WO2009152690A1 - 光栅外腔半导体激光器及其准同步调谐方法 - Google Patents

光栅外腔半导体激光器及其准同步调谐方法 Download PDF

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Publication number
WO2009152690A1
WO2009152690A1 PCT/CN2009/000642 CN2009000642W WO2009152690A1 WO 2009152690 A1 WO2009152690 A1 WO 2009152690A1 CN 2009000642 W CN2009000642 W CN 2009000642W WO 2009152690 A1 WO2009152690 A1 WO 2009152690A1
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Prior art keywords
grating
quasi
synchronous
rotation
tuning
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PCT/CN2009/000642
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English (en)
French (fr)
Inventor
臧二军
曹建平
李烨
方占军
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中国计量科学研究院
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Priority claimed from CN 200810127037 external-priority patent/CN101609959B/zh
Priority claimed from CN200810116638A external-priority patent/CN101630811B/zh
Application filed by 中国计量科学研究院 filed Critical 中国计量科学研究院
Priority to US12/990,594 priority Critical patent/US9036668B2/en
Publication of WO2009152690A1 publication Critical patent/WO2009152690A1/zh
Priority to US13/188,592 priority patent/US8681825B2/en
Priority to US14/155,548 priority patent/US8953649B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/14—External cavity lasers
    • H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/105—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length
    • H01S3/1055—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length one of the reflectors being constituted by a diffraction grating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings
    • H01S5/023—Mount members, e.g. sub-mount members
    • H01S5/02325—Mechanically integrated components on mount members or optical micro-benches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/14—External cavity lasers
    • H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
    • H01S5/143—Littman-Metcalf configuration, e.g. laser - grating - mirror

Definitions

  • the present invention relates to the tuning of the laser wavelength or frequency of a grating external cavity semiconductor laser in which quasi-synchronous tuning is achieved when selecting the tuning center of rotation of the grating or mirror. Background technique
  • ECDL external cavity semiconductor lasers
  • Figure 1 shows an external cavity semiconductor laser with a conventional grazing incidence (ie, an incident angle greater than the diffraction angle). This structure is also known as the Littman structure;
  • Figure 2 shows the patent of the same applicant in China.
  • Figure 3 shows a conventional Littrow structure external cavity semiconductor laser in which no reflection is applied. The mirror is thus tuned only by rotating the grating.
  • LD denotes a semiconductor laser diode
  • AL denotes an aspheric collimating lens
  • G denotes a grating
  • M denotes a feedback mirror
  • N denotes a grating normal
  • ⁇ denotes an incident angle of light on the grating
  • ⁇ ( 1 represents the diffraction angle of light on the grating
  • ⁇ is the difference between the incident angle and the diffraction angle
  • ie 9 01 - 6
  • ⁇ is generated by the intracavity optical elements (such as the aspheric collimating lens and the gain medium of the LD)
  • Optical path increase the amount.
  • the laser light emitted from the semiconductor laser diode LD is collimated by the aspherical mirror AL and incident on the diffraction grating G.
  • the first-order diffracted light of the grating G is incident on the feedback mirror M. After the beam is reflected on the mirror M, it is diffracted by the grating along the path collinear and opposite to the incident light.
  • the spherical mirror AL is returned to the semiconductor laser diode.
  • the laser light emitted from the semiconductor laser diode LD is collimated by the aspherical mirror AL, and is incident on the diffraction grating G.
  • the first-order diffracted light of the grating G is returned to the semiconductor laser diode directly through the aspherical mirror AL along the path collinear and opposite to the incident light.
  • a Cartesian coordinate system xOy is introduced in the drawing, wherein the O point represents the intersection of the laser beam emitted by the semiconductor laser diode LD and the diffraction surface of the grating G at the initial position, and the X axis passes through the O.
  • the point is in the opposite direction to the ray emitted by the LD, and the y-axis passes through the O point and is perpendicular to the X-axis and upward.
  • the three planes of the equivalent LD rear-end reflection surface, the diffraction surface of the grating G, and the reflection surface of the mirror M are perpendicular to the xOy coordinate plane.
  • SG is used to indicate the intersection of the plane where the grating diffraction surface is located and the xOy coordinate plane, where the O point is located;
  • SL is the intersection of the plane where the equivalent LD rear-end reflection surface is located and the xOy coordinate plane, which is from the O point.
  • the distance is 11;
  • SM represents the intersection of the plane of the reflective surface of the feedback mirror M and the xOy coordinate plane, and the distance from the point O is 12.
  • the actual optical cavity length of the semiconductor laser is the distance 11 from the O point to the equivalent LD rear end reflecting surface.
  • the rotation axis is perpendicular to the xOy coordinate plane, and the intersection of the rotation axis and the xOy coordinate plane (ie, the center of rotation) is represented by coordinates P ( x, y ) in FIGS. 1 to 3 .
  • distance parameters u, V and w are introduced, where u represents the distance from the center of rotation P to the line of intersection SM; V represents the distance from the center of rotation P to the line of intersection SG; w represents the center of rotation P to the line of intersection SL the distance.
  • the symbols of the values of the parameters u, V, and w are specified as follows: When the light and the center of rotation are on the same side of the intersection of the corresponding planes, a positive value is used, and when the light and the center of rotation are respectively on both sides of the intersection of the corresponding planes, Expressed as a negative value. When the grating G or the feedback mirror M is rotated around the point P, the distance V or u remains unchanged.
  • the frequency selection effect determined by the value and variation of the cavity length of the equivalent F-P cavity formed by SL, SM, and SG.
  • both the grating frequency selection and the frequency selection of the F-P cavity are changed.
  • the above changes are not synchronous, which will cause a mode change of the laser mode, interrupting the continuous tuning of the laser frequency, so that the continuous tuning range of the laser frequency that can be obtained without mode hopping is very small, for example, 1 to 2 GHz. .
  • ⁇ represents the initial phase change of the beam going back and forth within the cavity before rotational tuning
  • ⁇ ( ⁇ ) is a function related to the tuning rotation angle ⁇
  • ⁇ 0, ⁇ and C are functions independent of the angle ⁇
  • ⁇ 0, ⁇ ( ⁇ ), ⁇ , and C are related to the initial parameters of the external cavity semiconductor laser.
  • These initial parameters include the initial angle (such as initial incident angle ⁇ , initial diffraction angle 6d, etc.), initial position (such as initial cavity length 11 and 12). , initial distances u, V, and W, etc.), and the grating constant d and so on.
