WO2015100716A1 - 一种评价激光器稳定性的方法 - Google Patents

一种评价激光器稳定性的方法 Download PDF

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WO2015100716A1
WO2015100716A1 PCT/CN2014/070027 CN2014070027W WO2015100716A1 WO 2015100716 A1 WO2015100716 A1 WO 2015100716A1 CN 2014070027 W CN2014070027 W CN 2014070027W WO 2015100716 A1 WO2015100716 A1 WO 2015100716A1
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laser
laser power
power
value
stability
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PCT/CN2014/070027
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English (en)
French (fr)
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张书练
刘宁
刘维新
吴云
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清华大学
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Priority to PCT/CN2014/070027 priority Critical patent/WO2015100716A1/zh
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4257—Photometry, e.g. photographic exposure meter using electric radiation detectors applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam
    • 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
    • H01S3/0014—Monitoring arrangements not otherwise provided for

Definitions

  • the present invention relates to the field of laser measurement technology, and in particular to a test method for evaluating laser stability.
  • the stability of the laser has a great influence on the performance of the laser measuring device.
  • the first thing to do is to correctly evaluate the 'laser stability'.
  • Laser power stability is one of the key parameters to measure the stability of the laser.
  • the influencing factors can be divided into non-deterministic and deterministic.
  • the former is caused by unpredictable fluctuations in laser components such as pump source, resonant cavity, working medium, and transition quantum noise.
  • the latter is caused by laser oscillation mode drift caused by laser cavity length change.
  • the stability of the evaluation laser is mainly to determine the influence of non-deterministic factors, and the deterministic influence factors can be compensated by technical means in applications such as laser stabilization.
  • the evaluation of laser stability is to record the total power of the laser for a certain period of time, obtain the maximum and minimum values on the entire power curve, and the average value of the laser power, and calculate the percentage of the total change of the laser power relative to the average value of the laser power. That is the laser power stability.
  • the non-deterministic H-determination factor contributes to the change in laser power.
  • the fluctuation of the laser power caused by the deterministic H is small because the average effect is small relative to the non-deterministic factor, and can be neglected.
  • Laser power stability is to record the total power of the laser for a certain period of time, obtain the maximum and minimum values on the entire power curve, and the average value of the laser power, and calculate the percentage of the total change of the laser power relative to the average value of the laser power. That is the laser power stability.
  • the non-deterministic H-determination factor contributes to the change in laser power.
  • the deterministic factor causes a large amount of change in the laser power, and the stability of the laser cannot be correctly evaluated according to the method of the above.
  • the object of the present invention is to overcome the deficiencies in evaluating laser stability by using existing methods, and to propose a method for eliminating laser power fluctuation caused by laser cavity length drift, thereby distinguishing the effects of non-deterministic factors and deterministic factors on laser power.
  • the present invention is capable of accurately evaluating 'laser W stability, especially for a laser flJ ⁇ with less oscillation mode.
  • the invention proposes a method for evaluating the stability of a laser, which mainly comprises the following steps:
  • Step a In the long-stretching stage of the laser preheating chamber, the output optical power of the laser is received and recorded by the photodetector; step b) determining each passive power caused by the change of ⁇ length in the obtained laser power variation curve The peak value of the period ⁇ ⁇ , and the peaks are connected to form a peak curve of the laser power;
  • the laser operates in a single longitudinal mode state or a state in which the number of longitudinal modes is small, and the cavity length of the laser is in a freely stretchable state under temperature change and environmental disturbance conditions.
  • the method for evaluating the stability of the laser described above needs to obtain the peak value ⁇ ⁇ of each power fluctuation period caused by the change of the cavity length according to the laser power variation curve, and the steps include:
  • the minimum laser power in the interval is sought as the valley value ⁇ ⁇ in the laser power fluctuation period ;
  • the auxiliary reference line of the next laser power fluctuation curve is calculated, and the above steps are repeated.
  • the 'laser power fluctuation curve auxiliary reference line can be obtained from the average value of the laser power in a period of time before calculation;
  • the auxiliary reference line of the laser power fluctuation curve of the way can be obtained by calculating the average value of the peak ⁇ ⁇ and the valley value of the previous power fluctuation cycle plus the fixed offset threshold.
