自启动、宽调谐的ps掺Yb双包层光纤激光器

对连续泵浦的自启动、宽调谐的ps脉冲掺Yb^3＋双包层光纤激光器进行了实验研究。采用20m单模掺Yb^3＋双包层光纤作为增益介质,利用77MHz射频信号的声光调制器（AOM）作为频移器以及体光栅构成外腔,得到了重复频率为1GHz、平均功率为56．3mW以及脉宽小于60ps的脉冲,激光器的调谐范围超过40nm。     

Mode locking of Brewster-angled semiconductor lasers

Brewster-angled semiconductor laser diodes have been actively mode locked in an external cavity to produce mode-locked pulses of 11 ps duration and 0.5 W peak power with no evidence of temporal or spectral substructure.     

呼吸脉冲锁模的光子晶体光纤飞秒激光器

报道了一种掺Yb偏振型大模场面积光子晶体光纤(LMA-PCF)飞秒激光器。作为增益介质的光子晶体光纤的单模场面积比传统光纤高一个数量级,有效地降低了非线性系数,使激光器获得高能量输出。激光器基于线形腔结构,利用半导体可饱和吸收镜实现自启动锁模。光纤激光器利用光栅对进行腔内色散补偿,使其运转在呼吸脉冲锁模状态,即在谐振腔的零色散点附近实现锁模。当腔内净色散呈反常色散时,激光器获得了平均功率为400mW,重复频率为47MHz(对应于8.5nJ的单脉冲能量),脉冲宽度为500fs的稳定的锁模脉冲输出,经腔外色散补偿,脉冲压缩至98fs。当腔内净色散呈正常色散时,激光器输出的单脉冲能量为10.6nJ,脉冲宽度为1.76ps,经腔外色散补偿,脉冲压缩至160fs。     

完全锁模半导体激光器

本文对含F-P标准具的外腔半导体激光器进行了主动锁模研究。适当选择F-P标准具参数可形成单一的纵模群振荡,并可因此得到完全锁模光脉冲。实验中得到了脉宽为13.5ps、重复频率为925MHz的光脉冲输出。     

Low-threshold, self-tuned and passively mode-locked coupled-cavity all-fiber lasers

Low threshold, self-tuned, and passively mode-locked fiber lasers with compact all-fiber coupled-cavity structures have been investigated experimentally. It is shown that the Bragg gratings used in a coupled-cavity fiber laser must be matched in their spectral characteristics for the mode-locking of the laser. Stable mode-locked optical pulses as short as 60 ps at a repetition rate of 213 MHz have been generated without the need of cavity length stabilization.     

NdLMA激光器的附加脉冲锁模

用半导体激光泵浦ＮｄＬＭＡ激光器在１．０５４μｍ波长处获得连续６５０ｍＷ的激光输出，斜效率达３３％。利用一个包含光纤的非线性外腔，实现了自启动的ＮｄＬＭＡ附加脉冲锁模，输出平均功率为５８ｍＷ的接近带宽转移极限的１．８ｐｓ超短脉冲激光     

All-Optical Clock Recovery Using Erbium-Doped Fiber Laser Incorporating an Electroabsorption Modulator and a Linear Optical Amplifier

We demonstrated a 10-GHz all-optical clock recovery system using an erbium-doped fiber laser that incorporates an electroabsorption modulator and a linear optical amplifier. Stable pulses with peak power of 200 mW and pulsewidth of 6 ps are obtained. The output power and the pulsewidth of the recovered clock pulses are independent of the input data pattern. Stable optical clock can still be observed when the input data rate varies by more than 60% of the fundamental frequency without any optical tunable delay line inside the laser cavity. The scheme is essentially wavelength transparent for the whole C-band which recovers clock pulses from input data wavelength between 1525 and 1565 nm     

基于6H-SiC衬底外延石墨烯的被动锁模掺镱光纤激光器

报道了6H-SiC衬底外延生长的石墨烯作为可饱和吸收体,环形腔结构的全正色散被动锁模掺镱光纤激光器。在注入抽运功率为250mW时,得到稳定的重复频率为1.05MHz的自锁模脉冲,平均输出功率为6mW;当注入抽运功率增加到480mW时,最大平均输出功率为20mW,相应的最高单脉冲能量为19nJ,激光脉冲宽度约为520ps。     

1.48 μm pump-diode-driven mode-locked Er fiber laser

Mode-locked pulses with durations adjustable from 200 ps to less than 50 ps were generated by current modulation of a 1.48 μm pump laser diode incorporated in an Er-doped fiber laser cavity. The laser diode exhibits sufficient phase modulation without degradation in pump ability, and thus demonstrates a very practical and simple approach to optical pulse generation     

Tunable picosecond frequency-shifted feedback fiber laser at 1550 nm

A novel frequency-shifted feedback (FSF) fiber laser cavity is proposed and experimentally verified. The laser generates stable mode-locked pulses of <2 ps, mainly limited due to chirp induced by the frequency-shifting element (i.e., the acoustooptic modulator) on the pulses. Fourier transform-limited subpicosecond pulses were obtained by compensating this excess chirp using a piece of single-mode fiber SMF-28 outside the laser cavity. The unique cavity design also allow us to tune the pulse wavelength throughout the Er-gain band and the ability of the laser to self-start gives us the opportunity to characterize transient behavior of mode-locked pulses in an FSF fiber laser cavity.     

