとして形成することで製作される光学素子である。光
は厚さＴを通過する間に、両固有軸に射影した偏波成分
間で所望の位相差を生成し、出射時に所望の偏波状態を
得るように設計されている。例えば１／４波長板の場
合、図３にあるような両固有軸（ＴＥとＴＭ）の偏光の
位相があった光が１／４波長板に入射し通過した場合、
出射光は、固有軸の偏光に波長の１／４に相当する位相
差が生じる。これは、固有軸に対し４５度の方位角で直
線偏光を入射すれば、円偏光を得ることができることを
意味する。As shown in FIG. 3, a wave plate is made of a birefringent medium having optical eigen axes orthogonal to each other, that is, a birefringent crystal wave plate 21 or a plastic in which birefringence is induced by a load stress. This is an optical element manufactured by forming a constant thickness T in the passing direction. The light is designed so as to generate a desired phase difference between the polarization components projected on both eigen axes while passing through the thickness T, and to obtain a desired polarization state upon emission. For example, in the case of a quarter-wave plate, when light having a phase of polarization of both eigen axes (TE and TM) as shown in FIG.
In the emitted light, a phase difference corresponding to １ ／ of the wavelength is generated in the polarization of the intrinsic axis. This means that circularly polarized light can be obtained if linearly polarized light is incident at an azimuth angle of 45 degrees with respect to the intrinsic axis.
【０００４】[0004]
【発明が解決しようとする課題】前述のような波長板
は、結晶等の媒質の各固有軸の屈折率が互いに異なる温
度依存性を持つことおよび媒質の熱膨張によって、両固
有軸間で生成する位相差に温度依存性があり、温度変化
に対して安定した偏波状態を得ることができなかった。The above-mentioned wave plate is formed between the two eigenaxes due to the fact that the refractive indices of the eigenaxes of a medium such as a crystal have different temperature dependences and the thermal expansion of the medium. The phase difference has a temperature dependence, and a stable polarization state cannot be obtained with respect to a temperature change.
【０００５】また、従来の波長板では、位相差が固定さ
れており、位相差をフレキシブルに変化させることがで
きない。Further, in the conventional wave plate, the phase difference is fixed, and the phase difference cannot be flexibly changed.
【０００６】更に、従来の波長板は、ファイバとの直接
の接続が困難であるという欠点があった。Further, the conventional wave plate has a drawback that direct connection with the fiber is difficult.
【０００７】そこで本発明は、上記波長板の種々の欠点
を解決し、波長板に代わって所望の偏波状態の光に変え
ることができる光学素子を実現するものである。Accordingly, the present invention solves the various drawbacks of the above-mentioned wavelength plate and realizes an optical element capable of changing to a light of a desired polarization state instead of the wavelength plate.
【０００８】[0008]
【課題を解決するための手段】本発明は、前記課題を解
決するため、ニオブ酸リチウム結晶と、前記ニオブ酸リ
チウム結晶上に形成されたチタン拡散光導波路と、金属
膜による偏光子と、電気光学効果を利用した光位相シフ
タと、ＴＥ／ＴＭモード変換器とから構成され、入射光
は前記偏光子を通過した後に２分岐され、一方の分岐光
束が前記光位相シフタを通過し、他方の分岐光束が前記
ＴＥ／ＴＭモード変換器を通過し、その後前記両分岐光
束が合波され、前記光位相シフタによる相互に直交する
２つの直線偏波成分間に所望の位相差を有する合波光が
出射される位相差が可変の光集積回路を採用する。According to the present invention, there is provided a lithium niobate crystal, a titanium diffused optical waveguide formed on the lithium niobate crystal, a polarizer made of a metal film, It is composed of an optical phase shifter using an optical effect and a TE / TM mode converter. The incident light is split into two after passing through the polarizer, and one split light beam passes through the optical phase shifter and the other split light beam. The split light beam passes through the TE / TM mode converter, and then the two split light beams are multiplexed. The multiplexed light having a desired phase difference between two mutually orthogonal linearly polarized components by the optical phase shifter is formed. An optical integrated circuit whose output phase difference is variable is employed.
【０００９】[0009]
【発明の実施の形態】本発明の一実施の形態例について
図１と図２を参照して説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.
【００１０】ニオブ酸リチウム結晶１１上には、２つの
Ｙ型のチタン拡散光導波路１２が対称的に組み合わされ
て分岐および合波されるように形成される。一方のチタ
ン拡散光導波路１２の入射側に金属膜１３が形成されて
いる。この金属膜１３は、偏光子の役割を果たし、入射
した光をＴＥモードのみの偏光とし、Ｙ分岐で２分割す
る。その内の一方の分岐光束は、電気光学効果を利用し
た光位相シフタ１４が設けられ、そこを通過することに
より位相差がシフトした光束が得られる。他方の光束
は、電気光学効果を利用した櫛形電極より成るＴＥ／Ｔ
Ｍモード変換器１５を形成することによりＴＭモードに
変換される。上記で光位相シフタ１４を通過した光とＴ
Ｅ／ＴＭモード変換器１５を通過した光を合波すること
により、ＴＥおよびＴＭモードを有する光が他方のチタ
ン拡散光導波路１２から出射される。従って、温度変化
に対して、位相差のコントロールを必要とする光学系に
おいて、図２に示すように、上記光位相シフタ１４の電
圧を検出器１６で検出してフィードバック制御すること
により、ＴＥモードの光とＴＭモードの光に位相差を一
定に保つことができる。On the lithium niobate crystal 11, two Y-type titanium diffused optical waveguides 12 are formed so as to be symmetrically combined and branched and combined. A metal film 13 is formed on the incident side of one titanium diffusion optical waveguide 12. The metal film 13 plays a role of a polarizer, converts incident light into polarized light only in the TE mode, and divides the light into two by a Y-branch. One of the branched light beams is provided with an optical phase shifter 14 utilizing the electro-optic effect, and a light beam having a phase difference shifted by passing therethrough is obtained. The other light beam is a TE / T composed of a comb-shaped electrode utilizing the electro-optic effect.
