200424729 玖、發明說明： 【明 屬 3 發明領域 本發明係有關於非線性光學裝置，更特定言之’係有 5 關於二極體雷射結構式光線之頻率轉換用的一種裝置。 t先前技術3 發明背景 半導體雷射在光纖傳輸系統、信號放大系統、波分複 用傳輸系統、波分轉換系統、波長交叉連接系統以及類似 糸統扮演重要的角色。此外，半導體雷射在光學測里領域 中係為有用的。 半導體雷射（最先於1959年提出）係根據非平衡載體之 電流注入一半導體主動介質中，導致居量反轉及充分的模 態增益用以獲得雷射作用。 15 現參考該等圖式，基本上目前在雷射市場具支配地位 的有二類型半導體雷射，如第la-b圖中所示。第la圖係圖示 一垂直共振腔面射型雷射(VCSEL)，其中光子係於垂直方 向（於第la圖中為向上）上，在一高精度腔中循環。於此類雷 射中，該腔室為短的並且每一循環的增益係為極低的。因 20此，在每一反射時確保極低損失係極為重要的，否則，無 法達到雷射作用或將需過大電流密度，對於連續波作業、、 言係不適合。由於最早係於1962年提出，所以垂直共振2 面射型田射（VCSEL)已極為普及。垂直共振腔面射型雷專 (VCSEL)能夠製成為小的，能夠在低定限電流下作動，、士 ，教 5 200424729 係在一極為易於製造的平面技術下製成。 另一類型的半導體雷射係為一邊射型雷射，如第lb圖 中所示。於此類雷射中，一主動介質（例如，一薄層）係配置 在其之折射率係大於周圍包覆層的一波導中，用以確保約 5 束於波導中的雷射光。所產生的光線在典型之30度-60度的 大角度下，在元件之刻面出口處折射。邊射型雷射的優點 在於其之小型輸出孔徑，同時地具有高光線輸出功率。邊 射型雷射超越垂直共振腔面射型雷射（VCSEL)的缺點在於 像散現象，通常在使用環形輸出孔徑時發生。此外，與垂 10 直共振腔面射型雷射(VCSEL)相對地，於邊射型雷射中， 溫度增加導致因半導體隨著溫度增加之帶間隙窄化 (bandgap narrowing)所致使的顯著波長變換。 所有半導體雷射的其中之一缺點在於，發射光線之波 長（或頻率）係受限制在半導體材料之能量間隙（energy 15 bandgap)值所提供之數值上。此外，由於藉由所熟知量子 井、量子線或量子點異質結構之不同結構所造成的載體之 局部化’所以有效的波長可變換至―較大數值(所謂的紅移 (red shift))。半導體雷射技術已針對瓜_乂化合物半導體充 分成長，料蓋超越_奈米之波長。目前所熟知低於_ 20奈米波長的半導體雷射(例如，位在紫外光至絲頻譜範 係極不成熟。 ，半導體雷射的一附加缺點在於不良的光束品質、寬光 譜及波長之不良的溫度穩定性。 已有提出複數種方法用以產生波長低㈣時米的光 6 200424729 線’基本上使用非線性光學技術’將自半導體雷射輸出之 光線波長轉換。該等技術能夠產生極度寬廣光譜範圍之光 線，例如自中紅外光(mid-IR)至可見光。頻率轉換技術之實 例包括和頻產生（SFG)、倍頻（其係為SFG之一特別狀況）、 5 差頻產生（DFG)及光參量產生。 近年來，頻率轉換製程已可商業化用於製造諸如取代 多瓦氬離子(multi-Watt Ar+ ion)之倍頻綠光源雷射，以及在 用於國防應用的增強功率位準下產生中紅外光(mid-IR)輻 射的光參量振盪器等產品。 10 例如，於此併入本文以為參考資料的美國專利第 5，175,741號中揭露一種使用非線性光學(NL〇)單晶體的波 長轉換方法。一固態雷射係藉由一半導體雷射所激發，並 藉由该固態雷射振盡而產生一雷射光束。該非線性光學 (NLO)晶體接著將一雷射光束之波長及一激發雷射光束之 15波長轉換成一光波之波長，其之頻率係為雷射光束之頻率 的總和。 大體上因複數種論證引起對在頻率轉換製程中固態雷 射的需求。首先，一固態雷射提供一具相當低光束發散及 低像散的高品質雷射光束。再者，雷射光束之頻譜寬度係 夠】、谷5午非線性光學(NLO)晶體之最大波長轉換效率。例 如針對一銳酸鉀(KNb〇3)晶體而言，轉換效率的尖峰值之 半峰全幅值，典型地約為〇·5奈米。因此，頻譜寬度低於〇1 奈米的固態雷射係極適於藉由鈮酸鉀(KNb〇3)的頻率轉換。 然而，上述技術承受以下無效率的限制。由一半導體 7 200424729 二極體雷射光線轉換至一固態雷射的最大功率轉換效率， 並不高於30%。一方面，固態雷射利用一非線性光學(NLO) 晶體轉換至第二諧波的頻率轉換效率，能夠高達70%。因 此，製程之無效率性係源自於將二極體雷射（或燈）光轉換成 5 固態雷射光線的步驟。 例如，於美國專利第5,991，317號及6,241，720號中揭露 建議用於改良效率之技術，該等揭露内容於此併入本文以 為參考資料。於該等技術中，使用腔内轉換的概念。例如， 美國專利第5,991，317號揭露一種藉由二或更多的共振鏡所 10 界定的共振腔。一雷射晶體及複數之非線性光學(NLO)晶體 係配置在該共振腔中。一二極體激發源供給一激發光束至 一雷射晶體，並產生一具複數之軸向模態照射非線性光學 (NLO)晶體的雷射光束，以及產生一倍頻（或三倍）輸出光 束。 15 然而，該等技術之轉換效率仍然相當低。可確認的是， 低轉換效率需使用高功率二極體雷射，不可避免地必需受 冷卻。因此，該無效率問題，由於加熱造成能量損失而加 劇，其損失至少為總能量的90%。 此外，針對轉換效率，非線性光學(NLO)晶體的最佳波 20 長係視溫度而定（例如，就鈮酸鉀(KNb03)而言，最佳波長 為0.28奈米/°K)。如此係與固態雷射相矛盾，其中該波長係 為穩定的。就一有效率的作業而言，非線性光學(NLO)晶體 的溫度，係藉由將系統添加成分而精確地加以控制，從而 增加設計的複雜性。 8 200424729 另-缺點在於，固態雷射具有一嚴格定義的波長，限 制了取得一任意頻率轉換波長的可能性。 於上述技術中，二極體雷射係用於激發作用，同時間 接地使用固悲田射執行頻率轉換。用於改良頻率轉換效率 5的可又9解决方法，係使用邊射型二極體雷射用於一直 接頻率轉換。然而，針對該等雷射，雷射波長與最佳非線 性光學(NLO)晶體波長間的配合係極其困難，首先由於所產 生光線的寬廣光譜，其次係因為雷射波長為溫度相依。 另一缺點在於，二極體雷射之極高的光束發散。此發 10散致使雷射光束相關於所需的結晶方向強烈地偏向，並附 加地毀壞元件之性能。。 光束發散之修正典型地需要包含一些透鏡的一複雜設 置，該等透鏡如此配置用以將激發輻射聚焦在非線性光學 (NLO)晶體之表面上〔為此，例如，見υ·等人“使用 I5單模二極體雷射激發源在AgGaS2中的差頻產生 (Difference-Frequency Generation in AgGaS2 by Use of Single-Mode Diode-Laser Pump Sources)^，Optics200424729 (1) Description of the invention: [Ming 3] Field of the Invention The present invention relates to a non-linear optical device, more specifically, to 5 'a device for frequency conversion of light of a diode laser structure type. Prior Art 3 Background of the Invention Semiconductor lasers play an important role in optical fiber transmission systems, signal amplification systems, wavelength division multiplex transmission systems, wavelength division conversion systems, wavelength cross-connect systems, and similar systems. In addition, semiconductor lasers are useful in the field of optical measurement. Semiconductor lasers (originally proposed in 1959) are injected into a semiconductor active medium based on the current of an unbalanced carrier, resulting in inversion of population and sufficient modal gain to obtain the laser effect. 15 With reference to these drawings, there are basically two types of semiconductor lasers that currently dominate the laser market, as shown in Figure la-b. Figure la illustrates a vertical cavity-cavity surface-emitting laser (VCSEL), in which the photons are in the vertical direction (upward in figure la) and circulate in a high-precision cavity. In such lasers, the chamber is short and the gain per cycle is extremely low. Therefore, it is extremely important to ensure extremely low loss at each reflection, otherwise, the laser effect cannot be achieved or excessive current density will be required, which is not suitable for continuous wave operation. Since it was first proposed in 1962, the Vertical Resonance 2 Area Shot Field Shot (VCSEL) has become extremely popular. The Vertical Cavity Surface-Emitting Laser (VCSEL) can be made small and can operate at a low fixed current limit. It is made using a planar technology that is extremely easy to manufacture. Another type of semiconductor laser system is a one-shot laser, as shown in Figure lb. In such a laser, an active medium (for example, a thin layer) is arranged in a waveguide whose refractive index is larger than that of the surrounding cladding layer to ensure about 5 beams of laser light in the waveguide. The light produced is refracted at the exit of the facet of the element at a typical large angle of 30 to 60 degrees. The edge-type laser has the advantages of its small output aperture and high light output power at the same time. The disadvantage of edge-emitting lasers surpassing vertical cavity surface-emitting lasers (VCSELs) is the astigmatism, which usually occurs when a circular output aperture is used. In addition, in contrast to vertical vertical cavity surface-emitting lasers (VCSELs), in edge-emitting lasers, the increase in temperature leads to significant wavelengths due to bandgap narrowing of the semiconductor as the temperature increases. Transform. One of the disadvantages of all semiconductor lasers is that the wavelength (or frequency) of the emitted light is limited to the value provided by the energy 15 bandgap value of the semiconductor material. In addition, due to the localization of the carrier caused by the different structures of the well structures of quantum wells, quantum wires, or quantum dots, the effective wavelength can be converted to "larger values (so-called red shift). Semiconductor laser technology has been fully developed for melon semiconductors, and the material covers wavelengths beyond nanometers. Semiconductor lasers with wavelengths below -20 nanometers are currently well known (for example, the ultraviolet to silk spectrum range is extremely immature. An additional disadvantage of semiconductor lasers is the poor beam quality, wide spectrum, and poor wavelength A number of methods have been proposed to generate light with low wavelengths per hour. 6 200424729 The line 'basically uses non-linear optical technology' to convert the wavelength of light output from a semiconductor laser. These technologies can produce extreme Light in a wide spectral range, such as from mid-IR to visible light. Examples of frequency conversion techniques include sum frequency generation (SFG), frequency doubling (which is a special condition of SFG), and 5 frequency difference generation ( DFG) and optical parameters generation. In recent years, frequency conversion processes have been commercially available for manufacturing multi-frequency green light sources such as multi-Watt Ar + ion lasers, and enhanced power for defense applications. Products such as optical parametric oscillators that generate mid-IR radiation at a level. 10 For example, US Patent No. 5,175,741, which is incorporated herein by reference, discloses one A wavelength conversion method using a non-linear optics (NL0) single crystal. A solid-state laser is excited by a semiconductor laser, and a solid-state laser is used to generate a laser beam. The non-linear optics (NLO) The crystal then converts the wavelength of a laser beam and the 15 wavelength of an excited laser beam into a wavelength of a light wave, the frequency of which is the sum of the frequencies of the laser beam. Generally, multiple arguments have caused the frequency conversion process. The requirements of solid-state lasers. First, a solid-state laser provides a high-quality laser beam with relatively low beam divergence and low astigmatism. Furthermore, the spectral width of the laser beam is sufficient], Gu Wuwu nonlinear optics ( The maximum wavelength conversion efficiency of a NLO) crystal. For example, for a potassium sharp acid (KNb03) crystal, the full-value half-peak value of the peak of the conversion efficiency is typically about 0.5 nm. Therefore, the spectrum width A solid-state laser system below 〇1 nm is extremely suitable for frequency conversion by potassium niobate (KNbO3). However, the above technology suffers from the following inefficiency limitations. A semiconductor laser 20042004729 diode laser light Convert to one The maximum power conversion efficiency of the state laser is not higher than 30%. On the one hand, the solid-state laser uses a non-linear optical (NLO) crystal to convert the frequency to the second harmonic with a frequency conversion efficiency of up to 70%. Therefore, the process The inefficiency comes from the step of converting the diode laser (or lamp) light into 5 solid-state laser rays. For example, disclosed in US Patent Nos. 5,991,317 and 6,241,720 for improvement Technology, the disclosures are incorporated herein by reference. In these technologies, the concept of intracavity conversion is used. For example, US Patent No. 5,991,317 discloses a method using two or more resonant mirrors. The cavity defined by 10. A laser crystal and a complex non-linear optical (NLO) crystal are arranged in the resonant cavity. A diode excitation source supplies an excitation beam to a laser crystal, and generates a laser beam with a plurality of axial modalities illuminating a non-linear optical (NLO) crystal, and generates a doubled (or tripled) output beam. 15 However, the conversion efficiency of these technologies is still quite low. It can be confirmed that low conversion efficiency requires the use of high-power diode lasers, which inevitably must be cooled. Therefore, this inefficiency problem is exacerbated by the energy loss caused by heating, and the loss is at least 90% of the total energy. In addition, for conversion efficiency, the optimal wavelength 20 of a nonlinear optical (NLO) crystal depends on temperature (for example, for potassium niobate (KNb03), the optimal wavelength is 0.28 nm / ° K). This is in contradiction with solid-state lasers, where the wavelength is stable. For an efficient operation, the temperature of a nonlinear optical (NLO) crystal is precisely controlled by adding components to the system, thereby increasing the complexity of the design. 8 200424729 Another disadvantage is that solid-state lasers have a strictly defined wavelength, limiting the possibility of obtaining an arbitrary frequency-converted wavelength. In the above technique, a diode laser system is used for excitation, and a solid-field laser is used to perform frequency conversion at the same time. To improve the frequency conversion efficiency, the 5 and 9 solutions are based on the use of edge-emitting diode lasers for direct frequency conversion. However, for such lasers, the matching system between the laser wavelength and the optimal non-linear optical (NLO) crystal wavelength is extremely difficult, firstly because of the broad spectrum of the light produced, and secondly because the laser wavelength is temperature dependent. Another disadvantage is the extremely high beam divergence of the diode laser. This divergence causes the laser beam to be strongly deflected in relation to the required crystallographic direction and additionally destroys the performance of the element. . Correction of beam divergence typically requires a complex setup involving lenses that are configured to focus the excitation radiation on the surface of a non-linear optical (NLO) crystal [for this, see, for example, υ · et al. "Use Difference-Frequency Generation in AgGaS2 by Use of Single-Mode Diode-Laser Pump Sources ^, Opcs
