E. Salik

Tunable compensation of the dispersion slope mismatch in dispersion-managed systems using a sampled nonlinearly chirped FBG

We demonstrate dispersion slope compensation for three 10-Gbit/s wavelength-division-multiplexing (WDM) channels using a sampled nonlinearly chirped fiber Bragg grating (FBG) in a dispersion-managed transmission system. The replicated wavelength bands of the sampled FBG have a different wavelength separation than the WDM channels, causing each channel to experience a different dispersion compensation that can be tuned upon stretching of the FBG. We achieve significant power penalty reduction for all three channels using our dispersion-slope-compensation method with a tunable amount of dispersion over 900 and 1200 km fiber links.

Increase of photosensitivity in Ge-doped fibers under strain.

Straining a Ge-doped optical fiber increases its UV photosensitivity. The speed of grating fabrication in a standard AT&T telecommunication fiber increases by 18 times, while the final refractive-index change is enhanced by a factor of 5. Measurements reveal opposite changes in the stress of the fiber core induced by UV light in strained and unstrained fibers.

All-fiber WDM optical crossconnect using ultrastrong widely tunable FBGs

We demonstrate an all-fiber wavelength-division-multiplexed optical crossconnect using ultrastrong fiber Bragg gratings (FBGs) with wide tunability. These FBGs have 0.2-nm bandwidths and can be tuned over /spl sim/52 nm due to a novel grating preparation technique to reduce mechanical strength degradation. There is negligible distortion in the transmission spectra while tuning the grating, and the crossconnect architecture uses cascades of these gratings for WDM operation. The ability to tune these >98% reflectivity gratings completely out of the entire WDM signal band minimizes the leakage of unwanted signal power and leads to the improvements of >10-dB crosstalk and >0.6-dB power penalty compared with conventional gratings.

Thermally stable gratings in optical fibers without temperature annealing

Uniform UV light exposure of a fiber substantially increases the thermal stability of its Bragg grating. Both grating writing and thermal stabilization can now be performed without stripping the fiber coating.

Tunable compensation of the dispersion slope mismatch in dispersion-managed systems using a sampled nonlinearly-chirped FBG

We demonstrate tunable dispersion slope compensation for three 10 Gbit/s WDM channels using a sampled nonlinearly-chirped FBG. The replicated sampled-FBG wavelength bands have a different separation than the WDM channels, causing each channel to experience a different dispersion compensation that can be tuned upon stretching of the FBG. We achieve significant power penalty reduction using our tunable dispersion-slope-compensation method over 900 and 1200 km fiber links.We demonstrate dispersion slope compensation for three 10-Gbit/s wavelength-division-multiplexing (WDM) channels using a sampled nonlinearly chirped fiber Bragg grating (FBG) in a dispersion-managed transmission system. The replicated wavelength bands of the sampled FBG have a different wavelength separation than the WDM channels, causing each channel to experience a different dispersion compensation that can be tuned upon stretching of the FBG. We achieve significant power penalty reduction for all three channels using our dispersion-slope-compensation method with a tunable amount of dispersion over 900 and 1200 km fiber links.

Increase of photosensitivity in Ge-doped fibers under strain

The index change produced in Ge-doped fibers by UV light is enhanced by /spl sim/5 when the fiber is strained during UV exposure. This can open a door to faster fabrication of fiber gratings.

Picosecond pulse generation at two wavelengths by simultaneous active mode locking in an Er-doped fiber laser with wide-bandwidth (>1 nm) nonchirped fiber Bragg gratings

Generation of picosecond pulses at two distinct wavelengths is interesting for wavelength-division-multiplexing, fiber communication and sensing. For this purpose, we achieved harmonic active mode locking simultaneously at two wavelengths separated by about 15 m in an Erbium-doped fiber laser. Dual- wavelength lasing was obtained with two wide-bandwidth (greater than 1 nm) nonchirped high-reflectivity fiber Bragg gratings inserted in the laser cavity. The fiber Bragg gratings were written with 275-nm light from an Ar laser in hydrogen-loaded fibers. Optical path lengths and losses were carefully adjusted at each wavelength to obtain perfect mode locking at both wavelengths. Total cavity dispersion was set in the anomalous dispersion regime and optimized at each wavelength independently to generate solitons. Pulses at 3-GHz repetition rate were obtained at two wavelengths simultaneously with pulse widths of 16 ps and 13 ps, at 1547 nm and 1562 nm respectively. Time-bandwidth products of 0.37 and 0.34 respectively confirmed that the pulses were nearly transform-limited at each wavelength.