Due to recent investments by government and industry, silicon-based photonics has a chance of becoming "the" mainstream photonics technology. This paper presents a survey of recent results found in journal articles and conference proceedings. Emerging trends in silicon-based photonic components (waveguides, ultrafast modulators, switches, light sources, detectors, direct bandgap SiGeSn/GeSn devices, photonic-crystal and plasmonic devices) are identified and discussed. In principle, Si PICs and OEICs can operate anywhere within the 0.3 to 100 μm wavelength range -- enabling transceivers, on-chip processing, and interfacing with fibers or free-space light beams. Thus, in addition to the very important 1.55 μm telecomm applications, there are significant Si photonic opportunities throughout the infrared-and-visible spectrum. The push towards smarter, ever-denser on-chip photonic networks, drives a "convergence" of micro-, nano- and plasmo-photonic techniques for progressively smaller devices (Moore"s law for photonics) and for improved functionality of modulators, switches, emitters, detectors, waveguides, resonators, tapers and filters. This convergence includes composite components: monolithic integration of microstrip waveguides, 2D and 3D photonic-crystal elements and metal/Si plasmon-optics that ultilize buried or surface-mounted 2D arrays of metal stripes or nanodots.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.