Active tapered double-clad fiber with low birefringence.

We addressed the problem of a state of polarization (SOP) drift caused by heating under intense clad pumping in different types of active tapered double-clad fibers. We investigated experimentally the variations of the SOP and degree of polarization (DOP) under clad pumping in polarization-maintaining (PANDA type) and regular (non-PM) Yb-doped double-clad large mode area tapered fibers. We discovered that the birefringence of active fibers is highly dependent on the launched pump power.

The relation between QRS amplitude and left ventricular mass in patients with hypertension identified at screening.

Objective: The aim of this study was to analyze the relationship between QRS amplitude and left ventricular mass (LVM) in hypertensive patients identified by screening, with the focus on those without left ventricular hypertrophy (LVH).

Methods: The entire study group consisted of 189 healthy subjects (average 39.6 years) and 54 subjects with hypertension (average 52.