Efficient erbium-doped fibre amplifier pumped at 820 nm

The highest gain coefficients of 0.86 dB/mW at 1.552 mu m and 0.72 dB/mW at 1.534 mu m are realised at a pumping wavelength of 822 nm by using an erbium-doped fibre with a relative refractive index difference as high as 1.67%, a low intrinsic loss, and an erbium ion concentration of 210 p.p.m. The gains at 1.552 mu m reach 25 and 30 dB for launched pump powers of 30 and 40 mW, respectively.<>     

Multichannel crosstalk and pump noise characterisation of Er/sup 3+/-doped fibre amplifier pumped at 980 nm

It is shown that as a consequence of the long fluorescence lifetime in an Er/sup 3+/-doped fibre amplifier, interchannel crosstalk and pump-noise breakthrough are minimal for modulation frequencies >100 kHz.<>     

2.79 μm YSGG:Cr:Er laser pumped at 790 nm

2.79 μm quasi-CW laser operation at room temperature was achieved from a YSGG:Cr:Er crystal. The output from the crystal, which was longitudinally pumped with a Ti:sapphire laser at 790 nm, was self-terminating. Under quasi-CW pumping, the length of the emitted pulses decreased exponentially with increasing pump power. The self-terminating behavior is explained by thermal effects with a computer simulation of the population mechanisms in the crystal. This simulation considers not only the common cross-relaxation and up-conversion processes, but also the inverse processes. They turn out to be of the same importance as the normal processes. The YSGG:Cr:Er crystal depends so critically on the laser parameters that it is an ideal candidate for testing the system of rate equations     

Single transverse mode operation at 1345 nm wavelength of adiode-laser pumped neodymium:ZBLAN multimode fiber laser

A diode-laser pumped multitransverse-mode neodymium-doped fluoride fiber laser is shown to oscillate in the lowest-order transverse mode when the cavity conditions are optimized. The combination of good pump coupling efficiency, laser operating efficiency, and good overlap of the HE₁₁ mode to that of a single-mode fiber, allows up to 12 mW of continuous wave (CW) power to be coupled into a standard single-mode fiber at a 1345-nm wavelength. Improved lens design should significantly increase the power injected into the single-mode fiber from the multimode fiber laser     

35 dB optical gain at 2.716 mu m in erbium doped ZBLAN fibre pumped at 0.642 mu m

An optical gain of 35 dB at 2.716 mu m signal wavelength has been measured in an erbium doped ZBLAN fibre. A pump-wavelength scanning determined the pump wavelength for maximum gain. This pump wavelength was found to be 0.642 mu m. The maximum absorption wavelength for this Er/sup 3+/ doped fibre is 0.649 mu m. It was deduced that the excited state absorption process improves the gain performance of such fibres at the signal wavelength considered.<>     

Operation of diode laser pumped Tm3+ ZBLAN upconversionfiber laser at 482 nm

Lasing at 482 nm is observed in Tm³⁺-doped ZBLAN glass fiber pumped with single-mode InP semiconductor diode lasers. Up to 5 mW of 482 nm light is obtained with <40 mW of absorbed pump power from a single 1135 nm pump diode laser. The optimum pump wavelength is measured to be 1135-1340 nm. More efficient laser operation is observed in fiber with 2500 ppm Tm³⁺ compared to 1000 ppm Tm³⁺ because of the reduced length of the fiber laser cavity possible with increased doping. Improved slope efficiencies are also demonstrated when the fiber laser is co-pumped with up to 5 mW from a 1220 nm diode laser. The relative intensity noise (RIN) of the fiber laser displays a maximum of -90 dB/Hz at relaxation oscillation frequencies of a few tens of kHz. The measurement of RIN is limited by shot-noise of -152 dB/Hz above 2 MHz. At higher frequencies, self mode-locking was observed in the fiber laser, which may indicate the existence of saturable absorbers in the fiber core. The presence of such bleachable absorbers is indicated by the observed increase in threshold after upconversion lasing at 482 mm     

Argon pumped dye laser operation in the 690-700 nm region

A study of an argon pumped new red laser dye and mixture is reported for operation in the 690-700 nm region. Best reliability was achieved with the dye LD688.     

Highly efficient Er-doped fibre amplifiers pumped in 660 nm band

High gain coefficient in an erbium-doped fibre amplifier, 3.8 dB/mW at 1.536 mu m and 2.3 dB/mW at 1.552 mu m, is achieved for a pump wavelength of 664 nm by using an erbium-doped fibre with a high numerical aperture of 0.285 and thermally-diffused expanded core fibre ends. The gain at 1.536 mu m reaches 30 and 35 dB for launched pump powers of 10 and 15 mW, respectively.<>     

Proposal for an Er/sup 3+/-doped chalcogenide glass fiber upconversion laser operating at 980 nm and pumped at 1480 nm

We propose a novel fiber upconversion laser operating at 980 mn and pumped at 1480 nm, which will allow remote optical pumping of erbium-doped optical amplifiers. From the measured spectroscopy, we show Er/sup 3+/-doped gallium lanthanum sulphide glass to be a potential host for such a 1480-nm/980-nm upconversion laser. The small-signal gain is analyzed numerically and the lasing possibilities are discussed.     

1.47 /spl mu/m Tm/sup 3+/:ZBLAN fibre laser pumped at 1.064 /spl mu/m

A large core area (1257 /spl mu/m/sup 2/) Tm/sup 3+/-doped ZBLAN fibre laser operated at 1.47 /spl mu/m is demonstrated. The pump source is a Nd:YAG laser operated at 1.064 /spl mu/m. A laser output power of 1.56 W continuous wave was obtained for 5.2 W of launched pump power. The slope efficiency with respect to the launched pump power was measured to be 33%.     