Letters, 18,No. 13:1062-1064,1993 及美國專利第 5 912910、 6,229,828、及6,304,585號〕。然而，用於將雷射輸出轉換成 2〇 一平彳于光束的附加透鏡’係為所熟知用以致使光束直徑顯 著地變寬’因而降低功率密度’其係針對有效波長轉換的 一主要品求。由於該等問遽’邊射型二極體雷射並未在商 業上用於直接頻率轉換，通常係用作為固態雷射的激發源。 美國專利第6,097,540號中揭鉻另一使用半導體二極體 9 200424729 雷射用於直接頻率轉換的系統。於此系統，藉由數種雷射 所產生的光束，藉由一透鏡及反射鏡之系統結合成一單光 束，並經導引在一非線性光學(NLO)晶體之一表面上。然 而，此解決方案並未提供超越上述技術的顯著優點，所提 5 出的系統係極為複雜且價昂，包含大量的雷射，僅提供一 腔外轉換且非為波長穩定的。 因此，對於沒有上述限制的頻率轉換的一裝置，具有 廣泛認定的需求5並係為南度有利的。 【發明内容】 10 發明概要 根據本發明之一觀點，提供一種用於光線之頻率轉換 的裝置，該裝置包括：（a)—發光元件用於發射具有一第一 頻率的一光線，該發光元件係為一具有一選定之延伸波導 的邊射型半導體發光二極體，致使延伸波導的一基本橫向 15 模態其特徵在於一低光束發散；（b)—光反射器，其經建構 及設計因此光線通過界定在發光元件與光反射器之間的一 外部腔室數次，並提供一回饋用於產生具有第一頻率的一 雷射光；以及(c)一非線性光學晶體，配置在外部腔室中並 經選定，因此當具有第一頻率的雷射光通過非線性光學晶 20 體數次時，該第一頻率經轉換成與其不同的一第二頻率。 根據以下所說明本發明之較佳具體實施例的進一步特 性，該裝置進一步包括至少一附加的發光元件。 根據所說明之較佳具體實施例的進一步特性，該至少 一附加的發光元件係為一具有延伸波導的邊射型半導體發 10 200424729 光二極體。 根據所說明之較佳具體實施例的進一步特性，該裝置 進一步包括配置一光譜選擇性濾光鏡，俾便防止具第二頻 率之光線照射該發光元件。 5 根據所說明之較佳具體實施例的進一步特性，該裝置 進一步包括一透鏡，配置在介於發光元件與非線性光學晶 體之間的外部腔室中。 根據本發明之另一觀點，提供一種轉換光線之頻率的 方法，該方法包括：（a)利用一發光元件發射具有一第一頻 10 率的一光線，選定具有一延伸波導的一邊射型半導體發光 二極體的發光元件，致使一延伸波導的基本橫向模態其特 徵在於一低光束發散；（b)使用一光反射器，用於容許光線 通過界定在發光元件與光反射器之間的一外部腔室數次， 俾便提供一回饋用於產生具有第一頻率的一雷射光；以及 15 (c)使用一非線性光學晶體，配置在外部腔室中用以將雷射 光的第一頻率轉換成第二頻率，其中該第二頻率與第一頻 率不同。 根據以下所說明本發明之較佳具體實施例的進一步特 性，該方法進一步包括藉由將延伸波導暴露至一注入電流 20 而發光。 根據所說明之較佳具體實施例的進一步特性，該方法 進一步包括利用一透鏡將一微弱發散光束轉換成一平行光 束。 根據本發明之一附加觀點，提供一種製造用於光線之 11 200424729 頻率轉換的一裝置的方法，該方法包括：（a)提供一發光元 件用於發射具有一第一頻率的一光線，該發光元件係為一 具有一選定之延伸波導的邊射型半導體發光二極體，致使 延伸波導的一基本橫向模態其特徵在於一低光束發散；（b) ίο 提供一光反射器並將該光反射器配置與該發光元件相對， 該光反射器猶構及料因此光線通過界定在發光元件盘 光反射器之間的一外部腔室數次，並提供 具有第一頻率的一雷射光；以及（C)提供、 -回饋用於產生 非線性光學晶 體’其係配置在外部腔室中並經因此當具有第一頻 率的雷射光通過非線性光學晶體數次， 成與其不同的一第二頻率。 頻率經轉換 15 根據以下所說明本發明之較佳具體實施例的進_步特 性，該方法進一步包括提供至少一附加的發光元件。/、 根據所說明之較佳具體實施例的進〜步特〖生上 波導在暴露至一注入電流時，能夠發射光線 根據所說明之較佳具體實施例的進〜步特性，、竖—表 光元件之一帶條長度及注入電流，因此蕤 " 心错由注入電流僅產 生一非同調光線，並且該雷射光係藉結合 ϋ u /主入電流與回饋 而產生。 20 根據所說明之較佳具體實施例的進—步特性，該外部 腔至經δ又什致使大體上在基本橫向模態下產生★射光 根據所說明之較佳具體實施例的進〜步特性，、琴十光 反射器俾便反射頻率與第二頻率不同的光 、，π""疋 J九線，並用以傳輸 具弟二頻率的光線。 12 200424729 根據所說明之較佳具體實施例的進一步特性，該發光 元件係由複數層所構成。 根據所說明之較佳具體實施例的進一步特性，該發光 元件包括一與自一第一側邊的延伸波導相鄰的η-發射器 5 (n-emitter)，以及一與自一第二側邊的延伸波導相鄰的ρ-發 射器（p-emitter)。 根據所說明之較佳具體實施例的進一步特性，該延伸 波導包括一主動區域，其係構成在摻雜一η-雜質的一第一 延伸波導區域與換雜一 ρ-雜質的一第二延伸波導區域之 10 間，該第一及第二延伸波導區域係為光線可透射的。 根據所說明之較佳具體實施例的進一步特性，該主動 區域包括至少一層。 根據所說明之較佳具體實施例的進一步特性，該主動 區域包括一系統，其係由一量子井系統、一量子線系統、 15 一量子點系統以及該等系統之結合所組成之群組中選定。 根據所說明之較佳具體實施例的進一步特性，該η-發 射器之厚度係大於10微米。 根據所說明之較佳具體實施例的進一步特性，該發光 元件之一前刻面係以一抗反射塗層塗佈。 20 根據所說明之較佳具體實施例的進一步特性，該發光 元件之一後刻面係以一高度反射塗層塗佈。 根據所說明之較佳具體實施例的進一步特性，該高度 反射塗層包括複數層。 根據所說明之較佳具體實施例的進一步特性，該高度 13 200424729 反射塗層特徵在於一預定阻帶（stopband)係夠窄，俾便提供 一高反射性的基本橫向模態以及一低反射性的高階橫向模 態。 根據所說明之較佳具體實施例的進一步特性，該光反 5 射器包括複數層。 根據所說明之較佳具體實施例的進一步特性，該光反 射器特徵在於一預定阻帶（stopband)係夠窄，俾便提供一高 反射性的基本橫向模態以及一低反射性的高階橫向模態。 根據所說明之較佳具體實施例的進一步特性該高度反 10 射塗層及光反射器其個別的特徵在於一預定阻帶(stopband) 係夠窄，俾便提供一高反射性的基本橫向模態以及一低反 射性的高階橫向模態。 根據所說明之較佳具體實施例的進一步特性，該非線 性光學晶體的特徵在於一頻率轉換效率，進一步其中該高 15 度反射塗層之阻帶的溫度相依性，係相當於頻率轉換效率 之溫度相依性。 根據所說明之較佳具體實施例的進一步特性，該非線 性光學晶體的特徵在於一頻率轉換效率，進一步其中該光 反射器之阻帶的溫度相依性，係相當於頻率轉換效率之溫 20 度相依性。 根據所說明之較佳具體實施例的進一步特性，該高度 反射塗層之阻帶的溫度相依性，係相當於頻率轉換效率之 溫度相依性。 根據所說明之較佳具體實施例的進一步特性，該方法 14 200424729 進一步包括一具光譜選擇性濾光鏡並將該濾光鏡定位，俾 便防止具第二頻率的光線照射發光元件。 根據所說明之較佳具體實施例的進一步特性，該具光 譜選擇性滤光鏡係構成位在面向該發光元件之一側邊上的 5 非線性光學晶體上。 根據所說明之較佳具體實施例的進一步特性，該延伸 波導包括至少二部分，每一部分具有不同的折射率，致使 該延伸波導的特徵在於一可變化的折射率。 根據所說明之較佳具體實施例的進一步特性，該延伸 10 波導的至少二部分包括具有一中級折射率的一第一部分， 以及具有一高折射率的一第二部分，經設計並建構該第一 及第二部分致使基本的橫向模態係於該第一部分中產生， 洩漏進入該第二部分並在一預定角度下退出通過發光元件 之一前刻面。 15 根據所說明之較佳具體實施例的進一步特性，該延伸 波導的至少一部分包括一光子帶溝晶體(Photonic bandgap crystal) 〇 根據所說明之較佳具體實施例的進一步特性，該光子 帶溝晶體包括一具有一週期調制折射率的結構，於該處結 20 構包括複數層。 根據所說明之較佳具體實施例的進一步特性，該發光 元件包括至少一吸收層，能夠吸收位在該光子帶溝晶體之 一層中的光線。 根據所說明之較佳具體實施例的進一步特性，該發光 15 200424729 元件包括複數之吸收層致使該每一複數之吸收層係位在光 子帶溝晶體之一不同層中。 根據所說明之較佳具體貫施例的進一步特性，該延伸 波導的至少一部分包括一缺陷，與光子帶溝晶體之一第一 5側邊相鄰，選定該缺陷及光子帶溝晶體致使該基本橫向模 態係局部化在該缺陷處，並且所有其他的模態係延伸涵蓋 該光子帶溝晶體。 根據所說明之較佳具體實施例的進一步特性，該缺陷 包括一具有一η側邊及一p側邊的主動區域，當暴露至—注 10入電流時該主動區域能夠發射光線。 根據所說明之較佳具體實施例的進一步特性，選定光 子帶溝晶體及缺陷之總厚度，俾便容許低光束發散。 根據所說明之較佳具體實施例的進一步特性，該發光 元件包括一與光子帶溝晶體之一第二側邊相鄰的〜發射 15器，以及一Ρ·發射器係以缺陷和光子帶溝晶體隔開並與缺 陷相鄰。 根據所說明之較佳具體實施例的進一步特性，該發光 元件包括一具有一可變化折射率的ρ-摻雜層化結構，該 摻雜層化結構係介於ρ-發射器與缺陷之間。 2〇 根據所說明之較佳具體實施例的進一步特性，該 射為係構成在基板之一第一側邊上，該基板係為一瓜-V半 導體。 根據所說明之較佳具體實施例的進一步特性，該班_ ν 半導體係由GaAs、InAs、InP及GaSb所組成之群組中選定。 16 200424729 根據所說明之較佳具體實施例的進一步特性，該主動 區域的特徵在於一能量帶間隙係較基板之能量帶間隙為 窄。 根據所說明之較佳具體實施例的進一步特性，該發光 5 元件包括一 η-接點與基板接觸，以及一p-接點與p-發射器接 觸。 根據所說明之較佳具體實施例的進一步特性，選定可 變化的折射率用以防止基本橫向模態延伸至該η-接點及/或 Ρ-接點。 10 根據所說明之較佳具體實施例的進一步特性，該Ρ-發 射器包括至少一與該延伸波導接觸的Ρ摻雜層，以及至少一 與該Ρ-接點接觸的Ρ+-摻雜層。 根據所說明之較佳具體實施例的進一步特性，該缺陷 進一步包括一配置在主動區域之η-側邊並失合在一第一對 15 附加層之間，供電子所用的第一薄通道阻障層，以及一配 置在主動區域之Ρ-側邊並夾合在一第二對附加層之間，供 孔所用的第二薄通道阻障層。 根據所說明之較佳具體實施例的進一步特性，該第一 薄通道阻障層係由一微弱摻雜η -層及一未摻雜層所組成之 20 群組中選定的材料所構成。 根據所說明之較佳具體實施例的進一步特性，該第二 薄通道阻障層係由一微弱摻雜ρ -層及一未摻雜層所組成之 群組中選定的材料所構成。 根據所說明之較佳具體實施例的進一步特性，該缺陷 17 200424729 進一步包括一厚η-換雜層與遠離主動區域的第一對附加層 的其中之一層連續；以及一厚ρ-摻雜層與遠離主動區域的 第二對附加層連續。 根據所說明之較佳具體實施例的進一步特性，該第一 5 對附加層的至少其中之一層係由一微弱換雜η-層及一未換 雜層所組成之群組中選定的材料所構成。 根據所說明之較佳具體實施例的進一步特性，該第二 對附加層的至少其中之一層係由一微弱摻雜p-層及一未摻 雜層所組成之群組中選定的材料所構成。 10 根據所說明之較佳具體實施例的進一步特性，該方法 進一步包括配置一透鏡並將該透鏡定位在介於發光元件與 非線性光學晶體間的外部腔室中。 根據所說明之較佳具體實施例的進一步特性，設計並 建構該透鏡用以將一微弱發散光束變換成一平行光束。 15 根據所說明之較佳具體實施例的進一步特性，該光反 射器係為一平坦式光反射器，能夠反射該平行光束。 本發明藉由提供一遠超越先前技術，用於頻率轉換的 裝置，克服目前所熟知的概念與形式之該等缺點。 除非另有定義，否則本發明所屬於此所用的所有技術 20 及科學名詞，與熟知此技藝之人士通常所瞭解者具相同的 意義。儘管與於此所說明相似或等效的方法及材料能夠於 本發明之實務或測試中使用，但以下係說明適合的方法及 材料。若有抵觸，則由包括定義的專利說明書主導。此外， 材料、方法及實例僅具說明性並不意欲受到限定。 18 200424729 圖式簡單說明 於此相關於伴隨圖式，僅藉由實例說明本發明。現詳 細具體地相關於該等圖式，所強調的是，所示之細節係經 由實例並僅係為了說明本發明之較佳具體實施例的說明性 5 論述，並為了提供咸信係為本發明之原理及概念性觀點之 最為有用且能夠立即瞭解的說明。就這一點而言，並不試 圖針對本發明之一基本瞭解更為詳細地顯示本發明之結構 細節，相關於圖式所作的說明，熟知此技藝之人士對於實 務上本發明如何具體化為數種形式將為顯而易見的。 10 圖式中： 第la圖係為一先前技術之垂直共振腔面射型雷射 (VCSEL)的概略視圖； 第lb圖係為一先前技術之邊射型雷射的概略視圖； 第2圖係為一先前技術之垂直共振腔面射型雷射 15 (VCSEL)式頻率轉換裝置的概略視圖； 第3圖係為本發明之一用於光線頻率轉換的裝置之概 略視圖； 第4圖係為本發明之一用於頻率轉換的裝置之概略視 圖，包括一抗反射塗層及一高度反射塗層構成在一發光元 20 件的不同刻面上； 第5圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其中發光元件包括一光子帶溝晶體； 第6圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其中一洩漏雷射係用於產生主要光線； 19 200424729 第7圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其包括一用於提供一平行光束的透鏡以及一平坦式光 反射器； 第8圖係為本發明之一用於頻率轉換的裝置之概略視 5 圖，其在發光元件及光反射器上包括附加的多層式塗層； 第9圖係為本發明之轉換光線頻率的一方法的一流程 圖；以及 第10圖係為本發明之製造用於頻率轉換之裝置的一方 法的一流程圖。 10 【實施方式】 較佳實施例之詳細說明 本發明係為能夠用於轉換一雷射頻率的一頻率轉換裝 置及方法。具體地，本發明能夠用於提供一雷射光，其之 頻率位在一寬光譜範圍中。更特定言之，例如，本發明能 15 夠於光儲存應用中使用，其中需要短波長用以藉由減小特 有的特徵尺寸而增加儲存資料的密度，或應用在投影顯示 器，其中綠及藍光雷射係為全彩應用所需。本發明係為一 種製造該裝置的進一步方法。 為了對本發明有較佳的暸解，如第3-8圖中所示，首先 20 參考於第2圖中所示的一傳統式（亦即，先前技術)頻率轉換 裝置的結構及操作。 第2圖係圖示一先前技術之頻率轉換裝置，其係基於一 垂直共振腔面射型雷射(VCSEL)。 因此，該先前技術裝置包括一 VCSEL型結構101，其係 20 200424729 製成為一多層結構’在一基板102上磊晶地成長。VCSEL 型結構101包括一底部分布式布拉格反射鏡(DBR)103,以及 一主動區域106係位在一半導體腔室104中。於此裝置中， VCSEL型結構1〇1並未包括一頂部分布式布拉格反射鏡 5 (DBR)。亦為於業界中所熟知的相似裝置，其中包括一相關 於分布式布拉格反射鏡(DBR)103具有一相對低品質的頂部 分布式布拉格反射鏡(DBR)。 於使用中，該VCSEL型結構101係為藉由一外部雷射光 束109而光激發，並產生一光線其係藉由一外部鏡114反射 10 回至該VCSEL型結構101。選定該VCSEL型結構101及雷射 光束109之功率，致使該VCSEL型結構101並未自由鏡114 所反射光線產生不具一附加功率的雷射光。鏡114及VCSEL 型結構101界定一有效腔室，其包括半導體腔室104及一外 部腔室112。該有效腔室限制一增強的光線回饋，其足以產 15 生一雷射光111。一位在外部腔室112中的NLO晶體113，係 用於將雷射光111之頻率轉換成一具不同頻率（典型地高於 光線111之頻率）的雷射光115，其係自外部鏡114穿過而出。 VCSEL型結構所熟知地具有一寬的主光束之孔徑，典 型地大小為100微米。寬孔徑之優點在於低雷射光束發散， 20 並且在將光線聚焦回至VCSEL型結構而無顯著損失且無困 難性。使用外部鏡容許在腔室内部聚集光功率，係與在使 用傳統式腔外直接二極體激發狀況下的低效率單通道放大 成對比。 然而，當VCSEL型結構之光輸出孔徑係等於熱散逸所 21 200424729 用表面時，由該等結構獲得一高功率密度係極其困難。 再者，VCSEL型結構之光激發需求顯著地降低裝置的 總轉換效率，其已受VCSEL之低功率密度限制。熟知此技 藝之人士應察知的是，由於頂部接觸層之高阻力，所以 5 VCSEL無法藉由注入電流均勻地激發。因此，於上述及相 似的先前技術裝置中，因使用光激發之VCSEL而損及該轉 換效率。 上述限制的一解決之道在於，以邊射型半導體雷射（見 上述先前技術部分中的第lb圖）取代該VCSEL。邊射型雷射 10 超越VCSEL的優點有兩部分：⑴邊射型雷射的實體尺寸係 足以有效地散熱，有助於一高功率密度；以及(ii)能夠使用 一直接電激發而產生邊射型雷射，係與實務上僅能使用光 激發的VCSEL成對比。 然而，目前所熟知的邊射塑雷射具有一特別窄的波 15導，典型地係位在次微米範圍中。由於波導的窄化，所以 難以將藉由鏡反射回波導的光線聚焦而無顯著的功率損 失。此外，邊射型雷射的特徵在於一高光束發散，妨礙雷 射光相關於NLO晶體之最佳結晶方向的精確定向。 藉由提供一種具有一改良的邊射型雷射’於此亦視為 20 一邊射型半導體發光二極體，的頻率轉換裝置，本發明成 功地提供一針對上述問題的解決方案。 因此，根據本發明之一觀點，提供一用於光線之頻率 轉換的裝置，於此大體上視為裝置10 ° 在詳細說明本發明之至少一具體實施例之前’應暸解 22 200424729 的是’本發明並不限定應用在以下所說明或是於圖式中圖 示的結構細節及元件配置上。本發明可為其他的具體實施 例，或以不同的方式實踐或完成。同時，應瞭解的是，於 此所用的措辭及術語係針對說明之目的，不應視為具限制 5 性0 現再次參考該等圖式，第3圖係為裝置1〇之概略圖式， 其包括舍光元件201用於發射一具有一第一頻率的光 線。發光元件201係為一具有一延伸波導2〇4的邊射型半導 體發光二極體，經選定致使波導204之一基本橫向模態的特 10徵在於一低光束發散。裝置1〇進一步包括一光反射器214及 一NLO晶體213，配置在界定於發光元件與光反射器之間的 一外部腔室212中。NLO晶體可為任一熟知的NLO晶體，其 之特徵在於預定的頻率轉換效率，諸如，但不限定在銳酸 鉀(KNb03)或鈮酸鋰(LiNb03)。 15 根據本發明之一較佳具體實施例，當暴露至一注入電 流時，例如使用一順向偏壓218，波導204能夠發射光線通 過一前刻面210。較佳地，選定發光元件2〇1之帶條長度及 注入電流，因此注入電流並未提供雷射發光所用的最小狀 況，而產生一非同調主光線。 2〇 外部腔室212與波導204構成一界定在光反射器214與 波導204之一後刻面269之間的有效腔室。在裝置10之操作 模態下，此有效腔室對主發射光線提供一附加回饋，因而 產生一雷射光211。 根據本發明之一較佳具體實施例，藉由一足夠窄之阻 23 200424729 帶光反射器214之一決定部分(judici〇us secti〇n)，提供來自 光反射器214之雷射光211的基本橫向模態的一高反射性， 如之後進一步詳細地相關於第8圖，該部分較佳地係構成為 夕層結構。：知此技藝之人士應察知的是，光反射器2工4 5之一預定的窄阻帶亦用於藉由提供其之高階橫向模態之一 低反射性，濾除雷射光2Π之非所需模態。 因此，雷射光211通過NLO晶體213複數次，將雷射光 211轉換成具有一與第一頻率不同之第二頻率的雷射光 215。較佳地，選定光反射器214，俾便反射具有第二頻率 10外之一頻率的光線(例如，光線211)，並傳輸具有第二頻率 的光線（光線215)。此外，為了達到裝置1〇之最佳轉換效率， 光反射器214之阻帶較佳地具有如NL〇晶體213之頻率轉換 效率的相同（或相似的）溫度相依性。因此，視NL〇晶體213 之型式、定向、幾何形狀及尺寸而定，裝置1〇提供一高品 15質雷射光，其能夠具有一實質低波長，如之後進一步說明。 在提供裝置10之一進一步詳細說明之前，如上文中所 描述並根據本發明，將注意力放在所提供的優點上。 因此，本發明之較佳具體實施例的一特別優點，係為 發光元件201之設計，因此延伸波導2〇4提供一單模態雷射 20光211。使用一延伸波導典型地導致產生複數之光學模態的 雷射光。因而，基本光學模態沿著波導之方向傳播並顯示 一窄遠場圖（far-field diagram)，其係位在與發光元件2〇1之 前刻面210垂直的一方向上的中心處。高階橫向光學模態之 傳播可說明為，相關於此方向在一些角度下發生。 24 200424729 典型地，高階模態的遠場圖形係顯著地較基本模態之 运％圖形為見，並且通常包含侧波瓣（side i〇bes)。當藉由 光反射為214反射回至前刻面21 〇時，位在一高階光學模態 下的光線係經部分折射離開該腔室，與光反射器214之形式 5最佳化的基本模態之光線相對。因此，該等折射損失對於 咼階模態而言係為顯著的，並且對於基本模態而言係微不 足道地小。易言之，光反射器214所提供的回饋對於基本模 態而言係為強烈的，並且對於高階模態而言係為微弱的。 如此容許在注入電流下實現該等狀況，雷射帶之長度、外 10部鏡之形狀及位置致使雷射作用僅在基本橫向模態下發 生。 熟知此技藝之人士應察知的是，以上所述係為一般的 優點，與所使用的發光元件數目無關。更特定言之，根據 本發明之一較佳具體實施例，可使用一個以上的發光元 15 件，其中藉由附加的發光元件所產生的光線能夠經由一特 別的光學系統而受引導至NLO晶體213上。因此，倘若與發 光元件201相似地製造並操作至少其中之一發光元件，則能 夠為一和頻產生或為一差頻產生或是任何其他的頻率結 合0 20 根據本發明之一較佳具體實施例，發光元件201係成長 在一基板202上，其較佳地由任一瓜-ν半導體材料或是ΠΙ-V半導體合金所構成，例如，砰化銦(inAs)、填化銦(InP)、 或銻化鎵(GaSb)、或為其他合金。更佳的基板202係以砷化 鎵(GaAs)製成。 25 200424729 該裝置10之一特徵在於該延伸波導204，如所提及，提 供一光線其中基本橫向模態具有一低光束發散。根據本發 明之較佳具體貫施例，波導204係構成在一n_發射器203 兵發射為220之間，其中該卜發射器203較佳地係直接成 5長在基板202上，並係自一側邊與波導204相鄰，同時严發 射器係自另一侧邊與波導2〇4相鄰。 延伸波導204較佳地包括一主動區域2〇6，其係構成在 以一η-雜質摻雜的一第一波導區域2〇5，與以一雜質摻雜 的一第二波導區域2〇7之間。該第一波導區域2〇5及第二波 10導區域207二者係為光可透射的。 該第一波導區域205及第二波導區域207較佳地為與基 板202晶格匹配（iattice-matched)或幾乎晶格匹配的該等材 料所構成的層或是多重層結構。 導入該第一波導區域205中的雜質係為施體雜質（donor 15 lmpuntles)，諸如，但非限定在硫(S)、硒（Se)及碲(Te)。可 交替地’該第一波導區域205可以兩性雜質摻雜，諸如，但 非限定在石夕（Si)、鍺(Ge)及錫（Sn)，可在該等技術狀況下導 入，其主要地與陽離子次晶格結合，因此使用作為施體雜 貝。因此’該第一波導區域205，例如，可為藉由分子束蠢 20晶並摻雜濃度約為2 X 1017 cm-3的矽（Si)雜質而成長的砷化 鎵(GaAs)或砷鋁化鎵(GaAlAs)層。 於此所使用的用語“約為，，係為士50%。 可導入第二波導區域207的雜質係為受體（acceptor)雜 質’諸如，但非限定在鈹(Be)、鎂(Mg)、辞(Zn)、鎘(Cd)、 26 200424729 鉛(Pb)及錳(Μη)。可交替地，第二波導區域2〇7可以兩性雜 質摻雜，諸如，但非限定在矽（Si)、鍺(Ge)及錫（Sn)，可在 該等技術狀況下導入，其主要地與陰離子次晶格結合並使 用作為受體雜質。因此，該第二波導區域2〇7，例如，可為 5藉由分子束磊晶並摻雜濃度約為2 X 1〇17 cm·3的鈹(Be)雜質 而成長的砷化鎵(GaAs)或砷鋁化鎵(GaAlAs)層。 主動區域206較佳地係藉由任一具有能量帶間隙的插 入所構成，其之能量帶間隙係窄於基板202之能量帶間隙。 根據本發明之一較佳具體實施例，該主動區域2〇6，例如， 1〇可為一量子井、量子線、量子點或任何該等結合之系統。 该主動區域206可構成為一單層系統或是一多層系統。於較 佳具體實施例中，該基板202係以砷化鎵(GaAs)製成，主動 區域206，例如，可為、Ιηι·χ(}αχΑδ、InxGai x^As、 hxGahAsHNy或相似材料之插入的系統，其中乂及^係標明 15 —合金成分。 曰〜發射器203較佳地係以與基板2〇2晶格匹配或是幾乎 曰曰格匹配的材料製成，例如，合金材料GahALAs。此外， η·發射器203較佳地係為所產生光線可穿透的並摻雜施體 20 雜質，如同先前進-步詳述，與該第一波導區域205之捧: 作業相似。 I根據本發明之一較佳具體實施例，ρ_發射器220包括至 J —Ρ-摻雜層208以及至少一ρ+摻雜層2〇9，其中ρ_摻雜層 2⑽係配置在波導204與Ρ+摻雜層之間。ρ·摻雜層細與 t雜層2〇9|父佳地係為光可透射的，並係以基板搬晶格匹 27 200424729 配或是幾乎晶格匹配的一材料製成。層2〇8及2〇9係摻雜受 體雜質，與第二波導區域207之摻雜作業相似。層2〇8與2〇9 之間在摻雜程度上有所差異。較佳地，然而第二波導區域 207及p-摻雜層208之摻雜程度係為相似的，〆摻雜層2〇9之 5摻雜程度係較高的。例如，於具體實施例中，第二波導區 域207的摻雜程度係約為2χ i〇i7cm-3，p+摻雜層2〇9可為一 藉由分子束磊晶所成長的GaAlAs層，並以一濃度約為2 χ 1〇19 cm·3的Be雜質摻雜。 元件201之一較佳厚度係為1〇微米或更高，較佳的帶寬 1〇係約自7微米至約10微米或更高，以及元件201之一較佳長 度係約為100微米或更高。 如所提及，發光元件201經設計及建構，因此波導2〇4 k供一單杈態雷射光211。例如，如此能夠藉由選定&發射 态203及p-摻雜層2〇8之折射率低於波導2〇4之折射率。該形 15式確保雷射輻射之基本橫向模態係受限在波導204的範圍 内，並係在η-發射器2〇3及]> 摻雜層2〇8中衰變（decays)。 順向偏壓218較佳地係經由一仏接點216，與基板2〇2接 觸，而與發光元件2〇1連接，以及一卜接點217其係與p-發射 器220(或p+摻雜層2〇9)接觸。接點216及217係可製成為任一 20所熟知的結構，諸如，但不限定在多層金屬結構。例如， n一接點216可構成為一 Ni-Au_Ge之三層結構，以及p-接點217 可構成為一Ti-Pt-Au之三層結構。 根據本發明之一較佳具體實施例，裝置10進一步包括 配置一具光譜選擇性濾光鏡260，俾便防止光線215照射發 28 200424729 光元件201。於一具體實施例中，濾光鏡260可構成在NLO 晶體213上，與發光元件201相對。於此具體實施例中，例 如，濾光鏡260可由一介電沉積物構成，諸如，但不限定在 Si02、MgF2、或ZnS。 5 相關於第4圖，根據本發明之一較佳具體實施例，發光 元件201之前刻面210及後刻面269,分別地以一抗反射塗層 320及一高度反射塗層319塗佈。 該高度反射塗層319係用於將經由該後刻面269的損失 降至最低。如此能夠，例如，藉由構成一在反射性上具有 10 一阻帶的塗層而達成。