Search

Erbium-doped monomode optical fibers are widely used to build amplifiers, lasers, incoherent light sources and sensors. Since the performance of these devices can be modified by its spectral birefringence, it is important to characterize it. In the case of an elliptical retarder the determination of the sign of the linear birefringence and the relative value of the linear and circular distributed birefringence is not obvious. In this work we analyze the anisotropic response of erbium fibers assuming that they are uniform and behave as a distributed retarder with linear and circular birefringence. Taking advantage of the geometric properties of the Poincare sphere it is possible to separate the linear birefringence contribution from that of the circular birefringence and to determine their signs and relative values.

In this work we present a polarimetric method that uses a polarization description based on the Poincare sphere. The erbium fiber is modeled assuming that it is uniform and behaves as a distributed retarder with linear and circular birefringences. We show that taking advantage of the geometric properties of the Poincare sphere it is possible to separate the linear birefringence contribution from that of the circular birefringence while the measurement precision is optimized. The experimental procedure here presented provides reproducible results for the measurement of the linear and circular distributed birefringences in erbium-doped fibers.

A remote temperature sensor has been developed to measure the temperature of a metal alloy in microgravity conditions, on board an automatic and sealed experimental station in the Space Shuttle. The device is composed of an optical system, that allows thermal radiation from the hot body to pass through an orifice in the oven, and focus onto an infrared detector whose output photocurrent is a function of temperature. The experiment is fully microcomputer controlled, and temperature data is both, utilized to control the heating path, and stored in the memory for postflight analysis. In this paper, design, construction, calibration, testing and performance of the system are described.