Experimental phase-error extraction and modelling in silicon photonic arrayed waveguide gratings

We present a detailed study of parameter sweeps of silicon photonic arrayed waveguide gratings (AWG), looking into the effects of phase errors in the delay lines, which are induced by fabrication variation. We fabricated AWGs with 8 wavelength channels spaced 200 GHz and 400 GHz apart. We swept the waveguide width of the delay lines, and also performed a sweep where we introduced increments of length to the waveguides to emulate different AWG layouts and look into the effect of the phase errors. With this more detailed study we could quantitatively confirm the results of earlier studies, showing the wider waveguides reduce the effect of phase errors and dramatically improve the performance of the AWGs in terms of insertion loss and crosstalk. We also looked into the effect of rotating the layout of the circuit on the mask, and here we could show that, contrary to results with older technologies, this no longer has an effect on the current generation of devices

A checklist of the marine Harpacticoida (Copepoda) of the Caribbean Sea

Recent surveys on the benthic harpacticoids in the northwestern sector of the Caribbean have called attention to the lack of a list of species of this diverse group in this large tropical basin. A first checklist of the Caribbean harpacticoid copepods is provided herein; it is based on records in the literature and on our own data. Records from the adjacent Bahamas zone were also included. This complete list includes 178 species; the species recorded in the Caribbean and the Bahamas belong to 33 families and 94 genera. Overall, the most species family was the Miraciidae (27 species),followed by the Laophontidae (21), Tisbidae (17), and Ameiridae (13). Up to 15 harpacticoid families were represented by one or two species only. Excluding the Bahamian records, the number of species recorded herein for the Caribbean Basin is 139. The distribution of the species richness within the Caribbean Basin is asymmetrical; the northwestern sector (Mexican Caribbean) is the most species, it concentrates up to 45% of the species recorded in the Caribbean. The insular Caribbean is nearly as diverse as the continental areas (75 vs 83 species recorded, respectively). The dominance of taxa related to coastal systems with coarse and fine sands and carbonatesediments reveals the general trend in the type of habitats surveyed in the Caribbean Sea. Up to 37 species found in the Mexican Caribbean represent new records for this country. There are enormous hiatuses in the knowledge of the Caribbean harpacticoids in terms of geographic, bathymetric, and environmental coverage. It is expected this list will grow rapidly and many undescribed forms will be discovered when understudied or unexplored environments are surveyed in detail

Spiniferaphonte, a new genus of Laophontidae (Copepoda: Harpacticoida), with notes on the occurrence of processes on the caudal rami

A new genus and species of Laophontidae, Spiniferaphonte ornata n. gen., n. sp., is described from the coast of Kenya. The new genus is closely related to Laophontina and Wellsiphontina as shown by the following synapomorphies: a denticulate operculum, a sexually dimorphic P4 exopod (reduced chaetotaxy of the ultimate segment in the male), and the absence of sexual dimorphism in the P2 and P3 endopods. The two-segmented exopod of PI and the presence of a seta on the endopodal part of the male P5 are plesiomorphies indicating that the new genus represents a separate lineage within this group. The proposal of the new genus Spiniferaphonte is supported by the following autapomorphies: three smooth setae on the female P5 exopod and a robust, dorsally bent, and strongly sclerotised caudal seta V. Within the Laophontidae, it is striking that the presence of distinct, thorn-like processes on the caudal rami is limited to interstitial genera. Distinct processes on the proximal segments of the antennule and a proximally thickened caudal seta V also appear to be associated with this interstitiality. These structures may play a role in the movement and the anchoring of the animals in their interstitial habitat

Two new genera of Laophontidae (Copepoda: Harpacticoida) without sexual dimorphism in the endopods of the swimming legs

Two new monospecific genera of the harpacticoid family Laophontidae T. Scott, 1905 are described here. Apistophonte wasiniensis gen. et sp. n. was found along the Kenyan coast and Propephonte duangitensis gen. et sp. n. along the northern coast of Papua New Guinea. They differ from most other laophontid genera in the absence of sexual dimorphism in the endopods of the swimming legs. At first sight, both new species resemble each other very closely in habitus, integumental ornamentation, chaetotaxy of the swimming legs and absence of sexual dimorphism in the endopods. However, the detailed characteristics of A1, maxilla and male P5 show that the species are not congeneric. The structure of the first antennular segment of Propephonte gen. n. suggests a close relationship with Peltidiphonte Gheerardyn and Fiers, 2006. The exact affinities of Apistophonte gen. n. however remain difficult to assess