Showing papers by "Frans Huijskens published in 2004"

Optical signal processing based on self-induced polarization rotation in a semiconductor optical amplifier

Abstract: We demonstrate novel optical signal processing functions based on self-induced nonlinear polarization rotation in a semiconductor optical amplifier (SOA). Numerical and experimental results are presented, which demonstrate that a nonlinear polarization switch can be employed to achieve all-optical logic. We demonstrate an all-optical header processing system, an all-optical seed pulse generator for packet synchronization, and an all-optical arbiter that can be employed for optical buffering at a bit rate of 10 Gb/s. Experimental results indicate that optical signal processing functions based on self-polarization rotation have a higher extinction ratio and a lower power operation compared with similar functions based on self-phase modulation.

Novel cost-efficient techniques for microwave signal delivery in fibre-wireless networks

Abstract: The Optical Frequency Multiplying technique feeds very pure microwave signals to simple radio antenna stations through single-mode and multimode fibre networks. It supports operation at multiple radio standards, and dynamic capacity allocation by optical routing. Introduction Wireless communication services are steadily increasing their share of the telecommunication market. Next to their prime feature, mobility, they are offering growing bandwidths to the end users. This entails also an increase of the radio carrier frequencies, which leads to smaller radio cell coverage due to the increased propagation losses and line-of-sight needs. Wireless LANs in the 2.4 GHz range according to the IEEE 802.11b standard carry up to 11 Mbit/s, evolving up to 54 Mbit/s in the IEEE 802.11g standard. The IEEE 802.11a and the HIPERLAN/2 standard provide up to 54 Mbit/s in the 5.4 GHz range. Research is ongoing in systems that may deliver more than 100 Mbit/s in the radio frequency range well above 10 GHz (e.g., LMDS at 28 GHz, HyperAccess at 17 GHz and 42 GHz, MVDS at 40 GHz, MBS at 60 GHz, etc.). Due to the shrinkage of radio cells at higher radio frequencies, ever more antenna sites are needed to cover a certain area such as the rooms in an office building, in a hospital, the departure lounges of an airport, etc. Thus, it becomes increasingly important to simplify the antenna stations and to consolidate the signal processing in a centralised site. Carrying radio signals over fibre is an interesting solution to achieve this; it exploits the basic virtues of optical fibre, its large bandwidth and low loss, in supporting cheap ubiquitous broadband mobility. Single-mode fibre has adequate characteristics for efficient distribution of microwave signals, e.g. by means of optical heterodyning to remotely generate microwave carriers [1]. However, its tiny core necessitates delicate handling in installation, requiring highly skilled personnel, which results in relatively high installation costs. In highly cost-sensitive areas, such as in-building networks, multimode fibre is an interesting alternative. Its large core facilitates splicing, easier light injection at the source, and avoids non-linearities due to reduced light intensity. Polymer multimode optical fibre (POF) is even more easy to install, due to its flexibility and ductility; it allows e.g. connectorisation by just cramping a metal ferrule on the fibre, without cracks as would occur with silica fibre. Moreover, multimode fibre is already widely accepted for short-range data communications in broadband LANs, benefiting from low-cost transceiver modules and the installation easiness. Several Ethernet standards have been established using multimode fibre: 100 Mbit/s Fast Ethernet IEEE 802.3u standard 100BASE-SX for up to 2 km multimode fibre at 850 nm wavelength, and 100BASE-FX up to 2 km at 1310 nm; Gigabit Ethernet (line rate 1.25 Gbit/s) IEEE 802.3z standard 1000BASE-SX up to 550 m multimode silica fibre at 850 nm, and 1000BASE-LX up to 550 m at 1310 nm; even 10 Gigabit Ethernet (line rate 10.31 Gbit/s) up to 300 m multimode fibre, at 850 nm wavelength. Striving for convergence of in-building networks for reasons of service integration, upgradability, and economy of installation and maintenance, an attractive scenario would be to build radio-over-fibre systems on top of (already installed) multimode fibre data networks such as the Ethernet-based ones mentioned above. Such a multimode fibre-based integrated-services in-building network is exemplified in Fig. 1. Coaxial cable network FD MD POF Twisted pair network

All-optical signal processing for optical packet switching

Abstract: Feature Issue on Optical Interconnection Networks (OIN). We present three optical signal processing functional blocks that enable 1×N optical packet switching. An ultrafast asynchronous multioutput all-optical header processor is demonstrated with a terahertz optical asymmetric demultiplexer in combination with a header preprocessor. It is shown that self-induced polarization rotation can be used for both the header processor and the header preprocessor. The second functional block is optical buffering. This is shown with both a laser neural network and a recirculating buffer. Related to this is a three-state all-optical memory based on coupled lasers, which increases the number of possible output states of an optical packet switch.

Optical label switching by using differential phase shift keying and in-band subcarrier multiplexing modulation format

Abstract: Optical label switching based on combined differential phase shift keying (DPSK) modulation and subcarrier multiplexing is experimentally demonstrated at 10 Gbit/s DPSK encoded payload and 100 Mbit/s amplitude modulated subcarrier-multiplexed labeling. This scheme is spectral efficient and robust to fiber dispersion.

In-band time-to-live signaling system for combined DPSK/SCM scheme in OLS

Abstract: We propose and validate experimentally a time-to-live (TTL) signaling system for an optical label swapping scheme based on 10-Gb/s differential phase-shift-keying (DPSK) packets and with 100-Mb/s subcarrier multiplexing (SCM) label. The proposed scheme allows fast packet discarding by using a 3-GHz subcarrier tone. DPSK payload has only a 2.4-dB power penalty at 10/sup -9/ bit-error rate after superimposing the SCM and TTL labeling signal.

Optical frequency multiplication for low-phase noise microwave signal generation and delivery

Abstract: We demonstrate the capability of optical frequency multiplication, or optical harmonic up-conversion to preserve the low phase noise of low-frequency microwave signals while optically up-converting their frequencies. We use the approach to transport and deliver a 17 GHz microwave local oscillator signal to a significantly simplified remote radio access unit, which is fed by single mode fibre, and multimode fibre, having a modal bandwidth below 1-GHz. Measurement results show that the remotely generated carrier has a very narrow linewidth below 20-Hz, and also exhibits lower phase noise