High precision planar waveguide propagation loss measurement technique using a Fabry-Perot cavity

A high precision measurement technique for characterizing the propagation loss in silica low-loss optical waveguides, based on measuring the contrast of a Fabry-Perot cavity, is demonstrated. The cavity consists of the waveguide coupled to two polarization-maintaining fibers, each end facet coated with dielectric mirrors, leaving the reflectivity as an adjustable parameter. The contrast is measured by modulating the cavity length without influence on the waveguide characteristics and the coupling efficiency. A double modulation of the cavity length reduces the measurement uncertainty, and provides a measurement precision better than 0.1 dB, corresponding to 0.02 dB/cm in case of a 5 cm long waveguid

Optical Nonlinearities In Gaas-Gaalas Multiple Quantum-Well Hetero-Nipi Waveguides

This paper reports on measurements of large optical nonlinearities in GaAs-GaAlAs multiple quantum-well hetero-nipi (MQW-H nipi) waveguides using a Mach-Zehnder interferometer. A model shows how the distribution of the photogenerated carriers in the waveguide structure is affected by the finite sheet resistance of the neutral regions and the optical intensity. However, at normal operational powers and absorption levels the lateral spreading of the photogenerated carriers in the MQW-H nipi waveguide is so large that the nonlinearity must be defined from the ratio between the total optical power and the width of the MQW-H nipi region rather than from the optical intensity alone. The study concludes that the nonlinearity measured in a GaAs-GaAlAs MQW-H nipi waveguide at a wavelength far below the absorption edge, where the absorption coefficient is in the range 10–20 cm-1, is of the order of 10-5 cm2/W. This value is 2–3 orders of magnitude larger than the optical nonlinearity measured in a typical MQW p-i-n diode waveguide at similar absorption, but the increased nonlinearity is obtained at the expense of speed. The time response was found to be in the microsecond regime. Good agreement for the measured turn-on time was obtained for a model with no adjustable parameters. © 1992 IEE

Surface plasmon resonance sensors: a materials guide to design, characterization, optimization, and usage

This significantly extended second edition addresses the important physical phenomenon of Surface Plasmon Resonance (SPR) or Surface Plasmon Polaritons (SPP) in thin metal films, a phenomenon which is exploited in the design of a large variety of physico-chemical optical sensors. In this treatment, crucial materials aspects for design and optimization of SPR sensors are investigated and described in detail. The text covers a selection of nanometer thin metal films, ranging from free-electron to the platinum-type conductors, along with their combination with a large variety of dielectric substrate materials, and associated individual layer and opto-geometric arrangements. Whereas the first edition treated solely the metal-liquid interface, the SP-resonance conditions considered here are expanded to cover the metal-gas interface in the angular and wavelength interrogation modes, localized and long-range SP's and the influence of native oxidic ad-layers in the case of non-noble metals. Furthermore, a selection of metal grating structures that allow SP excitation is presented, as are features of radiative SP's. Finally, this treatise includes as-yet hardly explored SPR features of selected metal–metal and metal–dielectric superlattices. An in-depth multilayer Fresnel evaluation provides the mathematical tool for this optical analysis, which otherwise relies solely on experimentally determined electro-optical materials parameters

Surface plasmon resonance sensors: a materials guide to design and optimization

This book addresses the important physical phenomenon of Surface Plasmon Resonance or Surface Plasmon Polaritons in thin metal films, a phenomenon which is exploited in the design of a large variety of physico-chemical optical sensors. In this treatment, crucial materials aspects for design and optimization of SPR sensors are investigated and outlined in detail. The text covers the selection of nanometer thin metal films, ranging from free-electron to the platinum type conductors, along with their combination with a large variety of dielectric substrate materials, and associated individual layer and opto-geometric arrangements. Furthermore, as-yet hardly explored SPR features of selected metal–metal and metal–dielectric super lattices are included in this report. An in-depth multilayer Fresnel evaluation provides the mathematical tool for this optical analysis, which otherwise relies solely on experimentally determined electro-optical materials parameters