Passively modelocked 832 nm vertical-external-cavity surface-emitting semiconductor laser producing 15.3 ps pulses at 1.9 GHz repetition rate

A passively modelocked 832 nm vertical-external-cavity surfaceemitting laser, producing pulses of a duration of 15.3 ps at a repetition rate of 1.9 GHz, has been demonstrated. A fast surface-recombination semiconductor saturable absorber mirror, with a bi-temporal absorption recovery characteristic, consisting of fast and slow time constants of 1.5 and 200 ps, respectively, was used to form the pulses.     

100 W 50 ps gain-switched pulses from vertical-stack laser diode

The advantages of a vertical stack configuration of laser diodes for high peak power, short-pulse generation under fast electrical pumping are demonstrated. 50 ps, 5 nJ optical pulses from a stack of 10 laser diodes have been obtained. This is the best time performance obtained to date from a multi-element gain-switched laser diode     

紫外微微秒高功率激光脉冲的产生

采用被动锁模染料激光器作为振荡器,其输出为2～10微微秒的锁模脉冲系列,单脉冲能 量为5～10微焦耳。用XeCl准分子激光器泵浦的染料激光放大器放大,同时利用染料激光器可调谐特性,将其准确地调到616毫微米处,倍频后刚好落在XeCl准分子激光器的最大增益带宽中心,再经XeCl激光器放大后,可获得波长为308毫微米,带宽0.2毫微米,脉宽小于10微微秒,能量为8～10毫焦耳的紫外激光单一脉冲输出。     

Generation of 6.3 ps optical pulses at a 10 GHz repetition rateusing a packaged electroabsorption modulator and dispersion compensatingfibre

Sinusoidal modulation of an MQW InGaAsP/InGaAsP EA modulator at a 10 GHz repetition rate was used to generate optical pulses of width as low as 7 ps. Pulses were linearly compressed using 400 m of dispersion compensating fibre and approximately transform limited pulses of 6.3 ps width were measured     

Picosecond (<2.5 ps) wavelength-tunable ( approximately 20 nm) semiconductor laser pulses with repetition rates up to 12 GHz

A novel technique is used to produce picosecond wavelength-tunable optical pulses from gain-switched Fabry-Perot semiconductor lasers using fibre compression. Experiments are carried out with high power, large modulation-bandwidth lasers at 1.3 mu m. Pulses of 2.5 ps durations with repetition rates up to 12 GHz are obtained. Still shorter pulses ( approximately 1 ps) with higher repetition rates (18 GHz) are shown to be feasible.<>     

Transform-limited 14 ps optical pulse generation with 15 GHz repetition rate by InGaAsP electroabsorption modulator

A 15 GHz optical pulse train with time-bandwidth product of 0.32 for soliton transmission was generated by a sinusoidally driven InGaAsP electroabsorption modulator, for the first time. By using the pulse compression effect caused by the nonlinear attenuation response to the applied voltage, a transform-limited optical pulse train with a width of 14 ps and a spectral width of 23 GHz was successfully generated just using sinusoidal modulation, without using any electrical and optical resonators.<>     

Simple repetition rate tunable picosecond pulse-generating 10 GHz laser

A compact, passively fundamental-mode-locked, optically pumped Er:Yb:glass laser where the pulse repetition rate is continuously tunable in the range 8.8-13.3 GHz is demonstrated. The average output power exceeds 20 mW, and the pulse duration is between 1.7 and 1.9 ps over the whole tuning range. Tuning is turnkey and the main laser parameters remain unchanged during tuning.     

Transform-limited 5.6 ps optical pulse generation at 12 GHz repetition rate from gain-switched distributed feedback laser diode by employing pulse compression technique

12 GHz chirped optical pulses from a gain-switched 1.3 ?m distributed feedback laser diode are compressed to transform-limited 5.6 ps pulses by travelling through a dispersion shifted single-mode fibre with 46 ps/nm normal dispersion. A time-bandwidth product of 0.69 and a high on/off ratio of 20 dB are obtained for optimally compressed pulses.     

Fourier-limited 1.6-ps pulses with variable repetition rate from 1to 26 GHz by passive mode-locking of a semiconductor laser in anexternal cavity

By passive mode-locking of a semiconductor laser (λ=1.3 μm) in an external cavity, 1.6 ps sech²-shaped pulses are generated with variable repetition rates from 1 to 26 GHz, presently limited only by the geometry of the set-up. The time-bandwidth product is between 0% and 40% over the theoretical limit. Wavelength tuning up to 50 nm is possible     

Generation of <3 ps optical pulses by fibre compression of gain-switched InGaAsP DFB laser diode pulses

Generation of <3 ps full width at half maximum (FWHM) 1.3 mu m pulses by compressing the chirped output of a gain-switched distributed feedback laser diode (DFB-LD) with a fibre dispersive delay line is reported. Diode laser requirements for minimum pulse width and maximum pulse energy, as well as suppression of 'wings' on the optical pulse, are discussed.<>     

Generation of 4 ps light pulses from directly modulated V-groove lasers

4 ps light pulses at repetition rates up to 10 MHz with an output power of some milliwatts are generated at 840 nm by directly modulating commercial GaAlAs V-groove lasers by specially designed avalanche generators. The pulses are measured using an ultrafast streak camera and present the fastest light pulses obtained until now by direct modulation of a semiconductor laser. The avalanche generators produce pulses of 125?200 ps FWHM with voltages up to 25 and 38 V, respectively.     