該塗層319之阻帶能夠設計得夠窄， 俾便一南反射性的基本橫向模態以及一低反射性的高階橫 向模態。根據本發明之一較佳具體實施例，塗層319係以一 多層介電結構所構成，其經設計用以提供在一窄頻譜區域 中的高反射性。如於本具體實施例中之後進一步的詳細說 15明（見第8圖），對於基本橫向光學模態而言，反射性越高且 損失越低，同時對於高階模態而言，損失將顯著地較高。 因此，此具體實施例容許一附加選定的模態，並有助於獲 得單模態雷射作用。 如上述進一步的詳細說明，抗反射塗層32〇確保僅以附 口饋’並僅針對基本橫向光學模態發生雷射作用。 根據本發明之一較佳具體實施例，塗層及之阻 π具有與NLO晶體213之頻率轉換效率相同（或相似）的溫度 相依性。該每一塗層319及320較佳地包括以業界所熟知的 ^適合材料所構成的複數層，例如，該材料為介電沉積 29 200424729 物，諸如，但不限定在Si〇2、MgF2、或zns。 現茶考第5圖’其係為—較佳具體實施例之裝置的一 概略圖式，其中係使用光子帶隙晶體雷射之概念。為更適 當地識別本發明之目前的較佳具體實施例，於之後將進一 5步詳加說明’於第5圖中分別地以代表符號401及440代表私 光元件及波導。 '久 因此，於此具體實施例中，延伸波導44〇之至少一部分 包括一光子帶隙晶體(PBC)43〇2n週期431。光子帶隙晶體 (PBC)430之每-週期431，較佳地係由一為低折射率以及一 10為高折射率的二η-摻雜層所構成。 根據本發明之一較佳具體實施例，發光元件4〇1包括一 缺fe432，其係配置在光子帶隙晶體（pBC)43〇與摻雜層 208之間。缺陷432較佳地包括一具有_η_側邊433及一p-側 邊435的主動區域434，當暴露至注入電流時，例如使用偏 15壓218，用於發射光線。如之後進一步說明，使用用於光線 初步產生的光子帶隙晶體(PBC)430，提供具一極寬波導的 一高效率低臨限電流密度輻射源。 光子帶隙晶體（PBC)雷射之概念，首先係由 Ledentsov，N.N.及Shchukin，V.A.於文章中採用，文章標題為 20 “使用GaAs量子點的長波長雷射（Long Wavelength LasersLetters, 18, No. 13: 1062-1064, 1993 and U.S. Patent No. 5,912,910, 6, 229, 828, And 6, 304, 585]. however, The additional lens for converting the laser output into a 20-level beam is a well-known method for making the beam diameter significantly wider and thus reducing the power density. It is a main product for effective wavelength conversion. Since these interfering 'edge-emitting diode lasers are not used commercially for direct frequency conversion, It is usually used as an excitation source for solid-state lasers. U.S. Patent No. 6, 097, Chromium No. 540 discloses another system using semiconductor diode 9 200424729 laser for direct frequency conversion. In this system, With the light beams produced by several types of lasers, By a lens and mirror system combined into a single light beam, It is guided on a surface of a non-linear optical (NLO) crystal. However, This solution does not provide significant advantages over the above technologies, The proposed system is extremely complex and expensive. Contains a lot of lasers, Only one extra-cavity conversion is provided and is not wavelength stable. therefore, For a device without the above-mentioned frequency conversion, Having a widely recognized demand5 is beneficial to Nandu. [Summary of the Invention] 10 Summary of the Invention According to an aspect of the present invention, Providing a device for frequency conversion of light, The device includes: (A)-the light emitting element is used to emit a light having a first frequency, The light-emitting element is an edge-emitting semiconductor light-emitting diode having a selected extended waveguide. Causes a substantially transverse 15 mode of the extended waveguide which is characterized by a low beam divergence; (B)-light reflector, It is structured and designed so that light passes through an external cavity defined between the light emitting element and the light reflector several times, And providing a feedback for generating a laser light having a first frequency; And (c) a nonlinear optical crystal, Placed in an external chamber and selected, Therefore, when the laser light having the first frequency passes through the non-linear optical crystal body 20 times, The first frequency is converted into a second frequency different from the first frequency. According to further features of the preferred embodiments of the present invention described below, The device further includes at least one additional light emitting element. According to the further characteristics of the illustrated preferred embodiment, The at least one additional light-emitting element is an edge-emitting semiconductor light emitting diode with an extended waveguide. According to the further characteristics of the illustrated preferred embodiment, The device further includes a spectrally selective filter, This prevents the light having the second frequency from irradiating the light-emitting element. 5 According to the further characteristics of the illustrated preferred embodiment, The device further includes a lens, Arranged in an external cavity between the light emitting element and the non-linear optical crystal. According to another aspect of the invention, Provide a way to convert the frequency of light, The method includes: (A) using a light-emitting element to emit a light having a first frequency 10, Selecting a light-emitting element having a side-emitting semiconductor light-emitting diode with an extended waveguide, Causing the fundamental transverse mode of an extended waveguide to be characterized by a low beam divergence; (B) using a light reflector, For allowing light to pass through an external cavity defined between the light emitting element and the light reflector several times, 俾 providing a feedback for generating a laser light having a first frequency; And 15 (c) using a non-linear optical crystal, Arranged in an external cavity to convert a first frequency of the laser light into a second frequency, The second frequency is different from the first frequency. According to further features of the preferred embodiments of the present invention described below, The method further includes emitting light by exposing the extended waveguide to an injected current 20. According to the further characteristics of the illustrated preferred embodiment, The method further includes using a lens to convert a weakly divergent light beam into a parallel light beam. According to an additional aspect of the invention, Provided is a method for manufacturing a device for frequency conversion of 11 200424729 light, The method includes: (A) providing a light emitting element for emitting a light having a first frequency, The light-emitting element is an edge-emitting semiconductor light-emitting diode having a selected extended waveguide. Causing a fundamental transverse mode of the extended waveguide characterized by a low beam divergence; (B) providing a light reflector and positioning the light reflector opposite the light emitting element, The light reflector is structured so that light passes through an external cavity defined between the light reflectors of the light emitting element disk several times, And providing a laser light having a first frequency; And (C) provide, -Feedback is used to generate a non-linear optical crystal ’which is arranged in an external cavity and thus when laser light having a first frequency passes through the non-linear optical crystal several times, It is different from a second frequency. The frequency is converted according to the further characteristics of the preferred embodiment of the present invention described below, The method further includes providing at least one additional light emitting element. /, According to the description of the preferred embodiment, when the waveguide is exposed to an injected current, Able to emit light according to the further characteristics of the illustrated preferred embodiment, , Vertical—surface strip length and injection current of one of the optical components, So 蕤 " Heart misalignment produces only a non-homogeneous light from the injected current, And the laser light is generated by combining ϋ u / main input current and feedback. 20 According to the further characteristics of the illustrated preferred embodiment, The external cavity is caused by δ to produce substantially in the basic transverse mode. According to the further characteristics of the illustrated preferred embodiment, , Qin Shiguang The reflector reflects light with a frequency different from the second frequency, , π " " 疋 J nine lines, And used to transmit light with the second frequency. 12 200424729 According to further features of the illustrated preferred embodiment, This light-emitting element is composed of a plurality of layers. According to the further characteristics of the illustrated preferred embodiment, The light-emitting element includes an n-emitter 5 (n-emitter) adjacent to an extended waveguide from a first side, And a p-emitter adjacent to the extended waveguide from a second side. According to the further characteristics of the illustrated preferred embodiment, The extended waveguide includes an active region, It is formed between a first extended waveguide region doped with an η- impurity and a second extended waveguide region doped with a ρ- impurity, The first and second extended waveguide regions are light transmissive. According to the further characteristics of the illustrated preferred embodiment, The active area includes at least one layer. According to the further characteristics of the illustrated preferred embodiment, The active area includes a system, It consists of a quantum well system, A quantum wire system, 15 A quantum dot system and a combination of these systems are selected from the group. According to the further characteristics of the illustrated preferred embodiment, The thickness of the? -Transmitter is greater than 10 m. According to the further characteristics of the illustrated preferred embodiment, One front facet of the light-emitting element is coated with an anti-reflective coating. 20 According to further features of the illustrated preferred embodiment, One rear facet of the light-emitting element is coated with a highly reflective coating. According to the further characteristics of the illustrated preferred embodiment, The highly reflective coating includes a plurality of layers. According to the further characteristics of the illustrated preferred embodiment, The height 13 200424729 is characterized in that a predetermined stopband is narrow enough, It provides a basic lateral mode with high reflectivity and a high-order lateral mode with low reflectivity. According to the further characteristics of the illustrated preferred embodiment, The light reflector includes a plurality of layers. According to the further characteristics of the illustrated preferred embodiment, The optical reflector is characterized in that a predetermined stop band is narrow enough, It provides a basic lateral mode with high reflectivity and a high-order lateral mode with low reflectivity. According to further characteristics of the illustrated preferred embodiment, the highly reflective coating and light reflector are individually characterized by a predetermined stopband being narrow enough, It provides a highly reflective basic transverse mode and a low-reflection high-order transverse mode. According to the further characteristics of the illustrated preferred embodiment, The nonlinear optical crystal is characterized by a frequency conversion efficiency, Further, the temperature dependence of the stop band of the highly 15 degree reflective coating, This is the temperature dependence of the frequency conversion efficiency. According to the further characteristics of the illustrated preferred embodiment, The nonlinear optical crystal is characterized by a frequency conversion efficiency, Further, the temperature dependence of the stopband of the light reflector is It is equivalent to 20 degrees of temperature conversion efficiency. According to the further characteristics of the illustrated preferred embodiment, The temperature dependence of the stopband of this highly reflective coating, This is the temperature dependence of the frequency conversion efficiency. According to the further characteristics of the illustrated preferred embodiment, The method 14 200424729 further includes a spectrally selective filter and positioning the filter, 俾 Prevent light with a second frequency from illuminating the light-emitting element. According to the further characteristics of the illustrated preferred embodiment, The spectrally selective filter is composed of a 5 nonlinear optical crystal located on one side facing the light emitting element. According to the further characteristics of the illustrated preferred embodiment, The extended waveguide includes at least two parts, Each part has a different refractive index, This extension waveguide is characterized by a variable refractive index. According to the further characteristics of the illustrated preferred embodiment, At least two portions of the extended 10 waveguide include a first portion having a medium refractive index, And a second part with a high refractive index, The first and second parts are designed and constructed such that a basic transverse modal is generated in the first part, The leak enters this second part and exits through a front facet of one of the light emitting elements at a predetermined angle. 