Tuneable multiwavelength semiconductor laser with single fibre output

A new multiwavelength semiconductor laser with singlemode fibre output is reported. The laser consists of a semiconductor laser array which is incorporated into an external cavity comprising a diffraction grating and a fibre loop mirror. This laser has five wavelength-locked output channels with a fixed separation of 2.5 nm. The centre wavelength may be tuned over 80 nm.<>     

Short single frequency erbium-doped fibre laser

Very short erbium-fibre lasers with holographically written gratings in the erbium-doped fibre core are reported. An output power of 181 mu W was obtained from a 2cm long diode-pumped laser. A 1 cm long diode pumped laser had an output power of 57 mu W. As would be expected for such short cavity lengths, these lasers are robustly singlemode.<>     

Low noise single frequency linear fibre laser

The low frequency noise characteristics of a single frequency fibre laser with and without noise suppression are presented. With no thermal or mechanical isolation, the peak RMS relaxation oscillation at 182 kHz was 82.1 dB/Hz below the DC laser level without feedback and 112.1 dB/Hz below the DC laser level with feedback.<>     

基于连续线性调频激光器的测距方法

提出了一种基于线性调频激光器的外差测距实验理论,设计了一个较为具体的测距方案,利用延时光纤将两束特性相同、但进行了延时的线性调频激光进行混频,测出其拍频后的频率值,进而得到其中包含的频率信息,并用Matlab-Simulink仿真对此方案进行了仿真测试和实际光纤延时验证,通过模拟线性调频信号和线性调频外差测距的实验过程,分别对300、600、900 m处的线性调频激光回波信号和本振信号进行外差拍频,得到相应的拍频值,其结果与理论计算结果基本吻合。     

Broadband tunable single frequency diode-pumped erbium doped fibre laser

A single frequency erbium fibre laser with continuous wavelength tuning over the range 1525-68 nm has been demonstrated using a unidirectional loop mirror (ULM) configuration. The fibre laser is diode pumped at 1480 nm with a threshold of 9 mW, slope efficiency of 12% and has a linewidth of less than 295 kHz.<>     

Active mode-locking of an InGaAsP 1.55 ?m laser in a fibre resonator with an integrated single-mode-fibre output port

We describe the first 1.55 ?m InGaAsP optical-fibre composite-cavity laser with an integrated single-mode-fibre output port. Mode-locked pulsewidths of 4.8 ps at a 2 GHz repetition rate, with peak powers of 56 mW, are demonstrated. These are the shortest reported mode-locked pulses from InGaAsP lasers.     

Measurement of baseband frequency response of multimode fibre by using a new type of mode scrambler

For measuring the frequency response of an optical fibre, a mode scrambler utilising a sinusoidal bend and a new set-up based on the attenuation-comparison method have been proposed. Measurements for multimode step-index fibres have revealed that the long-fibre response can be closely predicted from the short-fibre response, using an appropriate choice for the scrambler parameter.     

Characterisation of frequency response of 1.5 ?m InGaAsP DFB laser diode and InGaAs PIN photodiode by heterodyne measurement technique

The frequency response of an InGaAs PIN photodiode and the ratio of the frequency modulation (FM) index to the intensity modulation (IM) index of a 1.5 ?m InGaAsP vapour-phase-transported DFB laser diode have been measured by an optical heterodyne measurement technique. From the response of the photodiode to the laser radiation beat frequency, a 20 GHz detector bandwidth is determined. The ratio of the FM and IM indices at 3 mW laser output power per facet decreases from 60 at 100 MHz modulation frequency to 3.3 above 2 GHz.     

Semiconductor laser output modulated in GHz frequency region observed by image tube streak camera

The image tube streak camera was applied to the observation of fast modulated continuous light signals. Intensity modulation of a semiconductor laser was observed up to 5 GHz.     

Wavelength-switchable DBR fibre laser with high spectral purity output

A compact, wavelength-switchable, singlemode DBR fibre laser configuration is demonstrated. Stable, high spectral purity single-line or wavelength-switching operations are achieved by controlling the cavities' resonance mode conditions through a simple strain mechanism, without pump power limitations     

Ytterbium-doped large-core fibre laser with 272 W output power

A highly efficient cladding-pumped Yb-doped large-core fibre laser, generating up to 272 W of continuous-wave output power at 1.08 /spl mu/m with a beam quality (M/sup 2/) of 3.2, is reported. The slope efficiency was 83% with respect to the launched pump power. No saturation (roll-off) was observed in output power with increasing pump power.     

