Fiber-feedback optical parametric oscillator for half-harmonic generation of sub-100-fs frequency combs around 2 μm
We demonstrate a femtosecond fiber-feedback optical parametric oscillator (OPO) at degeneracy. The OPO cavity comprises an 80-cm-long fiber composed of a combination of normal and anomalous dispersion sections that provide a net intracavity group delay dispersion close to zero. By using a mode-locked, Yb-doped fiber laser as the pump, we achieved half-harmonic generation of 250-MHz, 1.2-nJ nearly transform-limited 97-fs pulses centered at 2090 nm with a total conversion efficiency of 36%.
© 2015 Optical Society of America. Received 20 May 2015; revised 24 August 2015; accepted 27 August 2015; posted 27 August 2015 (Doc. ID 240510); published 15 September 2015. The authors thank Tim Brand for dicing and polishing the LiNbO_3 crystals. Funding. Joint Technologies Office.