15 According to further features of the illustrated preferred embodiment, At least a part of the extended waveguide includes a photonic bandgap crystal. According to further characteristics of the preferred embodiment described, The photonic band groove crystal includes a structure having a periodic modulation index, The structure here includes a plurality of layers. According to the further characteristics of the illustrated preferred embodiment, The light-emitting element includes at least one absorbing layer, Able to absorb light located in one layer of the photonic band groove crystal. According to the further characteristics of the illustrated preferred embodiment, The luminescent 15 200424729 element includes a plurality of absorption layers such that each of the plurality of absorption layers is located in a different layer of the photonic band groove crystal. According to the further characteristics of the illustrated preferred embodiment, At least a portion of the extended waveguide includes a defect, Adjacent to the first 5 side of one of the photonic band groove crystals, The defect and the photonic band groove crystal are selected to cause the basic transverse mode system to be localized at the defect. And all other modalities extend to cover the photonic band groove crystal. According to the further characteristics of the illustrated preferred embodiment, The defect includes an active region having an n-side and a p-side, This active area is capable of emitting light when exposed to a note-in current. According to the further characteristics of the illustrated preferred embodiment, The total thickness of the selected photonic band groove crystals and defects, It allows low beam divergence. According to the further characteristics of the illustrated preferred embodiment, The light emitting element includes a ~ 15 emitter adjacent to a second side of one of the photonic band groove crystals, And a P · emitter is separated by a defect and a photonic band trench crystal and is adjacent to the defect. According to the further characteristics of the illustrated preferred embodiment, The light-emitting element includes a p-doped layered structure having a variable refractive index. The doped layered structure is between the p-emitter and the defect. 2〇 According to the further characteristics of the illustrated preferred embodiment, The shot is formed on a first side of a substrate, The substrate is a melon-V semiconductor. According to the further characteristics of the illustrated preferred embodiment, The class _ ν The semiconductor system consists of GaAs, InAs, Selected from the group consisting of InP and GaSb. 16 200424729 According to further features of the illustrated preferred embodiment, The active region is characterized in that an energy band gap is narrower than the energy band gap of the substrate. According to the further characteristics of the illustrated preferred embodiment, The light-emitting element includes an η-contact in contact with the substrate. And a p-contact is in contact with the p-transmitter. According to the further characteristics of the illustrated preferred embodiment, A variable refractive index is selected to prevent the basic transverse mode from extending to the n-contact and / or the p-contact. 10 According to further features of the illustrated preferred embodiment, The P-transmitter includes at least one P-doped layer in contact with the extended waveguide, And at least one P + -doped layer in contact with the P- contact. According to the further characteristics of the illustrated preferred embodiment, The defect further includes a η-side disposed on the active area and misaligned between a first pair of 15 additional layers, A first thin channel barrier layer for electrons, And a P-side disposed on the active area and sandwiched between a second pair of additional layers, A second thin channel barrier layer for holes. According to the further characteristics of the illustrated preferred embodiment, The first thin channel barrier layer is composed of a selected material from a group of 20 consisting of a weakly doped n-layer and an undoped layer. According to the further characteristics of the illustrated preferred embodiment, The second thin channel barrier layer is composed of a selected material from a group consisting of a weakly doped p-layer and an undoped layer. According to the further characteristics of the illustrated preferred embodiment, The defect 17 200424729 further includes a thick η-doped layer continuous with one of the first pair of additional layers away from the active area; And a thick p-doped layer is continuous with a second pair of additional layers away from the active region. According to the further characteristics of the illustrated preferred embodiment, At least one of the first 5 pairs of additional layers is composed of a selected material from a group consisting of a weakly doped η-layer and an undoped layer. According to the further characteristics of the illustrated preferred embodiment, At least one of the second pair of additional layers is composed of a selected material from the group consisting of a weakly doped p-layer and an undoped layer. 10 According to further features of the illustrated preferred embodiment, The method further includes arranging a lens and positioning the lens in an external cavity between the light emitting element and the non-linear optical crystal. According to the further characteristics of the illustrated preferred embodiment, The lens is designed and constructed to transform a weakly divergent beam into a parallel beam. 15 According to further features of the illustrated preferred embodiment, The light reflector is a flat light reflector. Able to reflect this parallel beam. The present invention provides a method that far exceeds the prior art, Device for frequency conversion, Overcoming these shortcomings of concepts and forms that are currently well known. Unless otherwise defined, Otherwise, the present invention belongs to all the technologies and scientific terms used here, 20 It has the same meaning as those who are familiar with this technique usually know it. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, However, the following describes suitable methods and materials. If there is a conflict, It is dominated by patent specifications that include definitions. In addition, material, The methods and examples are illustrative only and are not intended to be limiting. 18 200424729 Brief description of the diagram This is related to the accompanying diagram, The invention is illustrated by way of example only. Now specifically related to these drawings, What is emphasized is that The details shown are by way of example and are merely illustrative of 5 preferred embodiments of the present invention, In order to provide the most useful and immediately understandable explanation of the principles and conceptual views of the present invention. In this regard, Without attempting to show the structural details of the present invention in more detail for a basic understanding of the present invention, Regarding the description made by the schema, It will be apparent to those skilled in the art how the present invention may be embodied in several forms in practice. 10 In the diagram: Figure la is a schematic view of a prior art vertical cavity surface-emitting laser (VCSEL); Figure lb is a schematic view of a prior art edge-emitting laser; Figure 2 is a schematic view of a prior art vertical cavity surface-emitting laser 15 (VCSEL) frequency conversion device; FIG. 3 is a schematic view of a device for light frequency conversion according to the present invention; FIG. FIG. 4 is a schematic view of a device for frequency conversion according to the present invention. Comprising an anti-reflective coating and a highly reflective coating formed on different facets of 20 luminescent elements; FIG. 5 is a schematic view of an apparatus for frequency conversion according to the present invention. Wherein the light emitting element includes a photonic band groove crystal; FIG. 6 is a schematic view of an apparatus for frequency conversion according to the present invention. One of the leaking lasers is used to generate the main light; 19 200424729 Figure 7 is a schematic view of a device for frequency conversion according to the present invention. It includes a lens for providing a parallel light beam and a flat light reflector; Fig. 8 is a schematic view of a device for frequency conversion according to the present invention. It includes an additional multilayer coating on the light emitting element and the light reflector; FIG. 9 is a flowchart of a method for converting light frequency according to the present invention; FIG. And FIG. 10 is a flowchart of a method of manufacturing a device for frequency conversion according to the present invention. [Embodiment] Detailed description of the preferred embodiment The present invention is a frequency conversion device and method that can be used to convert a laser frequency. specifically, The present invention can be used to provide a laser light, Its frequency lies in a wide spectral range. More specifically, E.g, The invention can be used in optical storage applications. Among them, short wavelengths are needed to increase the density of stored data by reducing unique feature sizes, Or applied to a projection display, The green and blue lasers are required for full-color applications. The present invention is a further method for manufacturing the device. In order to better understand the present invention, As shown in Figure 3-8, First, 20 refers to a conventional formula shown in Figure 2 (that is, Prior Art) Structure and operation of a frequency conversion device. FIG. 2 illustrates a prior art frequency conversion device. It is based on a Vertical Cavity Surface Emitting Laser (VCSEL). therefore, The prior art device includes a VCSEL-type structure 101, The system 20 200424729 is made into a multi-layer structure 'and is epitaxially grown on a substrate 102. The VCSEL-type structure 101 includes a bottom distributed Bragg reflector (DBR) 103, And an active region 106 is located in a semiconductor chamber 104. On this device, The VCSEL-type structure 101 does not include a top distributed Bragg reflector 5 (DBR). Is also a similar device known in the industry, This includes a distributed Bragg mirror (DBR) 103 with a relatively low quality top distributed Bragg mirror (DBR). In use, The VCSEL type structure 101 is optically excited by an external laser light beam 109. A light is generated which is reflected back to the VCSEL structure 101 by an external mirror 114. The power of the VCSEL structure 101 and the laser beam 109 is selected, As a result, the VCSEL-type structure 101 does not generate laser light without additional power from the light reflected by the free mirror 114. The mirror 114 and the VCSEL-type structure 101 define an effective cavity, It includes a semiconductor chamber 104 and an external chamber 112. The effective cavity limits an enhanced light feedback, It is enough to produce 15 laser light 111. A NLO crystal 113 in the outer chamber 112, Is used to convert the frequency of laser light 111 into a laser light 115 with a different frequency (typically higher than the frequency of light 111), It passes through the external mirror 114. The VCSEL type