Photonic wire bonding: a novel concept for chip-scale interconnects.

Photonic integration requires a versatile packaging technology that enables low-loss interconnects between photonic chips in three-dimensional configurations. In this paper we introduce the concept of photonic wire bonding, where polymer waveguides with three-dimensional freeform geometries are used to bridge the gap between nanophotonic circuits located on different chips. In a proof-of-principle experiment, we demonstrate the fabrication of single-mode photonic wire bonds (PWB) by direct-write two-photon lithography. First-generation prototypes allow for efficient broadband coupling with average insertion losses of only 1.6 dB in the C-band and can carry wavelength-division multiplexing signals with multi-Tbit/s data rates. Photonic wire bonding is well suited for automated mass production, and we expect the technology to enable optical multi-chip systems with enhanced performance and flexibility.

Surface plasmon polariton absorption modulator.

An electrically controlled ultra-compact surface plasmon polariton absorption modulator (SPPAM) is proposed. The device can be as small as a few micrometers depending on the required extinction ratio and the acceptable loss. The device allows for operation far beyond 100 Gbit/s, being only limited by RC time constants. The absorption modulator comprises a stack of metal/insulator/metal-oxide/metal layers, which support a strongly confined asymmetric surface plasmon polariton (SPP) in the 1.55 µm telecommunication wavelength window. Absorption modulation is achieved by electrically modulating the free carrier density in the intermediate metal-oxide layer. The concept is supported by proof-of-principle experiments.

Gastroscopic real-time 13C-urea breath test.

BACKGROUND AND STUDY AIMS: Biopsy-based Helicobacter urease testing (HUT) may constitute a hazard in patients with bleeding disorders, those receiving anticoagulant therapy, and those with communicable diseases. In addition, definitive test results may not immediately be available. The aim of this study was to investigate the feasibility of breath testing for H. pylori during gastroscopy (gastroscopic breath testing, GBT) in comparison with the standard HUT in a prospective, randomized, and controlled study. PATIENTS AND METHODS: A total of 119 patients were randomly allocated to undergo H. pylori testing with either HUT (n = 61) or GBT (n = 58) with 75 mg of 13C-labeled urea by endoscopic instillation. Breath samples were continuously analyzed using molecular correlation spectroscopy, displaying real-time results. The procedure time and time until definitive test results were obtained (mean plus or minus standard deviation) were recorded. RESULTS: H. pylori was detected in 10 of 49 patients (20.4 %) with HUT and in 16 of 53 (30.2 %) with GBT. Contraindications to biopsy prevented HUT in 12 of 61 patients. GBT results could not be obtained in one of the 58 patients due to respiratory disease and in four for technical reasons. Slightly less time was required to carry out HUT than GBT (121 +/- 30 s vs. 164 +/- 36 s; P < 0.001). Definitive test results were available within 14.0 +/- 2.2 min using GBT in comparison with 19.6 +/- 9.1 h for HUT ( P < 0.001). GBT prolonged the time spent by the patient in the endoscopy room by only 5.6 min in comparison with HUT (45.1 +/- 8.5 min vs. 39.5 +/- 10.3 min; P < 0.01). CONCLUSIONS: GBT provides immediate, definitive results and allows H. pylori testing in patients in whom biopsies are contraindicated, with only minimal prolongation of the procedure time.