Two Polarization Comb Dynamics in VCSELs Subject to Optical Injection

• Published in: Photonics Vol. 9; no. 2; p. 115
• Main Authors: Doumbia, Yaya, Wolfersberger, Delphine, Panajotov, Krassimir, Sciamanna, Marc
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2022; MDPI
• Subjects: Bandwidths; Broadband; Competition; Dichroism; Energy consumption; Injection; Injection current; Lasers; Linear dichroism; Nonlinear dynamics; Nonlinear systems; Optical communication; Optical frequency; optical frequency comb; optical injection; Optical properties; Optics; Parameters; Physics; Polarization; polarization switching; Power; Quantum dots; Spectroscopy; Spectrum analysis; VCSEL; Optical injection; Optical frequency comb; Nonlinear dynamics; Polarization switching; VCSEL
• ISSN: 2304-6732; 2304-6732
• DOI: 10.3390/photonics9020115

Optical frequency comb technologies have received intense attention due to their numerous promising applications ranging from optical communications to optical comb spectroscopy. In this study, we experimentally demonstrate a new approach of broadband comb generation based on the polarization mode competition in single-mode VCSELs. More specifically, we analyze nonlinear dynamics and polarization properties in VCSELs when subject of optical injection from a frequency comb. When varying injection parameters (injection strength and detuning frequency) and comb properties (comb spacing), we unveil several bifurcation sequences enabling the excitation of free-running depressed polarization mode. Interestingly, for some injection parameters, the polarization mode competition induces a single or a two polarization comb with controllable properties (repetition rate and power per line). We also show that the performance of the two polarization combs depends crucially on the injection current and on the injected comb spacing. We explain our experimental findings by utilizing the spin-flip VCSEL model (SFM) supplemented with terms for parallel optical injection of frequency comb. We provide a comparison between parallel and orthogonal optical injection in the VCSEL when varying injection parameters and SFM parameters. We show that orthogonal comb dynamics can be observed in a wide range of parameters, as for example dichroism linear dichroism (γa=−0.1 ns−1 to γa=−0.8 ns−1), injection current (μ=2.29 to μ=5.29) and spin-flip relaxation rate (γs=50 ns−1 to γs=2300 ns−1).