  • the phase change ⁇ should be independent of the tuning rotation angle ⁇ , that is, both ⁇ and C in Equation 1 should be zero.
  • the distance parameter of the center of rotation ⁇ 0 of fully synchronous tuning shall satisfy:
  • the center of rotation ⁇ 0 satisfying the synchronous tuning limit condition should be located on the intersection SG of the plane where the grating diffraction surface is located and the xOy coordinate plane; meanwhile, the distances from the center of rotation P0 to the plane of the mirror reflection surface u0 and P0 are equal.
  • the absolute value of the distance w0 of the plane where the back surface of the LD back surface is located is the same and the sign is opposite.
  • x0 and y0 respectively represent the abscissa and ordinate of the synchronous tuning center P0
  • 1 is the equivalent cavity length of the FP cavity at the initial position
  • d is the grating constant
  • 0i is the incident angle of the beam on the grating
  • ⁇ is Laser wavelength.
  • the synchronous tuning center P0 should be located at the intersection of the straight lines SG and SL.
  • the position of the synchronous tuning center ⁇ 0 is always described by the equations of the two equations, and both of the above constraints must be satisfied, which means Two adjustment mechanisms with independent degrees of freedom are required to design the laser.
  • the position of the synchronously tuned center of rotation P0 cannot be separated from the plane SG where the grating diffraction surface is located, whether in the case of grazing incidence, grazing diffraction or Littrow structure. This limitation makes the design, adjustment and application of the laser very unfavorable and difficult, and at the same time creates the complexity of the mechanical system and increases the instability.
  • the technical problem is solved by a method for tuning a grating external cavity semiconductor laser in which a grating or mirror of a semiconductor laser is rotated with a quasi-synchronous tuning point as a center of rotation, so that grating diffraction during rotation
  • the distance between the plane in which the surface or the mirror reflecting surface is located and the quasi-synchronous tuning point remains unchanged, thereby achieving quasi-synchronous tuning of the frequency selective action of the grating and the cavity, wherein the quasi-synchronization is determined in the following manner Tuning point:
  • the angle of the straight line with respect to the direction of the light incident on the grating is determined according to the difference ⁇ between the incident angle of the laser beam on the grating and the diffraction angle, that is, when the grating is rotated, the angle is It is ⁇ /2; when the mirror is rotated, the angle is ⁇ .
  • a corresponding external cavity semiconductor laser comprising a quasi-synchronous tuning mechanism for performing the quasi-synchronous tuning method described above, the quasi-synchronous tuning mechanism rotating the grating or reflecting around the quasi-synchronous tuning center determined as described above Mirror, thus achieving quasi-synchronous tuning of the grating and resonator frequency selection.
  • the round-trip phase change can be made one.
  • the order approximation that is, the second-order term in the formula 1 and its higher-order term are omitted. If the second term in the brackets of the formula 1 is omitted, the round-trip phase change ⁇ can be approximated as:
  • the number of constraints for synchronous tuning is reduced, so that the adjustment mechanism only needs one adjustment degree of freedom.
  • the position of the center of rotation does not have to be limited by the plane intersection SG which cannot leave the grating surface, which makes the synchronous tuning more flexible and more flexible, and is easy to design to achieve the approximate synchronous rotation frequency or wavelength tuning of the laser.
  • Figure 1 shows a simplified view of a grating outer cavity semiconductor laser of a Littman structure
  • Figure 2 shows a simplified view of a grating external cavity semiconductor laser of a grazing diffractive structure
  • Figure 3 shows a simplified view of a grating outer cavity semiconductor laser of the Littrow structure
  • Figure 4 illustrates the determination of a conventional synchronously tuned rotational center for a Littman structure
  • Figure 5 illustrates the determination of a conventional synchronously tuned rotational center for a grazing diffractive structure
  • Figure 6 illustrates the determination of a conventional synchronously tuned rotational center for a Littrow structure
  • Figure 7 illustrates the determination of a quasi-synchronously tuned rotational center for a Littman structure during raster rotation tuning in accordance with the present invention
  • Figure 8 illustrates the determination of a quasi-synchronously tuned center of rotation for a grazing diffractive structure during raster rotation tuning in accordance with the present invention
  • Figure 9 illustrates the determination of a quasi-synchronously tuned rotational center for a Littman structure during mirror rotational tuning in accordance with the present invention
  • Figure 10 illustrates the determination of a quasi-synchronously tuned rotational center for a grazing diffraction structure during mirror rotational tuning in accordance with the present invention
  • Figure 11 illustrates the determination of a quasi-synchronous tuning rotational center for a Littrow structure in accordance with the present invention
  • Figure 12 shows a quasi-synchronous tuning mechanism for a Littman structured grating external cavity semiconductor laser during raster rotation tuning
  • Figure 13 shows the grazing diffraction structure grating external cavity semiconductor during grating rotation tuning a quasi-synchronous tuning mechanism for the laser
  • Figure 14 shows the quasi-synchronous tuning mechanism of the Littman structured grating outer cavity semiconductor laser during mirror rotation tuning
  • Figure 15 illustrates a quasi-synchronous tuning mechanism for a grazing diffractive structure grating outer cavity semiconductor laser during mirror rotational tuning
  • Figure 16 shows the quasi-synchronous tuning mechanism of a Littrow structured grating external cavity semiconductor laser.
  • Figures 7 through 11 illustrate various embodiments of determining a quasi-synchronously tuned rotational center of a grating external cavity semiconductor laser in accordance with the present invention.
  • Fig. 7 and Fig. 8 show the case where the rotating grating is tuned, in which the incident angle ⁇ and the diffraction angle ⁇ of the ray on the grating G are changed.
