Accurate method for measuring the thermal coefficient of group birefringence of polarization-maintaining fibers.

We present a method to accurately measure the group birefringence variation with temperature in high-birefringence polarization-maintaining (PM) fibers using a distributed polarization analyzer. By analyzing polarization cross-talk peaks purposely induced at both ends of a PM fiber, the temperature coefficient of group birefringence can be accurately obtained. We confirm the theoretical prediction that the group birefringence of PANDA and TIGER PM fibers decrease linearly with temperature from −40 °C to 80 °C, and find that the temperature coefficients are −5.93×10−7 °C−1 and −5.29×10−7 °C−1 for two types of PANDA fibers, and −5.36×10−7 °C−1 for a TIGER fiber.