structure is well known to have a wide main beam aperture, A typical ground size is 100 microns. The advantage of a wide aperture is the low divergence of the laser beam, 20 And focus the light back to the VCSEL-type structure without significant loss and difficulty. The use of external mirrors allows the optical power to be concentrated inside the chamber, This is in contrast to the low-efficiency single-channel amplification when using conventional extracavity direct diode excitation. however, When the light output aperture of the VCSEL type structure is equal to the surface used for heat dissipation, 21 200424729, Obtaining a high power density from these structures is extremely difficult. Furthermore, The light excitation requirements of the VCSEL-type structure significantly reduce the overall conversion efficiency of the device, It has been limited by the low power density of VCSELs. Those familiar with this technology should be aware that, Due to the high resistance of the top contact layer, Therefore, the 5 VCSEL cannot be uniformly excited by the injection current. therefore, In the above and similar prior art devices, This conversion efficiency is compromised by the use of a photo-excited VCSEL. One solution to the above limitation is that Replace the VCSEL with an edge-emitting semiconductor laser (see Figure lb in the previous section above). Edge shot laser 10 has two advantages over VCSEL: The physical size of the side-fire laser is sufficient to effectively dissipate heat. Contribute to a high power density; And (ii) the use of a direct electrical excitation to generate an edge-emitting laser, This is in contrast to a VCSEL that can only be practically excited with light. however, Currently known edge-emitting plastic lasers have a particularly narrow wave 15 guide, Typically located in the sub-micron range. Due to the narrowing of the waveguide, It is therefore difficult to focus the light reflected back to the waveguide by the mirror without significant power loss. In addition, Edge-fired lasers are characterized by a high beam divergence, Obstructs the precise orientation of the laser light relative to the optimal crystallographic direction of the NLO crystal. By providing an improved edge-emitting laser ', which is also considered here as a 20-side-emitting semiconductor light emitting diode, Frequency conversion device, The present invention successfully provides a solution to the above problems. therefore, According to an aspect of the invention, Providing a device for frequency conversion of light, Here, it is generally regarded as a device 10 °. Before describing at least one specific embodiment of the present invention in detail, it should be understood that 22 200424729 is the present invention is not limited to the structural details described below or illustrated in the drawings And component configuration. The present invention may be other specific embodiments. Or practice or accomplish it differently. Simultaneously, It should be understood that The wording and terminology used herein is for the purpose of illustration, Should not be considered to be restrictive FIG. 3 is a schematic diagram of the device 10, It includes a light-cutting element 201 for emitting a light having a first frequency. The light-emitting element 201 is an edge-emitting semiconductor light-emitting diode having an extended waveguide 204, A characteristic selected to cause one of the fundamental transverse modes of the waveguide 204 is a low beam divergence. The device 10 further includes a light reflector 214 and an NLO crystal 213. Arranged in an external cavity 212 defined between the light emitting element and the light reflector. The NLO crystal can be any well-known NLO crystal, It is characterized by a predetermined frequency conversion efficiency, Such as However, it is not limited to potassium sharp acid (KNb03) or lithium niobate (LiNb03). 15 According to a preferred embodiment of the present invention, When exposed to an injected current, For example, using a forward bias 218, The waveguide 204 is capable of emitting light through a front facet 210. Preferably, Select the strip length and the injected current of the light emitting element 201 Therefore, the injected current does not provide the minimum conditions for laser emission, A non-homogeneous principal ray is generated. 20 The outer cavity 212 and the waveguide 204 form an effective cavity defined between the light reflector 214 and one of the rear facets 269 of the waveguide 204. In the operating mode of the device 10, This effective cavity provides an additional feedback to the main emitted light, As a result, a laser light 211 is generated. According to a preferred embodiment of the present invention, With a narrow enough resistance 23 200424729 with one of the light reflectors 214 determining part (judici〇us secti〇n), Provides a high reflectivity of the fundamental transverse mode of the laser light 211 from the light reflector 214, As related to Figure 8 in more detail later, This part is preferably constituted as an evening structure. : Those who know this skill should be aware that, One of the predetermined narrow stop bands of the light reflector 2 and 4 5 is also used by providing one of its higher order lateral modes with low reflectivity, Filter out unwanted modes of laser light 2Π. therefore, The laser light 211 passes through the NLO crystal 213 multiple times, The laser light 211 is converted into a laser light 215 having a second frequency different from the first frequency. Preferably, Selected light reflector 214, 反射 reflects light with a frequency other than 10 (for example, Ray 211), And transmits a light having a second frequency (ray 215). In addition, In order to achieve the best conversion efficiency of the device 10, The stop band of the light reflector 214 preferably has the same (or similar) temperature dependency as the frequency conversion efficiency of the NLO crystal 213. therefore, Depending on the type of NL〇 crystal 213, Orientation, Depending on geometry and size, Device 10 provides a high-quality 15-quality laser light, It can have a substantially low wavelength, As explained further below. Before providing one of the devices 10 in further detail, As described above and in accordance with the present invention, Focus on the benefits provided. therefore, A special advantage of a preferred embodiment of the invention, Is the design of the light-emitting element 201, Therefore, the extended waveguide 204 provides a single-mode laser 20 light 211. The use of an extended waveguide typically results in laser light generating a plurality of optical modalities. thus, The basic optical mode propagates along the direction of the waveguide and displays a narrow far-field diagram, It is located at the center in a direction perpendicular to the front facet 210 of the light emitting element 201. The propagation of higher-order lateral optical modes can be explained as Related to this direction occurs at some angles. 24 200424729 Typically, The far-field pattern of the higher-order mode is significantly better than that of the basic mode. And usually contains side lobes. When reflected back to the front facet 21 by 214, The light in a higher-order optical mode is partially refracted away from the chamber, In contrast to the light of the optimized basic mode of the form 5 of the light reflector 214. therefore, These refraction losses are significant for first-order modes, And it is insignificantly small for the basic modal. In other words, The feedback provided by the light reflector 214 is strong for the basic mode, And it is weak for higher order modes. This allows these conditions to be achieved under injected current, The length of the laser strip, The shape and position of the outer 10 mirrors cause the laser effect to occur only in the basic transverse mode. Those familiar with the art should be aware that, The above are general advantages, It is independent of the number of light-emitting elements used. More specifically, According to a preferred embodiment of the present invention, Can use more than 15 light-emitting elements, The light generated by the additional light-emitting element can be guided to the NLO crystal 213 through a special optical system. therefore, Provided that at least one of the light-emitting elements is manufactured and operated similarly to the light-emitting element 201, Then it can be generated for a sum frequency or a difference frequency or any other frequency combination. 0 20 According to a preferred embodiment of the present invention, The light-emitting element 201 is grown on a substrate 202. It is preferably composed of any guan-ν semiconductor material or Π-V semiconductor alloy, E.g, Indium (inAs), Filled with indium (InP), Or gallium antimonide (GaSb), Or for other alloys. A more preferred substrate 202 is made of gallium arsenide (GaAs). 25 200424729 One of the devices 10 is characterized by the extension waveguide 204, As mentioned, A light beam is provided in which the fundamental transverse mode has a low beam divergence. According to a preferred embodiment of the invention, The waveguide 204 is composed of an n_transmitter 203 and a soldier transmitting 220. The transmitter 203 is preferably formed directly on the substrate 202. And is adjacent to the waveguide 204 from one side, At the same time, the strict transmitter is adjacent to the waveguide 204 from the other side. The extension waveguide 204 preferably includes an active area 206, It is formed in a first waveguide region 205 doped with an η- impurity, And a second waveguide region 207 doped with an impurity. Both the first waveguide region 205 and the second waveguide region 207 are light-transmissive. The first waveguide region 205 and the second waveguide region 207 are preferably a layer or a multi-layer structure composed of such materials that are lattice-matched or nearly lattice-matched with the substrate 202. The impurities introduced into the first waveguide region 205 are donor impurities (donor 15 lmpuntles). Such as But not limited to sulfur (S), Selenium (Se) and tellurium (Te). Alternatively, the first waveguide region 205 may be doped with an amphoteric impurity, Such as But not limited to Si Xi, Germanium (Ge) and tin (Sn), Can be imported under these technical conditions, It is mainly bound to the cationic sublattice, It is therefore used as a donor. Therefore, the first waveguide region 205, E.g, It can be a gallium arsenide (GaAs) or gallium arsenide (GaAlAs) layer grown by 20 molecular beams and doped with silicon (Si) impurities at a concentration of about 2 X 1017 cm-3. The term "approximately, , Department is 50%. The impurities that can be introduced into the second waveguide region 207 are acceptor impurities, such as, But not limited to beryllium (Be), Magnesium (Mg), Word (Zn), Cadmium (Cd), 26 200424729 Lead (Pb) and manganese (Mn). Alternately, The second waveguide region 207 may be doped with an amphoteric impurity, Such as But not limited to silicon (Si), Germanium (Ge) and tin (Sn), Can be introduced under these technical conditions, It binds predominantly to an anionic sublattice and functions as an acceptor impurity. therefore, The second waveguide region 207, E.g, It can be a gallium arsenide (GaAs) or gallium arsenide (GaAlAs) layer grown by molecular beam epitaxy and doped with beryllium (Be) impurities at a concentration of about 2 × 1017 cm · 3. The active area 206 is preferably formed by any insertion with an energy band gap, The energy band gap is narrower than the energy band gap of the substrate 202. According to a preferred embodiment of the present invention, The active area 206, E.g, 10 can be a quantum well, Quantum wire, Quantum dots or any such combined system. The active area 206 can be configured as a single-layer system or a multi-layer system. In a preferred embodiment, The substrate 202 is made of gallium