High-efficiency CW operation of 890 nm pumped holmium fluoride fibre laser

Highly efficient CW operation has been observed from the holmium transition centred at 2.024 mu m in a Tm:Ho codoped single-mode fluoride fibre laser. When pumping holmium directly at 890 nm a minimum threshold of 8.2 mW launched pump power was observed for oscillation at 2.076 mu m. A maximum slope efficiency of 30% was achieved for operation at 2.054 mu m, which corresponds to a photon conversion efficiency of 69%.<>     

980 nm band pumped Er/sup 3+/-doped tellurite-based fibre amplifier with low-noise figure of less than 4.5 dB

The amplification characteristics of an Er/sup 3+/-doped tellurite-based fibre amplifier (EDTFA) with 980 nm band pumping are described. The optimum pump wavelength and length of the newly developed EDTF are investigated in order to obtain both a low noise figure and a high gain simultaneously. We realise a low noise figure of less than 4.5 dB with a pump wavelength of 976.5 nm and a 0.4 m EDTF.     

Diode-laser pumped erbium-doped fluorozirconate fibre amplifier for the 1530 nm communications window

An erbium-doped fluorozirconate fibre amplifier has been pumped at 1480 nm using a semiconductor diode laser. The small signal gain was 15 dB for 25 mW launched pump power. The ASE bandwidth was 45 nm and the predicted noise figure was 5 dB.<>     

Efficient operation of an Yb-sensitised Er fibre laser pumped in0.8 μm region

The dependence of threshold and slope efficiency on pump wavelength around 0.8 μm has been investigated for an Yb-sensitised fibre laser. Results confirm a wider choice of pump wavelength compared with unsensitised Er fibre. A 5 mW threshold and slope efficiency of 8.5% were observed for 820-830 nm pumping     

High-power pulsed fibre source at 1567 nm

A pulsed fibre source based on an Er/Yb-codoped fibre amplifier producing 1567 nm-wavelength, spectrally narrow, /spl sim/2 ns pulses with maximum energy 303 /spl mu/J, average power of up to 12 W, and peak power in excess of 130 kW is reported.     

InP-based optically pumped VECSEL operating CW at 1550 nm

We present a vertical external-cavity surface-emitting laser operating at 1550 nm. The laser comprises an InGaAsP-based gain element, with a resonant periodic gain structure on top of a distributed Bragg reflector, and a high reflectivity spherical mirror as the external reflector. Optical pumping is achieved using a 1250-nm fiber Raman laser. A maximum continuous output power of 70 mW was obtained under multitransverse mode operation at 233 K. Under single-mode operation, we obtained a maximum power of 60 mW with a beam quality factor M/sup 2/ less than 1.1.     

Efficient Er:YAG laser operating at 1645 and 1617 nm

A 1534-nm fiber laser pumped Er:YAG laser action at room temperature has been demonstrated with high efficiency at two emission wavelengths: 1645 and 1617 nm. Multiwatt continuous-wave power was demonstrated at both wavelengths and active electrooptic Q-switch operation with >90% Q-switch efficiency was achieved at 1645 nm. Etalon tuned wavelength selection showed excellent agreement with theoretical analysis.     

1342nm激光输出的LD端面抽运Nd:YVO4激光器

研究大功率激光二极管端面抽运的Nd:YVO4连续波1342nm激光器的输出特性.实验结果表明,小功率抽运时,激光器的输出功率基本随抽运功率线性增加;当抽运功率超过一定值时,斜率效率下降,对于长腔斜率效率下降更为明显,甚至出现输出功率降低.通过对晶体中的振荡激光基模半径和热致衍射损耗计算得出:高抽运功率下,热效应影响了激光器的输出功率,为了获得最大的输出功率,激光晶体内不考虑热效应时的基模半径与抽运激光光束尺寸的比值ω/ωp在0.8～0.9之间最佳,而且抽运功率越大,比值越小.理论分析与实验结果基本一致.     

A widely tunable erbium-doped fiber laser pumped at 532 nm

A tunable erbium-doped fiber laser with a very wide continuous-tuning range (1522-1567 nm) is discussed. The wide tuning range was achieved using an aluminum/erbium-doped fiber; the aluminum codoping is known to broaden the gain spectrum substantially. The tunable fiber laser has a ring laser configuration utilizing an inline tunable etalon as the tuning element. Continuous tuning over 45 nm in the spectral range of 1522-1567 nm was achieved with 80 nW of pumping at 532 nm, using the second harmonic of a Nd:YAG laser as the pump source     

1064 nm波段泵浦掺铥光纤激光器的理论研究

文章对1064 nm波段泵浦掺铥光纤激光器进行理论分析,以获得到对实际研究有用的结论.先从理论分析计算了1064 nm泵浦掺铥光纤激光器的粒子速率方程和传输方程,并在传输方程中考虑了泵浦光和激光本征吸收影响.利用matlab软件理论模拟不同长度光纤的正反向泵浦光和激光在光纤中的分布.模拟讨论了输出功率与最佳光纤长度的关系,以及激光本征吸收系数和掺铥离子浓度对输出功率的影响.最佳光纤长度时的激光输出功率最高.考虑激光本征吸收是合理的,较小的本征吸收有较高的最大的输出功率.存在一个最佳的掺杂离子浓度使得输出功率最大.