Gerald F. Sauter

Second‐order nonlinear optical measurements in guest‐host and side‐chain polymers

The second harmonic generation (SHG) coefficients dij of several corona‐poled guest‐host and side‐chain polymers have been measured and studied over time using a new Maker Fringe analysis. The electro‐optic coefficient r33 and scattering losses have also been measured in thin‐film waveguides, on silicon and glass substrates, made from some of the polymers. Kleinman symmetry (d15=d31) was not valid for near‐resonant SHG in these materials and d15/d31 was determined. Stable values of d33, for a fundamental of 1.064 μm, were as high as 40 pm/V for one of the side‐chain polymers. Optical waveguide losses determined from scattering measurements were as low as 0.4 dB/cm at 1.06 μm.

Gradient-index lens optical backplane

An optical backplane design based on gradient-index lenses is described. This design is based on a tapped bus architecture and offers an affordable and efficient card-to-card communication method. It was found that the use of gradient-index lenses reduced the alignment tolerances by a factor of 10 over an equivalent free-space model. Results from simulation and from the construction of a five-node, proof-of-concept demonstration unit are presented. The excess loss measured for the 25 different combinations varied from a low of 0.7 dB to a high of 4.0 dB.

Electro-Optic Properties Of New Nonlinear Side-Chain Polymers

A new Greens function method of analyzing Maker fringes from second-harmonic generation experiments was used to determine the nonlinear properties of corona-poled polymer films. Electro-optic properties were determined by fashioning the polymers into planar waveguides on silicon substrates and measuring the polarization rotation induced by the electro-optic effect. The two measurements were compared to test the applicability of the two-level model in the polymer system. Waveguide-loss measurements were performed on the same substrates by launching a guided wave via the prism method and monitoring the scattered light with a CCD video camera. Both guest-host and side-chain polymers were studied in this way. The advantages of the side-chain polymer over the guest-host polymer mixture are higher molar concentration of the nonlinear species, decreased mobility and greater overall film homogeneity.