Widely tunable femtosecond soliton generation in a fiber-feedback optical parametric oscillator

Abstract

Optical parametric oscillators (OPOs) are uniquely versatile—albeit complex—platforms for the generation of tunable coherent light in difficult-to-access spectral regions. A synchronously pumped χ ( 2 ) femtosecond OPO producing sub-100-fs pulses, by means of optical soliton formation in a single-mode fiber-feedback cavity, is presented for the first time. This approach removes the requirement for active stabilization and bulk dispersion compensation elements associated with traditional OPOs, while reducing the physical footprint by a factor of 3. Transform-limited pulses of 80–120 fs are generated for both normal and anomalous dispersion, while a new type of spectral sideband formation is observed and studied. Experimental results are supported by detailed simulations based on nonlinear pulse propagation theory, which serve to enrich the understanding of femtosecond pulse evolution in OPOs perturbed by strong Kerr nonlinearity. The OPO provides a unique platform for the study of intracavity soliton phenomena across a wide wavelength range.

A random optical parametric oscillator

“…Even so, the spectral tuneability remains significantly inferior compared to that of conventional OPOs. For instance, an OPO also making use of optical fibre in a hybrid fibre/free-space configuration allowed wavelength tuning in the range 1051–1700 nm 48 , where tuning was accomplished by both varying the grating period of a periodically poled crystal and adjustment of the cavity length. Nevertheless, the concept of random parametric oscillation goes far beyond the setup explored in this work.…”

Temporal-filtering dissipative soliton in an optical parametric oscillator

“…In 2018, Liu and Zhang [ 35 ] further demonstrated chirped pulse OPOs by introducing a material with a large nonlinearity in the cavity. In addition, spectra with steep edges were observed in a normal-dispersion fiber OPO [ 36 ] and a normal-dispersion fiber-feedback OPO [ 37 ] , respectively. These works laid the foundation for the observation of dissipative solitons in OPOs.…”

High-energy, mid-IR, picosecond fiber-feedback optical parametric oscillator

“…An alternative method to reduce the footprint of SPOPOs is to use a piece of optical fiber inside the cavity to replace the free-space beam path for synchronous pumping [9,10]. Apart from creating the temporal delay, silica fiber has large material group velocity dispersion and can be used to manage the intra-cavity dispersion within femtosecond OPOs [11,12]. In the hundreds-of-picosecond regime, where dispersion is less critical, a fiber-feedback OPO has been demonstrated at a repetition rate of 7.19 MHz using a 42-m length of single-mode fiber and generated MIR idler pulses with a peak power of up to 1.8 kW (0.19 µJ pulse energy) [13].…”