Generation of 4 ps light pulses from directly modulated V-groove lasers

4 ps light pulses at repetition rates up to 10 MHz with an output power of some milliwatts are generated at 840 nm by directly modulating commercial GaAlAs V-groove lasers by specially designed avalanche generators. The pulses are measured using an ultrafast streak camera and present the fastest light pulses obtained until now by direct modulation of a semiconductor laser. The avalanche generators produce pulses of 125?200 ps FWHM with voltages up to 25 and 38 V, respectively.     

2-kHz repetition rate XeF laser

High-repetition-rate laser action, up to 2 kHz, has been demonstrated in XeF molecules at 351 and 353 nm by using a blowdown fast transverse-flow system and a four-circuit, thyratron-switched, low inductance pulse generator. For a typical run, the transverse flow was uniform, and the average flow velocity was 25 m/s across a discharge region of1.4 times 0.4 times 30cm³. The gas mixture used was He:Xe:NF3= 100:1.5:0.5, and the total pressure was varied from 600-1200 torr. For single-pulse operation, the maximum laser output energy was 22 mJ/pulse, and the electric efficiency was 0.4 percent. For a 2-kHz repetition rate, the average laser output energy was approximately 12 mJ/pulse with 50 percent variations. Hence, an average output power of 24 W was obtained.     

高重复率全光纤被动锁模飞秒激光产生研究

报道了高重复频率全光纤被动锁模飞秒激光产生的实验研究,采用全光纤环形腔结构和非线性偏振旋转可饱和吸收被动锁模机理实现了100MHz级掺铒光纤锁模飞秒激光的稳定运转,最高重复频率为99.91MHz,光谱带宽为25nm,中心波长为1570nm,脉宽最短为194fs,实验同时研究了在不同重复频率下的全光纤被动锁模激光器运转动力学特性。研究为高重复频率飞秒光纤激光器在光频梳产生技术中的应用提供了高集成、高稳定超快光源技术途径。     

Inexpensive equipment for driving GaAs lasers with 100 ps risetime pulses

A single-stage current amplifier permits 250 Mb/s modulation of a GaAs laser. The compensated 50 ? bias input can be used to inject a 100 ps-risetime pulse, produced by a charged line generator with mercury-wetted reed relays and skin-effect compensated signal delay line.     

Femtosecond Cr/sup 4+/:YAG laser with 4 GHz pulse repetition rate

The construction of a compact, high-repetition-rate femtosecond Cr/sup 4+/:YAG laser is reported. Transform-limited pulses as short as 80 fs were generated at pulse repetition frequencies up to 4 GHz. The femtosecond pulses were tunable from centre wavelengths of 1505 to 1550 nm.     

Tunable picosecond pulse-generating laser with repetition rateexceeding 10 GHz

A compact, fundamental-repetition-rate modelocked, optically-pumped Er:Yb:glass laser producing near transform-limited picosecond pulses at a repetition rate of 10.67 GHz and average power exceeding 10 mW is presented. Wavelength tuning over the entire C-band is demonstrated at 2 GHz     

Generation of 140 GHz optical pulses with suppressed amplitudemodulation by subharmonic synchronous modelocking of Fabry-Perotsemiconductor laser

140 GHz optical pulses with a pulsewidth of 2.7 ps are generated from a standard Fabry-Perot semiconductor laser using subharmonic optical injection. A new technique based on optical feed forward modulation is also presented to suppress the amplitude modulation associated with subharmonic injection     

Generation and kilohertz rate amplification of synchronizedfemtosecond and picosecond laser pulses

Synchronized femtosecond and tunable picosecond laser pulses have been generated using a linear cavity configuration in both lasers. The long-term stability of the synchronization, as well as the frequency of the synchronously pumped femtosecond dye laser, is assured by active stabilization of the cavity length. Additionally, the picosecond and femtosecond pulses have been amplified in dual amplifier chains to pulse energies in the microjoule range at a 1 kHz repetition rate. The total peak intensity available for two-photon, nonlinear excitations is on the order of 10⁹ times greater than that available from unamplified beams     

Generation of super-stable 40 GHz pulses from Fabry-Perot resonator integrated with electro-optic phase modulator

A simple technique for converting a continuous-wave laser beam into a stable pulse train with high repetition frequency is demonstrated. The generated train is based on the synthesis of its Fourier spectrum which is composed of higher-order sidebands produced by a Fabry-Perot resonator integrated with an electro-optic phase modulator. Super-stable 40 GHz, transform-limited optical pulses are successfully generated.