Dual sideband receiver for radio-over-fiber.

A dual sideband reception scheme for radio-over fiber (RoF) links is introduced. It is shown that the new receiver can increase the performance of noise-limited systems by up to 3 dB (2.97 dB in a lab back-to-back experiment). The receiver scheme exploits the fact that current RoF links do not realize their full potential. This is because in typical RoF receivers, the radio-frequency (RF) signals are mapped back to the optical domain by means of electro-optical modulator. In this process energy typically is lost as only one of the two generated sidebands is subsequently used. The suggested receiver exploits the signal of both sidebands. The receiver scheme was subsequently tested in a full optical-RF-optical transmission link at RF carrier frequencies of 228 GHz over a free-space channel spanning distances of 1400 m for symbol rates of up to 48 Gbaud 4 QAM. Here, we could achieve SNR improvements of up to 2.6 dB.

What Do We Find Attractive about the Face?: Survey Study with Application to Aesthetic Surgery.

The appearance of the face is one of the most important factors influencing our perception of beauty. However, few studies have attempted to quantitate what one perceives as beauty. Therefore, this study was conducted with the goal of providing physicians with anatomical data that demonstrate which facial traits most influence our perception of one's attractiveness. In the first phase of the study, faces of 60 participants (30 males and 30 females) were photographed. Next, the photographs were shown to another group of 120 study members (60 males and 60 females), who evaluated the facial features using a Visual Analogue Scale. The highest rated facial parts were then measured using the ImageJ program. In men, the most attractive parts of the face were Type 1:2 lips, a Type IV nose of medium width, blue eyes, brown hair, and a very narrow face. Among females, the most attractive parts of the face were Type 2:1 lips, Type III and V noses of medium width, dark brown eyes, blonde hair, and a narrow face. This is the first study in which the most aesthetically important facial parts have been comprehensively examined. The results obtained in our study show a higher degree of representativeness compared to other studies due to a different methodological approach and can be used as an aesthetic guide and can help in the planning of aesthetic surgery such as lip augmentation and rhinoplasty. Clin. Anat. 33:214-222, 2020. © 2019 Wiley Periodicals, Inc.

C- and O-Band Dual-Polarization Fiber-to-Chip Grating Couplers for Silicon Nitride Photonics.

Highly efficient coupling of light from an optical fiber to silicon nitride (SiN) photonic integrated circuits (PICs) is experimentally demonstrated with simple and fabrication-tolerant grating couplers (GC). Fully etched amorphous silicon gratings are formed on top of foundry-produced SiN PICs in a back-end-of-the-line (BEOL) process, which is compatible with 248 nm deep UV lithography. Metallic back reflectors are introduced to enhance the coupling efficiency (CE) from -1.11 to -0.44 dB in simulation and from -2.2 to -1.4 dB in experiments for the TE polarization in the C-band. Furthermore, these gratings can be optimized to couple both TE and TM polarizations with a CE below -3 dB and polarization-dependent losses under 1 dB over a wavelength range of 40 nm in the O-band. This elegant approach offers a simple solution for the realization of compact and, at the same time, highly efficient coupling schemes in SiN PICs.