Ulrich H.P Fischer

By U. H. P. Fischer, M. Haupt and M. Joncic

Part of the book: Optoelectronics

By Ulrich H. P. Fischer

Part of the book: Optoelectronics

By Ulrich H.P. Fischer-Hirchert, Matthias Haupt, Mladen Joncic, Stefanie Haupt and Sebastian Höll

Data communication over polymer optical fibers (POF) is a good alternative method for local area networks to use an optical medium to transmit data in short-range environments like cars or copper in-house networks on the basis of IEEE 802.3. Many companies offer transceivers for the area of Ethernet networks in the visible wavelength range. In the first part of the chapter, a system comparison of manufacturers with interoperability check is presented. Here, the real transfer rates within a manufacturer and between all manufacturers are measured as a cross-check. In the second part of the chapter, the limitation of bandwidth due to the use of only one wavelength channel is discussed. Wavelength Division Multiplexing (WDM) is a promising candidate to significantly increase bandwidth in POF to more than 40 Gbit/s. Here, the problems in the development and manufacture of a demultiplexer (DEMUX) for WDM over POF as well as the results of the optical separation of four wavelength channels are described. At least, the possible extension of a WDM grid of ITU G.694.2 is discussed, which seems to be a hopeful candidate to introduce a standardized WDM grid for POF in the visible range to reach data rates of 40 Gbit/s up to 50 m POF.

Part of the book: Broadband Communications Networks

By Ulrich H.P. Fischer-Hirchert and Mladen Joncic

In short-range communication 1 mm PMMA SI-POF established itself as a reasonable alternative to the traditional data communication media such as glass fibers, copper cables, and wireless systems. Due to multiple advantages such as a large core diameter, tolerance to fiber facet damages, and low installation costs, the SI-POF is already applied in industrial automation, automotive industry, and in-house/office networks. To experimentally demonstrate the feasibility and potential of a high-speed POF WDM concept, a four-channel data transmission setup was realized. A four-legged multiplexing POF bundle was developed to combine the signals from four visible laser diodes onto SI-POF link. For the separation of wavelength channels, the interference filter-based demultiplexer with two-stage configuration was used. It was shown that POF WDM with lower channel rates and simple transmission technique (NRZ + FFE) could provide aggregate bit rates comparable to those achieved with the single-wavelength systems that used advanced modulation formats (DMT or PAM + DFE) and required significant signal processing. In addition, the 50 m SI-POF link at an aggregate bit rate of 7.8 Gb/s was demonstrated over 50 m SI-POF, respectively, at the BER = 10–3.

Part of the book: Optical Fiber Applications

By Ulrich H.P. Fischer, Sabrina Hoppstock, Peter Kußmann and Isabell Steuding

In the industrialized countries, the very old part of the population has been growing rapidly for many years. In the next few years in particular, the age cohort over 65 will increase significantly. This goes hand in hand with illnesses and other physical and cognitive limitations. In order to enable these people to remain in their own homes for as long as possible despite physical and cognitive restrictions, technologies are being used to create ambient assisted living applications. However, most of these systems are neither medically verified nor are latencies short enough, for example, to avoid falls. In order to overcome these problems, a promising approach is to use the new 5G network technology. Combined with a suitable sensor data analysis frame work, the fast care project showed that a real-time situation picture of the patient in the form of an Avatar could be generated. The sensor structure records the heart rate, the breathing rate, analyzes the gait and measures the temperature, the VOC content of the room air, and its humidity. An emergency button has also been integrated. In a laboratory demonstrator, it was shown that the infrastructure realizes a real-time visualization of the sensor data over a heterogeneous network.

Part of the book: Data Acquisition

By Ulrich H.P. Fischer, Matthias Haupt and Peter Kußmann

Optical fiber networks are currently the standard for delivering high bandwidth to customers. Various access technologies to business networks with a very high bandwidth up to access networks for buildings and individual consumers have emerged. In the area of business networks, bandwidths of 10 Gb/s have become established, while in the area of customer bandwidths of 100 Mb/s to 1 Gb/s are used. This chapter will focus on the optical network connections inside buildings. The use of optical glass fibers or/and polymeric optical fibers in different network topologies in connection to high-speed actual WIFI- technologies will be discussed.

Part of the book: Fiber Optics