Robert Adam Modavis

Direct measurement of 248- and 193-nm excimer-induced densification in silica–germania waveguide blanks

The densification of a waveguide blank of composition 14GeO2:86SiO2 produced by 193- and 248-nm excimer exposure was measured by an interferometric technique. With the aid of a finite-element model, we derive the unconstrained densification from the experimentally determined optical phase shift. The densification versus exposure can be fitted to a power law and is compared with the behavior of fused silica. Again, with the finite-element model, an estimate is made of the refractive-index change that would be produced in a single-mode fiber. For the exposure levels typically used for the 248-nm exposure, the densification contribution to the optical index change is found to be negligible for this composition. On the other hand, for the high 193-nm exposure, the densification contribution can be dominant.

Bend-optimized dispersion-shifted single-mode designs

A bend-optimized design for a dispersion-shifted single-mode fiber with segmented-core profile is described. With this design, dispersion-shifted fibers having the highest cutoff wavelengths reported to date have been achieved. Results on dispersion, attenuation, mode radius, bending, and microbending loss for such fibers are presented and compared to alternate designs.

Space Division Multiplexing in Short Reach Optical Interconnects

Many technical capabilities of space division multiplexed systems like low loss and crosstalk have been established in numerous long-haul system experiments. Recently more attention has been given to applications of space division multiplexing for short reach systems, including data center transmission and sensing applications. Short reach systems may be the first high volume application, as space division multiplexing for short reach systems has fewer remaining technical challenges. In addition to higher bandwidth density, space division multiplexed systems offer potential advantages in lower power consumption and cost. In this paper we present penalty-free bit error ratio results down to

Coupled mode analysis of crosstalk in multicore fiber with random perturbations

10^{-12}

Dispersion managed optical waveguide

from system tests on 200 meters of 8-core multicore fiber with fan-outs and up to 2 km in dual-core multicore fiber with connectors and fan-outs.

Anamorphic microlens for coupling optical fibers to elliptical light beams

A simple, general crosstalk formula is derived for multicore fibers with random perturbations using coupled mode theory. Analytical crosstalk expressions under exponential and Gaussian correlation length distributions are presented. Experimental results agree well with theory.