  • the quasi-synchronous tuning rotation center coordinate Pq (xq, yq ) of the grating G satisfies the following conditions:
  • Equation 8 the trajectory of the grating rotation center coordinate Pq(xq, yq) satisfying Equation 8 is a straight line that is synchronously tuned to the rotation center P0 (x0, y0), and the angle between the line and the negative direction of the X axis is ⁇ /2. If the distance parameters uq, vq and wq are used, under the condition of quasi-synchronous tuning, the distance parameters uq, vq and wq of the grating rotation tuning satisfy:
  • the trajectory of the mirror rotation center coordinate Pq(xq, yq) satisfying the formula 10 is also a straight line that is synchronously tuned to the rotation center P0 (x0, y0), and the angle between the line and the negative X-axis direction is ⁇ . If the distance parameters uq, vq, and wq are expressed, the distance parameters uq, vq, and wq at the mirror rotation tuning are satisfied under the condition of quasi-synchronous tuning:
  • the center of rotation Pq(xq, yq) satisfying the quasi-synchronous tuning condition can be regarded as the center of rotation P0 (x0, y0) from the conventional synchronous tuning condition. ) extended to a point through the P0 point The interval on the straight line near the point P0, which can be on either side of the P0 point.
  • the line is parallel to the normal N of the mirror M.
  • the mirror M is coincident with the equivalent LD rear-end reflection surface, and the grating G is rotated to perform tuning, and the line is parallel to the light emitted by the semiconductor laser diode LD. .
  • a large synchronous tuning range that is significantly better than the other positions can be obtained, and the closer to the synchronous tuning point P0 (x0, y0), the larger the resulting synchronous tuning range.
  • Figures 12 and 13 respectively show the quasi-synchronous tuning mechanism of the grazing incidence structure and the grazing diffractive structure outer cavity semiconductor laser when the rotating grating is tuned.
  • the semiconductor diode LD emits, for example, a laser beam having a power of 30 mW and a wavelength of 689 nm, and is collimated by an aspheric collimating lens AL having a focal length of 4 mm and a numerical aperture of 0.6, and is incident on a scribe line density of 1800 g/
  • the holographic diffraction grating G having a suitable diffraction efficiency, a reticle area of 12.5 mm x 1.5 mm, and a thickness of 6 mm
  • the zero-order diffracted light or the direct mirror-reflected light of the grating G serves as an output beam of the laser.
  • the first-order diffracted light of the grating is incident on the plane mirror M. After being reflected on M, the light is reversed, along the path collinear with the original incident beam, and again diffracted along the original path through the grating, and then returned to the semiconductor diode.
  • LD the semiconductor diode
  • the laser diode LD realizes temperature control by means of a heat sink 2, for example, using a temperature sensor and a semiconductor refrigerator.
  • the specific implementation of the quasi-synchronous tuning mechanism is described below:
  • the collimating lens AL is adjusted and fixed by the frame 4, and the diffraction grating G is fixed to the adjusting frame 6 in such a direction that the adjusting screw 8 on the fixing plate 7 can be adjusted.
  • the adjustment can also be finely adjusted by the piezoelectric ceramic 10 on the moving plate, and the mirror M is fixed to the bottom plate 13 by the fixing frame 11.
  • the frequency selective action of the outer cavity and the grating is achieved by rotating the diffraction grating G around the quasi-synchronous rotation center Pq.
  • the angle of the diffraction grating G is changed by the fine adjustment screw 8 to perform coarse adjustment, and/or fine adjustment is performed by applying a control voltage to the piezoelectric ceramic 10.
  • the quasi-synchronous tuning rotation center Pq (xq, yq) of the grating rotation is located in a negative direction of the X-axis through a conventional synchronous tuning rotation center P0 ( ⁇ , y0). On a straight line with an angle of ⁇ /2, ⁇ >0 because ⁇ > ⁇ 1.
  • the grating-tuned grazing diffractive structure outer cavity semiconductor laser shown in Fig. 13 is similar to the grazing diffraction structure shown in Fig. 12 except that the position of the mirror ⁇ is different, so that 0i ⁇ ed, and thus ⁇ ⁇ ⁇ 0.
  • the grating rotation quasi-synchronous tuning rotation center Pq (xq, yq) is also located on a line passing through the conventional synchronous tuning rotation center P0 (x0, y0) and the angle with the X axis negative direction is ⁇ /2, but the inclination of the line The direction is opposite to that shown in FIG.
  • Figures 14 and 15 show the quasi-synchronous tuning mechanism of the grazing incidence structure and the grazing diffractive structure external cavity semiconductor laser, respectively, when the rotating mirror is tuned.
  • the grating G is fixed on the bottom plate 13 by the fixing frame 11, and the mirror M is fixed on the adjusting frame 6 in the direction of which the adjusting plate 7 can be adjusted.
  • the adjustment screws 8 and 9 are adjusted and can also be fine-tuned by the piezoceramic 10 on the moving plate.
  • the frequency selection of the outer cavity and the grating is achieved by rotating the mirror M around the quasi-synchronous center of rotation Pq.
  • the angle of the mirror M is changed by fine-tuning the screw 8 to make a coarse adjustment, and/or fine-tuned by applying a control voltage to the piezoelectric ceramic 10.
  • a line that has been rotated by the normal synchronization to rotate the center P0 (x0, y0) and the angle with the negative direction of the X axis is ⁇ , since ⁇ > ⁇ (1, thus ⁇ >0.
  • the mirror-externally tuned tuned-difference structure outer-cavity semiconductor laser shown in Fig. 15 is similar to the grazing diffraction structure shown in Fig. 14, except that the position of the mirror ⁇ is different, so that ⁇ ⁇ ⁇ (1, thus ⁇ ⁇ 0.
  • Mirror rotation quasi-synchronous tuning rotation center Pq (xq, yq) is also located on a straight line passing through the normal synchronous tuning rotation center P0 (x0, y0) and the angle with the X axis negative direction is ⁇ , but the line The direction of the tilt is opposite to that shown in FIG.
  • the first-order diffracted light of the grating G returns to the semiconductor diode LD along the original path along a path collinearly opposite to the original incident beam.
  • the grating G is fixed to the adjustment carriage 6, which can be adjusted by adjusting screws 8 and 9 on the adjustment frame 7.
  • the tuning of the laser wavelength is achieved by rotating the diffraction grating G around the synchronous rotation center Pq.
  • the angle at which the light beam is incident on the diffraction grating G is changed by fine-tuning the screw 8 and/or the piezoelectric ceramic 10, and the alignment adjustment of the quasi-synchronous rotation center Pq and the grating G can be achieved by adjusting the screw 9.
  • the quasi-synchronous tuning rotation center Pq (xq, yq) is located on a straight line passing through the conventional synchronous tuning rotation center P0 (x0, y0) and parallel to the X axis. .
  • the semiconductor laser tube in the above example may also use other wavelengths and output powers.
