Patent ID: 7633990

Claim:
A method of improving lasing efficiency of an erbium-based medium comprising: a. exposing the medium to a first pump radiation of a first wavelength, such that a first erbium ion is excited from a first state to a second state, b. thereby increasing the population of erbium ions in the second state, creating a population inversion necessary for lasing between the second state as the upper lasing state and a third state as the lower lasing state, said third state being different in energy level than the first state, and c. exposing the medium to a second pump radiation of a second wavelength, such that a second erbium ion is excited from the third state to a fourth state, thereby reducing the population of erbium ions in the third state, reducing a bottleneck created by erbium ions populating the third state, and improving the population inversion necessary for lasing between the second state and the third state, wherein the third state is an 4 I 13/2 lower lasing state and the fourth state is an 4 I 9/2 metastable state or a Stark level in the 4 I 11/2 state above said second state, and wherein the lasing efficiency between the second state as the upper lasing state and the third state as the lower lasing state is improved.