arsenide (GaAs). Active area 206, E.g, Can be, Ιηι · χ (} αχΑδ, InxGai x ^ As, hxGahAsHNy or similar material insertion system, Where 乂 and ^ are marked 15-alloy composition. The emitter 203 is preferably made of a material that is lattice-matched or nearly lattice-matched to the substrate 202, E.g, Alloy material GahALAs. In addition, The η-emitter 203 is preferably transparent to the generated light and doped with the donor 20 impurities, As detailed earlier, With the first waveguide region 205: The assignments are similar. According to a preferred embodiment of the present invention, The p-emitter 220 includes a J-P-doped layer 208 and at least one p + doped layer 209, The p-doped layer 2 is arranged between the waveguide 204 and the P + doped layer. The ρ · doped layer is finer than the t-heterolayer 209 | And it is made of a material that matches the lattice of the substrate 27 200424729 or is almost lattice-matched. Layers 208 and 209 are doped with acceptor impurities, This is similar to the doping operation of the second waveguide region 207. There is a difference in the doping levels between layers 208 and 209. Preferably, However, the doping levels of the second waveguide region 207 and the p-doped layer 208 are similar. The doping level of the erbium doped layer 5109 is relatively high. E.g, In a specific embodiment, The degree of doping of the second waveguide region 207 is about 2 × i0i7cm-3, The p + doped layer 209 may be a GaAlAs layer grown by molecular beam epitaxy. And doped with a Be impurity with a concentration of about 2 x 1019 cm · 3. One preferred thickness of the element 201 is 10 microns or more. The preferred bandwidth 10 is from about 7 microns to about 10 microns or higher, And one of the preferred lengths of the element 201 is about 100 micrometers or more. As mentioned, The light-emitting element 201 is designed and constructed, Therefore, the waveguide 204 k provides a single-state laser light 211. E.g, So that by selecting & The refractive index of the emission state 203 and the p-doped layer 208 is lower than the refractive index of the waveguide 204. This form 15 ensures that the fundamental transverse mode of the laser radiation is confined within the range of the waveguide 204. And tied to the η-transmitter 203 and] > Decays in the doped layer 208. The forward bias 218 is preferably via a stack of contacts 216, In contact with the substrate 2 And connected to the light emitting element 201, And a contact 217 is in contact with the p-emitter 220 (or p + doped layer 209). Contacts 216 and 217 can be made into any of the well-known structures. Such as It is not limited to a multilayer metal structure. E.g, The n-contact 216 can be configured as a three-layer structure of Ni-Au_Ge. And the p-contact 217 can be constructed as a three-layer structure of Ti-Pt-Au. According to a preferred embodiment of the present invention, The device 10 further includes a spectrally selective filter 260. The stool prevents the light 215 from irradiating the light. In a specific embodiment, The filter 260 may be formed on the NLO crystal 213. Opposite the light emitting element 201. In this specific embodiment, E.g, The filter 260 may be made of a dielectric deposit. Such as But not limited to Si02, MgF2, Or ZnS. 5 Related to Figure 4, According to a preferred embodiment of the present invention, Front facet 210 and rear facet 269 of light emitting element 201, They are coated with an anti-reflective coating 320 and a highly reflective coating 319, respectively. The highly reflective coating 319 is used to minimize losses through the rear facet 269. So capable, E.g, This is achieved by forming a coating with a 10 stop band in reflectivity. The coating 319 can have a narrow stop band. It has a basic transverse mode with a south reflectivity and a higher-order transverse mode with a low reflectivity. According to a preferred embodiment of the present invention, The coating 319 is composed of a multilayer dielectric structure, It is designed to provide high reflectivity in a narrow spectral region. As described in further detail in this specific embodiment (see FIG. 8), For the fundamental transverse optical mode, The higher the reflectivity and the lower the loss, For higher-order modes, The losses will be significantly higher. therefore, This embodiment allows an additional selected mode, It also helps to obtain single-mode laser effects. As further detailed above, The anti-reflection coating 32 ensures that the laser effect occurs only with the mouth-feeding 'and only for the fundamental transverse optical mode. According to a preferred embodiment of the present invention, The coating and its resistance π have a temperature dependency that is the same (or similar) as the frequency conversion efficiency of the NLO crystal 213. Each of the coating layers 319 and 320 preferably includes a plurality of layers made of suitable materials known in the art, E.g, This material is a dielectric deposition 29 200424729, Such as But not limited to Si〇2 MgF2, Or zns. Figure 5 of the current tea test is a schematic diagram of the device of the preferred embodiment. Which uses the concept of photonic band gap crystal laser. In order to more appropriately identify the presently preferred embodiments of the present invention, In the following, it will be further explained in 5 steps. In Fig. 5, the symbols 401 and 440 represent the private optical element and the waveguide, respectively. 'For a long time, In this specific embodiment, At least a portion of the extended waveguide 44o includes a photonic band gap crystal (PBC) 4302n period 431. Photonic Band Gap Crystal (PBC) 430 per-period 431, It is preferably composed of a two η-doped layer having a low refractive index and a high refractive index. According to a preferred embodiment of the present invention, The light emitting element 401 includes a missing fe432, It is arranged between the photonic band gap crystal (pBC) 43 and the doped layer 208. The defect 432 preferably includes an active region 434 having a side 433 and a p-side 435. When exposed to injected current, For example, using partial pressure 218, Used to emit light. As explained further below, Using the photonic bandgap crystal (PBC) 430 for the initial generation of light, Provides a high-efficiency, low-threshold current density radiation source with an extremely wide waveguide. The concept of photonic band gap crystal (PBC) laser, First by Ledentsov, N. N. And Shchukin, V. A. Adopted in the article, titled 20 "Long Wavelength Lasers Using GaAs Quantum Dots (Long Wavelength Lasers
Using GaAs-Based Quantum Dots)”，出版於photonics andUsing GaAs-Based Quantum Dots) ", published in photonics and
Quantum Technologies for Aerospace Applications IV， proceedings of SPIE，Donkor，E.et al.，editor，4732:15-26, 2002。大體上而言，光子帶隙晶體(PBC)係為一多維結構， 30 200424729 其特徵在於週期性折射率調制。為簡化起見，考量一結構 僅在一方向上，例如Z方向，具有折射率之週期性調制。於 一無限、完全週期性光子帶隙晶體(PBC)中，電磁波或光子 特徵在於一定義明確的波向量，於X方向上的1<^，以及於y 5 方向上的1%，致使電場E或是磁場Η在X及y空間座標上的每 一分量之空間相依性，係說明為一平面波， E，H exp(ikxx)exp(ikyy)? (EQ.l) 然而，根據Bloch’s原理，在z座標上的相依性並非說明 為一平面波而係為一平面波與一週期函數，u(z)，之乘積， 10 具有與折射率之調制相同之週期。因此，場之總空間相依 性係為： E，H exp(ikxx)exp(ikyy)exp(ikzz)u(z)5 (EQ.2) 電磁波或是光子能量之頻率的特徵頻帶，包括週期電 磁波傳播整個晶體的容許能帶(allowed bands)，以及電磁波 15 無法傳播的禁帶隙（forbidden bandgaps)。 光子帶隙晶體(PBC)之一理想週期性，能夠因終止該等 層（插入）之連續或是違反折射率之週期性量變曲線的任一 缺陷之類型而被蓄意地中斷。該一缺陷能夠將電磁波局部 化，或是使電磁波局不定域化。就局部化效應而言，能夠 20 有二型式之電磁波：⑴波局部化在缺陷處並衰變離開該缺 陷以及（ii)波延伸涵蓋整個光子帶隙晶體(PBC)，其中延伸 波之空間量變曲線可因一缺陷而受擾動。 於一更為傳統形式之基於層之週期連續性的雷射，光 線在與折射率調制轴，例如z轴，平行的方向上傳播，然而 31 200424729 波向量之X及y分量符合kx=〇及k广〇。此情況典型地係針對 一VCSEL。於此型式之雷射中，層之週期連續性經設計， 在某些臨界波長下提供高反射性頻譜範圍（阻帶）。缺陷，， 層經設計用以在此阻帶内提供一約束模態。 5 10 15 如由Ledenstov等人所提出之PBC雷射的一極佳優點在 於，此雷射得益於PBC魏，其未與特定波長之反射相關。 於此方法中，PBC經設計致使在z方向上發生折射率之週期 調制，光線之主要傳播係發生在χ方向上。中斷週期性致使 於橫向基本模態下的光線係在缺陷處局部化在ζ方向上，並 於ζ方向上衰變離開該缺陷。於此狀況下，對於在反射性上 阻帶之特別頻譜位置，或是對於已知波長的外部腔室厚度 並無存在-般的需求。當PBC之週期性並未直接地與傳播 光線之波長相關時，裝置1〇可同時地使用於寬的波長範 圍，例如，1微米、〇·9微求及〇·8微米。應察知的是，裝置 10之此特性，在設計及製造上提供極高的容限，該容限對 於直接頻率轉換係特別有利的。 缺fe432用以將雷射輪射之模態局部化的能力，係由二 乡數所&㈣4第-參數係為缺陷4 3 2與p B C之參考層的折 射率之間的差異，An。纺给_ ^ 20 μ第一參數係為缺陷之容積。就一 隹、BC而。#中僅在—方向上則折射率，該第二參數 系為缺fe432之厚度。大體上，當△峨值增加時，在一固定 缺陷厚度下，亦增加藉由缺陷而受局部化之模態數。當缺 陷之厚度增加日守，在一固定的下，亦增加藉由缺陷而受 局部化之模態數。選定該等二參數，Δη及缺陷之厚度，因 32Quantum Technologies for Aerospace Applications IV, proceedings of SPIE, Donkor, E. et al., Editor, 4732: 15-26, 2002. Generally speaking, the Photonic Band Gap Crystal (PBC) is a multi-dimensional structure, 30 200424729, which is characterized by periodic refractive index modulation. For simplicity, consider a structure with periodic modulation of the refractive index in only one direction, such as the Z direction. In an infinite, fully periodic photonic band gap crystal (PBC), an electromagnetic wave or photon is characterized by a well-defined wave vector, 1 < ^ in the X direction, and 1% in the y 5 direction, resulting in an electric field E Or the spatial dependence of each component of the magnetic field 空间 in the X and y space coordinates is explained as a plane wave, E, H exp (ikxx) exp (ikyy)? (EQ.l) However, according to Bloch's principle, in The dependence on the z-coordinate is not meant to be a plane wave but a product of a plane wave and a periodic function, u (z), 10, which has the same period as the modulation of the refractive index. Therefore, the total spatial dependence of the field is: E, H exp (ikxx) exp (ikyy) exp (ikzz) u (z) 5 (EQ.2) The characteristic frequency band of electromagnetic waves or the frequency of photon energy, including periodic electromagnetic waves Allowed bands that propagate the entire crystal, and forbidden bandgaps that electromagnetic waves cannot propagate. One of the ideal periodicity of a photonic bandgap crystal (PBC) can be intentionally interrupted by the type of any defect that terminates the continuity of these layers (insertion) or violates the periodic variation curve of the refractive index. This defect can localize electromagnetic waves or localize electromagnetic waves. As far as the localization effect is concerned, there can be two types of electromagnetic waves: chirped waves are localized at the defect and decay away from the defect; and (ii) the wave extension covers the entire photonic band gap crystal (PBC), where the spatial variation curve of the extended wave Can be disturbed by a defect. In a more traditional form of layer-based periodic continuity lasers, light travels in a direction parallel to the refractive index modulation axis, such as the z-axis, however the X and y components of the 31 200424729 wave vector conform to kx = 0 and k 广 〇. This situation is typically for a VCSEL. In this type of laser, the periodic continuity of the layer is designed to provide a highly reflective spectral range (stopband) at certain critical wavelengths. Defect, the layer is designed to provide a constrained mode within this stopband. 5 10 15 An excellent advantage of the PBC laser, as proposed by Ledenstov et al., Is that this laser benefits from PBC Wei, which is not related to reflection at a specific wavelength. In this method, PBC is designed to cause periodic modulation of the refractive index in the z direction, and the main propagation of light occurs in the x direction. The interrupted periodicity causes the light in the transverse fundamental mode to be localized in the z direction at the defect and decay away from the defect in the z direction. In this case, there is no general need for a special spectral position of the stop band in reflectance, or for the thickness of an external cavity of known wavelength. When the periodicity of the PBC is not directly related to the wavelength of the transmitted light, the device 10 can be simultaneously used in a wide wavelength range, for example, 1 micron, 0.9 micron, and 0.8 micron. It should be noted that this characteristic of the device 10 provides an extremely high tolerance in design and manufacture, which is particularly advantageous for direct frequency conversion systems. The lack of fe432's ability to localize the mode of the laser wheel is determined by the difference between the refractive index of the reference layer of the 2nd & ㈣4th parameter and the defect layer of the reference layer of p BC, An . Spinning _ ^ 20 μ The first parameter is the volume of the defect. Just a moment, BC. In #, the refractive index is only in the-direction, and the second parameter is the thickness lacking fe432. In general, when the value of ΔE is increased, the number of modes that are localized by the defect also increases at a fixed defect thickness. As the thickness of the defect increases, the number of modalities that are localized by the defect increases under a fixed condition. Select these two parameters, Δη and the thickness of the defect, because 32
