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We demonstrate a novel on-board chip-to-chip optical interconnect using long-range surface plasmon polariton (LR-SPP) waveguides that feature 2.5-cm-long gold strips embedded in a low loss polymer cladding. A TM-mode vertical-cavity surface-emitting laser (VCSEL) operating at a wavelength of 1.3 microm was butt-coupled into the waveguides in order to excite a fundamental LR-SPP mode and then the transmitted light was received with a photo-diode (PD). The waveguide width is varied in the range of 1.5-5.0 microm in order to optimize the insertion loss where the 3-microm-wide waveguide provides a minimum insertion loss of -17 dB, consisting of 6 dB/cm propagation loss and 2 dB coupling loss. An interconnect system based on the optimized waveguide with a 4-channel array is assembled with the arrayed optoelectronic chips. It shows the feasibility of 10 Gbps (2.5 Gbps x 4 channels) signal transmission indicating that the LR-SPP waveguide is a potential transmission line for optical interconnection.

We developed an accurate and efficient method for measuring the refractive indices of a transparent plate by analyzing the transmitted intensity versus angle of incidence. By using two different wavelengths, we resolved the 2pi-ambiguity inherent to the phase measurement involving a thick medium, leading to independent determination of the absolute index of refraction and the thickness with a relative uncertainty of 10(-5). The validity and the accuracy of our method were confirmed with a standard reference material. Furthermore, our method is insensitive to environmental perturbations, and simple to implement, compared to the conventional index measurement methods providing similar accuracy.

Based on the thermo-optic tuning of a polymer waveguide Bragg reflector, we demonstrated a cost-effective tunable wavelength laser for WDM optical communications. The excellent thermo-optic effect of the polymer waveguide enabled direct tuning of the Bragg reflection wavelength by controlling the electrical power on a micro-heater. Wavelength tuning for 32 channels with 0.8 nm wavelength spacing was demonstrated as well as a continuous tuning with wavelength steps of 0.1 nm. To be qualified as a tunable laser for WDM-PON applications, wavelength stability within 0.15 nm was confirmed for an operating temperature range from -10 to 70 degrees C.

A hybrid plasmonic waveguide structure is proposed and fabricated for low-loss lightwave guiding along a metal stripe core. By embedding Au stripe in dual slab waveguides with high refractive-index contrast, the field of the guided mode is confined more in the two dielectric core layers. Thus, the propagation loss is significantly reduced. The guided mode is like a combination of a fundamental long-range surface plasmon polariton strip mode and a dual symmetric dielectric slab mode. We fabricate 5 nm-thick Au stripe optical waveguides and measure the optical properties at a wavelength of 1.31 microm. The propagation loss is less than 1.0 dB/cm with the metal stripe width of 1-5 microm.