  • the evaluation method proposed by the invention records the peak value of each power fluctuation period caused by the change of the laser power with the cavity length, and the change is only caused by the non-deterministic factor, so the influence of the deterministic factor can be effectively eliminated, and the power stability of the laser can be accurately obtained. degree.
  • FIG. 1 Schematic diagram of the frequency distribution of the laser operating in less frequent mode
  • Figure 2 is a flow chart of a method for evaluating laser stability
  • Figure 3 is a flow chart showing the determination of the reference auxiliary line and finding the peak and valley values of the laser power fluctuation period between the partitions. detailed description
  • the stability of the laser will largely affect the performance of the system.
  • lasers are required to have high power stability to reduce system errors.
  • fine metering such as single-frequency/dual-frequency dry sputum
  • the stability of the laser frequency is accurate to Important, surface laser stabilization is usually judged by the light intensity signal. in accordance with. Therefore, this puts high demands on the stability of the laser, especially the power stability.
  • the factors affecting the stability of the output power of the laser can be divided into two categories: Aspect, variation of the laser pump source, uneven heating of the cavity or deformation due to vibration, causing the mirror to deviate from the parallel state, the fluctuation of the working medium gain atom, the transition Various non-deterministic factors such as quantum noise will cause laser power variation; on the other hand, the slow variation of the laser cavity length with temperature will cause the laser oscillation mode to drift within the gain band. Since the gain curve is usually not uniform, the laser mode Different gains in the gain band will not affect the laser output power. As long as the laser does not have a line of frequency stabilization, that is, the cavity is in a freely stretchable state, the change in cavity length causes the laser mode to drift and the laser frequency changes. And power fluctuations.
  • this change in cavity length causes a significant fluctuation in the total power of the laser, even more than the power variation caused by non-deterministic factors.
  • laser power fluctuations and laser mode drift The shift or frequency drift is related. That is, when the laser!! long unidirectional change, the laser power fluctuation will periodically appear according to a certain rule. Different from the first case, this can be regarded as one that affects the stability of the laser. a certainty factor.
  • dual-frequency lasers usually require frequency stabilization (such as for dual-frequency laser detectors).
  • frequency stabilization techniques such as equal-light intensity stabilization, use the light intensity signal as the detection physical quantity, and generate error signal feedback to control the laser cavity length, and then control the laser frequency to stabilize at the set working point.
  • the stability of the frequency is based on the light intensity, and the above two factors affecting the stability of the laser play different roles. The role of non-deterministic factors is unfavorable. Even when the laser frequency (or mode) does not change, it causes random fluctuations in laser power. If this effect is non-common to the laser frequencies, it will cause a false positive in the loop and control the laser frequency to deviate from the set operating point.
  • the ⁇ 8 ⁇ length can be controlled for active compensation, which is beneficial to achieve stable laser frequency. Therefore, the above two factors affecting laser stabilization should be treated as a zone.
  • the former can be considered as unpredictable and feedback compensated in the 'laser frequency stabilization process. Only by selecting a laser system with better performance can reduce its influence on the stability of the laser as much as possible; while the latter has a certain physical law, which can be used as laser stabilization.
  • the frequency is based on the implementation of the basis.
  • the laser power variation curve thus obtained actually includes two kinds of influencing factors of laser stability.
  • cavity length drift causes The deterministic fluctuations in laser power are small compared to non-deterministic effects and can be ignored.
  • This method can reflect the undetermined variation of the chopper and obtain the stability index.
  • the deterministic fluctuation of the laser power caused by the cavity length drift cannot be ignored. As shown in Fig.
  • the mode in which the light-inviting device satisfies the threshold condition is V (J and v ?+1).
  • the laser oscillation mode obtains the gain at the non-n-frequency position when the emission band is drifting. ? Vi is different, its power (or light intensity) will change accordingly. If the laser cavity length changes continuously along the elongation direction, the oscillation mode sweeps out the light band, and the optical power curve forms a fluctuation period consistent with the gain curve. The situation occurs in the laser heating process ⁇ . If the laser is stabilized, the oscillation mode is stabilized at the position determined on the exit band, and the power will not change periodically.
  • the output power of the oscillation mode is determined by the gain obtained.
  • the influence of non-deterministic factors on the laser is mainly caused by the deformation of the value of the oscillation (3 ⁇ 4 up and down translation or gain curve ⁇ v). Sex factors cause the oscillation mode to move differently on the gain curve.