  • the grating may also use a blazed grating or a transmission grating, which may have other reticle density, size and thickness, and the collimating lens may also be used.
  • Adjustment screw fine adjustment

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  • Condensed Matter Physics & Semiconductors (AREA)
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Description

光栅外腔半导体激光器
及其准同步调谐方法 技术领域
本发明涉及对光栅外腔半导体激光器的激光波长或频率的 调谐， 其中在选择光栅或反射镜的调谐转动中心时实现了准同步 的调谐。 背景技术
在外腔半导体激光器（ECDL ) 中往往需要对所产生的激光 波长或频率进行调谐， 这种调谐是通过转动光栅从而改变光线在 光栅上的入射角和衍射角、 或者通过转动反射镜从而改变光线在 光栅上的衍射角来实现的。
在图 1、 图 2和图 3中分别示出了三种类型的光栅外腔半导 体激光器。 其中图 1所示的是常规的掠入射 (即入射角大于衍射 角）结构的外腔半导体激光器，这种结构也被称为 Littman结构； 图 2 中所示的是由同一申请人在中国专利申请 200810097085.4 中提出的一种新型的掠衍射（即衍射角大于入射角）结构的外腔 半导体激光器； 而图 3中所示的是常规的 Littrow结构的外腔半 导体激光器， 在该结构中没有反射镜， 因而仅通过转动光栅来进 行调谐。
如图 1至 3所示， LD表示半导体激光二极管， AL表示非 球面准直透镜， G表示光栅， M表示反馈反射镜， N表示光栅法 线， θί表示光线在光栅上的入射角， θ(1表示光线在光栅上的衍 射角， ΔΘ为入射角与衍射角之差， 即 9 = 01 - 6(1， Δχ为腔内光学 元件（例如非球面准直透镜和 LD的增益介质） 所产生的光程增 量。
在图 1所示的掠入射结构和图 2所示的掠衍射结构中，半导 体激光二极管 LD发出的激光经非球面镜 AL准直后， 入射到衍 射光栅 G上。 光栅 G的一级衍射光正入射在反馈反射镜 M上， 该光束在反射镜 M上被反射后， 沿着与入射光共线且反向的路 径， 按原路被光栅再次衍射后， 经非球面镜 AL返回到半导体激 光二极管中。
在图 3所示的 Littrow结构中， 半导体激光二极管 LD发出 的激光经非球面镜 AL准直后， 入射到衍射光栅 G上。 光栅 G 的一级衍射光沿着与入射光共线且反向的路径， 按原路直接经非 球面镜 AL返回到半导体激光二极管中。 可以看到， 在 Littrow 结构中光束在光栅上的入射角和衍射角相等， 即 θί=θ(1==θ, 因而 Δθ=0。
为了说明外腔半导体激光器的调谐原理，在附图中引入了直 角坐标系 xOy,其中 O点表示半导体激光二极管 LD所发出的激 光光束与光栅 G在初始位置的衍射表面的交点， X轴经过 O点且 方向与 LD发出的光线共线反向， y轴经过 O点并与 X轴垂直且 方向向上。
等效 LD后端反射面、 光栅 G的衍射表面和反射镜 M的反 射表面这三个平面均与 xOy坐标平面垂直。用 SG表示光栅衍射 表面所在的平面与 xOy坐标平面的交线， O点位于该交线上； SL 表示等效 LD后端反射面所在的平面与 xOy坐标平面的交线，它 距 O点的距离为 11; SM表示反馈反射镜 M的反射表面所在的 平面与 xOy坐标平面的交线， 它距 O点的距离为 12。
在图 1和图 2所示的掠入射和掠衍射结构中， 11和 12分别 表示 O点到等效 LD后端反射面和反馈反射镜 M的光学距离， 即光栅外腔的两个子腔长度， 整个半导体激光器的光学腔长用它 们之和 1= 11+ 12来表示。 在图 3所示的 Littrow结构中， 半导体 激光器的实际光学腔长即为 O点到等效 LD后端反射面的距离 11。
当转动光栅 G或反射镜 M进行调谐时，转动轴与 xOy坐标 平面垂直， 该转动轴与 xOy坐标平面的交点（即转动中心）在图 1至 3中用坐标 P ( x，y )来表示。 为了有助于分析， 引入了距离 参量 u、 V和 w， 其中 u表示转动中心 P到交线 SM的距离； V 表示转动中心 P到交线 SG的距离； w表示转动中心 P到交线 SL 的距离。 这里各参量 u、 V和 w取值的符号规定如下： 当光线与 转动中心在相应平面交线的同侧时用正值表示， 而当光线与转动 中心分别在相应平面交线的两侧时用负值表示。当光栅 G或反馈 反射镜 M围绕 P点转动时， 距离 V或 u保持不变。
在光栅外腔半导体激光器中，决定激光波长或频率的两个主 要因素是：
1. 由光线在光栅上的入射角和衍射角的取值和变化所决定 的选频作用；
2. 由 SL、 SM、 SG所形成的等效 F-P腔的腔长的取值和 变化所决定的选频作用。
在以转动中心 P 为轴转动光栅或反射镜的过程中， 光栅 选频作用和 F-P腔的选频作用均发生改变。 一般而言， 上述改变 不是同步的， 这将引起激光模式的跳模变化， 中断了激光频率的 连续调谐， 因而能够得到的激光频率不跳模时的连续调谐范围非 常小， 例如为 1至 2GHz。
为了实现激光波长或频率的同步调谐，即实现大范围不跳模 的频率连续调谐， 需要有目的地选择光栅 G或反馈反射镜 M的 转动中心 P。
假设在转动调谐之后光栅或反射镜相对于其初始位置转动 的角度为 α， 则激光光束在 F-P 腔内往返一周后的相位变化 ψ可 表示
Figure imgf000006_0001
其中 ψθ表示在转动调谐之前光束在腔内往返一周的初始相 位变化， Α(α)是与调谐转动角度 α有关的函数， 而 ψ0、 Β和 C是 与角度 α无关的函数。 ψ0、 Α(α)、 Β和 C与外腔半导体激光器的 初始参数有关， 这些初始参数包括初始角度（如初始入射角 θί、 初始衍射角 6d等） 、 初始位置 （如初始腔长 11和 12、 初始距离 u、 V和W等） 、 以及光栅常数 d等等。 当满足完全同步调谐的 条件时， 相位变化 ψ应当与调谐转动角度 α无关， 即公式 1中的 Β 和 C均应为零。
