In-fiber modal Mach-Zehnder interferometer based on the locally post-processed core of a photonic crystal fiber.

We demonstrate a novel, compact and low-loss photonic crystal fiber modal Mach-Zehnder interferometer with potential applications to sensing and WDM telecommunications. By selectively collapsing a ~1-mm-long section of a hole next to the solid core, a pair of modes of the post-processed structure are excited and interfere at its exit. A modulation depth of up to ~13 dB and an insertion loss as low as 2.

Supercontinuum generation in a water-core photonic crystal fiber.

Supercontinuum generation is demonstrated in a 5-cm-long water-core photonic crystal fiber pumped near water's zero-dispersion wavelength. Up to 500-nm spectral width (evaluated at -20 dB from the peak) is achieved, while spectral widths were over 4 times narrower with a bulk setup at the same wavelength and peak power, and over 3 times narrower if the PCF was pumped away from the zero-dispersion wavelength. The supercontinuum generation mechanisms for bulk and waveguide setups are compared and tuning of the zero-dispersion wavelength via waveguide dispersion is theoretically investigated.

Global and partial synchronism in phase-locked loop networks.

We analytically investigate the existence of global and partial synchronism in neural networks where each node is represented by a phase oscillator. Partial synchronism, which is important to pattern recognition, can be caused by increasing the natural frequency of an oscillator and restricting the frequencies of others in certain ranges.