Coupling modulation of microrings at rates beyond the linewidth limit.

We demonstrate optical modulation rates exceeding the conventional cavity linewidth limit using a silicon coupling modulated microring. Small-signal measurements show coupling modulation was free of the parasitic cavity linewidth limitations at rates at least 6× the cavity linewidth. Eye diagram measurements show coupling modulation achieved data rates > 2× the rate attainable by conventional intracavity phase modulation. We propose to use DC-balanced encoding to mitigate the inter-symbol interference in coupling modulation. Analysis shows that coupling modulation can be more efficient than intracavity modulation for large output swings and high-Q resonators. Coupling modulation enables very high-Q resonant modulators to be simultaneously low-power and high-speed, features which are mutually incompatible in typical resonant modulators studied to date.

[The question of indication for surgery in renovascular hypertension]. / Zur Frage der Operationsindikation bei renovaskulärer Hypertonie

11 of 22 patients with angiographical identified unilateral stenosis of renal artery underwent a reconstruction of vessels. 11 patients were treated according to conservative methods. To achieve a prognosis, we compared pressure gradient and methods based on determination of plasma renin activity (PRA) including the difference of concentration of PRA in both renal veins as well the relationship between the concentration in the renal veins and peripheral blood and the suppression of the renin secretion in the undamaged kidney. In cases when all prognostic criteria were in positive accordance, operation was successful (7 cases). When there was no accordance, we noticed a correlation between pressure gradient and surgical success in 3 cases and predicaments based on PRA and success in 2 cases. Pressure gradient is pointed out as important parameter, 3 of non operated patients showed a progression of this disease.