Affiliation:
1. Shanghai Institute of Technical Physics, Chinese Academy of Sciences
2. National Institute of Metrology
Abstract
We demonstrate a GHz U-band fiber laser harnessing soliton self-frequency shift (SSFS). The seed source is a passively harmonic mode-locked (HML) fiber laser based on carbon nanotubes (CNTs) polymer film. By adjusting the pump power and polarization controller (PC) appropriately, the repetition rate can be tuned up to 1.104 GHz with a side mode suppression ratio (SMSR) of 42.5 dB. The seed source with different repetition rates can be frequency shifted from C-band to U-band in a piece of dispersion-shifted fiber (DSF) after amplification. We selected three repetition rates (457.8 MHz, 700.1 MHz, and 1104.1 MHz) and systematically studied the impact of different repetition rates on SSFS. The broad tuning range of wavelengths covering the entire U-band can be obtained by adjusting the pump power of the main amplifier. To the best of our knowledge, the demonstrated laser is the first U-band femtosecond fiber laser based on passively HML with a repetition rate over 1 GHz.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
Overseas Expertise Introduction Project for Discipline Innovation
Natural Science Foundation of Shanghai Municipality
Shanghai Rising-Star Program
Youth Innovation Promotion Association of the Chinese Academy of Sciences