In-band pumping of Tm doped single mode tellurite composite fiber

Mechanical strength is one of the biggest limitations of practical application for tellurite fiber. In this study, we design and fabricate a single mode tellurite composite fiber to overcome the flaw. The fiber has a double cladding structure with tellurite core and inner cladding, the outer cladding, which is made of non-tellurite glass, possesses of appropriate softening temperature and coefficient of thermal expansion, well matched the novelty tellurite glass. The propagation loss of the fiber is less than 0.02 dB/cm @1310 nm. We also investigate the laser property of the fiber by using a homemade watt-class 1590 nm fiber laser. 2 micron fiber laser is demonstrated with a 2 cm length of the fiber.