共查询到20条相似文献,搜索用时 15 毫秒
1.
A generalized model for 3-μm (4I 11/2 →4I 13/2)Er lasers is proposed. The essential energy transfer processes present in the single-doped Er 3+ systems (up-conversion from 4I 13/2, up-conversion from 4 I 11/2, cross-relaxation from 4S 3/2), as well as those present in Cr3+ codoped Er 3+ systems, are taken into account. In the frame of this model, the main features of 3 μm Er3+ lasers, such as long pulse or CW operation, the change of emission wavelength as a function of pumping conditions, and the effects of codoping with Ho3+ or Tm3+ ions, are explained 相似文献
2.
Wang R.H. Stintz A. Varangis P.M. Newell T.C. Li H. Malloy K.J. Lester L.F. 《Photonics Technology Letters, IEEE》2001,13(8):767-769
The first self-assembled InAs quantum dash lasers grown by molecular beam epitaxy on InP (001) substrates are reported. Pulsed room-temperature operation demonstrates wavelengths from 1.60 to 1.66 μm for one-, three-, and five-stack designs, a threshold current density as low as 410 A/cm2 for single-stack uncoated lasers, and a distinctly quantum-wire-like dependence of the threshold current on the laser cavity orientation. The maximal modal gains for lasing in the ground-state with the cavity perpendicular to the dash direction are determined to be 15 cm-1 for single-stack and 22 cm-1 for five-stack lasers 相似文献
3.
We report data on GaAsSb single-quantum-well lasers grown on GaAs substrates. Room temperature pulsed emission at 1.275 μm in a 1250-μm-long device has been observed. Minimum threshold current densities of 535 A/cm2 were measured in 2000-μm-long lasers. We also measured internal losses of 2-5 cm-1, internal quantum efficiencies of 30%-38% and characteristic temperatures T0 of 67°C-77°C. From these parameters, a gain constant G0 of 1660 cm-1 and a transparency current density Jtr of 134 A/cm2 were calculated. The results indicate the potential for fabricating 1.3-μm vertical-cavity surface-emitting lasers from these materials 相似文献
4.
Zmudzinski C.A. Zory P.S. Lim G.G. Miller L.M. Beernink K.J. Cockerill T.L. Coleman J.J. Hong C.S. Figueroa L. 《Photonics Technology Letters, IEEE》1991,3(12):1057-1060
Differential gain (g ') of bulk and single-quantum-well (SQW) lasers was determined from threshold current density and differential quantum efficiency measurements. The threshold measurement technique was used to show that g ' is a function of cavity length (L ) in SQW lasers and independent of L in bulk lasers. It was found that g ' of long SQW lasers (1000 μm) is about 7×10-16 cm2 , approximately two times that of bulk lasers. At short cavity lengths (250 μm), g ' is about the same for both laser types 相似文献
5.
Novel vertical-cavity surface emitting lasers fabricated using selective oxidation to form a current aperture under a top monolithic distributed Bragg reflector mirror are reported. Large cross-sectional area lasers (259 μm2) exhibit threshold current densities of 150 A/cm2 per quantum well and record low threshold voltage of 1.33 V. Smaller lasers (36 μm2) possess threshold currents of 900 μA with maximum output powers greater than 1 mW. The record performance of these oxidised vertical-cavity lasers arises from the low mirror series resistance and very efficient current injection into the active region 相似文献
6.
Distributed Bragg-reflector (DBR) diode lasers were designed and fabricated from lattice-matched Pb1-x Snx Te/PbSey Te1-y single heterostructures grown by liquid-phase epitaxy. These DBR lasers operated in a single longitudinal mode within a limited range of heat-sink temperatures, 8.5-38 K, with a threshold current density of ∼3 kA/cm2at 20 K. Single longitudinal mode operation was maintained up to more than three times the threshold current. Continuous tuning of the laser output frequency over a range of ∼6 cm-1, near 775 cm-1(12.9 μm), was acheived by varying the heat-sink temperature. The average tuning rate was 0.21 cm-1/K, and it was much smaller than the rate for corresponding Fabry-Perot lasers, which was 2.3 cm-1/K. The measured effective mode index of the DBR lasers agrees well with the calculated one. 相似文献
7.
