James F. Brennan

Dispersion and dispersion-slope correction with a fiber Bragg grating over the full C-band

Long-length wide-bandwidth fiber Bragg gratings for use as dispersion compensators that cover the full C-band have been fabricated. These devices are shown to work well in a 10 Gbit/s NRZ optical communications system.

Dispersion correction with a robust fiber grating cover the full c-band at 10-gb/s rates with <0.3-dB power penalties

Robust wide-bandwidth fiber Bragg gratings have been produced for use as dispersion compensators that yield <0.3-dB power penalties due to distortion over an 80-km transmission fine of nonzero dispersion-shifted fiber in a 10-Gb/s nonreturn-to-zero optical communications system.

Chirped fiber grating characterization with phase ripples

The performance of chirped fiber gratings as dispersion compensators can be specified with the variance of their phase ripples weighted by the input signal spectrum.

Dispersion management with long-length fiber Bragg gratings

Grating fabrication technology has advanced considerably over the past several years. Grating-based dispersion management modules exist that yield low system power penalties and have proper thermal management, mechanical reliability, and packaging.

Packaging to reduce thermal gradients along the length of long fiber gratings

We have reduced the effect of thermal gradients across a fiber grating-based dispersion compensation module by embedding the grating in a thermal conductor surrounded by a thermal insulator, which keeps the grating length at a nearly uniform temperature. We modeled the package performance with finite-element methods and confirmed the results experimentally. We have found no measurable perturbation in the device dispersion during thermal testing, even as 80/spl deg/C thermal gradients were imposed across the module.

Dispersion compensation in an optical communications system with an electroabsorption modulated laser and a fiber grating

The robustness of an optical communications system with an electroabsorption modulated laser (EML) to dispersion mismatch is investigated, where a fiber grating is used for dispersion compensation. We use 12-nm bandwidth 1360-ps/nm dispersion fiber gratings, which were fabricated to match the dispersion of 80 km of standard fiber, and an EML transmitter in a 10-Gb/s communications system testbed. We demonstrate a maximum power penalty <2 dB over a wide range of standard fiber lengths (30-110 km).

The behavior of silica optical fibers exposed to very high-pressure hydrogen environments

We placed silica optical fibers into hydrogen environments of up to 30,000 psi (2,041 atm) and characterized their photosensitivity, mechanical strength, and H/sub 2/ diffusion rate and solubility. UV-induced index changes in the fibers were >10/sup -2/.

PMD measurement of dispersion compensation grating and its effect on system penalty estimation

Both direction and magnitude of the PMD vector of dispersion compensation grating must be considered when estimating its system penalty. We propose high bandwidth measurements to obtain 1st order PMD in these devices.

Photosensitivity and UV-induced optical loss of silica optical fibers exposed to very high pressure hydrogen environments

We placed silica optical fibers into hydrogen environments of up to 30,000 psi (2,041 atm) and characterized their photosensitivity and UV-induced optical loss. We detail the relationship between the hydrogen content in the fiber and the UV-induced index change for a delivered radiation dose. We also observed high UV-induced optical loss (greater than 30 dB/cm) in these fibers and studied the cause of this loss.

Indication of re-circulating catalyst in photosensitive reactions with H/sub 2/-saturated silica fibers

The dynamics of Bragg grating growth in UV-sensitized, hydrogen saturated silica fibers are explained using a transient kinetic model. Re-circulation of hydrogen, functioning as catalyst in the photosensitive reactions is believed to be responsible for the increase in the steady state value of the refractive index changes.