完全同步调谐的转动中心 Ρ0的距离参量应满足：
Figure imgf000006_0002
也就是说， 满足同步调谐限制条件的转动中心 Ρ0应当位于 光栅衍射表面所在的平面与 xOy坐标平面的交线 SG上； 同时， 转动中心 P0到反射镜反射表面所在平面的距离 u0和 P0到等效 LD后端反射面所在平面的距离 w0的绝对值相同而符号相反。
当用坐标 P0 ( x0, y0 )表示这种满足同步调谐限制条件的 转动中心时， 对于掠入射和掠衍射结构可以得到：
Figure imgf000006_0003
y0 = IdoosOi/ λ
其中 x0、 y0分别表示同步调谐转动中心 P0 的横坐标和纵 坐标， 1为在初始位置时的 F-P腔的等效腔长， d为光栅常数， 0i为光束在光栅上的入射角， λ为激光波长。 关于掠入射和掠衍射结构的同步调谐分别在图 4和图 5中示 出。
图 6示出了 Littrow结构的同步调谐， 由于在 Littrow结构 中没有反射镜， 即相当于 u0=w0, 因而公式 （2 ) 所描述的距离 参量 件变为：
Figure imgf000007_0001
即同步调谐中心 P0应位于直线 SG和 SL的交点处。
当用坐标 P0 ( x0， yO ) 表示时， 由于在 Littrow 结构中 θί=θά=θ, 实际光学腔长为 11， 因而公式（3 )所描述的距离参量 约束 ：
Figure imgf000007_0002
从上面的说明可以看出， 无论是采用坐标参量还是距离参 量， 同步调谐转动中心 Ρ0的位置总是要由两个方程的方程组来 描述， 必须同时满足上述两个约束条件， 这意味着在设计激光器 时需要两个具备独立自由度的调整机构。而且，无论是在掠入射、 掠衍射还是 Littrow结构的情况下， 同步调谐转动中心 P0的位 置均不能离开光栅衍射表面所在的平面 SG。 这种限制使得激光 器的结构设计、 调整和应用十分不利和困难， 同时造成了机械系 统的复杂性， 并增加了不稳定因素。
实际中，大的连续不跳模调谐范围还会受到许多其它因素影 响， 例如 LD表面是否镀有增透膜和镀膜质量等。 然而， 一般近 百个 GHz甚至几十个 GHz的激光频率的连续调谐范围已经能够 满足相当多应用的需求。 发明内容 本发明要解决的技术问题是找到一种对光栅外腔半导体激 光器进行近似同步调谐（即准同步调谐）的方法， 它不必受到严 格同步调谐的约束奈件限制， 使得调整机构更加稳定、 可靠和简 单， 同时又使得所得到的连续不跳模调谐范围近似于严格同步调 谐， 不会显著影响激光器的品质。
根据本发明，该技术问题通过一种用于对光栅外腔半导体激 光器进行调谐的方法来解决， 其中以一个准同步调谐点为转动中 心转动半导体激光器的光栅或反射镜， 使得在转动期间光栅衍射 表面所在的平面或反射镜反射表面所在的平面与该准同步调谐 点之间的距离保持不变， 从而实现光栅和谐振腔的选频作用的准 同步调谐， 其中以下述方式确定所述准同步调谐点：
确定一个同步调谐点，使得当以该同步调谐点为转动中心转 动光栅或反射镜时， 在半导体激光器的谐振腔内激光光束的往返 相位差保持不变， 所述准同步调谐点位于一条经过所述同步调谐 点的直线上， 该直线相对于入射到光栅上的光线方向的夹角根据 激光光束在光栅上的入射角与衍射角之差 ΔΘ来确定， 即当转动 光栅时， 所述夹角为 ΔΘ/2; 当转动反射镜时， 所述夹角为 Δθ。
根据本发明，还提供了相应的外腔半导体激光器， 其中包括 用于执行上述准同步调谐方法的准同步调谐机构， 该准同步调谐 机构围绕如上所述确定的准同步调谐转动中心转动光栅或反射 镜， 从而实现光栅和谐振腔选频作用的准同步调谐。 其中所述外 腔半导体激光器既可以是 Littman结构或掠衍射结构， 也可以是 Littrow结构。在 Littrow结构外腔半导体激光器的情况下， 由于 入射角与衍射角之差 Αθ=0， 因而准同步调谐中心与同步调谐中 心之间的连线平行于入射到光栅上的光线方向。
本 发 明 是 基 于 以 下 发 现 ： 在 上 述 公 式 ^ = ^ + ^ . [ sina +c (i - c。s «)] (公式 D所描述的调谐相位变化中， 调谐转动角度 α在用弧度表示时是一个远小于 1且接近于零的微 小量。 根据泰勒级数展开定理， 可知公式 1的中括号内的第一项 since是从调谐转动角度 α 的一阶项开始的奇次高阶项， 而第二项 (1-cosa)是从调谐转动角度 α 的二阶项开始的偶次高阶项， 它是 一个比 sina更高阶的微小量， 对往返相位变化 ψ的贡献远小于 sina。 因此， 可以对往返相位变化 ψ作一阶近似， 即略去公式 1 中的二阶项及其更高阶项。如果忽略公式 1的中括号内的第二项， 则往返相位变化 ψ可近似表示为：
ψ = ψ + ^(c ' 'sin Gi ^ ( 6 ) 在此情况下，为了使往返相位变化 ψ与调谐转动角度 α无关， 可令系数 Β为零。 即：
Β = ο ( 7 ) 这种近似被称为准同步调谐近似，在这一近似下对外腔半导 体激光器频率的调谐为准同步调谐， 相应的光栅或反射镜的转动 中心被称为准同步调谐转动中心 Pq， 其坐标可表示为 Pq ( xq,yq ) 。 在这种近似范围内， 调谐转动角度 α引起的往返位相 变化可以忽略， 即 ψ«ψ0, 近似于一个与调谐转动角度无关的常 数。 在实际应用中， 外腔半导体激光器参数及调谐转动角度 α的 调谐范围几乎完全满足这一近似条件。
通过本发明所述技术方案， 减少了同步调谐的约束条件数 目， 使得调整机构只需要一个调整自由度。 而且转动中心的位置 不必再受到不能离开光栅表面所在平面交线 SG的限制， 这使得 同步调谐具有更灵活的选择和更大的发挥余地， 易于设计实现激 光的近似同步转动频率或波长调谐。 附图说明
图 1示出了 Littman (掠入射）结构的光栅外腔半导体激光 器的简化视图；
图 2 示出了掠衍射结构的光栅外腔半导体激光器的简化视 图；
图 3示出了 Littrow结构的光栅外腔半导体激光器的简化视 图；
图 4示出了针对 Littman结构的常规同步调谐转动中心的确 定；
图 5 示出了针对掠衍射结构的常规同步调谐转动中心的确 定；
图 6示出了针对 Littrow结构的常规同步调谐转动中心的确 定；
图 7示出了根据本发明在光栅转动调谐时针对 Littman结构 的准同步调谐转动中心的确定；
图 8 示出了根据本发明在光栅转动调谐时针对掠衍射结构 的准同步调谐转动中心的确定；