At並僅有一雷射輻射模態係藉由缺陷432局部化。其他模 態係延伸涵蓋PBC。 、 口此’根據本發明之—較佳具體實施例，選定缺陷切 及光子帶隙晶體(PBC)430，致使基本光學模態，其係在與 5 =率_軸垂直的方向上傳播，係局部化在缺陷432處並 讀離開缺陷432，，然而所有其他（高階）光學模態係延伸涵 蓋整個光子帶隙晶體。增益區域因而能夠直接地安置在光 子V隙晶體之缺陷處或與其接近。 遍及整個結構的所需之折射率量變曲線係如下地計算 而得導入一模型結構。基本ΤΕ模態及高階ΤΕ模態，係自 對波動方程式之特徵向量問題的解法而得。當經計算而得 基本杈態時，該遠場圖形係藉使用以下方法計算而得，例 如 H.C.Casey，Jr.及μ·Β· Panish之半導體雷射 (Semiconductor Lasers)，Pan A，Academic Press，N.Y·，1978, 15 Copter 2。由於在最低光束發散、在主動區域中基本模態 之最大振幅、與在主動區域該較高模態之振幅和基本模態 之振幅的最低比值之間提供較佳的相互影響之最佳化，而 得所需的結構。 如所提及，主動區域434較佳地係配置在缺陷432中， 20於該處雷射輻射之基本模態係局部化。基本模態之所需局 部化長度，係藉由二傾向之相互影響而確定。一方面，該 局部化長度需夠大，用以提供一低遠場光束發散。另一方 面’局部化長度應足夠地短於PBC之長度。在PBC之總厚度 的比例下，提供基本模態的有效局部化，因而與其他模態 33 200424729 相較，在基本模態下顯著地增強電場強度。例如，於一具 體實施例中，PBC雷射達到一4度的光束發散，同時在一具 有0.8¼米GaAs腔室及GabXAlxAs包覆層，其中χ=0·3，的一 標準雙異質結構雷射中約束係數為〇.丨j。 5 應察知的是，此設計促進自延伸波導440的一單橫向模 態雷射作用，導致裝置1〇之更為有效的光線頻率轉換。 根據本發明之一較佳具體實施例，選定製成接點層216 及217的材料，因此僅有延伸高階模態係由層216及217散 射，而基本模態隙藉由缺陷432充分局部化，並未及接點區 10域因此並未散射。接點層216及217的適當材料包括，例如， 合金金屬。 此外，發光元件401可進一步包括一或更多的吸收層 420，位在光子帶隙晶體430的其中之一第一層431中，離開 該缺陷432,致使吸收該所有延伸高階模態，同時該局部化 15基本模態仍不受影響。吸收層420亦可位在光子帶隙晶體 430的該等不同層431内。 光子帶隙晶體(PBC)較佳地係由與基板202晶格匹配或 幾乎晶格匹配的一材料所構成並為發射光線可穿透的。於 上述位在一GaAs基板上的一元件之實例中，較佳具體實施 20例係為具一調制鋁成分，X，的合金Gai_xAlxAs。較佳地選 定週期數，η，每一層之厚度，以及每一層中合金成分，用 以提供雷射輻射之一且僅有一模態的局部化。 視裝置10之製程以及裝置1〇之應用而定，可變化發光 元件401中層的數目及主動區域的位置。因此，一具體實施 34 200424729 例包括與第5圖之具體實施例相似At and only one laser radiation mode is localized by defect 432. Other modalities extend to cover the PBC. According to the preferred embodiment of the present invention, the defect cut and photonic band gap crystal (PBC) 430 are selected so that the basic optical mode is propagated in a direction perpendicular to the 5 = rate_axis. Localized at defect 432 and read away from defect 432, however all other (higher order) optical modalities extend to cover the entire photonic band gap crystal. The gain region can thus be placed directly at or near the defect of the photon V-gap crystal. The required refractive index profile over the entire structure is calculated as follows to import a model structure. The basic TE mode and higher-order TE mode are derived from the solution of the eigenvector problem of the wave equation. When the basic branch state is calculated, the far-field pattern is calculated by using the following methods, for example, Semiconductor Lasers by HCCasey, Jr., and μB Panish, Pan A, Academic Press, NY ·, 1978, 15 Copter 2. As the optimization of the better interaction is provided between the lowest beam divergence, the maximum amplitude of the basic mode in the active region, and the lowest ratio of the amplitude of the higher mode and the amplitude of the basic mode in the active region, To get the required structure. As mentioned, the active region 434 is preferably arranged in the defect 432, where the basic mode of the laser radiation is localized. The required localized length of the basic modal is determined by the interaction of the two tendencies. On the one hand, the localization length needs to be large enough to provide a low far-field beam divergence. On the other hand, the localized length should be sufficiently shorter than the length of the PBC. In the ratio of the total thickness of the PBC, it provides effective localization of the basic mode, and thus significantly enhances the electric field strength in the basic mode compared to other modes 33 200424729. For example, in a specific embodiment, the PBC laser achieves a beam divergence of 4 degrees, and at the same time a standard double heterostructure mine with a 0.8¼ meter GaAs chamber and a GabXAlxAs coating, where χ = 0.3. The shot constraint coefficient is 0.1.j. 5 It should be noted that this design promotes a single transverse mode laser action of the self-extending waveguide 440, resulting in a more efficient light frequency conversion of the device 10. According to a preferred embodiment of the present invention, the material used to make the contact layers 216 and 217 is selected, so only the extended higher-order modes are scattered by the layers 216 and 217, and the basic mode gap is sufficiently localized by the defect 432 , And the 10 domains of the contact area are not scattered. Suitable materials for the contact layers 216 and 217 include, for example, alloy metals. In addition, the light-emitting element 401 may further include one or more absorption layers 420 located in one of the first layers 431 of the photonic bandgap crystal 430, leaving the defect 432, causing absorption of all the extended higher-order modes, while the Localized 15 basic modalities remain unaffected. The absorption layer 420 may also be located in the different layers 431 of the photonic bandgap crystal 430. The photonic bandgap crystal (PBC) is preferably composed of a material that is lattice-matched or nearly lattice-matched to the substrate 202 and is transmissive to emitted light. In the above-mentioned example of a component placed on a GaAs substrate, the preferred embodiment 20 is an alloy Gai_xAlxAs with a modulated aluminum component, X ,. The number of cycles, η, the thickness of each layer, and the alloy composition in each layer are preferably selected to provide localization of only one mode of the laser radiation. Depending on the manufacturing process of the device 10 and the application of the device 10, the number of layers in the light-emitting element 401 and the position of the active area may be changed. Therefore, a specific implementation 34 200424729 example includes similar to the specific embodiment of FIG. 5
:二是主動區域係、位在缺陷外部。另-具體包L 一二外部的該等結構，在具低折射率的每 5 /7 相鄰層之間導入漸近式折射率 層。—附加具體實施例，其中主動區域係位在缺陷" 包括載體用之薄通道阻障層，環繞該主動區域。本發明之 其他具體實施财，主動區域係位在缺陷外部，包括一些 或所有元件，例如"及收層、漸近式折料層及環繞載體 用的溥通道阻障層。本發明之其他具體實蘭包括該等結 10 構’其中缺陷係位在主動區域之n，邊或卩_側邊上。 元件401之較佳尽度係約為10微米或更厚，光子帶隙 晶體(PBC)430之較佳的週期431數係約自5至1〇或更多，較 佳的帶寬係約自7微米至10微米或更高，以及元件4〇1之較 佳長度係約為100微米或更高。 I置10之效率可進一步藉由發光元件401之一適當洩 漏設計而加強’其中所有的延伸高階模態係為洩漏並貫穿 進入基板202或接點層216及217，與基本模態相反，如所提 及，其並未及基板202或接點層216及217並且未受任何洩漏 損失。 現參考第6圖，於一較佳具體實施例中，裝置1〇中使用 一洩漏雷射用於產生主要光線。 因此，於此具體實施例中，波導204較佳地包括二部 分，一具有一中級折射率的第一部分539以及較佳地一具有 一高折射率的第二部分540。主動區域206係夾合在層205及 35 207之間，該每一層的特徵在於一中級折射率。在主動ι域 206中產生自第一部分539(具有中級折射率）洩漏而出至第 一^卩分540(具有高折射率）的光線’係沿著一路徑541傳播 並由前刻面210退出在外部腔室512内沿著路徑511傳播。光 5 線51丨係於腔室中傳播，大體上係於一相關於與前刻面21〇 之垂直方向傾斜的方向上傳播。在一特定角度下傳播，、生 成一回饋係僅針對一單橫向洩漏模態選擇性地存在。成為 一單模態光線，一旦光線511進入NLO晶體213，發生有饮 率的頻率轉換，以及產生一經轉換光線515。如上述進—步 10 的詳細說明，光線515經由光反射器214出現。 第二部分540，發生基本模態洩漏進入該部分，較佳地 係以與基板202晶格匹配或幾乎晶格匹配的一材料所構 成，發射光線可穿透的，η-摻雜，並具有一高折射率。換 雜雜質之型式及摻雜程度較佳地與如上述進一步詳細說明 15的層203相同。於上述位在一 GaAs基板上的一元件之實例 中，較佳材料係為Ga^AlxAs，其中根據折射率的需求選定 調制铭成分，X。 可任擇地並為較佳地，可製造用於產生主要光線的洩 漏雷射，致使波導204僅包括第一部分539，而不具第二部 20分540。於此具體實施例中，所產生的光線直接地洩漏進入 基板202。 相關於第7圖，根據本發明之一較佳具體實施例，裝置 10可進一步包括一透鏡65〇，用於將一微弱發散光束611轉 換成一平行光束651。於此具體實施例中，使用一平坦光反 36 200424729 射為614取代一聚焦光反射器。此具體實施例之一特別的優 點在於，平坦光反射器之所需設計大體上較一聚焦光反射 為之設計簡單。透鏡650能夠以任一業界所熟知的材料製 成’諸如’但不限定在玻璃或是石英玻璃。 5 第8圖圖示另一較佳具體實施例中的裝置10，其中包括 複數之塗層。因此，如上述之說明，發光元件2〇 1可包括位 在前刻面210上的抗反射塗層32〇，以及位在後刻面269上的 一可以多層介電結構所構成的高度反射塗層719。於具體實 施例中’使用一附加高度反射塗層714作為一光反射器。可 10交替地，塗層714可構成在光反射器214或614上。較佳地設 計塗層714之厚度、形狀及層數，有助於塗層714之選擇性 反射、吸收及/或傳輸特性。具體地，塗層714較佳地提供 基本橫向模態（211、511或651)的高反射性及低損失，以及 針對轉換光線215的高傳輸係數及低損失，及針對高階非戶 15 需模態的高損失。 應瞭解的是，本發明之範疇係意欲包括所有上述 之結合。例如，於一些具體實施例中，一或更多塗層可^ 立地成為一單層或是一多層塗層。此外，於其他具㉟〒於 例中，塗層714可包括塗層320及/或塗層319。 20 對於塗層使用多層結構容許選擇該等組成材料， NLO晶體之光學頻率轉換之最大效率的頻譜位置的相门方 式下，根據溫度變化移動窄阻帶之頻譜位置。如此容 到裝置10之頻率轉換效率的一極高溫度穩定性。 用以具有 塗層714及719可以任一所熟知的材料構成 37 200424729 特疋反射、吸收及/或傳輪特性，諸如，但不限定在可交替 的介電材料沉積物，例如，以〇2、Mgj72、或ZnS。 現參考第9圖，根據本發明之另一觀點，提供一種轉換 光線頻率的方法。該方法包括以下的方法步驟，如第9圖中 5 的流程圖所示。 10 15 20 因此，於一第一步驟中，以方塊8〇2代表，自一發光元 件發射一具有一第一頻率的光線，該發光元件，例如，可 為發光元件201或是發光元件4〇1，如上述進一步之詳細說 明。於一第二步驟中，以方塊8〇4代表，使用一光反射器用 於容許光線在一外步腔室内通過多次並通過一 NL〇晶體， 其中外部腔室，例如，可設計成外部腔室212或外部腔室 512,以及該NLO晶體可為具有適合光轉換特性的任一所熟 知之NLO晶體，例如，如上述進—步之詳細說明的具有或 不具塗層260之NLO晶體213。使光線在外步腔室内通過多 次，提供-回饋叙以產生具有_第_頻率的雷射光。於 -第三步驟中，以方塊8G6代表，具有第—頻率的雷射光通 過非線性光學晶體數次。該麵性光學晶體將雷射光之第 -頻率轉㈣第三解，該第二解係與第—頻率不同。 根據本發明之-較佳的具體實施例，該光反射器 光反射器214、614、714或是與其相似的任—光反射器。附 加並為較佳地，該光反射器可塗佈_單層塗層或是—多厚 塗層，如上述的進-步詳細朗。可任擇地，該方法可二 一步包括—附加步驟，以方塊_代表，其中使用-透鏡， 例如，透鏡⑽，將-微弱發散光束變換成-平行光束 38 200424729 根據本發明之一附加觀點，提供一種製造用於光線之 頻率轉換之裝置的方法。 第10圖係為該方法之方法步驟的一流程圖，其中於一 第一步驟中，以方塊902代表，提供一發光元件，例如，發 5 光元件201或發光元件401。於一第二步驟中，以方塊904代 表，提供並配置一光反射器與該發光元件相對，以及於一 第三步驟中，以方塊906代表，在界定介於發光元件與光反 射器之間的一外部腔室中提供並配置一NLO晶體。根據本 發明之一較佳的具體實施例，建構及設計該發光元件、光 10 反射器及非線性光學晶體，因此光線通過NLO晶體數次並 提供一回饋用於產生具有經轉換頻率的一雷射光，如上述 進一步的詳細說明。 應察知的是，為了清楚起見，於個別具體實施例中之 上下文中說明的本發明之特性，亦可以於一單一具體實施 15 例中以結合方式提供。相反地，為了簡潔起見，於一單一 具體實施例之上下文中說明的本發明之不同特性，亦可以 分別地或是以任一適合的次結合方式提供。 儘管本發明已結合其之特定具體實施例加以說明，但 明顯可知的是，複數種可交替方式、修改形式及變化形式 20 對於熟知此技藝之人士而言係為顯而易見的。因此，本發 明意欲包含所有該等可交替方式、修改形式及變化形式， 涵蓋於附加之申請專利範圍的精神與廣泛之範疇内。於本 說明書中所提及的所有公開案、專利及專利申請案，於此 以全文引用方式併入說明書中以為參考資料，該引用的程 39 200424729 度就如同已個別地及特定地將各個個別公開案、專利或專 利申請案以引用的方式併入内容一般。此外，於本申請案 中任一參考文獻的引用或確認，不應視為許可該適用於先 前技術之參考文獻適用於本發明。 5 【圖式簡單說明】 第la圖係為一先前技術之垂直共振腔面射型雷射 (VCSEL)的概略視圖； 第lb圖係為一先前技術之邊射型雷射的概略視圖； 第2圖係為一先前技術之垂直共振腔面射型雷射 10 (VCSEL)式頻率轉換裝置的概略視圖； 第3圖係為本發明之一用於光線頻率轉換的裝置之概 略視圖； 第4圖係為本發明之一用於頻率轉換的裝置之概略視 圖，包括一抗反射塗層及一高度反射塗層構成在一發光元 15 件的不同刻面上； 第5圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其中發光元件包括一光子帶溝晶體； 第6圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其中一洩漏雷射係用於產生主要光線； 20 第7圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其包括一用於提供一平行光束的透鏡以及一平坦式光 反射器； 第8圖係為本發明之一用於頻率轉換的裝置之概略視 圖，其在發光元件及光反射器上包括附加的多層式塗層； 40 200424729 第9圖係為本發明之轉換光線頻率的一方法的一流程 圖，以及 第10圖係為本發明之製造用於頻率轉換之裝置的一方 法的一流程圖。 5 【圖式之主要元件代表符號表】 10…裝置 210…前刻面 101...VCSEL 型結構 214、614…光反射器 102、202…基板 216· "η-接點 103···分布式布拉格反射鏡 217···ρ-接點 104···半導體腔室 218…順向偏壓 106···主動區域 220···ρ-發射器 109···外部雷射光束 260…濾光鏡 111、115、211、215···雷射光 269…後刻面 112、212、512…外部腔室 319…高度反射塗層 113、213"*NLO晶體 320…抗反射塗層 114···外部鏡 420…吸收層 201、401···發光元件 430…光子帶隙晶體 203、230···η-發射器 431…週期/第一層 204···延伸波導 432···缺陷 205···第一波導區域 433…η-側邊 206、434···主動區域 43 5…ρ-側邊 207···第二波導區域 440…波導 208···ρ-摻雜層 511、541···路徑 209···ρ+摻雜層 515…經轉換光線: Second, the active area is located outside the defect. In addition, the specific structures of L and II are introduced externally, and an asymptotic refractive index layer is introduced between every 5/7 adjacent layers having a low refractive index. -An additional embodiment, wherein the active area is located at the defect " including a thin channel barrier layer for the carrier, surrounding the active area. In other embodiments of the present invention, the active area is located outside the defect and includes some or all of the components, such as " receiving layer, asymptotic folding layer, and ytterbium channel barrier layer surrounding the carrier. Other specific embodiments of the present invention include such structures, wherein the defects are located on the n, side, or side of the active area. The best degree of the element 401 is about 10 micrometers or more. The preferred period 431 of the photonic band gap crystal (PBC) 430 is about 5 to 10 or more, and the preferred bandwidth is about 7 Micrometers to 10 micrometers or more, and the preferred length of the element 401 is about 100 micrometers or more. The efficiency of setting I to 10 can be further enhanced by a proper leakage design of one of the light-emitting elements 401. Among them, all extended high-order modes are leaking and penetrate into the substrate 202 or the contact layers 216 and 217, contrary to the basic mode, such as As mentioned, it is