Real-time characterization of optical soliton molecule dynamics in an ultrafast thulium fiber laser

We present an experimental characterization of the internal oscillations, vibrations, and transients of optical soliton molecules generated in a passively mode-locked thulium-doped fiber laser. We use custom linearly chirped Bragg grating filters to perform real-time spectral measurement of the ultrafast dynamics at wavelengths around 2 μm.