Hybrid-Integrated Tunable Hollow Waveguide DBR Laser
We propose a novel hybrid-integrated tunable laser with a hollow waveguide distributed Bragg reflector, enabling a wide continuous tuning with a single-tuning parameter. The wavelength tuning of hollow waveguide lasers is demonstrated for the first time.
Fabrication and characterization of hollow waveguide distributed bragg reflectors
We present the fabrication and characterization of a novel distributed Bragg reflector consisting of a grating loaded slab hollow waveguide. In this structure, we are able to obtain a high reflectivity even by using thin and short surface gratings because of the large contrast in refractive indices between a grating material and an air-core. We fabricated a slab hollow waveguide Bragg reflector with 620µm long, 190nm deep 1st-order circular grating composed of SiO2 exhibiting strong Bragg reflection at 1558nm with an air-core thickness of 10µm for TM mode. The peak reflectivity is 65% including fiber coupling loss, the 3dB bandwidth is 2.8nm and the grating-induced loss is less than 0.5dB.
Redescription of two ghost shrimps (Decapoda: Axiidea: Callianassidae) from the Middle Miocene of the Central Paratethys: systematics, intraspecific variation, and in situ preservation
A redescription of two Middle Miocene burrowing ghost shrimps of the Central Paratethys, Callianassa brocchii L renthey, 1897 and Callianassa pseudorakosensis L renthey in L renthey & Beurlen, 1929, is provided. Material forming the basis of this study comes from the Studienka Formation (lower 'Sarmatian', Serravallian) of the Slovak part of the Vienna Basin and exhibits preservation allowing reassignment of the studied taxa to the genera Neocallichirus Sakai, 1988 and Eucalliax Manning & Felder, 1991 respectively. The major cheliped of both species exhibits two distinct morphotypes interpreted herein as possible sexual dimorpism. Several specimens of both taxa are preserved within the tube structures and are interpreted as in situ preservation within the burrows. Type material of both studied taxa and additional collections from the roughly coeval strata of Hungary and Austria were also studied.