Antisymmetric solitons and their interactions in strongly dispersion-managed fiber-optic systems

By means of the variational approximation (VA), a system of ordinary differential equations (ODEs) is derived to describe the propagation of antisymmetric solitons in a multi-channel (WDM) optical fiber link subject to strong dispersion management. Results are reported for a prototypical model including two channels. Using the VA technique, conditions for stable propagation of the antisymmetric dispersion-managed (ASDM) solitons in one channel are found, and complete and incomplete collisions between the solitons belonging to the different channels are investigated. In particular, it is shown that formation of a bound inter-channel state of two ASDM solitons is possible under certain conditions (but may be easily avoided). The VA predictions for the single- and two-channel systems are compared with direct simulations of the underlying partial differential equations. In most cases, the agreement is very good, but in some cases (very closely spaced channels) the collision may destroy the ASDM solitons. The timing-jitter suppression factor (JSF) for the ASDM soliton in one channel, and the crosstalk timing jitter induced by collision between the solitons belonging to the different channels are also estimated analytically. In particular, the JSF for the ASDM soliton may be much larger than for its fundamental-soliton counterpart in the same system.Comment: 15 pages, 10 figures, accepted for publication in Optics Communication

A Didactic Architecture for Rural Early Education

CONTENTION It is possible to create a physical environment which will serve as a didactic tool for both pupils and educators. The tectonic language will be didactic on three levels: that of explicatively detailed timber framing, that of participatory and reconfigurable play modules, and that of demonstrative sustainable resource management. It will merge playground and classroom space, both modulated within a timber frame and allowing reconfiguration of physically and intellectually educational partitions. DESIGN PROBLEM The kindergarten is to be sited in Saranac Lake, NY, at the Jackrabbit Trailhead, near Moody Pond. The building will merge playground and classroom programs for the kindergarten level and use a didactic architectural language. A timber frame module will be used for both programs, with the playground elements freely reconfigurable and existing as subdivisions of the larger ‘classroom-sized’ module. The tectonics of timber frame assembly will be expressed and highlighted, as they represent a higher order of didactic toys. The kindergarten building will also serve as a didactic tool for demonstrating sustainable resource management, including water collection as well as passive heating, cooling, and air quality control. This will reinforce the natural site as one of the ‘teachers’ of the progressive kindergarten