W. Pleibel

Linear polarization in birefringent single‐mode fibers

Single‐mode fibers which maintain linear polarization are described. The fibers are birefringent and linear polarization is maintained along either of the two principal axes. The birefringence arises from the deliberate enhancement of anisotropic strains.

Soliton switching in a fiber nonlinear loop mirror

We observe all-optical, ultrafast switching at an energy of 55 pJ in a fiber nonlinear-optical loop mirror. The entire 310-fsec soliton waveform switches with 90% peak transmission. The soliton self-frequency shift lowers the peak transmission and splits the output pulse at higher powers, in agreement with numerical simulations.

Birefringence in elliptically clad borosilicate single-mode fibers

Experimental results indicate that the stress-induced strain birefringence in borosilicate elliptically clad fibers arises from the expansion coefficient mismatch between the borosilicate elliptical cladding and the pure silica outer jacket. This strain birefringence cannot be annealed even after repeated thermal cycling. It is shown that, for a given dopant concentration, the birefringence depends primarily on the cladding ellipticity e and increases linearly with increasing ellipticity and expansion coefficient mismatch.

Observation of resonant enhancement of photoinduced second-harmonic generation in Tm-doped aluminosilicate glass fibers.

We report a 10(3) increase in efficiency of second-harmonic generation in Tm(3+)-doped aluminosilicate glass fibers when the wavelength of the fundamental beam is tuned to the maximum of the (3)H(6) ? (3)F(4) absorption of Tm(3+) at 785 nm. This result shows the role of resonance enhancement in the nonlinear optical process that is responsible for the formation of the X((2)) grating.

Seeded second-harmonic generation in optical fibers: the effect of phase fluctuations.

Phase fluctuations between the infrared and green beams during seeding of second-harmonic generation (SHG) in optical fibers lead to a drastic reduction of the initial SHG intensity and to a strong time dependence of the SHG after seeding. Experiments using mode-locked lasers with a stable phase relation between the infrared and green writing beams lead to reliable, reproducible results. Under these conditions we do not observe a significant difference in SH efficiency between fibers with Ge concentrations of 3 and 14 mol. %.

Properties of Rectangular Polarizing and Polarization Maintaining Fiber

Polarization maintaining fiber with a near rectangular cross section, made by preform deformation, has demonstrated extinction ratios for 5 meter lengths of 43 dB, h parameter values of 1.7x10-6 m-1 for 100 meter lengths and losses of 0.8 dB/km at 1.3 and 1.5ttm. Polarizing fiber with a W type index profile, also made by preform deformation, has demonstrated extinction ratios of greater than 30 dB in straight lengths as short as 5 cm. with orthogonal polarization cutoff wavelengths separated by 0.1μm and insertion loss of less than 3 dB. The rectangular shape of these fibers facilitates location of the principal axes and allows winding such that a principal axes can be aligned with the bending plane.