Cognitive Digital Receiver for Burst Mode Phase Modulated Radio over Fiber Links Neil Guerrero Gonzalez(1), Darko Zibar(1) and Idelfonso Tafur Monroy(1) (1) DTU Fotonik, Technical University of Denmark, Kgs. Lyngby, Denmark, nggo@fotonik.dtu.dk Abstract A novel cognitive receiver for modulation format recognition with reconfigurable carrier recovery scheme is proposed and experimentally demonstrated for phase modulated radio-over-fibre links. Demodulation of burst-mode mixed modulation formats (PSK and QAM) is demonstrated after 40km of transmission. Introduction The next generation of broadband access networks is striving for a convergence of wired and wireless service delivery to the end users over a unified networking platform1 (see Fig. 1). In addition to the increasing demand for greater bandwidth, in combination with diverse modulation formats and mixed bit rates of emerging services, access networks will need to be flexible while keeping the overall cost and complexity low2. The challenge of designing digital receivers compatible with different standards has started to be addressed by the Wireless Personal Area Networks (WPAN)2 research community. However, in current WPANs, bit rates are low. For the next generation hybrid wireless-optical links which rely on radio-over-fiber (RoF) systems, a new set of challenges is added such as high-bit-rates and signal distortions from both the optical channel and the wireless environment. To our knowledge, no solutions for cognitive receivers for radio-over-fibre links employing optical phase modulation have been reported so far. Fig. 1: Next generation broadband access networks supporting mixed services, mix bit rate and diverse modulation formats. In this paper, we propose a cognitive digital receiver capable of signal modulation format recognition with corresponding reconfigurable carrier recovery scheme for phase shift keying (PSK) and quadrature amplitude modulated (QAM) signals. We experimentally demonstrate its successful operation for an optically phase- modulated RoF link transporting bursts of mixed modulation formats at 312.5 Mbaud QPSK, 8PSK and 16QAM data payloads. Error free operation achieved including 40 km of fiber transmission. Setup Description The experimental setup for a phase-modulated RoF optical link transporting burst mode mixed modulation formats (QPSK, 8PSK and 16QAM) is shown in Fig. 2. The transmitter consists of a tuneable Distributed Feedback Laser (DFB), with a linewidth of ~3 MHz in the range of 1550 nm. The output of the transmitter laser is then connected to an optical phase modulator (PM). We use an Agilent N8241A arbitrary waveform generator (AWG) to generate bursts of 312.5 Mbaud QPSK, 8PSK and 16QAM modulated digital data streams (see Fig. 2). Each burst is comprised of a 200-bit preamble of alternating ones and zeros and 16QAM 8PSK QPSK Preamble Payload Guard PM 3 dB ASE source Tunable LO PBS Cognitive Digital Coherent Receiver RF 5 GHz AWG 40 Km + VSG Fig. 2: General outline for the experimental setup for demonstration of burst mode mixed modulation formats phase-modulated RoF signals using the cognitive digital receiver. ECOC 2010, 19-23 September, 2010, Torino, Italy 978-1-4244-8535-2/10/$26.00 ��2010 IEEE P6.11