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1.
The properties of low-frequency fluctuations in semiconductor lasers with optical feedback from a long external cavity are experimentally studied. Frequency-locking of the laser light output to the injection current modulation is observed when the modulation frequency approaches the external cavity mode. The modulation frequency for the successful frequency-locking is always less than the external cavity mode frequency and the locking domains as a function of the modulation amplitude is asymmetric with respect to the frequency detuning. 相似文献
2.
We present the noise suppression of an amplified diode laser by using an optical filter and resonant optical feedback. The
intensity noise of the amplified diode laser has been significantly decreased by using the optical filter cavity. It was further
suppressed and reached the shot noise limit at 15 MHz by introducing resonant optical feedback from the transmission of the
filter cavity. The filter cavity transmits 53% of injection power, and the output power of the filter cavity is more than
200 mW. The observed frequency fluctuations were less than 100 kHz in one minute. This level of noise suppression and output
power may allow diode lasers to be utilized in many quantum-optics experiments.
PACS 42.55-f; 42.55-Px; 42.50.-p 相似文献
3.
A simple variable length (10–50 cm) air-spaced Fabry-Perot interferometer has been used to calibrate the tuning characteristics of a c.w. InSb spin-flip Raman laser (SFRL). The SFRL output frequency is determined by competition between the spontaneous spin-flip resonance line and the cavity axial modes of the InSb crystal. Over several cavity modes the SRFL is found to tune linearly within ±250 MHz and inside a single mode to ±50 MHz. The tuning rate over several modes is found to be 2.35 cm-1/kgauss and within a single mode the tuning rate is 1.80 cm-1/kgauss. Frequency jumps of ≈500 MHz between modes are inferred. Used in conjunction with the observation of known molecular absorption lines as frequency standards, the interferometer provides a calibration of the SFRL suitable for infra-red Doppler limited spectroscopy. of gases. The observed frequency asymmetry in the SFRL output power and the non-linear tuning rate (variable from ≈70-40 MHz/gauss) over a single axial mode show plane-wave cavity theory to be inadequate. These effects can be explained by considering gain controlled refraction induced by a pump beam of gaussian profile. The near resonant dispersion of the refractive index of InSb is inferred from a measurement of the spacing between adjacent peaks in the SFRL output. 相似文献
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基于外腔的高效频率转换, 尤其是当系统运行在抽运不消耗近似机理下, 信号光可实现大于90%的转换, 因此无法通过信号光直接获得其到腔模频率锁定的误差信号. 本文通过对信号光调制、和频光解调的方法获得了该误差信号, 实现了双波长激光到外腔腔模的级联锁定. 实验中外部环形腔将1.3 W的1064 nm抽运光放大到约14.3 W. 当1583 nm信号光从10 μW变化到50 mW, 其到636 nm和频光的转化效率约为73%; 当从50 mW变化到295 mW时, 转换效率呈线性降低到60%, 最终获得了440 mW的636 nm激光. 相似文献
6.
F. N. Timofeev G. S. Simin M. S. Shatalov S. A. Gurevich P. Bayvel R. Wyatt I. Lealman R. Kashyap 《Fiber and Integrated Optics》2000,19(4):327-353
An experimental and theoretical study of the effect of temperature on the static and dynamic characteristics of packaged external fiber grating semiconductor lasers (FGL) is reported on. Operating in single frequency mode, the laser exhibits high output power (> 8 mW), high temperature stability of operating frequency (-3.4 GHz/K), and low static chirp (-60 MHz/mA). The observed hysteresis in wavelength versus temperature dependence is explained in the frame of a time-domain FGL model accounting for asymmetric nonlinear gain. The laser has low dynamic chirp (~16 MHz/mA) under 2.5 GB/s direct modulation, which is the key factor determining low penalty transmission over 312 km of SSM fiber. Dense WDM transmission performed at 2.6 Gbit/s over 117 km of SSM fiber shows that an FGL-based transmitter is a factor of 7 more tolerant to temperature variations than externally modulated DFB lasers. 相似文献
7.
