From optical parametric oscillation to frequency-comb generation in whispering gallery resonators made of CdSiP2

Microresonator frequency combs have seen remarkable progress in the past decade. In this work, we investigate optical parametric oscillation in a mm-sized cadmium silicon phosphide (CdSiP2) whispering gallery resonator for X(2) frequency comb generation in the mid-infrared region. The comb formation starts with optical parametric oscillation (OPO) near degeneracy followed by a series of internally pumped second-order nonlinear processes. The first step of OPO has been achieved with thresholds below 100 μW, efficiencies of up to 17 % and wavelength tunability from 2.3 to 5 μm. The control of the wavelength tuning is hampered when the OPO is operated close to degeneracy. Nevertheless, we have observed sideband generation around the pump wavelength, indicating that frequency combs can be generated using this scheme. However, improved control of the wavelength tuning near degeneracy is needed to increase the number of sidebands, leading to broadband frequency combs in the mid-infrared.

[1]  S Wabnitz,et al.  Modulation Instability Induced Frequency Comb Generation in a Continuously Pumped Optical Parametric Oscillator. , 2017, Physical review letters.

[2]  C. Koos,et al.  Ultrafast optical ranging using microresonator soliton frequency combs , 2017, Science.

[3]  T. Kippenberg,et al.  Microwave to optical link using an optical microresonator , 2014, 2015 Conference on Lasers and Electro-Optics (CLEO).

[4]  Ingo Breunig,et al.  Frequency comb up- and down-conversion in synchronously driven χ(2) optical microresonators. , 2018, Optics letters.

[5]  M. Gorodetsky,et al.  Dissipative Kerr solitons in optical microresonators , 2015, Science.

[6]  P. Maddaloni,et al.  Optical Frequency Combs in Quadratically Nonlinear Resonators , 2020, Micromachines.

[7]  Lauri Halonen,et al.  High-power mid-infrared frequency comb from a continuous-wave-pumped bulk optical parametric oscillator. , 2014, Optics express.

[8]  Peter G. Schunemann,et al.  Advances in nonlinear optical crystals for mid-infrared coherent sources , 2016 .

[9]  S. Diddams,et al.  A six-octave optical frequency comb from a scalable few-cycle erbium fiber laser , 2020, 2005.13673.

[10]  Ingo Breunig,et al.  Three‐wave mixing in whispering gallery resonators , 2016 .

[11]  Lauri Halonen,et al.  Frequency comb generation by a continuous-wave-pumped optical parametric oscillator based on cascading quadratic nonlinearities. , 2013, Optics letters.

[12]  Michal Lipson,et al.  Photonic-chip-based frequency combs , 2019, Nature Photonics.

[13]  Nobuyuki Imoto,et al.  Frequency comb generation in a quadratic nonlinear waveguide resonator. , 2018, Optics express.

[14]  T. Kippenberg,et al.  Microresonator based optical frequency combs , 2012, CLEO 2012.

[15]  J. McCarthy,et al.  Efficient, 2-5  μm tunable CdSiP2 optical parametric oscillator pumped by a laser source at 1.57  μm. , 2018, Optics letters.

[16]  Christian Reimer,et al.  Quantum optical microcombs , 2019, Nature Photonics.

[17]  Pasquale Maddaloni,et al.  Frequency comb generation in quadratic nonlinear media , 2014, CLEO 2015.

[18]  Ingo Breunig,et al.  Continuous-wave whispering-gallery optical parametric oscillator based on CdSiP2. , 2018, Optics express.

[19]  M.L. Gorodetsky,et al.  Geometrical theory of whispering-gallery modes , 2006, IEEE Journal of Selected Topics in Quantum Electronics.

[20]  M. Lipson,et al.  Frequency-Comb Spectroscopy , 2022 .

[21]  Pasquale Maddaloni,et al.  Direct generation of optical frequency combs in χ(2) nonlinear cavities , 2015, 1510.08074.

[22]  H. Tang,et al.  Pockels soliton microcomb , 2020, Nature Photonics.

[23]  Miles H. Anderson,et al.  Microresonator-based solitons for massively parallel coherent optical communications , 2016, Nature.

[24]  Ingo Breunig,et al.  Frequency Comb Generation via Cascaded Second-Order Nonlinearities in Microresonators. , 2019, Physical review letters.

[25]  Miro Erkintalo,et al.  Experimental observation of internally pumped parametric oscillation and quadratic comb generation in a χ(2) whispering-gallery-mode microresonator. , 2020, Optics letters.

[26]  Albert Schliesser,et al.  Mid-infrared frequency combs , 2012, Nature Photonics.