摘要
Nonlinear optical gain modulation(NOGM)is an effective approach for generating highly coherent femtosecond Raman pulses.In a typical NOGM system,the pump pulse energy boosting unit and nonlinear frequency conversion unit are separated,which poses a difficulty in generating Raman solitons with pulse energy over theμJ level.Here,we demonstrate an integrated ultrafast ytterbium-Raman fiber amplifier,which accomplishes pump pulse amplification and Raman pulse conversion simultaneously in ytterbium-doped fiber(YDF).The integrated ytterbium-Raman fiber amplifier could generate approximately 1μJ 1121 nm Raman pulses with a pulse duration of 589 fs under a conversion efficiency of 69.9%.The result represents the highest pulse energy experimentally recorded in NOGM systems.Simulation further reveals that YDF gain could promote Raman conversion efficiency and reduce nonlinear chirp accumulation,which leads to improved performance of generated Raman pulses.Meanwhile,the feasibility of generating 10μJ level Raman pulses using such a hybrid gain setup was also confirmed numerically.
基金
supported by the National Key R&D Program of China(Grant No.2024YFB3907802)
the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2022247)
the National Natural Science Foundation of China(Grant Nos.62175244,62075226,12341404 and 62305358)
the Natural Science Foundation of Shanghai(Grant No.21ZR1472200).
