Matthias Haupt

Four-Channel WDM Transmission Over 50-m SI-POF at 14.77 Gb/s Using DMT Modulation

Wavelength division multiplexing (WDM) is a promising solution for upgrading the capacity of polymer optical fiber (POF)-based telecommunication networks. In this letter, we report on the successful realization of a four-channel highspeed WDM transmission system for 1-mm diameter step-index POF (SI-POF). For combining the optical signals coming from 405-, 450-, 515-, and 639-nm laser diodes onto 1-mm SI-POF, a 4 × 1 coupler with low insertion loss (IL) has been developed. To spatially separate different wavelength channels, a fourchannel demultiplexer with low IL (<;5.7 dB) and high (non)adjacent channel isolation (>30 dB) has been realized in bulk optics. The 14.77-Gb/s data transmission based on the offline-processed discrete multitone modulation technique has been demonstrated over 50-m SI-POF at a bit-error rate of 10-3.

Demultiplexer for WDM over POF in prism-spectrometer configuration

Polymer Optical Fibres (POFs) show clear advantages compared to copper and/or glass fibres. In essence, POFs are inexpensive, space-saving and not susceptible to electromagnetic interference. Thus, the usage of POFs have become a reasonable alternative in short distance data communication. Today, POFs are applied in a wide number of applications due to these specific advantages. These applications include automotive communication systems and In-House-Networking. The current transfer mode system via POF is based only on one channel (or rather on one wavelength), making the usable bandwidth the limiting factor of this technology. One potential solution to expand the usable bandwidth of POF-based systems is wavelength division multiplexing (WDM). Because of the attenuation behaviour of POF, the only transmission window is situated in the visible spectrum. The solution proposed in this paper makes it possible to transfer several signals on different wavelengths through a single polymeric fibre. In order to separate the transmitted signals, special separators - called demultiplexers - are utilized. These demultiplexers are realized by employing the principle of the prism-spectrometer. Thus, the signals transmitted over different wavelengths will not be refracted equally strong. In the set-up described in this paper, the light emitted by the polymeric fibre is collimated by an off-axis parabolic mirror and then broken up by a prism, making it possible to restore the data originally transmitted via each wavelength-channel.

Four-channel CWDM system design for multi-Gbit/s data communication via SI-POF

The Polymer Optical Fiber (POF) has certain advantages over alternative data communication media such as glass fibers, copper cables, and wireless systems. It is pliable, durable, and cost effective, has small weight and a short bend radius, allows easy installation and quick troubleshooting, and provides immunity to electromagnetic interference. Due to its advantages, POF is a promising candidate for broadband in-house networks. Among different types of POF, the 1 mm PMMA Step-Index POF (SI-POF) is the best known and by far the most widely used type of POF. Present communication systems over POF use a single channel for data transmission. To increase the capacity of a single POF, multiple bandwidth-efficient channels can be transmitted over the same fiber. The technique is known as wavelength division multiplexing (WDM). This paper reports on the current development status of a four-channel coarse WDM (CWDM) transmission system for Multi-Gbit/s in-house data communication via SI-POF. The block diagram of the experimental setup and the complete description of established communication system will be given in the full paper. The key photonic component in a CWDM system under development is a demultiplexer (DEMUX). To spatially separate different wavelength channels, a four-channel DEMUX with low insertion loss (<6 dB) and low crosstalk (<-30 dB) is realized in bulk optics technology at the Harz University. The operating principle, the description of the opto-mechanical setup, and the transfer function of the DEMUX will be shown. In addition, an optical link power budget analysis, based on the experimentally obtained data, will be carried out for all four channels. Finally, Multi-Gbit/s data transmission experiments will be performed with violet, blue, green, and red laser diodes via up to 25 m SI-POF links, and the results and their analysis will be presented.

High speed WDM transmission on standard polymer optical fibers

We have developed WDM multiplexer and demultiplexer in the visible spectral range for POF transmission links and have carried out transmission experiments using different lengths of standard SI-POF. Our 4-channel WDM system with laser diode sources is operated in the violet, blue, green and red spectral range. Using discrete multitone modulation (DMT), we demonstrated a total data rate of 14.77 Gbit/s over 50 m and 8.26 Gbit/s over 100 m of SI-POF.

Polymeric demultiplexer component for wavelength division multiplex communication systems using polymer fibers

Data communication over Polymer Optical Fibers using Wavelength Division Multiplexing, offer high extension capabilities for the overall data rates. Here, a de/multiplexer as a key component was developed im PMMAusing an optical grating placed on an aspheric mirror by injection molding. A demonstrator is fabricated by directly machining it in the PMMA material by means of diamond turning technique. The paper presents the results of the different simulations followed by the development steps and the measurements done with the first demonstrator accompanied by the first BER measurements using a 4 channel WDM transmission The record 8.26 Gb/s data transmission based on the offline-processed discrete multitone modulation technique has been demonstrated over 100-m SI-POF at a bit-error ratio of 10-3.

WDM over POF ¿ A way to increase transmission capacity of POF

Polymer optical fibers (POFs) are having an increasing role in short range optical communication systems. Home networks present a very interesting application sector due to numerous advantages of POFs over traditional communication mediums.

Demultiplexer for wavelength division multiplexing over polymer optical fibers applicable for high-volume production

Abstract. Polymer optical fibers (POF) offer only transmission so far with one wavelength at 650 nm. In order to increase the overall transfer rate, the key element for wavelength division multiplexing (WDM) over POF will be presented. This element is a demultiplexer (DEMUX), which was designed in polymethylmethacrylate with an optical grating on an aspherical mirror to be produced by injection molding in a further development steps. The master was produced by diamond turning as a master for injection molding replication. The results of the different simulations followed by the development steps and the measurements of the prototype are presented. This prototype is used as a DEMUX in a WDM system with four wavelengths. In the WDM system, bit-error ratio (BER) measurements with an 8.26  Gb/s cumulated data rate in an offline processed discrete multitone modulation technique have been achieved over 100 m SI-POF at a BER of 10−3.

Simulations and first manufacturing steps of a fully integrated WDM-element in the visible spectrum

Due to their economical and easy-manageable advantages, POFs (polymer optical fiber) are going to replace traditional communication media such as copper and glass step by step within short distance communication systems. POFs are already used in various fields of optical communication, e.g. the automotive sector or in-house communication. Though single channel communication systems are state of the art technology, using of only one channel/wavelength for communication limits the bandwidth. For future scenarios this traditional technology is the bottleneck of bandwidth, particularly for HDTV with IP-TV. One solution to breakthrough this limitation is to use more than one wavelength over one single fiber, this is called WDM (wavelength division multiplexing) and is well-established for GOF communication. This technique will be adapted for the visible spectrum for POF. However this multiplexing technology requires two more key-elements: a multiplexer, which combines the multiple wavelengths signals into one fiber, and a demultiplexer at the end of the network to separate the colored signals. In this paper, the development of this key-element based on a Rowland spectrometer will be shown. It starts with the simulation, this is done by means of raytracing. Also the next process steps and solutions for injection molding are described.

Theoretical and experimental analysis of single mode fiber-to-fiber joint loss due to lateral misalignment

This paper shows the calculated loss due to lateral misalignment in single mode fibers (SMFs) with basic wave functions. Experiment setup for measuring loss due to lateral misalignment is presented and used for loss measurement. Measured values and the results obtained by formulas are compared in order to confirm validity of the established experiment setup.