Study of the spectral characteristics of a femtosecond Ti:sapphire laser after propagation of its radiation through a tapered fibre

The method and results of precision measurements of the intermode frequency of a Ti:sapphire laser after the propagation of its radiation through a tapered optical fibre are described. It is shown that the stability of the intermode frequency is impaired by half at short averaging times (10 s) and by a factor of 1.1 at long averaging times (1000 s). The results of investigations of the spectrum of a femtosecond Ti:sapphire laser, which is broadened in a tapered optical fibre are presented. It is shown that, by varying the fibre parameters and the characteristics of input pulses, the envelope of the broadened spectrum can be profiled, which is important for practical applications.