Pump and thermal impact on heavily erbium-doped fiber laser generation.

A detailed comparative study of heavily erbium-doped fiber laser generation features was carried out in the case of 1490 nm and 976 nm wavelength pumping. The laser cavity was designed using point-by-point fiber Bragg grating inscription technology with femtosecond laser pulses. The CW and -switched lasing regimes were achieved depending on temperature and heat sink performance. It was found experimentally for the first time, to the best of our knowledge, that the frequency and pulse duration of -switched laser operations are primarily determined by the output laser power and do not depend on the pump wavelength. The pulse formation is caused by the lasing process itself and depends on the up-conversion rate at the generation wavelength. Additionally, the level of laser cavity heating at the -switched generation regime was defined.