  • the laser gain tube will be unevenly heated, and the thermal expansion along the laser axis will cause the resonator mirror to deviate from each other in parallel with each other.
  • the corresponding laser power is the maximum value in one fluctuation period, and the peak value of the laser power fluctuation is convenient for determination.
  • the elongation of the cavity will cause the oscillations of each level to enter the light strip and sweep through the center frequency to form periodic fluctuations.
  • various non-deterministic factors will occur.
  • the oscillation threshold or gain curve is changed irregularly, and the peak value in the fluctuation period is affected accordingly. According to the variation of the peak value, the influence of non-deterministic factors on the laser stability can be obtained.
  • P p is the maximum power peak of the ship during the test lasers'
  • P p ta is the minimum value of the peak power of the laser during the test, a laser power during the peak of the average value of the test
  • this method is more effective for a laser operating in a single longitudinal mode state or a state in which the number of longitudinal modes is small, and the cavity length of the laser is in a freely stretchable state under temperature change and environmental disturbance conditions. .
  • a feasible method is to test the process ⁇ to establish an auxiliary reference line and each power fluctuation curve intersect, divide it into different intervals, and then find the power peaks in different intervals.
  • the auxiliary reference line can be obtained from the power average of the previous period.
  • the laser power variation is small for a period of time, and the power average is very close to the measured value.
  • the slight fluctuation of the power causes the false judgment of the laser power peak.
  • This B inch can improve the acquisition of the auxiliary reference line, which is obtained by superimposing a certain offset threshold from the average value of the peak and valley values of the previous power fluctuation.