Davis L. Lam Y. Nichols D. Singh J. Bhattacharya P.K. 《Photonics Technology Letters, IEEE》1993,5(2):120-122
The authors have experimentally determined Auger recombination rates in compressively strained InxGa1-xAs/InGaAsP/InP MQW lasers for the first time. The Auger recombination rates were derived from the measured turn-on delay times during large-signal modulation of single-mode lasers. The Auger coefficient increases from 5±1×10-30 to 13±1×10-30 cm6 s-1 as the indium composition in the quantum well active region, x , increases from 0.53 to 0.73 相似文献
8.
High power and high quantum efficiency Al-free InGaAs/GaInAsP/GaInP GRINSCH SQW lasers emitting at 0.98 μm are reported. A CW output power as high as 580 mW and single lateral mode power up to 280 mW were achieved for the Al-free ridge waveguide lasers at room temperature. The lasers exhibited a high internal quantum efficiency of 99% and low internal waveguide loss of 3.2 cm-1. A high characteristic temperature of 217 K and low threshold current density of 109 A/cm2 were also obtained. The results are the best obtained for Al-free 0.98 μm pumping lasers 相似文献
9.
Barnes W.L. Poole S.B. Townsend J.E. Reekie L. Taylor D.J. Payne D.N. 《Lightwave Technology, Journal of》1989,7(10):1461-1465
Single-mode fiber lasers operating at ~1.57 μm are described. Output powers of >2 mW are reported for laser diode pumped operation. Direct comparison is made between fiber lasers using sensitized erbium (Er3+ and Yb3+) and erbium on its own. The performance of Er3+-Yb3+ fiber lasers is analyzed in more detail as a function of fiber length. Both CW and Q-switched operations are studied and the results obtained demonstrate that practical sources at 1.5 μm are available from diode pumped Er3+ -Yb3+ systems 相似文献
10.
Investigations have been performed on harmonic generation from solid-vacuum interfaces using a 2.2-ps 1054-nm laser pulse at maximum intensities of ~2×1017 W·cm-2. It is found that the divergence of the harmonics gradually increases at intensities between Iλ2=2×1015 and 2×1016 W·cm-2·μm2. We experimentally observe that the divergence of the harmonics decreases as the order of the harmonic increases. We also found that the divergence of the third harmonics emission is smaller for 2.2-ps pulsewidth for the driving lasers as compared with those for 100-ps pulsewidth lasers 相似文献
11.
Hains C.P. Li N.Y. Yang K. Huang X.D. Cheng J. 《Photonics Technology Letters, IEEE》1999,11(10):1208-1210
The lasing operation of three-quantum-well GaInNAs stripe geometry lasers grown by MOCVD on 0° and 6° misoriented (100) GaAs substrates, respectively, have been demonstrated and their performance is compared for the first time. Both devices achieved room temperature, pulsed lasing operation at an emission wavelength of 1.17 μm, with a threshold current density of 667 A/cm2 for lasers grown on 6° misoriented substrates, and 1 kA/cm2 for lasers grown on 0° misoriented substrates. The threshold for the lasers grown on 6° misoriented substrates compares favorably with the best results for GaInNAs lasers. Lasers with narrower stripe width and a planar geometry have also been demonstrated by the use of lateral selective wet oxidation for current confinement, with a threshold current density of 800 A/cm2 for 25-μm-wide devices 相似文献
12.
Lester L.F. Schaff W.J. Song X. Eastman L.F. 《Photonics Technology Letters, IEEE》1991,3(12):1049-1051
The optical and RF characteristics of short-cavity, strained-layer In0.3Ga0.7As graded-index separate-confinement-heterostructure (GRINSCH) multiple-quantum-well ridge waveguide lasers are described. Short-cavity-length strained-layer lasers with four In0.3Ga0.7As quantum wells have been fabricated using chemically assisted ion beam etching (CAIBE). These lasers have a very low K factor of 0.14 ns and a high differential gain of 1.1×10-15 cm2. A 3 dB modulation bandwidth of 23.5 GHz has been measured on a 50 μm cavity-length device. This is the highest reported bandwidth for a quantum well laser 相似文献
13.
Tensile-strained GaAsP/GaInAsP/GaInP separate-confinement-heterostructure single-quantum-well (SCH-SQW) lasers are reported for the first time. A low threshold current density of 261 A/cm2 and a high characteristic temperature of 190 K were obtained for a 1600-μm long broad-area laser having ~0.3% lattice strain. The internal quantum efficiency was as high as 93% and internal waveguide loss 3.3 cm-1. Some primary results of unstrained GaAs/GaInAsP and compressive-strained (1.4%) InGaAs/GaInAsP SCH-SQW lasers are also presented. Both the tensile and compressive-strained lasers exhibited higher quantum efficiency than the unstrained lasers. On the other hand, the tensile-strained lasers had nearly the same internal waveguide loss and threshold current as the unstrained lasers 相似文献
14.
