S E Kanellopoulos

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High-spatial-resolution measurements of axial-stress profiles of UV-irradiated fibers are reported, providing diagnostic information and a technique for the direct observation of UV-written grating structures. Measurements have been made with a spatial resolution of approximately 0.3 microm, which is capable of resolving detail within the pitch of the(More)
A new tunable dispersion compensator that does not suffer from higher order dispersion is reported. The device consists of two quadratically chirped fiber Bragg gratings, each with linear strain actuators. The module has a tuning range of 500 ps/nm and a bandwidth of 0.5 nm. In a 40-Gb/s return-to-zero system, the dispersion penalty tolerance is extended(More)
A new technique for simultaneous strain and temperature sensing is demonstrated. The approach employs two different types of photogenerated fiber grating, namely, a fiber Bragg grating and a fiber polarization-rocking filter. The method relies on the different dependencies of the fiber refractive index and birefringence on strain and temperature. Both of(More)
A new type of Mach-Zehnder interferometer has been fabricated in an elliptical-core high-birefringence fiber. The directional couplers of a conventional fiber interferometer are replaced by two photoinduced polarization rocking filters written on the same fiber. The resonant wavelength of the interferometer was 787 nm, with an operational bandwidth of 18(More)
Photobleaching and photorefractive effects caused by intense pulsed laser irradiation at 532 nm have been observed simultaneously in a germanium-doped monomode fiber. A decrease of up to 4.1*10/sup -4/ in the refractive index of the core at 633 nm was inferred from the change in the radiation pattern of a probe beam and also from the change in the cutoff(More)
A new type of internally written grating filter is proposed and demonstrated in single-mode optical fibers. A photoinduced rocking birefringence is created by polarization interference between two counterpropagating and orthogonal linear-polarization modes at 514.5 nm. This birefringent grating has the correct submicrometer pitch for efficient phase-matched(More)
Photorefractive polarization couplers written internally in germanium-doped elliptical core fibers at 488, 514, and 532 nm are reported. Complete power transfer between the orthogonal polarization modes of the fiber was achieved for couplers written at 514 and 488 nm, respectively. It is shown that the couplers are nonuniform in length because of the high(More)
The polarization properties of photorefractive reflecting gratings formed in Ge-doped high-birefringence (hi-bi) fibers by the internal method are presented. The gratings reflect only the polarization eigenmode used in fabrication and a polarization selectivity of 20 dB is demonstrated. It is also shown that there are two different photorefractive effects(More)
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