Life and Quantum Biology, an Interdisciplinary Approach

The rapidly increasing interest in the quantum properties of living matter stimulates a discussion of the fundamental properties of life as well as quantum mechanics. In this discussion often concepts are used that originate in philosophy and ask for a philosophical analysis. In the present work the classic philosophical tradition based on Aristotle and Aquinas is employed which surprisingly is able to shed light on important aspects. Especially one could mention the high degree of unity in living objects and the occurrence of thorough qualitative changes. The latter are outside the scope of classical physics where changes are restricted to geometrical rearrangement of microscopic particles. A challenging approach is used in the philosophical analysis as the empirical evidence is not taken from everyday life but from 20th century science (quantum mechanics) and recent results in the field of quantum biology. In the discussion it is argued that quantum entanglement is possibly related to the occurrence of life. Finally it is recommended that scientists and philosophers should be open for dialogue that could enrich both. Scientists could redirect their investigation, as paradigm shifts like the one originating from philosophical evaluation of quantum mechanics give new insight about the relation between the whole en the parts. Whereas philosophers could use scientific results as a consistency check for their philosophical framework for understanding reality.Comment: 13 page

Densely Integrated Photonic Devices based on Microring Resonators in Access Networks

The application of optical fibers has led to virtually lossless point to point data links in the core network with practically unlimited bandwidth. In response to increasing bandwidth demands of consumers the optical techniques employed in these networks are now gradually extended towards the consumers premises. At the access network level, where equipment is shared by a few users at the most, cost is the major issue. In addition the demand of optical transparency at the nodes and hubs, excluding conversion between the optical and electrical domains, results in a high degree of complexity of the devices. Fortunately, through the use of flexible WDM bandwidth allocation schemes that provide bandwidth where needed, and cheap mass-produced densely integrated optical components, the cost can be reduced significantly. Promising building blocks in these components are Microring Resonators (MRs) built using high refractive index waveguides which can be used to create densely integrated wavelength filters as well as more complex functionality.\ud In this work we present a 1x4 reconfigurable optical add-drop multiplexer (rOADM) as well as a 1x4x4 reconfigurable wavelength router in variants operating in the second and third telecom window. The devices, which can be used at bit rates up to 40 Gbit/s, have a footprint less than 2 mm2 and are based on thermally tunable vertically coupled microring resonators fabricated in the high contrast (Δn≈0.55) Si3N4/SiO2 materials system. In addition to the presented devices a new polarization diversity scheme is proposed that solves the issue of polarization dependence behavior of microring resonators without the need of doubling the optical circuit

The Puzzle of the Origin of Human Persons

The fundamental question about the origin of human persons asks for a multidisciplinary approach. Biology and genetics have made remarkable progress in the last two decades. In addition, (pre-) history, philosophy, and anthropology could contribute significantly to a correct solution. Also, the Jewish-Christian tradition could provide elements to the complex puzzle. The present study attempts to show that recent genetic data can be an integrated part of a coherent view of the origin of human persons

Ultrafast all-optical switching by cross phase modulation induced wavelength conversion in silicon-on-insulator waveguides and ring resonators

We present new results on ultrafast alloptical wavelength conversion in Silicon-on-Insulator waveguides through cross phase modulation. We demonstrate sub-picosecond all-optical switching with 13dB on/off ratio by combining the nonlinear wavelength conversion in the port waveguide with passive filtering using an integrated SOI microring resonator.\u

The Quest for Truth of Stephen Hawking

With his bestselling publication, A Brief History of Time, Stephen Hawking in-troduced in 1988 a new genre by connecting modern science with the question of the existence of God. In the posthumous publication Brief Answers to the Big Questions, he continues his quest for the ultimate truth. The current study presents a philosophical analysis of this search in terms of Aristotle’s and Aquinas’s classical philosophy. Cau-sality is the central concept employed by Hawking. However, in modern scientific and philosophical literature, its meaning is limited to temporal causality compared to the view of classical philosophy. Only the latter one accepts causality from outside space and time, in other words, a reality transcending the material world. In a quote presented in the discussion, Hawking defines himself as an atheist. After a careful reading of his writings, however, doubts arise about his unbelief

Waveguides, bends and Y-junctions with improved transmission and bandwidth in hexagon-type SOI photonic crystal slabs

This paper presents novel ways of implementing waveguide components in photonic crystal slabs based on silicon-on-insulator (SOI). The integration platform we consider consists of hexa¬gonal holes arranged in a triangular lattice (‘hexagon-type’ photonic crystal). The waveguides are made of one missing row of holes (W1) with triangular air inclusions symmetrically added on each side of the waveguide. \ud Size and position of these inclusions are tuning parameters for the band diagram and can be used for minimizing the distributed Bragg reflection (DBR) effect. The waveguides show single-mode behavior with reasonably high group velocity and large transmission window, inside the gap between H-like modes**. These waveguides, closely resembling conventional ridge waveguides, can be combined to form efficient bends and Y-junctions. The bends and Y-junctions include intermediate short waveguide sections at half the bend angle playing the role of corner ‘mirrors’. Qualitative design rules were obtained from 2D calculations based on effective index approximation.\u

Nd-doped polymer waveguide amplifiers

Nd3+-complex-doped polymer channel waveguide amplifiers with various lengths and Nd3+ concentrations are fabricated by a simple procedure. Internal net gain at 840–950 nm and 1064 nm is experimentally and theoretically investigated under continuous-wave excitation at 800 nm. Internal net gain in the range 865–930 nm is observed and a peak gain of 2.8 dB at 873 nm is obtained in a 1.9-cm-long waveguide with a Nd3+ concentration of 0.6x10e20 cm-3 at a launched pump power of 25 mW. The small-signal gain measured in a 1-cm-long sample with a Nd3+ concentration of 1.03x10e20 cm-3 is 2.0 dB/cm and 5.7 dB/cm at 873 nm and 1064 nm, respectively. By use of a rate-equation model, the internal net gain at these two wavelengths is calculated and the macroscopic parameter of energy-transfer upconversion as a function of Nd3+ concentration is derived. Ease of fabrication, compatibility with other materials, and low cost make such rare-earth-ion-doped polymer waveguide amplifiers suitable for providing gain in many integrated optical devices

Nd-doped polymer waveguide amplifiers at 850-930 nm

Nd-complex-doped, polymer channel waveguides were realized on thermally oxidized silicon wafers by a simple fabrication procedure. Broadband optical gain was demonstrated at 850-930 nm. Internal net gain up to 5.3 dB/cm was obtained at 850 nm, which is very promising for optical amplification in optical backplanes. With this result a route toward low-cost integrated waveguide amplifiers for optical interconnects has been opened

Silicon oxynitride in integrated optics

A review on the state of the art of silicon oxynitride deposition at the MESA Research Institute will be given. The recent progress in the application of silicon oxynitride in communication devices will be discusse