Dispersion Tailoring and Four-Wave Mixing in Silica Microspheres with Germanosilicate Coating

Abstract

Optical whispering gallery mode microresonators with controllable parameters in the telecommunication range are demanded for diverse applications. Controlling group velocity dispersion (GVD) in microresonators is an important problem, as near-zero GVD in a broad wavelength range could contribute to the development of new microresonator-based light sources. We demonstrated theoretically near-zero dispersion tailoring in the SCL-band in combination with free-spectral range (FSR) optimization for FSR = 200 GHz and 300 GHz in silica glass microspheres with micron-scale germanosilicate coating. As an illustration of a possible application of such a GVD, we also performed a theoretical study of degenerate four-wave mixing (FWM) processes in the proposed microresonators for pumping in the SCL-band. We found that in some cases the generation of two or even three pairs of waves–satellites in a FWM process is possible in principle due to the specific GVD features. We also determined optimal microresonator configurations for achieving gradual change in the satellite frequency shift for the pump wavelengths in the SCL-, S-, CL-, C-, and L-bands. The maximum obtained FWM satellite tunability span was ~78 THz for a pump wavelength change of ~30 nm, which greatly exceeds the results for a regular silica microsphere without coating.

Theoretical Study of Multicascade Raman Microlasers Based on TeO2–WO3–Bi2O3 Glass

“…However, it is known that when phase matching conditions are met, anti-Stokes light components can be generated with reasonable efficiencies in microresonators even with a normal dispersion [27,28]. We checked using the previously implemented model [29] that for our resonators the phase matching conditions are not met. The calculated second-order dispersion coefficients β 2 vs. wavelength are plotted in Figure 2c.…”

Cladding-Pumped Er/Yb-Co-Doped Fiber Amplifier for Multi-Channel Operation

“…However, telecom-related applications have also gained momentum by proving their particular significance in such applications. The multifold of different fiber structures and techniques can be designed to address specific telecom amplifier needs, for instance, a multi-cladding optical fiber with a non-circular symmetry that aims to enhance pump absorption via twisting and coiling [1], the reduction in nonlinear effects with tapered fiber [2], fiber dispersion engineering [3,4]. The simulation of cladding-pumped doped fiber amplifier performance is also of particular interest due to the necessity of obtaining initial estimates of the key performance indicators, such as noise figure (NF) and gain [5].…”