Efficient Optical Saturable Absorbers with Graphene on Polymer Waveguides for Femtosecond Laser Pulse Formation

Abstract

Photonic integrated circuits (PICs) are notable for their enhanced functionalities with material flexibilities to find applications in wearable high-speed data management systems. Due to the miniaturized dimensions of PICs, the employment of a nanomaterial having significant optical nonlinearity is critical. Here, it is demonstrated that a polymer waveguide can be harmonized with nonlinear graphene to form ultrashort laser pulses. The graphene works as nonlinear saturable absorber on the polymer waveguide prepared with a perfluorinated acrylic resin. The evanescent field of a laser propagating through the waveguide interacts with graphene to induce intracavity intensity modulation for femtosecond-scale pulse formation. The laser output is characterized quantitatively as the central wavelength, spectral width, repetition rate, extinction ratio, and pulse duration, which are 1553.32 nm, 10.21 nm, 4.18 MHz, 76.03 dB, and 874 fs, respectively. Stable operation is verified over 3 h.