MODELING OF THRESHOLD AND EXTRACTION EFFICIENCY IN PR3-CONVERSION FIBER LASERS USING 2-PHOTON PUMPING( ZBLAN UP)

We model the steady-state threshold and extracted power of a two-photo n incoherently pumped upconversion fibre laser. Our threshold analysis is entirely analytic, and along with this derivation we obtain an ana lytic threshold cutback formula. This takes a particularly simple form when the ground state pump absorption follows exponential absorption. We also numerically simulate the extracted laser power. The experimen t which we simulate is upconversion in Pr3+ doped ZBLAN fibre lasing a t 491 nm and pumped with 1017 nm and 835 nm diode lasers. Our formulas and simulations are mutually consistent and agree with the experiment to within 10%.