not in contact with the substrate 202 or the contact layers 216 and 217 and has not suffered any leakage losses. Referring now to FIG. 6, in a preferred embodiment, a leaky laser is used in the device 10 to generate the main light. Therefore, in this embodiment, the waveguide 204 preferably includes two parts, a first part 539 having a middle refractive index, and preferably a second part 540 having a high refractive index. The active region 206 is sandwiched between layers 205 and 35 207, each of which is characterized by an intermediate refractive index. In the active domain 206, the light rays 'producing from the first part 539 (with intermediate refractive index) leaking out to the first ^ (540) with high refractive index' propagate along a path 541 and exit from the front facet 210 It travels along the path 511 within the outer chamber 512. The light 5 line 51 丨 propagates in the cavity, and is generally propagated in a direction related to the oblique direction perpendicular to the front facet 21 °. Propagating at a specific angle, generating a feedback system exists selectively for only a single lateral leakage mode. It becomes a single-mode light. Once the light 511 enters the NLO crystal 213, the frequency conversion of the drinking rate occurs, and the converted light 515 is generated. As described in detail above in step 10, the light 515 appears via the light reflector 214. The second part 540, into which a basic modal leakage occurs, is preferably made of a material that is lattice-matched or nearly lattice-matched to the substrate 202, and emits light that is transmissive, η-doped, and has A high refractive index. The type and degree of doping of the impurity impurities are preferably the same as those of the layer 203 described in further detail above. In the above-mentioned example of an element on a GaAs substrate, the preferred material is Ga ^ AlxAs, and the modulation component, X, is selected according to the requirement of the refractive index. Optionally and preferably, a leaky laser for generating the main light can be made such that the waveguide 204 includes only the first portion 539 and not the second portion 20 minutes 540. In this embodiment, the generated light directly leaks into the substrate 202. In relation to FIG. 7, according to a preferred embodiment of the present invention, the device 10 may further include a lens 650 for converting a weakly divergent light beam 611 into a parallel light beam 651. In this embodiment, a flat light reflector 36 200424729 is used instead of a focused light reflector. One particular advantage of this embodiment is that the required design of a flat light reflector is substantially simpler than that for a focused light reflection. The lens 650 can be made of 'such as' but not limited to glass or quartz glass from any material well known in the industry. 5 Figure 8 illustrates the device 10 in another preferred embodiment, including a plurality of coatings. Therefore, as described above, the light-emitting element 201 may include an anti-reflection coating 32 on the front facet 210, and a highly reflective coating on the rear facet 269, which may be composed of a multilayer dielectric structure. 719. In a specific embodiment ' an additional highly reflective coating 714 is used as a light reflector. Alternatively, the coating 714 may be formed on the light reflector 214 or 614. The thickness, shape, and number of layers of the coating 714 are preferably designed to help the selective reflection, absorption, and / or transmission characteristics of the coating 714. Specifically, the coating 714 preferably provides high reflectivity and low loss in the basic transverse mode (211, 511, or 651), and high transmission coefficient and low loss for the converted light 215, and for high-order non-household 15 demand modes State of high loss. It should be understood that the scope of the present invention is intended to include all combinations of the above. For example, in some embodiments, one or more coatings can stand as a single layer or a multilayer coating. In addition, in other embodiments, the coating 714 may include a coating 320 and / or a coating 319. 20 Using a multilayer structure for the coating allows the selection of these constituent materials, and the spectral position of the maximum efficiency of the optical frequency conversion of the NLO crystal in a phase-gated manner, shifting the spectral position of the narrow stopband according to temperature changes. This allows an extremely high temperature stability of the frequency conversion efficiency of the device 10. The coatings 714 and 719 may be constructed of any of the well-known materials. 37 200424729 Special reflection, absorption, and / or transmission characteristics, such as, but not limited to, deposits of alternate dielectric materials, such as , Mgj72, or ZnS. Referring now to FIG. 9, according to another aspect of the present invention, a method for converting the frequency of light is provided. The method includes the following method steps, as shown by the flowchart in FIG. 10 15 20 Therefore, in a first step, represented by a block 802, a light having a first frequency is emitted from a light-emitting element. The light-emitting element may be, for example, the light-emitting element 201 or the light-emitting element 4. 1. As detailed above. In a second step, represented by block 804, a light reflector is used to allow light to pass through an outer step cavity multiple times and through an NLO crystal. The external cavity, for example, can be designed as an external cavity. The chamber 212 or the external chamber 512, and the NLO crystal may be any well-known NLO crystal having suitable light conversion characteristics, such as the NLO crystal 213 with or without a coating 260 as described in detail above. Pass the light through the outer step cavity multiple times, and provide-feedback to generate laser light with the _th frequency. In the third step, represented by block 8G6, the laser light having the first frequency passes through the nonlinear optical crystal several times. The planar optical crystal converts the third frequency of the laser light to a third solution, which is different from the first frequency. According to a preferred embodiment of the present invention, the light reflector is a light reflector 214, 614, 714 or any similar light reflector. Additionally and preferably, the light reflector can be coated with a single-layer coating or a multi-thick coating, as detailed above. Alternatively, the method may include two additional steps, an additional step, represented by a square, where a-lens, for example, a lens, is used to transform a-weakly divergent beam into a-parallel beam 38 200424729 according to an additional aspect of the invention Provide a method for manufacturing a device for frequency conversion of light. FIG. 10 is a flowchart of the method steps of the method. In a first step, represented by block 902, a light emitting element is provided, for example, a light emitting element 201 or a light emitting element 401. In a second step, represented by block 904, a light reflector is provided and arranged opposite the light emitting element, and in a third step, represented by block 906, which is defined between the light emitting element and the light reflector. An NLO crystal is provided and configured in an external chamber. According to a preferred embodiment of the present invention, the light emitting element, the light 10 reflector and the non-linear optical crystal are constructed and designed, so the light passes through the NLO crystal several times and provides a feedback for generating a thunder with a converted frequency. Light emission is described in further detail above. It should be noted that, for the sake of clarity, the characteristics of the present invention described in the context of individual specific embodiments may also be provided in combination in a single specific embodiment. Conversely, for the sake of brevity, the different features of the invention described in the context of a single specific embodiment may also be provided separately or in any suitable sub-combination. Although the present invention has been described in conjunction with specific embodiments thereof, it will be apparent that a plurality of alternative ways, modifications, and variations 20 will be apparent to those skilled in the art. Therefore, this invention intends to include all such alternative ways, modifications, and variations, which are encompassed within the spirit and broad scope of the scope of additional patent applications. All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference in their entirety into the specification as reference material, and the cited process 39 200424729 degrees is as if each individual has been individually and specifically Publications, patents, or patent applications are generally incorporated by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that the reference applied to the prior art is applicable to the present invention. 5 [Schematic description] Figure 1a is a schematic view of a prior art vertical cavity surface-emitting laser (VCSEL); Figure 1b is a schematic view of a prior art edge-emitting laser; FIG. 2 is a schematic view of a prior art vertical cavity surface emitting laser 10 (VCSEL) frequency conversion device; FIG. 3 is a schematic view of a device for frequency conversion of light according to the present invention; FIG. Is a schematic view of a device for frequency conversion according to the present invention, including an anti-reflective coating and a highly reflective coating formed on 15 different facets of a light-emitting element; FIG. 5 is a view of the present invention A schematic view of a device for frequency conversion, in which the light-emitting element includes a photonic band groove crystal; FIG. 6 is a schematic view of a device for frequency conversion in the present invention, in which a leaky laser is used to generate a main Light; 20 FIG. 7 is a schematic view of a device for frequency conversion according to the present invention, which includes a lens for providing a parallel light beam and a flat light reflector; FIG. 8 is one of the present invention For frequency conversion A schematic view of a device including an additional multilayer coating on a light-emitting element and a light reflector; 40 200424729 FIG. 9 is a flowchart of a method for converting light frequency according to the present invention, and FIG. 10 is A flowchart of a method of manufacturing a device for frequency conversion in accordance with the present invention. 5 [Representative symbols for main components of the drawing] 10 ... device 210 ... front facet 101 ... VCSEL type structure 214,614 ... light reflector 102,202 ... substrate 216 · " η-contact 103 ··· Distributed Bragg Mirror 217 ... ρ-contact 104 ... Semiconductor cavity 218 ... Bias forward bias 106 ... Active area 220 ... ρ-Transmitter 109 ... External laser beam 260 ... Filters 111, 115, 211, 215 ... Laser light 269 ... Rear facets 112, 212, 512 ... External cavity 319 ... Highly reflective coating 113, 213 " NLO crystal 320 ... Anti-reflective coating 114 ... External mirror 420 ... Absorptive layers 201, 401 ... Light emitting element 430 ... Photonic band gap crystals 203, 230 ... η-emitter 431 ... Period / first layer 204 ... Extension wave 432 ... Defect 205 First waveguide region 433 ... n-side 206, 434 ... Active region 43 5 ... ρ-side 207 ... second waveguide region 440 ... waveguide 208 ... p-doped layer 511, 541 ... Path 209 ... ρ + doped layer 515 ... converted light
41 200424729 539···第一部分 650…透鏡 540···第二部分 651…平行光束 611···微弱發散光束 714、719…高度反射塗層41 200424729 539 ... Part I 650 ... Lens 540 ... Part II 651 ... Parallel beam 611 ... Weak divergent beam 714, 719 ... Highly reflective coating
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