图 9 示出了根据本发明在反射镜转动调谐时针对 Littman 结构的准同步调谐转动中心的确定；
图 10示出了根据本发明在反射镜转动调谐时针对掠衍射结 构的准同步调谐转动中心的确定；
图 11示出了根据本发明针对 Littrow结构的准同步调谐转 动中心的确定；
图 12示出了在光栅转动调谐时 Littman结构光栅外腔半导 体激光器的准同步调谐机构；
图 13示出了在光栅转动调谐时掠衍射结构光栅外腔半导体 激光器的准同步调谐机构；
图 14示出了在反射镜转动调谐时 Littman结构光栅外腔半 导体激光器的准同步调谐机构；
图 15示出了在反射镜转动调谐时掠衍射结构光栅外腔半导 体激光器的准同步调谐机构； 以及
图 16示出了 Littrow结构光栅外腔半导体激光器的准同步 调谐机构。 具体实施方式
图 7至 11分别表示出了根据本发明确定光栅外腔半导体激 光器的准同步调谐转动中心的各种实施方式。
图 7和图 8示出了转动光栅进行调谐的情况，此时光线在光 栅 G上的入射角 θί和衍射角 θ(1均发生改变。 对于掠入射和掠衍 射结构的外腔半导体激光器来说， 当前述公式 6中的系数 Β为零 时， 光栅 G的准同步调谐转动中心坐标 Pq ( xq，yq )满足以下条 件：
yq ~ y = ~(xq― θ) · tan-^ ( 8 ) 其中 χθ和 y0为由公式 3所给出的同步调谐转动中心坐标， ΔΘ为入射角与衍射角之差， 即厶0 = 9 03。 在 xOy平面上， 满足 公式 8的光栅转动中心坐标 Pq(xq，yq)的轨迹为一奈经过同步调 谐转动中心 P0 ( x0,y0 ) 的直线， 该直线与 X轴负方向的夹角为 ΔΘ/2。 如果用距离参量 uq、 vq和 wq来表示的话， 在准同步调 谐的条件下， 光栅转动调谐时的距离参量 uq、 vq和 wq满足：
(uq + νν^)· (cos ^ " + cos 2 · · (l + cos Δ^) = 0 ( 9 ) 图 9和图 10示出了转动反射镜进行调谐的情况， 此时只有 衍射角 ed发生改变， 而入射角 θί 不变。 对于掠入射和掠衍射结 构的外腔半导体激光器来说， 当公式 6中的系数 B为零时， 反射 镜 M的准同步调谐转动中心坐标 Pq( xq，yq )坐标满足以下条件： yq - yQ = -{xq - Λ:0)· tan Αθ ( 10 ) 其中 χθ和 y0为由公式 3所给出的同步调谐转动中心坐标， ΔΘ为入射角与衍射角之差， 即 Δθ = θί - θά。 在 xOy平面上， 满足 公式 10的反射镜转动中心坐标 Pq(xq，yq)的轨迹同样为一条经过 同步调谐转动中心 P0 ( x0,y0 ) 的直线， 该直线与负 X轴方向的 夹角为 Δθ。 如果距离参量 uq、 vq和 wq来表示的话， 在准同步 调谐的条件下， 反射镜转动调谐时的距离参量 uq、 vq和 wq满 足：
(uq + wq)- cos θά - - vq - (\ + cos Δ^) = 0 ( 11 ) 从上述公式 8和公式 10可以看出， 当衍射角 和入射角 0i 相等， 即 θ(1=θί=θ时， Δθ=0, 则可得到 Littrow结构的准同步调 谐条件， 即：
yq = y0 ( 12 ) 其中 y0为由公式 5给出的同步调谐转动中心 P0的纵坐标。 在 xOy平面上， 满足以上奈件的准同步转动中心坐标 Pq(xq，yq) 的轨迹为一条经过同步调谐转动中心点 P0 ( x0,y0 ) 且与 X轴平 行的直线（参见图 11 )。 当用距离参量 uq、 vq和 wq来表示时， 则需满足以下公式：
wq - cos 0 - - vq = 0 ( 13 ) 这里， 距离参量 uq、 vq和 wq的符号规定为： 若光线与准 同步调谐转动中心 Pq在相应平面交线的同侧则为正，反之为负。
因而，从激光器的实际物理空间上看，在 xOy坐标平面上， 满足准同步调谐条件的转动中心 Pq(xq，yq)可以看作是从常规的 同步调谐条件下的转动中心 P0(x0,y0)拓展到经过该 P0点的一条 直线上的位于 P0点附近的区间，该区间可以位于 P0点的任意一 侧。 对于掠入射和掠衍射结构的外腔半导体激光器来说， 当光栅 转动调谐时 （图 7和图 8 ) ， 该直线平行于反射镜 M的法线 N 和半导体激光二极管 LD发出的光线之间的角平分线； 当反射镜 转动调谐时（图 9和图 10 )， 该直线平行于反射镜 M的法线 N。 对于 Littrow结构的外腔半导体激光器来说（图 11 ) ， 相当于反 射镜 M与等效 LD后端反射面重合， 转动光栅 G来进行调谐， 此时该直线平行于半导体激光二极管 LD发出的光线。 在根据本 发明所确定的这条直线上， 可以获得明显优于其它位置的大的同 步调谐范围， 且越接近同步调谐点 P0(x0，y0), 所得到的同步调谐 范围就越大。
图 12和图 13分别示出了转动光栅进行调谐时掠入射结构和 掠衍射结构外腔半导体激光器的准同步调谐机构。
如图 12所示， 半导体二极管 LD发出例如功率为 30mW、 波长为 689nm 的激光光束， 经过焦距为 4mm、 数值孔径为 0.6 的非球面准直透镜 AL准直后， 入射到刻线密度为 1800g/mm、 具有适当衍射效率、 刻线面积大小为 12.5mmxl2.5min、 厚度为 6mm的全息衍射光栅 G上， 光栅 G的零阶衍射光或直接镜反射 光作为激光器的输出光束。 光栅的一级衍射光正入射到平面反射 镜 M上， 在 M上反射后光线被反向， 沿着与原入射光束共线反 向的路径， 沿原路经光栅再次衍射后， 返回到半导体二极管 LD 中。
激光二极管 LD通过热沉 2例如采用温度传感器和半导体制 冷器实现温度控制。 下面描述准同步调谐机构的具体实现： 准直 透镜 AL通过镜架 4被调整和固定，衍射光栅 G被固定在调节架 动板 6上， 其方向可通过调节架定板 7上的调节螺钉 8和 9进行 调整， 还可以通过动板上的压电陶瓷 10进行细调， 反射镜 M通 过固定架 11固定在底板 13上。 外腔和光栅的选频作用通过围绕 准同步转动中心 Pq转动衍射光栅 G来实现。 例如， 通过微调螺 钉 8改变衍射光栅 G的角度进行粗调， 和 /或经过在压电陶瓷 10 施加控制电压进行微调。
在图 12所示的 L man结构外腔半导体激光器中， 光栅转 动的准同步调谐转动中心 Pq (xq, yq)位于一条经过常规同步 调谐转动中心 P0 (χθ, y0) 且与 X轴负方向的夹角为 ΔΘ/2的直 线上， 此时由于 θί>θ<1， 因而 Δθ>0。