  • the laser power is received by the photodetector; it is judged according to the recorded laser power variation curve: (S05) determining whether the laser cavity length changes rapidly; (S06) if the cavity length changes faster, according to the laser in the previous period of time The average value of the power is calculated to obtain the value of the current auxiliary reference line; (S07) If the cavity length changes slowly, the peak value and the valley value of the previous power fluctuation period can be calculated and the average value can be added to obtain an auxiliary reference.
  • the value of the line; (S08) The next step is to judge whether the measured laser power is greater than the value of the auxiliary reference line; (S09) If the current laser power is greater than the reference auxiliary line value, find the maximum value of the laser power in the interval that remains greater than the condition Is the peak value P p in the laser power fluctuation period ; (S10) if the current laser power is less than the reference auxiliary line value, the minimum value of the laser power in the interval remaining under the condition is sought as the laser power fluctuation period The valley value! ⁇ (S11) to determine whether the test is over, if not, return to the step (S04) to repeat the above process, Laser power probe continued next time.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Semiconductor Lasers (AREA)
  • Lasers (AREA)

Abstract

一种评价激光器稳定性的方法，不同于以往在一定时间内检测激光功率变化量来衡量其稳定性的方法。对于可以工作在单纵模或共振模较少状态下的激光器，输出功率因为激光腔长的漂移会产生幅度较大的周期性波动，不同于其他因素造成的激光功率非规律性变动。提出了测量激光器极值功率变化的方法，可以剔除前一种影响，给出非确定性因素造成的激光功率变动量，能更准确地反映激光器的稳定性。

Description

一种评价激光器稳定性的方法
本发明涉及激光测量技术领域， 特别涉及一种评价激光器稳定性的测试方法。 黄景技术
在实际应用中， 激光器的稳定性对激光测量仅器的性能影响很大。 在设计过程中需要选 取满足要求的激光器， 因丽首先要对 '激光器的稳定性《行正确评价。 激光器功率稳定性是衡 量激光器稳定性的关键参数之一， 其影响因素可分为非确定性和确定性两种。 前者是由于激 光器组成单元如泵浦源、 谐振腔、 工作介质以及跃迁量子噪声等不可预知的变动会造成激光 功率变化； 后者是由于激光器谐振腔长变化会引起激光振荡模式漂移使激光功率变化。 实际 上， 评价激光器的稳定性主要是确定非确定性因素的影响有多大， 确定性影响因素在激光稳 频等应用 是可以通过技术手段补偿的。
通常评价激光器稳定性是在一定时间内记录激光器总功率， 得到整个功率变化曲线上的 最大值和最小值， 以及激光功率的平均值， 计算激光功率总改变量相对于激光功率平均值的 百分比， 即为激光功率稳定度。 在这种评价方法中， 非确定性 H素》确定性因素对激光功率 的变化都有贡献。 当激光器工作在多振荡模式下并振荡模式个数很多时， 确定性 H素造成激 光功率的波动由于平均效应相对于非确定性因素的而言很小， 可以忽略不计， 因而能采用上 述方法得到激光器功率稳定度。 但当激光器工作在单級模， 或者多振荡模式且个数较少时， 确定性因素造成激光功率的变化量较大， 根据上途方法就无法正确评价激光器的稳定性。
¾明内容
本发明的目的在于克服采用现有方法评价激光器稳定性的不足， 提出消除激光腔长漂移 引起的激光功率波动的方法， 从而区别非确定性因素和确定性因素各自对激光功率的影响。 本发明能够准确评价'激光器 W稳定性， 特别对于振荡模式较少的激光器 flJ昼。
本发明提出了一种评价激光器稳定性的方法， 其主要包括下列步骤：