It is shown that the absorption loss coefficient of the active layer for 1.48-μm bulk lasers is 66 cm-1 which is between 45 and 107 cm-1 for 1.3-μm bulk lasers and for 1.55-μm bulk lasers, respectively. It is also described that the absorption loss coefficient of the active layer for 1.48-μm multiple-quantum-well (MQW) lasers is 28 cm-1 which is about two-fifths of that for 1.48-μm bulk lasers. Therefore, the high slope efficiency of the 1.48-μm MQW lasers is attributed not only to the small optical confinement factor but also to the small absorption loss coefficient of the active layer 相似文献
15.
Using MOVPE, we fabricated strained quantum well 1.3 μm lasers with an InGaP cladding layer on a GaAs substrate. The lasers had a high gain coefficient of 60 cm-1. Lasers with high reflection facets had a low threshold current density of 500 A/cm2, and a high characteristic temperature of 100 K 相似文献
16.
Highly strained (Δa/a ~ 2.5%) In0.4Ga0.6 As and In0.4Ga0.6As0.995N0.005 -quantum-well (QW) active lasers utilizing strain-compensating InGaP-GaAsP buffer layers and GaAs0.85P0.15 barrier layers, grown by metal-organic chemical vapor deposition (MOCVD), are demonstrated with lasing emission wavelength of 1.185 and 1.307 μm, respectively. Threshold and transparency current density for the strain compensated InGaAsN QW lasers, with emission wavelength of 1.295 μm, are measured to be as low as 290 A/cm2 (L = 1500 μm) and 110 A/cm2, respectively, with characteristic temperature of T0 and T1 of 130 K and 400 K 相似文献
17.
《Lightwave Technology, Journal of》1997,15(11):2141-2146
High-performance multiquantum-well 1.55 μm InP-based tunneling injection lasers are fabricated using a conventional single mode ridge waveguide fabrication process and characterized. The lasers consist of an eight quantum-well strain-compensated gain region and a 30-Å InP tunneling barrier. The bandwidth of these lasers is measured to be 20 GHz with a damping limited bandwidth extracted from the K-factor (determined from optical modulation measurements) of 26 GHz. To our knowledge, this is the highest measured bandwidth recorded for an InP-based simple ridge waveguide structure. The differential gain is measured to be as high as 1×10-15 cm2, with a measured gain compression coefficient ϵ of 5×10-17 cm3. It is shown that the K-factor can also be extracted solely from measurements of the small signal electrical impedance. The carrier escape time τesc is determined to be 0.5 ns, independent of bias. This high frequency performance is achieved with a very simple device structure at room temperature under constant drive currents 相似文献
18.
Tertiarybutylarsine and tertiarybutylphosphine are less hazardous alternatives to arsine and phosphine as group V sources for crystal growth of InxGa1-xAsyP1-y alloys by metalorganic chemical vapor deposition. Compressive and tensile-strained quantum-well lasers emitting at 1.55 μm have been fabricated using these sources. Threshold current density as low as 93 A/cm2, transparency current density as low as 38 A/cm2 and internal efficiency of 91% were obtained for 1.5% compressive-strained single quantum-well lasers. These devices represent the best lasers emitting at this wavelength that have been reported in the literature. An analysis of some of the characteristics of these devices such as transparency current, differential gain and nonradiative recombination is also presented in this paper 相似文献
19.
20.
Nine schemes for direct optical pumping of multiatmosphere CO2 and N2O lasers at pump wavelengths in the 1.4-3.6-μm region are discussed. Most of these wavelengths can be generated by solid-state lasers, which are more attractive pump sources than the chemical lasers (HBr, HF) used previously to pump high-pressure CO2 and N2O lasers. Including previously studied pump schemes, there are altogether 14 possible pump transitions in CO 2 and N2O in the 1.4-4.5-μm region. Numerical laser simulations are carried out to compare all of these pump schemes. Assuming 10 J/cm2 pump energy in a pulse of 100 ns FWHM, and 5% output coupling as the only resonator loss, the calculated energy conversion efficiencies are in the range of 6-40%. The pump thresholds are in the range of 0.1-3.1 J/cm2 相似文献