图 13所示的光栅转动调谐的掠衍射结构外腔半导体激光器 与图 12所示的掠衍射结构类似， 区别仅在于反射镜 Μ的位置不 同， 使得 0i<ed， 因而 Δθ<0。 光栅转动准同步调谐转动中心 Pq (xq, yq) 同样位于一条经过常规同步调谐转动中心 P0 (x0， y0)且与 X轴负方向的夹角为 ΔΘ/2的直线上， 但该直线的倾斜方 向与图 12所示相反。
类似地，图 14和图 15分别示出了转动反射镜进行调谐时掠 入射结构和掠衍射结构外腔半导体激光器的准同步调谐机构。
在图 14和图 15所示的准同步调谐机构中， 光栅 G通过固 定架 11固定在底板 13上， 反射镜 M被固定在调节架动板 6上， 其方向可通过调节架定板 7上的调节螺钉 8和 9进行调整， 也可 通过动板上的压电陶瓷 10进行微调。 通过围绕准同步转动中心 Pq转动反射镜 M来实现外腔和光栅的选频作用。 例如， 通过微 调螺钉 8改变反射镜 M的角度进行粗调， 和 /或经过在压电陶瓷 10施加控制电压进行微调。
在图 14所示的反射镜转动调谐的 Littman结构外腔半导体 激光器中， 反射镜转动准同步调谐转动中心 Pq (xq， yq)位于 642
一条经过常规同步调谐转动中心 P0 (x0, y0) 且与 X轴负方向 的夹角为 ΔΘ的直线上， 此时由于 θί>θ(1， 因而 Δθ>0。
图 15所示的反射镜转动准同步调谐的掠衍射结构外腔半导 体激光器与图 14所示的掠衍射结构类似， 区别仅在于反射镜 Μ 的位置不同， 使得 θί<θ(1， 因而 Δθ<0。 反射镜转动准同步调谐 转动中心 Pq (xq, yq) 同样位于一奈经过常规同步调谐转动中 心 P0 (x0， y0)且与 X轴负方向的夹角为 ΔΘ的直线上， 但该直 线的倾斜方向与图 14所示相反。
图 16示出了准同步调谐的 Littrow结构外腔半导体激光器 的示意图， 其中 9i = ed = e。 如图 16所示， 光栅 G的一级衍射光 沿着与原入射光束共线反向的路径， 沿原路返回到半导体二极管 LD中。 在其准同步调谐机构中， 光栅 G被固定在调节架动板 6 上， 该动板 6可通过在调节架定板 7上的调节螺钉 8和 9进行调 整。 通过绕准同步转动中心 Pq转动衍射光栅 G来实现激光波长 的调谐。 例如， 通过微调螺钉 8和 /或压电陶瓷 10改变光束入射 到衍射光栅 G上的角度，而准同步转动中心 Pq和光栅 G的对准 调整可通过调整螺钉 9来实现。
从图 16中可以看到，在 Littrow结构外腔半导体激光器中， 准同步调谐转动中心 Pq (xq, yq)位于一条经过常规同步调谐 转动中心 P0 (x0， y0) 且与 X轴平行的直线上。
本领域技术人员可知，上述例子中的半导体激光管也可选用 其它波长和输出功率， 光栅也可采用闪耀光栅或透射光栅， 其可 以具有其它刻线密度、 大小和厚度， 准直透镜也可以采用其它焦 距和数值孔径。 附图标记列表
1. 半导体二极管 LD . 热沉
. 准直透镜 AL . 镜架
. 反射镜 M
. 调节架动板
. 调节架定板
. 调节螺钉（微调） . 调节螺钉
10. 压电陶瓷
11. 固定架
12. 光栅 G
13. 底板

Claims

1. 一种用于对光栅外腔半导体激光器进行准同步调谐的方 法， 其中以一个准同步调谐点（Pq )为转动中心转动半导体激光 器的光栅或反射镜， 使得在转动期间光栅衍射表面所在的平面或 反射镜反射表面所在的平面与该准同步调谐点（ Pq )之间的距离 保持不变， 从而实现光栅和谐振腔的选频作用的准同步调谐， 其 中以下述方式确定所述准同步调谐点 （Pq ) ：
确定一个同步调谐点 （P0 ) ， 使得当以该同步调谐点 （P0 ) 为转动中心转动光栅或反射镜时， 在半导体激光器的谐振腔内激 光光束的往返相位差保持不变， 所述准同步调谐点（Pq )位于一 条经过所述同步调谐点（P0 )的直线上， 该直线相对于入射到光 栅上的光线方向的夹角根据激光光束在光栅上的入射角与衍射 角之差 ΔΘ来确定， 即当转动光栅时， 所述夹角为 ΔΘ/2; 当转动 反射镜时， 所述夹角为 Αθ。
2. 根据权利要求 1所述的方法， 其特征在于， 所述半导体激 光器是 Littman结构或掠衍射结构激光器。
3. 根据权利要求 1所述的方法， 其特征在于， 所述半导体激 光器是 Littrow结构激光器， 并通过以所述准同步调谐点 （Pq ) 为转动中心转动光栅来进行调谐， 其中所述准同步调谐点 （Pq ) 与所述同步调谐点（P0 )之间的连线平行于入射到光栅上的光线 方向。
4. 一种 Littman结构或掠衍射结构的光栅外腔半导体激光器， 包括： 半导体激光管 （1 ) 、 非球面准直透镜（3 ) 、 光栅（12 ) 和反射镜（5 ) ， 其中所述半导体激光器还包括准同步调谐机构， 所述准同步调谐机构围绕一个准同步调谐转动中心（ Pq )转动所 述光栅（12) 或反射镜（5) ， 使得在转动期间光栅衍射表面所 在的平面或反射镜反射表面所在的平面与该准同步调谐点 （Pq) 之间的距离保持不变， 从而实现光栅和谐振腔选频作用的准同步 调谐， 其中以下述方式来确定所述准同步调谐转动中心 （Pq) ： 确定一个同步调谐点 （P0) ， 使得当以该同步调谐点 （P0) 为转动中心转动光栅（12)或反射镜 （5) 时， 在半导体激光器 的谐振腔内激光光束的往返相位差保持不变， 所述准同步调谐点 (Pq)位于一条经过该同步调谐点（P0)的直线上， 该直线相对 于入射到光栅上的光线方向的夹角根据激光光束在光栅上的入 射角与衍射角之差 ΔΘ来确定， 即当转动光栅（G)时， 所述夹角 为 ΑΘ/2; 当转动反射镜（M) 时， 所述夹角为 Δθ。
5. 根据权利要求 4所述的光栅外腔半导体激光器， 其特征在 于，所述准同步调谐机构通过调节螺钉（ 8 )来调整所述光栅（ 12 ) 或反射镜（5) 的转动角度， 和 /或通过在压电陶瓷（10) 上施加 控制电压来对该转动角度进行微调。
6. 一种 Littrow结构的光栅外腔半导体激光器， 包括： 半导 体激光管 （1) 、 非球面准直透镜（3)和光栅（12) ， 其中所述 半导体激光器还包括准同步调谐机构， 所述准同步调谐机构围绕 一个准同步调谐转动中心（Pq)转动所述光栅（12) ， 使得在转 动期间光栅衍射表面所在的平面与该准同步调谐点（ Pq )之间的 距离保持不变， 从而实现光栅和谐振腔选频作用的准同步调谐， 其中以下述方式来确定所述准同步调谐转动中心 （Pq) ：