拍频自反馈锁模光纤环形激光器

报道一种由光纤环形激光器的拍频信号中提取高重复率正弦电信号，并以此信号调制腔内强度调制器，实现调制频率与腔长自适应的主动锁模方法。采用此方法获得重复率为２．５ＧＨｚ，脉宽为１１ｐｓ的变换极限超短光脉冲。     

1 015~1 046 nm可调谐飞秒掺镱光纤激光器

近年来,超快掺镱锁模光纤激光器由于其转换效率高、操作方便、免维护、尺寸紧凑等优点,被广泛应用于工业加工、医疗外科、多光子成像等领域。在激光器中补偿群速度色散是获得皮秒甚至飞秒脉冲的有效方法。通过利用光栅对与光谱滤波器,实现了对激光波长、腔内色散和光谱宽度的灵活调节。该激光器能输出稳定的锁模脉冲,对应的基本重复频率为19.41 MHz。在+ 0.0127 ps2色散时中心波长1015~1037 nm可调;在+0.007 ps2色散时中心波长1015~1045 nm可调以及在?0.0127 ps2色散时中心波长1020~1046 nm可调。同时,当净腔色散从反常色散到近零色散变化时,光谱带宽可从1.40 nm调到19.38 nm,对应的压缩后脉冲宽度可从1.03 ps调至175.9 fs。该方案具备连续调整激光器状态的能力,有望用于高功率大能量飞秒激光前端,可以满足对激光器有多种谱宽及波长的应用需求。     

Generation of 2.5-ps light pulses with 15-nm wavelength tunabilityat 1.3 μm by a self-seeded gain-switched semiconductor laser

The generation of 2.5-ps pulses by a Fabry-Perot semiconductor laser with 15-nm wavelength tunability is demonstrated. A commercial laser is switched to single longitudinal mode pulse emission by self-seeding, using an external grating. The sidemode suppression ratio is better than 15 dB, with a peak value of 21 dB. The linearly red chirped pulses are compressed from 21-30 ps to 2.5-3.5 ps in a dispersion-shifted fiber. The simple experimental setup consists of a fiber coupler, a grating, and the dispersion-shifted fiber     

Wavelength and duration tunable subpicosecond source usingadiabatic Raman compression

A wavelength and pulse duration tunable source of subpicosecond pulses has been demonstrated at a repetition rate of 10 GHz using adiabatic Raman compression of 10 ps pulses from an external cavity laser and an electro-absorption modulator     

Active-passive mode locking of a flashlamp-pumped dye laser

A simple dye laser system for obtaining relatively high energy, synchronized, picosecond pulses is described. The novel combination of active and passive mode locking within a single flashlamp-pumped dye laser cavity produced 2.5 μJ, sub-10 ps pulses capable of being synchronized to an external event with better than 100 ps accuracy. The single pulse energy was subsequently increased to 40 μJ by using a larger twin flashlamp-pumped oscillator.     

Picosecond pulses (2 ps) from hybrid mode-locked AlGaAs QW lasers with integrated active waveguide cavities

Single ultrashort optical pulses (2 ps with 17.6 GHz repetition rate) have been generated with hybrid mode-locked monolithic GaAs/AlGaAs lasers at lambda =856 nm. Instead of an external cavity, long active waveguides were used as resonators with a roundtrip frequency of 5.9 GHz. Increasing the pump current in the waveguide far above transparency led to 10 ps pulses with a high peak power of 110 mW.<>     

Direct generation of subpicosecond chirp-free pulses at 10 GHz froma nonpolarization maintaining actively mode-locked fiber ring laser

0.7-1.3 ps highly stable, transform-limited, sech²-shaped pulses at 10 GHz in the 1536-1569 nm wavelength region from a nonpolarization maintaining (PM), single intensity modulator, actively and harmonically mode-locked fiber ring laser have been directly generated. Little degradation of long-term stability of the laser operation was observed due to the non-PM nature of the laser cavity     

Tunable dual-wavelength picosecond optical pulses generated from aself-injection seeded gain-switched laser diode

A novel scheme to generate dual-wavelength picosecond optical pulses has been demonstrated. The pulses are obtained by self-injection seeding of a gain-switched laser diode simultaneously at two different wavelengths. Optical feedback is provided by a partially reflecting fiber mirror. Single-mode pulses at alternate wavelengths around 1.3 μm have been generated. The pulse width varies from about 40 to 50 ps. The output wavelengths can be tuned by changing the electrical modulation frequency. Spacing between the wavelengths can also be controlled by adjusting the length of the dispersive fiber cavity. Our experimental data are in good agreement with the calculated results     

Stability and compression of pulses in the soliton laser

We present a theory of the soliton laser which examines how an external optical fiber enables a laser to produce shorter pulses than it could produce alone. We begin by discussing a phenomenological laser model which shows how the lower limit to the mode-locked pulse width can arise. This model is coupled to an external optical fiber cavity, into which a part of the output beam is launched. The returning pulse from the fiber cavity is then mixed with a circulating pulse in the laser at the output mirror. We have found stable solutions which are nearly periodic in the external cavity. We also find more than one solution for a given set of model parameters, depending on the initial conditions. The radiation (non-soliton) part of the propagation in the optical fiber cannot be ignored. It acts as a buffer between the tendency of the fiber to produce solitons, and the fact that a pure soliton is not an exact fixed point of the laser model.     

Mode-locked hybrid soliton pulse source with extremely wideoperating frequency range

The authors report a mode-locked pulse source with extremely wide operating frequency range and very stable operation, through the use of a long, linearly chirped Bragg reflector as the output coupler integrated in a fiber external cavity. A 1.55 μm strained MQW laser diode is used, with one facet high reflectivity (HR) coated for improved cavity Q, and the other antireflection (AR) coated to allow coupling to the external cavity and suppress Fabry-Perot modes. Near-transform-limited pulses are obtained over a frequency range of 700 MHz around a system operating frequency of 2.488 GHz, with pulsewidths of 50 ps, as required for a practical soliton transmission system