歩骤 a)在激光器预热腔长伸縮阶段， 所述激光器输出光功率由光电探测器接收并记录; 歩骤 b) 判断所得到的激光功率变化曲线中隨 β长改变引起的每个功率被动周期的峰值 ΡΡ , 并连接各峰值形成激光功率峰值曲线；
歩骤 c) _根据所述的激光功率峰值曲线， 得到测试过程中的激光功率峰值的平均值 , 以及最大值 魏和最小值 ι^η , 代入计算公式： rl>mm= ―— 其中 激光功率峰 值稳定度， 为评价激光器稳定性《指标。 '
特别的， 所述的激光器工作在单纵模状态或者纵模个数较少的状态， 并 JL所述激光器腔 长随温度改变和环境扰动条件下处于自由伸缩状态。
上面所述的评价激光器稳定性的方法， 需要根据所述激光功率变化曲线得到隨腔长改变 引起的每个功率波动周期的峰值 Ρρ , 其歩骤包括：
根据已经记录的激光功率数值计算得到与激光功率被动曲线都相交的辅助参考线； 当激光功率测量值大于辅助参考线时， 寻找该区间内激光功率最大值为所述激光功率 ¾ 动周湖内的峰值
当激光功率测量值小亍辅助参考线时 , 寻找该区间内激光功率最小值作为所述激光功率 波动周期内的谷值 Ρν ;
根据得到的激光功率波动峰值 和谷值 ， 以及测量的激光功率值， 计算下一个激光功 率波动曲线的辅助参考线， 重复上述步骤。
在上述根据激光功率变化曲线确定每个功率波动周期的峰值 Ρρ , 计算域激光功率波动曲 线都相交的辅助参考线时， 可以根据下面两种不同情况分别得到：
当激光器腔长变化较快时， 所述的 '激光功率波动曲线辅助参考线可由计算前一段时间内 的激光功率平均值得到；
当激光器腔长变化较慢时， 所途的激光功率波动曲线辅助参考线可根据前一个功率波动 周期的峰值 Ρρ和谷值 计算平均值再加上' 定的偏置阈值得到。
本发明提出的评价方法¾录激光器功率隨腔长改变引起的每个功率波动周期的峰值， 其 变化仅由非确定性因素引起， 因此可以有效消除确定性因素的影响， 准确得到激光器的功率 稳定度。
图 1 激光器工作在较少娠荡模式下频率分布示意图；
图 2评价激光器稳定性的方法流程图；
图 3具体实施例提供的确定参考辅助线并分区间寻找激光功率波动周期的峰值和谷值的 流程图。 具体实施方式
实际应用中， 激光器的稳定性很大程度上会影响系统的性能。 在光学测量、 光电检测等 应用中， 需要激光器具有高功率稳定度减小系统误差； 在精蜜计量（如单频 /双频干渉仪）等 应用中， 激光器频率的稳定性对 «量精度至关重要， 面激光稳频通常利用光强信号作为判断 依据。 因此， 这对激光器的稳定性， 特别是功率稳定性都提出了很高要求„
影响激光器输出功率稳定性的因素可分为两类： 方面， 激光泵浦源的变动， 谐振腔受 热不均或受到震动而变形使腔镜偏离平行状态， 工作介质增益原子的隨视波动、 跃迁量子噪 声等各种非确定性因素会造成激光功率变化； 另一方面， 激光器谐振腔长隨温度等缓慢变化 会引起激光振荡模式在增益带内漂移， 由于增益曲线通常都不是均一的， 激光模式在增益带 内不 I司位置会获得不同增益也会影响激光输出功率大小„ 只要激光器没有 a行稳频， 即谐振 腔处于自由伸缩状态， 腔长的改变使得激光模式漂移进而会造成激光频率变化和功率波动。 特别对于工作在单级模状态或振荡模式比较少的激光器， 这种腔长改变造成激光总功率的波 动尤为明显， 甚至比非确定性因素造成的功率变化量还要大很多。 在这种情况下》 激光功率 波动与激光模式漂移或频率漂移是关联在一起的。 即当激光！!长单向变化时， 激光功率波动 会按一定规律周期性出现。 区别于第一种情况， 这可以看作是影响激光器稳定性的一种确定 性因素。
在精密测量中， 双频激光器通常需要稳频（如用于双频激光千涉仪）。 常用的稳频技术， 如等光强稳频， 都是以光强信号为检测物理量， 并生成误差信号反馈控制激光谐振腔长， 进 而控制激光频率稳定在设定的工作点上。 在这个闭环控制中， 频率的稳定是以光强为参考依 据的， 而上述两种影响激光稳定性的因素所起的作用却各不相同》 其中非确定性因素所起的 作用是不利的， 即使在激光频率（或模式）未发生变化时， 也会造成激光功率的隨机变动。 如果这种影响对于激光各频率是非共模的， 就会使反«环路发生误判， 控制激光频率偏离设 定的工作点。 而确定性因素 成的激光功率波动真实准确地反映了激光频率的漂移， 在反镄 环路中可以控制谐搌8§长进行主动补偿， 对实现稳定激光频率 有利作用。 所以， 对于上述 两种影响激光稳定的因素应该区 a对待。 前者可以认为是在'激光稳频过程中无法预知和反馈 补偿的， 只有通过选取性能更优的激光器系统尽可能降低其对激光器稳定性的影响； 而后者 有确定的物理规律， 可以作为激光稳频的实现依据而加以运用。
因此， 为了实现激光稳频的目的， 需要在激光器设计和测试盼段准确评价激光器的稳定 性， 如果对两类激光器不稳定性的影响因素不加以区分， 则难以逾取非确定性园素影响较小 的激光器。 实际上， 探測激光器的总光强， 得到激光总功率的变化是两类影响因素共同作兩 的结果。 通常评价激光器稳定性是在一定时间内记录激光功率， 其功率稳定度根据如下计算 公式（1) 得到：
Figure imgf000005_0001
