100-GBd Waveguide Bragg Grating Modulator in Thin-Film Lithium Niobate

An integrated electro-optic modulator based on a waveguide Bragg grating in thin-film lithium niobate is introduced. The compact device with a footprint of 10 × 400 μm2 displays an optical extinction ratio of 53.8 dB at a wavelength of 1555.9 nm in the C-band. With a simple intensity modulation and direct detection scheme, data rates up to 100 Gbit/s are demonstrated with 2-, 4- and 8-level pulse-amplitude modulation formats. The optical filter characteristic of a waveguide Bragg grating modulator suppresses one optical sideband, resulting in inherent single sideband modulation. This enables transmission of a 100 Gbit/s on-off keying signal over 12 km of standard single-mode fiber at 1559.05 nm, without the need for chromatic dispersion compensation.ISSN:1041-1135ISSN:1941-017

Two giant retroperitoneal schwannomas mimicking adrenal malignancy – a case report

Schwannomas are benign tumors in 95% of cases and very rarely occur in the retroperitoneum. We report the cases of a 35-year-old man with abdominal discomfort and a 50-year-old asymptomatic woman with large retroperitoneal masses. Both underwent multivisceral surgery to exclude an adrenal carcinoma, and the pathologic diagnosis showed schwannomas in both cases. Despite morphological imaging, it was not possible to get a clear diagnosis preoperatively

Verification of straylight rejection of optical science payloads using a pulsed laser source

editorial reviewedThe performance of astronomical space telescopes can be greatly impacted by straylight. That is why characterizing the straylight in such telescopes before they are deployed is paramount. Nowadays such characterization can be done by simulation or by test. Simulation can provide very useful information on the origin of straylight, helping devise solutions to reduce it and improve the performance of the telescope. However, simulation suffers from limitations due to processing power needed and assumptions made in the model which can lead to simulation results quite far from the actual performances. Standard straylight tests on the other hand provide accurate measurement of the straylight but without any insight about its origin, making it difficult to mitigate. Emerging technologies now offer new possibilities for straylight measurement using time-of-flight technics to help identify the origin of the straylight. Such technologies were reviewed and analysed in a first activity called TRIPP (Time-Resolved Imaging of Photon Paths). The results and outcome of this study are presented in the first chapter of this paper. A second chapter then presents the ongoing status of a second activity, SLOTT (Straylight Lidar Ogse verificaTion Tool) which aims to develop a demonstrator for such a time-resolved straylight verification system. With the development and test of such a tool, CSEM and its partners (TAS-CH, Difrotec, CSL, LusoSpace), supported by ESA, hopes to establish new methods to characterize and reduce the straylight propagation in future space-based telescopes