P. Bakule P.E.G. Baird M.G. Boshier S.L. Cornish D.F. Heller K. Jungmann I.C. Lane V. Meyer P.H.G. Sandars W.T. Toner M. Towrie J.C. Walling 《Applied physics. B, Lasers and optics》2000,71(1):11-17
A Q-switched alexandrite laser suitable for high-resolution spectroscopy is described which produces pulses of 35 mJ energy in a 10 MHz bandwidth, with a high-purity TEM00 mode. The laser can be synchronised to external event to within 100 ns. The output pulse length is 120 ns and the repetition rate 25 Hz. The laser is injection-seeded by a Ti:sapphire laser operating around 730 nm. To preserve single-mode seeding under external triggering conditions, and to obtain small time-jitter, active cavity length control was used. In order to achieve the 10 MHz output bandwidth, intra-cavity electro-optic modulators were used to compensate for the frequency chirp. The refractive index of alexandrite was found to vary linearly with inversion density with a constant of proportionality equal to 1.6᎒-24 cm3. In pulsed operation at 730 nm, the index change due to this effect is only partially compensated by changes due to ground state phonon relaxation. 相似文献
8.
We demonstrate the single mode operation of a broad-area diode laser at 670 nm by means of an external cavity configuration using a diffraction grating. The output power of 150 mW is obtained with a spectral width of 40 MHz. 相似文献
9.
《Infrared physics》1985,25(3):569-574
In order to stabilize the 118.8 μm CH3OH laser output, frequency stabilization of the CW 9P(36) CO2 laser pump is carried out using external CH3OH Stark-cell modulation without internal frequency modulation. The CO2 laser output power around the CH3OH absorption center is stabilized to within ±1.0% for 60 min. The frequency stability of the CO2 laser is estimated to be within ±1.4 MHz for 60 min, assuming the output fluctuation to be caused by this frequency fluctuation. As a result of the CO2 pump laser stabilization, an output power stability of about ± 1.0% for 30 min is obtained for the 118.8 μm CH3OH laser. 相似文献
10.
电光晶体调谐的外腔反馈半导体激光器 总被引:1,自引:0,他引:1
报道一种用电光晶体实现快速调谐和凋制激光频率的方法.在Littrow型外腔反馈半导体激光中插入LiNbO3晶体,利用LiNbO3晶体的电光效应,通过改变晶体电压来调节激光器的有效腔长,可以对激光频率进行快速的调谐和调制.采用该方法,自制外腔反馈半导体激光器的调谐频率可达到2 kHz,它的调谐范围为350 MHz,激光频率调谐系数约为1.06 MHz/V,用饱和吸收光谱观测频率调谐的效果.快速激光频率调制可以应用在稳频技术上,将外腔反馈半导体激光器调制在5~100 kHz频率下,均获得了87Rb原子D2线的饱和吸收光谱的色散信号,并实现了激光频率在饱和吸收峰上的长期稳定. 相似文献
11.
High frequency stabilization of a 2.2-W injection-locked laser-diode-pumped Nd:YAG laser to a high-finesse optical cavity has been realized by frequency control of the master laser. With the help of an external electro-optical modulator, the feedback bandwidth was extended to 1 MHz and the frequency noise relative to the reference cavity was suppressed to 3 x 10(-4) Hz/Hz(1/2) below 1 kHz. This feedback laser system is an ideal laser source for gravitational wave detectors, which require both ultralow frequency noise and high output power. 相似文献
12.
A method is presented to generate tunable millimetre waves by photomixing one TE mode and one TM mode of a dual-polarization
external cavity diode laser emitting in the 1.55 μm wavelength domain. Beat notes in the frequency range 0.2 to 60GHz have
been measured where the upper frequency is limited by the detector system bandwidth only. The frequency and amplitude stability
are investigated. Typical beat intensity fluctuations are within 0.5 dB. The frequency stability is around 5MHz. The relative
intensity noise of a TE and a TM mode was measured and a correlation found around multiples of the cavity roundtrip frequency
and in the low frequency regime. Theoretical calculations show qualitative agreement with the measurement results.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
13.