1645 nm单纵模NPRO激光器短期频率稳定度的测量

利用光纤延时自外差法对单块非平面Er∶YAG环形振荡器(NPRO)输出单纵模激光的短期频率稳定度进行了测量。激光器输出波长为1645 nm。测量了延时时间分别为0.25 μs,0.75 μs,1.25 μs,1.75 μs,2.25 μs,2.75 μs,5.25 μs,7.25 μs,9.75 μs,108.5 μs,166 μs 的输出激光的自外差拍频信号。设置频谱仪的span为20 kHz,扫描时间为10 s,Res BW为51 Hz,VBW为1 Hz,测量拍频信号的3 dB带宽。在延时时间0.25~9.75 μs范围内,通过线性拟合在不同延时下的3 dB带宽,得到单纵模NPRO激光器的短期频率稳定度为201 Hz/μs。光纤延时长度为21.7 km和33.2 km时,测量的3 dB带宽约为14 kHz。     

All fibre, 1.5 mu m widely tunable single frequency and narrow linewidth semiconductor ring laser with fibre Fabry Perot filter

An all fibre, widely tunable, single frequency, semiconductor ring laser was constructed with a narrow linewidth of 35kHz. Tuning over 50nm was electronically obtained using a fibre Fabry Perot filter as a selected wavelength element. Single-frequency operation was demonstrated with sidemode suppression higher than 35dB.<>     

Ytterbium-doped large-core fibre laser with 1 kW of continuous-wave output power

A ytterbium-doped fibre laser with up to 1 kW of continuous-wave output power at 1.09 /spl mu/m with a slope efficiency of 80% and a good beam quality (M/sup 2/=3.4) is reported. The fibre was pumped by two diode-stack sources launched through opposite ends. No undesirable roll-over was observed in output power with increasing pump power.     

半导体激光器线性调频干涉仪的多路复用

利用半导体激光器线性调频技术,研究了于涉仪的多路复用.介绍了复用原理,研究了干涉仪之间的串话.理论分析表明,干涉仪的动态范围为1mm时,串话<-20dB.进行了相应的实验研究.     

Ytterbium-doped large-core fibre laser with 610 W of near diffraction-limited output power

A cladding-pumped ytterbium-doped fibre laser, generating up to 610 W of continuous-wave output power at 1.1 /spl mu/m with slope efficiency of 80% and near diffraction-limited beam quality (M/sup 2/=1.3) is reported. No undesirable roll-over was observed in output power with increasing pump power.     

Theory of the frequency comb output from a femtosecond fiber laser

The output of a femtosecond fiber laser will form a frequency comb that can be phase-locked through feedback to the cavity length and pump power. A perturbative theory is developed to describe this frequency comb output, in particular for a solitonic fiber laser. The effects of resonant dispersion, saturation of the self-amplitude modulation, cavity loss, third-order dispersion, Raman scattering, self-phase modulation, and self-steepening on the spacing and offset of the fiber-laser frequency comb are given. The mechanisms by which the pump power, cavity length and cavity loss control the frequency comb spacing and offset are identified. Transfer functions are derived for the comb response to change in cavity length, pump power or cavity loss. This theory can potentially be applied to other frequency comb sources as well.     

All fibre laser system with 0.1 W output power in blue spectralrange

A ytterbium sensitised thulium-doped blue upconversion ZBLAN fibre laser pumped at 1065 nm by a high power, diode pumped, double clad fibre laser is demonstrated. With a pump power of 2.8 W at 1065 nm, a blue output power of 106 mW at 482 nm is achieved     

二种单频自稳频高输出功率的长腔He－Ne激光器

作者用高气压加纵向非均匀磁场获得了二种单频自稳频高输出功率的长腔Ｈｅ－Ｎｅ激光器，其相干长度均大于１４ｍ，１ｍ放电管长（腔长为１１４０ｍｍ）单频激光器功率输出为１８～２５ｍＷ，在没有采取任何稳频措施的情况下，用这种激光器与碘稳定的Ｈｅ－Ｎｅ激光器拍频，经计算机自动采样，并进行阿仑方差（ＡｌｌａｎＶａｒｉａｎｃｅ）处理，测得其频率非稳定度为６．１７５×１Ｏ￣（－９）（≤１０ｓ）和３．３８×１０￣（－９）（≤１ｓ）．１．８ｍ放电管长（腔长为１９００ｍｍ）单频激光器功率输出为４０～５０ｍＷ，用测ｌｍ激光器同样的方法，亦在没有采用任何外加稳频措施的情况下，测得频率非稳定度为１．１×１Ｏ￣（－８）（ｒ≤１ｓ）和２×１０￣（－８）（≤１０ｓ），所有测试数据由中国计量科学院测定。