The conversion into the TM mode is performed by forming the M mode converter 15. The light passing through the optical phase shifter 14 and T
Light having TE and TM modes is emitted from the other titanium diffused optical waveguide 12 by multiplexing the light that has passed through the E / TM mode converter 15. Therefore, in an optical system that needs to control the phase difference with respect to a temperature change, as shown in FIG. 2, the voltage of the optical phase shifter 14 is detected by the detector 16 and the feedback control is performed. And the TM-mode light can have a constant phase difference.
【００１１】また、従来の波長板は、図３に示すような
形状であり、ファイバとの接続が困難であったが、本発
明は、光導波路形状のため、通常のピグテール接続が可
能である。The conventional wave plate has a shape as shown in FIG. 3 and is difficult to connect to a fiber. However, in the present invention, ordinary pigtail connection is possible because of the optical waveguide shape. .
【００１２】[0012]
【発明の効果】以上の説明から明らかなように、本発明
によれば、両固有軸の偏波の位相差を所望値にコントロ
ールできる。つまり、温度変化等によって、位相差が生
じても、制御可能である。さらに、本発明によれば、フ
ァイバとの直接接続が容易となる。As is apparent from the above description, according to the present invention, the phase difference between the polarizations of the two eigenaxes can be controlled to a desired value. That is, even if a phase difference occurs due to a temperature change or the like, control is possible. Further, according to the present invention, direct connection with the fiber is facilitated.
【図１】本発明の一実施の形態例の光集積回路の模式的
斜視図である。FIG. 1 is a schematic perspective view of an optical integrated circuit according to an embodiment of the present invention.
【図２】本発明の一実施の形態例の光集積回路の模式的
ブロック図である。FIG. 2 is a schematic block diagram of an optical integrated circuit according to an embodiment of the present invention.
【図３】従来の波長板の斜視図である。FIG. 3 is a perspective view of a conventional wave plate.
１１ ニオブ酸リチウム結晶 １２ チタン拡散光導波路 １３ 金属膜 １４ 光位相シフタ １５ ＴＥ／ＴＭモード変換器 １６ 検出器 DESCRIPTION OF SYMBOLS 11 Lithium niobate crystal 12 Titanium diffusion optical waveguide 13 Metal film 14 Optical phase shifter 15 TE / TM mode converter 16 Detector
Claims (1)
リチウム結晶上に形成されたチタン拡散光導波路と、金
属膜による偏光子と、電気光学効果を利用した光位相シ
フタと、ＴＥ／ＴＭモード変換器とから構成され、入射
光は前記偏光子を通過した後に２分岐され、一方の分岐
光束が前記光位相シフタを通過し、他方の分岐光束が前
記ＴＥ／ＴＭモード変換器を通過し、その後前記両分岐
光束が合波され、前記光位相シフタによる相互に直交す
る２つの直線偏波成分間に所望の位相差を有する合波光
が出射されることを特徴とする位相差が可変の光集積回
路。1. A lithium niobate crystal, a titanium diffusion optical waveguide formed on the lithium niobate crystal, a polarizer made of a metal film, an optical phase shifter using an electro-optic effect, and a TE / TM mode conversion. The incident light is split into two after passing through the polarizer, one of the split light beams passes through the optical phase shifter, and the other split light beam passes through the TE / TM mode converter. The two-branch light beams are multiplexed, and multiplexed light having a desired phase difference between two linearly polarized components orthogonal to each other by the optical phase shifter is output. circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11046861A JP2000241779A (en) | 1999-02-24 | 1999-02-24 | Optical integrated circuit with tunable phase difference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11046861A JP2000241779A (en) | 1999-02-24 | 1999-02-24 | Optical integrated circuit with tunable phase difference |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000241779A true JP2000241779A (en) | 2000-09-08 |
Family
ID=12759130
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11046861A Withdrawn JP2000241779A (en) | 1999-02-24 | 1999-02-24 | Optical integrated circuit with tunable phase difference |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000241779A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7515803B2 (en) | 2004-03-31 | 2009-04-07 | Kazuyuki Hirao | Optical element, manufacturing method thereof, and optical device |
| CN103852916A (en) * | 2012-11-30 | 2014-06-11 | 鸿富锦精密工业（深圳）有限公司 | Electro-optical modulator |
-
1999
- 1999-02-24 JP JP11046861A patent/JP2000241779A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7515803B2 (en) | 2004-03-31 | 2009-04-07 | Kazuyuki Hirao | Optical element, manufacturing method thereof, and optical device |
| CN103852916A (en) * | 2012-11-30 | 2014-06-11 | 鸿富锦精密工业（深圳）有限公司 | Electro-optical modulator |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20060509 |