确定一个同步调谐点 （P0) ， 使得当以该同步调谐点 （P0) 为转动中心转动光栅（12) 时， 在半导体激光器的谐振腔内激光 光束的往返相位差保持不变， 所述准同步调谐点（Pq)位于一条 经过该同步调谐点（P0)的直线上， 该直线平行于入射到光栅上 的光线方向。
7. 根据权利要求 6所述的光栅外腔半导体激光器， 其特征在 于，所迷准同步调谐机构通过调节螺钉（ 8 )来调整所述光栅（ 12 ) 的转动角度， 和 /或通过在压电陶瓷（ 10 )上施加控制电压来对该 转动角度进行微调。
PCT/CN2009/000642 2008-06-18 2009-06-10 光栅外腔半导体激光器及其准同步调谐方法 WO2009152690A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29606494U1 (de) * 1996-04-10 1997-05-07 Sacher, Joachim, Dr., 35041 Marburg Abstimmvorrichtung
US6018535A (en) * 1998-04-23 2000-01-25 Ando Electric Co., Ltd. External cavity type wavelength-tunable light source
US6026100A (en) * 1997-06-06 2000-02-15 Ando Electric Co., Ltd. External cavity-type of wavelength tunable semiconductor laser light source and method for tuning wavelength therefor
US6778564B2 (en) * 2001-01-31 2004-08-17 Ando Electric Co., Ltd. Wavelength-variable light source
US6850545B2 (en) * 2000-12-21 2005-02-01 Ando Electric Co., Ltd. Wavelength tunable light source
US20070223554A1 (en) * 2006-03-09 2007-09-27 Inphase Technologies, Inc. External cavity laser

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8807385D0 (en) * 1988-03-29 1988-05-05 British Telecomm Semiconductor device assembly
SE463181B (sv) * 1989-09-07 1990-10-15 Radians Innova Ab Saett att saekestaella modhoppsfri avstaemning av resonansfrekvens och q-vaerde hos en optisk resonator samt anordning foer utoevande av saettet
US5867512A (en) * 1997-02-10 1999-02-02 Sacher; Joachim Tuning arrangement for a semiconductor diode laser with an external resonator
FR2775390B1 (fr) * 1998-02-20 2000-05-05 Photonetics Source laser monomode continument accordable en longueur d'onde
CN101582561B (zh) 2008-05-12 2012-07-04 中国计量科学研究院 光栅掠衍射外腔半导体激光器
US8681825B2 (en) * 2008-06-18 2014-03-25 National Institute of Metrology Peoples Republic of China Grating external-cavity laser and quasi-synchronous tuning method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29606494U1 (de) * 1996-04-10 1997-05-07 Sacher, Joachim, Dr., 35041 Marburg Abstimmvorrichtung
US6026100A (en) * 1997-06-06 2000-02-15 Ando Electric Co., Ltd. External cavity-type of wavelength tunable semiconductor laser light source and method for tuning wavelength therefor
US6018535A (en) * 1998-04-23 2000-01-25 Ando Electric Co., Ltd. External cavity type wavelength-tunable light source
US6850545B2 (en) * 2000-12-21 2005-02-01 Ando Electric Co., Ltd. Wavelength tunable light source
US6778564B2 (en) * 2001-01-31 2004-08-17 Ando Electric Co., Ltd. Wavelength-variable light source
US20070223554A1 (en) * 2006-03-09 2007-09-27 Inphase Technologies, Inc. External cavity laser

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