High power pump modules are used for industrial as well as telecom applications such as for fiber lasers and cladding pumped erbium doped fiber amplifiers (EDFA) Lichtenstein, N., et al., 2004. Key ...element of a pump module is a single emitter laser diode, which normally has an aperture of around 90 mum, in order to provide best coupling into an optical multi-mode fiber with a 105 mum core diameter. Increasing the brightness of the pump module lends additional flexibility in the design of fiber lasers and amplifiers and enables higher output power. In this communication we report on two approaches to increase the brightness of our latest generation of high power pump modules. Within the first approach the electro-optical performance of the single emitter laser diode is improved by optimizing Bookham's mature chip technologies such as InGaAs/AlGaAs structures grown by MBE, the ridge-waveguide manufacturing process, the E2 facet passivation and the mounting technology. The combination of improved chip design and new coupling scheme leads to reliable broad area modules with outstanding brightness.
Reply to Letter Lichtwarck-Aschoff, Michael; Beale, Richard; Pfeiffer, Ulrich J.
Journal of critical care,
9/1997, Letnik:
12, Številka:
3
Journal Article
Continuous positive-pressure ventilation and PSV were compared prospectively in patients at a surgical intensive care unit. All patients suffered from mild to moderate ARI (PaO2/FIo2 of 125 to 350 mm ...Hg). The patients were randomly assigned to a PSV group (n = 28) or a control group with continued CPPV (n = 27). The usual hemodynamic and oxygenation variables, ITBV, and extravascular lung water (ETV) were assessed before and six hours after switching to PSV. The changes (d) of PaO2/FIo2, RI, and P(A-a)O2 were used for evaluation of the effect of PSV. Significant correlations were found between the ETV(CPPV) and dPaO2/FIo2 (r = – 0.672), ETV(CPPV) and dRI (r = 0.722), and ETV(CPPV) and dP(A-a)O2 (r = 0.601), which led to the conclusion that the level of ETV determined the efficacy of PSV. In the subgroup with ETV less than 11 ml/kg (n = 15), PSV significantly improved PaO2/FIo2 (248 to 286 mm Hg), RI (1.55 to 1.22), ITBV (801 to 888 ml/m2), cardiac index (4.21 to 4.76 L/min·m2), stroke index (42.2 to 48.1 ml/m2), and oxygen delivery (735 to 833 ml/min·m2). In the subgroup with ETV greater than 11 ml/kg (n = 13), PSV caused a significant deterioration of PaO2/FIo2, RI, and intrapulmonary shunt. It is concluded that in patients with moderate ARI in whom ETV is almost normal, PSV is superior to CPPV, and the efficacy of PSV is independent of the level of oxygenation during CPPV.
AIM: To evaluate the safety and efficacy of pegylated interferon alfa-2a and ribavirin therapy in elderly patients with chronic hepatitis C infection.METHODS: Patients characteristics, treatment ...results and safety profiles of 4859 patients with hepatitis c virus(HCV) infection receiving treatment with pegylatedinterferon alfa-2a and ribavirin were retrieved from a large ongoing German multicentre non-interventional study. Recommended treatment duration was 24 wk for GT 2 and GT 3 infection and 48 wk for GT 1 and GT 4 infection. Patients were stratified according to age(< 60 years vs ≥ 60 years). Because of limited numbers of liver biopsies for further assessment of liver fibrosis APRI(aspartate aminotransferase- platelet ratio index) was performed using pre-treatment laboratory data.RESULTS: Out of 4859 treated HCV patients 301(6.2%) were ≥ 60 years. There were more women(55.8% vs 34.2%, P < 0.001) and predominantly GT 1(81.4% vs 57.3%, P < 0.001) infected patients in the group of patients aged ≥ 60 years and they presented more frequently with metabolic(17.6% vs 4.5%, P < 0.001) and cardiovascular comorbidities(32.6% vs 6.7%, P < 0.001) and significant fibrosis and cirrhosis(F3/4 31.1% vs 14.0%, P = 0.0003). Frequency of dose reduction and treatment discontinuation were significantly higher in elderly patients(30.9% vs 13.7%, P < 0.001 and 47.8% vs 30.8%, P < 0.001). Main reason for treatment discontinuation was "virological non-response"(26.6% vs 13.6%). Sustained virological response(SVR) rates showed an age related difference in patients with genotype 1(23.7% vs 43.7%, P < 0.001) but not in genotype 2/3 infections(57.7% vs 64.6%, P = 0.341). By multivariate analysis, age and stage of liver disease were independent factors of SVR.CONCLUSION: Elderly HCV patients differ in clinical characteristics and treatment outcome from younger patients and demand special attention from their practitioner.
We describe the extension of excitation correlation to the mid-infrared. This technique provides a convenient alternative to more complicated pump-probe and time-resolved photoluminescence approaches ...for investigating electron–hole recombination in semiconductors. Excitation correlation is used to determine the Shockley–Read–Hall and Auger coefficients for a GaInSb/InAs multiple quantum sample with an absorption edge near 3.6 μm. The results are
A
=
0.20
±
0.02
ns
−
1
,
C
=
4.0
±
0.4
×
1
0
−
27
cm
6
/
s
, and
n
tr
=
8.5
±
0.2
×
10
16
cm
−
3
, where
n
tr
is a saturation density for Shockley–Read–Hall recombination and also an estimate for the density of mid-gap trap levels.
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