Grant: Research Tools and Instruments - Category 1 (<$150,000)

This proposal aims to acquire an optical detection system for establishing the first sound velocity meter with ultrahigh spatial resolution in waveguide structures. This includes a) 40Gs/s high-speed digitizers (only in market a few months ago) to record the location of the acoustic wave and b) a high power tunable laser providing the energy to the acoustic wave at a measurable distance. By optically measuring the sound velocity on different modes of the waveguide materials, we can calculate the refractive index via the Brillouin frequency shift and dispersion at different wavelengths. Because of the mode structural information is associated with acoustic modes and birefringence properties, the requested optical detection system will have a pivotal impact on 1) designing the high threshold stimulated Billouin scattering (SBS) fiber to reduce nonlinear effects; 2) dispersion measurement and 3) designing the low birefringence fiber to reduce the polarization mode dispersion (PMD) and polarization dependent loss (PDL). These three outcomes are the limiting factors for high speed fiber communication systems. In addition, the distributed sound velocity and birefringence information provides material characterization leading to high quality composite materials for aerospace industry; to fuel cell monitoring, and to non-destructive detection of the health conditions of civil and aerospace structures. Optical fiber sound velocity meter can also be used as pulse squeezer, trapping the pulse as delay element for optical signal processing. The new system will enhance international collaboration with Europe, Japan and US through HQP exchange and will improve training in two of the directions of my research program.