Abstract

Laser development in 1.5-1.6-μm range is mostly based on Er³⁺-doped laser materials [1]. Er³⁺-doped laser materials are amenable to operating in the “low quantum defect (QD)” mode. Laser operation with the quantum defect of less than 1.5% has been recently reported for Er³⁺-doped scandia laser ceramic operated in a cryogenically-cooled mode [2]. Despite all these “pros”, Er³⁺-doped laser operation is known to be heavily affected by detrimental up-conversion effects, which confines laser designer to using low-concentrated gain elements, thus significantly limiting design space [1]. Er³⁺-doped crystalline laser materials also have extremely narrow absorption features, which calls for an in-band pumping by spectrally-narrowed sources. These two “contras” of Er³⁺-doped materials, along with the need for new materials amenable to “ultra-low” quantum defect operation, motivate the search for alternative, non-Er³⁺, laser materials capable of resonantly-pumped ~1.5-μm laser operation.

© 2009 IEEE