其中 ' p„„为測试过程中的激光器的功率最大值， 为测试过程中的激光器的功率最小值, 为测试过程中的潋光器的功率平均值。 根据上面的分析， 这样得到的激光功率变动曲线实 际包含了激光器稳定性两类影响因素。 对于工作在很多模式状态下的激光器， 腔长漂移引起 激光功率的确定性波动与非确定影响相比很小， 可以忽略不计。 采用这种方法能够反映澂光 器的非确定变动， 得到稳定性指标。 但对于工作在纵模个数比较少的激光器， 腔长漂移引起 激光功率的确定性波动已经不可以忽略。如图 1所示,邀光器满足阈值条件振荡的模式是 V(J和 v?+1 » 当腔长改变时， 激光摄荡模式在出光带 ή漂移时， 在不 η频率位置其获得增益 ?Vi不同， 其功率 （或光强） 大小会相应改变。 如果激光腔长沿伸长方向持续变化， 振荡模式扫 出光 带， 在光功率曲线会形成一个与增益曲线一致的波动周期， 这种情况出现在激光器升温过程 Φ。 如果对激光器实施了稳频措施， 振荡模式稳定在出光带上确定的位置上， 功率将不会再 周期性改变。
由于目前使用的上述评价方法没能区别给出非确定性因素和确定性因素各自对激光器稳 定性的影响， 需要建立一种新的评价方法更准确评价激光器的稳定性， 这特别对激光稳频而 言尤为重要。 根据激光物理， 振荡模式输出功率由所获得增益所决定《 参考图 1， 非确定性 因素对激光器的影响主要是造成振荡《值(¾的上下平移或者增益曲线 ^v)的变形， 这同确 定性因素使振荡模式在增益曲线上移动不同 比如气体激光器毛细管在放电时， 激光增益管 各部分会受热不均，沿激光轴线上的热膨胀不同会使谐振腔反射镜偏离 *来的相互平行位置， 从而引起 «值(¾向上平移，激光功率下降 如果在增益曲线上确定一个特征点， 仅记录激光 振荡模式位于该特征点时的输出功率， 就可以避幵腔长漂移造成的激光功率波动， 得到仅由 非确定性 H素造成的激光功率变化。 此时由功率变动量可以反推激光器稳定性的优劣。 根据 ffl l , 这个特征点可以选在激光增益曲线的中心频率 v。， 此时对应激光功率在一个波动周期 内为最大值， 激光功率波动的峰值， 便于确定。 在激光器升温过程 Ψ, 隨着激光器 ¾歩通入 热平衡状态， 腔长伸长会使各级振荡纵摸依次进入出光带并扫过中心频率， 形成周期波动； 同时各种非确定性因素会使振荡阈值或增益曲线发生无规律的改变， 并相应影响波动周期内 的峰值大小。 根据此峰值的变化量， 就可以得到非确定性因素对激光稳定性的影响。 类同激 光功率稳定度的计算公式 （1)， 可以得到由记录峰值功率变化的方法计算激光功率稳定度的 公式为：
Figure imgf000006_0001
其中， 为激光功率峰值稳定度， Pp舰为测试过程中的激光器功率峰值的最大值' Pp ta为 测试过程中的激光器功率峰值的最小值， 为测试过程中的激光器功率峰值的平均值 这就 是本发明给出的评价激光器稳定性的基本原理。
根据上述分析， 可以得到这种改进后的评价激光器稳定性的方法主要步骤如图 2所示：
(SOD 在激光器预热腔长伸縮阶 a， 由光电探测器接受激光输出光功率并记录；
( 502 ) 判断所得到的激光功率隨腔长改变引起的每个功率波动周期的峰值 ;
(503) 根据测试过程中激光功率峰值的平均值 最大值 龍和最小值 Ρ „， 代入上 述计算公式 （2), 得到激光功率峰值稳定度^ m , 为评价激光器稳定性的指标。
同时， 根据图 1的分析， 这种方法对工作在单纵模状态或者纵模个数较少的状态的激光 器效果更明显， 而且激光器的腔长随温度改变和环境扰动条件下处于自由伸缩状态。 为了计 算得到激光功率峰值稳定度， 如何桉照一定方法和步骤由激光功率变化曲线得到 »腔长改变 引起的每个功率波动周期的峰值 是关键步骤。 一种可行的办法是测试过程 Φ确立一条辅助 参考线与每个功率波动曲线都相交， 将其划分为不同的区间， 然后分别寻找不同区间内的功 率峰值。 对于激光器在升温变化较迅速， 腔长漂移较快的情况下， 辅助参考线可以由前一段 时间内功率平均值得到。 而对于激光腔长变化较缓慢的情况， 在一段时间内激光功率变化狼 小， 功率平均值与测量值非常接近， 由于功率的微小波动会造成 '激光功率峰值的误判。 此 B寸 可以改进辅助参考线的获取办法， 由前一功率波动周観的峰值与谷值的平均值再叠加一定的 偏置阈值得到。 这样， 就可以实现上述由激光功率峰值稳定度评价激光器稳定性的方法 作 为一个优选的实施方式， 具体流程围如图 3所给出的：
(S04) 由光电探测器接收激光器功率； 根据记录的激光功率变化曲线进行判断： （S05) 判断激光器腔长是否变化较快； （S06)如果腔长变化较快， 以根据前一段时间内激光功率 的平均值计算得到当前辅助参考线的数值； （S07)如果腔长变化较慢， 可根据前一个功率波 动周期的峰值 和谷值^计算平均值再加上一定的偏置阈值得到辅助参考线的数值； (S08) 下一步判斷测得的激光器功率是否大于辅助参考线的值； (S09)如果当前激光器功率大于参 考辅助线值， 寻找在保持大于条件下的区间内激光功率的最大值为所述激光功率波动周期内 的峰值 Pp ; (S10)如果当前激光器功率小于参考辅助线值， 则寻找在保持小于条件下的区间 内激光功率的最小值作为所述激光功率波动周肅内的谷值!^ (S11 )判断测试是否结束， 如 果没有结束， 返回歩骤（S04)循环重复上述流程， 继续下一时刻的激光器功率探测。

Claims

权利要求 书
1、 一种评价激光器稳定性的方法， 其特征在于， 包括下列歩骤：
步骤 a)在潋光器预热腔长伸縮阶段， 所述激光器输出光功率由光电探测器接收并记录； 歩骤 b )判断所得到的激光功率变化曲线中隨腔长改变引起的每个功率波动周期的峰值 Pp , 并连接各峰值形成激光功率峰值曲线；
