Integrated polarization beam splitter with relaxed fabrication tolerances.

Polarization handling is a key requirement for the next generation of photonic integrated circuits (PICs). Integrated polarization beam splitters (PBS) are central elements for polarization management, but their use in PICs is hindered by poor fabrication tolerances. In this work we present a fully passive, highly fabrication tolerant polarization beam splitter, based on an asymmetrical Mach-Zehnder interferometer (MZI) with a Si/SiO(2) Periodic Layer Structure (PLS) on top of one of its arms. By engineering the birefringence of the PLS we are able to design the MZI arms so that sensitivities to the most critical fabrication errors are greatly reduced. Our PBS design tolerates waveguide width variations of 400nm maintaining a polarization extinction ratio better than 13dB in the complete C-Band.

Polarization rotator for InP rib waveguide.

A polarization rotator, suitable for integration in a polarization diversity optical receiver fabricated in InP technology, is proposed. The device, based on a two steps waveguide rotator, includes tapered input and output ports that provide very low insertion loss (<0.04 dB). An extinction ratio of 40 dB at 1550 nm wavelength is calculated, comparable or even superior to other state of the art polarization converters. The main advantage of the proposed design is the capability of implementation using a standard fabrication process with only two dry etch steps, significantly reducing complexity and cost.

Continuous wave terahertz systems exploiting 1.5 microm telecom technologies.

A fiber-assembled CW THz System operating at 1.5 microm is presented. High speed telecom photodiodes integrated with planar THz antennas serve as THz emitters with power up to 10 microW. Photoconductive antennas based on LT InGaAs/InAlAs multi-layer structures allow coherent detection. The system operates in a wide frequency range of 0.1 -1.6 THz.

[The medical expert and his standards]. / Der medizinische Gutachter und seine Standards.

The expert needs clearly outlined principles which are accepted by the majority of carefully and scrupulously working physicians. These principles are world-wide known as standards. They can be changed by progress in medical science. Their value is restricted by the fact that in the particular case with its individual peculiarities they may be of no help. Presenting a few cases, some problems for the medical expert are shown. Cardiotocography, Apgar-score, ureter, problems of organisation, the lethal outcome and the difficulties of preoperative information of the patient find particular consideration. The importance of the dialogue between physician and lawery is pointed out.

[Bilateral malignant lymphoblastic lymphoma of the female breast (author's transl)]. / Bilateraler Befall der weiblichen Brust durch ein malignes Lymphom vom lymphoblastischen Typ.

Primary bilateral malignant lymphoma of the breast was diagnosed in these women. All were of the lymphoblastic type of high malignancy. Two patients were pregnant and all died of generalised malignant lymphoma. Survival time between initial or early manifestation in the breast and death was two to four months.