Micro and Nano Optics
Optical Second-Order Nonlinearity in Poled Organic Thin Film Doped with PTOPDT
An optical second-order nonlinear compound was developed by doping organic dye molecules (PTOPDT) in a UV curing host polymer system (OG146). A systematic evaluation of the film physical and optical properties was presented. The film absorption spectrum shows a promising advantage for frequency doubling in the blue color window. As for the future work, we will perform a more detail investigation of the film fabrication process to obtain the best combination of the dye doping concentration and poling conditions that yield the optimum physical and optical properties of this film.
“Fabrication and Characterization of Poled Pyrylium Doped Nonlinear Organic Thin Film,” K. Le, N. Stelmakh, M. Zhou, M. Pomerantz, and J.C. Chiao, The OSA Annual Meeting, Rochester, New York, Oct. 10-14, 2004. Download
Electro-Optically Tunable Folded Arrayed Waveguide Grating Multiplexer
Channel tunability of 10 GHz has been demonstrated in a 40-channel 50-GHz-spaced folded silica-on-silicon arrayed waveguide grating (AWG) multiplexer using quadratic nonlinearity in phosphorous-doped glass and a specially-shaped electrode. Such AWG can be stabilized and tuned around ITU grid without power-consuming thermo-electric coolers.
"Electro-Optically Tunable Folded Arrayed Waveguide Grating Multiplexer, " K. Le, N. Stelmakh, M. Vasilyev, and J.C. Chiao, IEEE Photonics Technology Letters, Vol. 17, No. 1, pp. 112-114, January, 2005. Download
"Electro-Optically Tunable Folded Arrayed Waveguide Grating Multiplexer," K. Le, N. Stelmakh, M. Vasilyev, and J.C. Chiao, OPTO News and Letters, No. 119, Jan., 2005.
MicroElectroMechanical Optical Systems MEMOS
Microelectromechanical system (MEMs) devices have been attracting a lot of attention because of their unique features. The device sizes are usually in the range from 10µm to 1mm. The thickness of moveable parts on the silicon chips are usually in the order of microns, therefore, the mass of moveable parts are very small which require very small force to move. This is appropriate for photonic applications since photons have no mass. Small forces such as electrostatic force and magnetic force are suitable for the mechanical actuation. The miniature feature reduces the size and weight of the integrated components which also reduces power consumptions. In most of the cases, the electrostatic actuation only requires voltages and consumes very little currents. Furthermore, in photonic applications, the electrostatics or magnetics will not interfere with optics.
Silicon micromachining techniques also allow monolithic fabrication using the existing VLSI or CMOS processes, which can reduce manual labor and fabrication costs. The monolithic feature also allows precise positioning for the optical components on the same chips. The accuracy of alignment can be less than 0.1µm. The mechanical characteristics of silicon has been well studied and shows great promise for robust and reliable devices. Using surface MEMs technologies to build optical components also benefit from the free-space transmission of lights, which eliminates the dielectric losses of lasers in semiconductor-waveguide integrated-optical devices.
A lot of different MEMs components can be integrated on a single chip, which also reduces extra connector or fiber-splicing losses which occur when we use multiple individual components in a network element. The moveable feature of optical parts on the chips also allows dynamic steering of the laser beams. This function can correct the fiber-misalignment error, even after the devices are built and used in a practical environment. This also solves the stability or reliability issues of the epoxy used to glue the fibers on the chips. The laser beams can always be corrected to get a maximum coupling and minimum insertion losses.
MOEM optical bench integration
Tunable arrayed waveguide grating (AWG)
Optical scanners and switches
Created by J.C. Chiao