歩骤 c )根据所述的激光功率峰值曲钱， 得到測试过程中的激光功率峰值的平均值 ^；, 以及最大值 Pp匪靠最小愤 代入计算公式： y ( = P 2 f— 其中^„激光功率峰 值稳定度， 为评价激光器稳定性的指标。 '
2、 根据权利要求 1所述的评价激光器稳定性的方法， 其特征在于：
所述激光器工作在单裂模状态或者级模个数较少的状态， 并且所述激光器腔长隨温度改 变和环境扰动条件下处于自由伸縮状态。
3、根据权利要求 1所述的评价激光器稳定性的方法， 其特征在于， 根据所述激光功率变 化曲线得到隨腔长改变引起的每个功率波动周期的峰值 Pp的歩骤包括：
根据已经记录的潫光功率数值计算得到与激光功率波动曲线都相交的辅助参考线； 当澂光功率测量值大于辅助参考线时， 寻找该区阆内澂光功率最大值为所述激光功率波 动周期内的峰值
当激光功率测量值小于辅助参考线时， 寻找该区间内激光功率最小值作为所述潋光功率 波动周期内的谷值 ;
根据得到的激光功率波动峰值！^和谷值 P¥， 以及测量的潋光功率值， 计算下一个激光功 率波动曲线的辅助参考线， 重复上述歩骤
4、 根 fi权利要求 3所述的评价激光功率稳定性的方法， 其特征在于：
当激光器腔长变化较快时， 所述的激光功率波动曲线辅助参考线可由计算前一段时间内 的激光功率平均值得到；
当激光器腔长变化较慢时， 所述的激光功率波动曲线辅助参考线可根据前 -个功率波动 周期的峰值 Pp和谷值 Pv计算平均值再加上一定的偏置阈值得到。
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4907885A (en) * 1986-09-24 1990-03-13 The United States Of America As Represented By The United States Department Of Energy Heterodyne laser diagnostic system
US5004890A (en) * 1990-02-20 1991-04-02 Amada Company, Limited Method of evaluating quality of a laser beam in a laser processing machine
JPH07151701A (ja) * 1993-11-29 1995-06-16 Hajime Sangyo Kk ストロボスコープの光量補正機能を有する検査装置
US20090219548A1 (en) * 2008-02-07 2009-09-03 Semiconductor Energy Laboratory Co., Ltd. Making Method of Sample for Evaluation of Laser Irradiation Position and Making Apparatus Thereof and Evaluation Method of Stability of Laser Irradiation Position and Evaluation Apparatus Thereof
CN201508234U (zh) * 2009-10-16 2010-06-16 北京工业大学 智能化激光功率计

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4907885A (en) * 1986-09-24 1990-03-13 The United States Of America As Represented By The United States Department Of Energy Heterodyne laser diagnostic system
US5004890A (en) * 1990-02-20 1991-04-02 Amada Company, Limited Method of evaluating quality of a laser beam in a laser processing machine
JPH07151701A (ja) * 1993-11-29 1995-06-16 Hajime Sangyo Kk ストロボスコープの光量補正機能を有する検査装置
US20090219548A1 (en) * 2008-02-07 2009-09-03 Semiconductor Energy Laboratory Co., Ltd. Making Method of Sample for Evaluation of Laser Irradiation Position and Making Apparatus Thereof and Evaluation Method of Stability of Laser Irradiation Position and Evaluation Apparatus Thereof
CN201508234U (zh) * 2009-10-16 2010-06-16 北京工业大学 智能化激光功率计

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