设计了一种可调制的高稳定度半导体激光器驱动电路。该电路的直流稳定度高达1.5×10-5,输出电流在0~200mA内连续可调,长时间工作(12h以上)电流变化小于1μA;在直流基础上注入100kHz~300kHz的调制电流,其调制深度为0~100mA连续可调,可实现在激光干涉测量中对光波频率和光波强度的调制。将该电路驱动的光栅外腔半导体激光器和辅助温度控制电路应用于光干涉测量技术中,得到了功率稳定、波长单一的激光输出,解决了激光器的跳模现象,完成了对远距离微小振动(纳米量级)的测量。 相似文献
14.
针对窄线宽激光器输出谱线窄,难以被锁定的情况,利用F-P腔特有极窄线宽、高精细度特性对激光器谱线线宽实施压窄及频率锁定。通过设计实验方案并搭建锁频测试平台,利用F-P腔外部光反馈将窄线宽半导体激光器线宽压窄来提高锁频精度。通过监测正弦波调制下F-P腔对于4种不同直流电压下激光PZT扫频段的透射谱线,并对其分别进行解调和锁频精度测试,得到直流高压放大器电压为73 V时对窄线宽激光器进行扫频,激光器反馈锁频精度最高可达1.5 MHz。 相似文献
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Passively mode-locked diode-pumped solid-state (DPSS) Nd:GdVO4 laser by using a saturable output coupler (SOC) in stable two-mirror linear cavity design is demonstrated. The laser was pumped by low-power single laser diode without any active cooling and external optics. Robust CW mode-locked operation was obtained with a repetition of 150–250 MHz, the pulsewidth was 12 ps, the lowest threshold for CW mode-locked was 185 mW. The optimal condition is found when the laser provides the set of characteristics: low CW mode-locking threshold (~260 mW), compact size (total cavity length 60 cm), good efficiency (~20%), and very stable output. At the output power of 270 mW an average power fluctuations within ±2% for long-term operation was obtained. 相似文献
17.
A diode-pumped passively Q-switched and mode-locked Nd:GdVO4 laser at 1.34 μm with V3+:YAG as the saturable absorber is realized in a V-type folded cavity. About 100% modulation depth of mode locking can be obtained as long as the pump power reaches the oscillation threshold. The width of the mode-locked pulse is estimated to be less than 280 ps with 200 MHz repetition rate within an about 980 ns-long Q-switched pulse envelope. A maximum output power of 200 mW and Q-switched pulse energy of 5.7 μJ is obtained. 相似文献
18.
射频强度调制激光作为激光雷达系统的载波可以有效提高系统的抗干扰和抗散射能力,高功率宽带射频强度调制光源是实现高分辨率远距离探测的关键.本文采用在Nd:YAG激光器的耦合腔中插入一对四分之一波片的方法实现了频差调谐范围为30 MHz—1.5 GHz的双频激光输出,结合光纤振荡功率放大技术,将双频信号光功率放大为50 W.耦合腔双频种子源具有良好的功率和频率稳定性,输出功率为9.5 mW时,功率标准差为0.145 mW,稳定性为1.52%,输出双频激光的频差为250 MHz时,拍频的标准差为1.6144 MHz.种子光进行三级光纤功率放大,得到50 W双频激光输出.放大后的双频激光功率波动范围小于0.1 W,双频拍频的标准差为1.777 MHz,很好地保持了放大之前的功率稳定性和双频频差稳定性. 相似文献
19.
高重复频率掺Er光纤飞秒激光器在光学频率梳、超高速光学采样等领域具有很重要的作用. 本文采用非线性偏振旋转锁模机理, 在掺Er光纤飞秒激光器中实现了重复频率为303 MHz的锁模脉冲输出. 通过优化腔内色散, 激光器腔内色散在零色散附近偏负值, 锁模后工作在展宽脉冲锁模状态. 在817 mW抽运功率下, 激光器在连续光状态下可以输出125 mW的平均功率, 在锁模状态下可以输出69 mW的平均功率, 脉冲宽度为90 fs. 当抽运功率处于700-817 mW时, 激光器可以实现自启动锁模. 激光器重复频率在5 h内的漂移量为30 Hz. 相似文献