Nonlinear Silicon Waveguides for Integrated Fiber Laser Systems

Silicon-on-insulator (SOI) based photonic devices have attracted great interest from photonics community because of its compatibility with state-of-the-art CMOS fabrication processes and its potential of making energy efficient and low cost photonic integrated circuits (PICs) for high bandwidth optical interconnects and integrated optical sensors. Wavelength division multiplexing (WDM) is already widely used in optical communications and is also of interest for optical sensors, providing advantages of low cost, and high speed compared with single wavelength approach. However, the cost and the bulkiness of WDM systems increase proportionally with the number of wavelengths if conventional external laser source is used. Therefore, low cost and compact laser source with stable and high line quality is of great interest for integrated sensors.;In this thesis, we investigate the incorporation of silicon photonic devices as intracavity elements in fiber lasers for various applications. Therefore, the high flexibly and rich functionalities of fiber lasers can be directly used in the PIC. Also, high-speed feedback control of the cavity becomes possible. The possibility of applying nonlinear SOI waveguides to fiber lasers is investigated. We propose and demonstrate a multiwavelength erbium-doped fiber laser stabilized by four-wave mixing (FWM) in a nonlinear SOI waveguide. Such multiwavelength lasers are potentially suitable for WDM sensing. The wavelength selectivity was achieved by an intracavity Fabry-Perot comb filter. Making use of the nonlinearity of the SOI waveguide, a multiwavelength laser with six output wavelengths at 0.8 nm spacing was achieved.;We study a passive mode-locked erbium-doped fiber ring laser based on a nonlinear SOI microring resonator (MRR). By using the MRR as the comb filter and the nonlinear medium, a stable mode-locked pulse train at 100 GHz was produced by filter-driven four-wave mixing. Such lasers can act as high repetition rate optical clocks for high speed applications and coherent optical comb source for high spectral efficiency modulation schemes such as orthogonal frequency division multiplexing (OFDM).;Besides the parametric processes, we study a graphene based saturable absorber which can be used to achieve ultrafast passive mode-locked laser for SOI sensing platform. Graphene based photonic devices have attracted considerable interest because of their unique zero bandgap and linear electronic dispersion. The graphene on silicon waveguide structure offers the advantage of greatly increasing the interaction length compared to the geometry with light incident normal to the graphene plane. We describe a mode-locked fiber laser using graphene on silicon saturable absorber.;Finally, we study the possibility of expanding the working wavelengths to mid-infrared (mid-IR) for chemical sensing or free-space communications. MRRs were fabricated on silicon-on-sapphire (SOS) wafer and characterized at 2.75 microm. We developed a characterization technique to measure the Q of MRRs using a fixed wavelength source by only varying the temperature of the device. The proposed method provides an alternative method of Q measurement for MRRs in mid-IR where tunable lasers may not be easily available.