Synchronously pumped femtosecond optical parametric oscillator based on an improved pumping concept

摘要

We present an improved pumping concept for a synchronously pumped optical parametric oscillator (OPO). The validity of this new concept has been verified by an experiment of a synchronously pumped femtosecond OPO based on periodically poled LiNbO_(3) (PPLN). With this new concept, not only can we obtain high harmonic repetition rate from an OPO, but also we can design the OPO with one more freedom, that is to choose the cavity length of the OPO. We also propose a simple method to compensate for intracavity group velocity dispersion (GVD) in a synchronously pumped ring-cavity PPLN OPO at the telecom wavelengths (1.3-1.6 μm), that is to insert a piece of type-I noncritical phase-matching (NCPM) lithium tri-borate (LBO) (θ=90°, φ=0°) in the ring cavity.