Photon Netw Commun DOI 10.1007/s11107-017-0695-y ORIGINAL PAPER UWB over fiber transmission to multiple radio access units using all-optical signal processing Bilal Aziz 1 · Tayyab Mehmood 1 · Salman Ghafoor 1 Received: 23 July 2016 / Accepted: 27 February 2017 © Springer Science+Business Media New York 2017 Abstract An ultra-wideband over fiber architecture is pro- posed where multiple coherent pulsed optical signals are used for transmitting high data rate signals to five differ- ent radio access units (RAUs). The RAUs are placed in a star topology to form a broadcast distributive antenna system architecture. The architecture transmits 5 × 1.25 Gbps data from control unit to the RAUs using a wavelength division multiplexed signal. The multiple pulsed optical carriers form- ing the wavelength division multiplexed signal are generated using a single continuous wave optical source. The data modulated coherent optical pulsed signals are all-optically converted to electrical Gaussian mono-cycle pulses at the RAUs. The proposed architecture is cost-efficient and gives good bit-error rate results. Keywords Ultra-wideband over fiber · All-optical signal processing · Gaussian mono-cycle pulses 1 Introduction During the past decade, internet traffic has increased expo- nentially through wired and wireless media. This has moti- vated the research community to explore new techniques in order to provide scalable and inexpensive communication services. Therefore, techniques such as Analogue Radio over B Salman Ghafoor salman.ghafoor@seecs.edu.pk Bilal Aziz 13mseebaziz@seecs.edu.pk Tayyab Mehmood 14mseetmehmood@seecs.edu.pk 1 National University of Sciences and Technology (NUST), Islamabad, Pakistan Fiber (ARoF) [1], Baseband Radio over Fiber (BRoF) [2], UWBoF [3] and short range optical-wireless applications are being researched to provide communication services in giga-bit range per user [4]. UWBoF transmission has recently got special attention due to large available band- width, high data rate transmission, multi-path immunity and use of off-the-shelf equipment [4]. A particular advantage of UWBoF transmission is the direct generation of UWB wire- less signals using all-optical techniques. Furthermore, UWB is an emerging radio technology with the capability of sup- porting bandwidth hungry applications of next generation access networks. UWBoF offers centralized network design which enables the Base Station (BS) and the RAUs to have simplified architecture. Data modulated optical signals are transmitted from the central unit (CU) to the RAUs, where they are all-optically converted to electrical UWB signals [4]. UWBoF transmission has been proposed in various stud- ies. In [5], simultaneous transmission of a 1.25 Gbps mm- wave signal, a 1.25 Gbps IR-UWB signal and a 10 Gbps wire-line signal is experimentally demonstrated. The pro- posed scheme employs a combination of polarization mod- ulator as well as Mach Zehnder Modulators (MZMs) to transmit the electronic signals by polarization multiplexing to a single BS. In another study proposed in [6], polariza- tion modulator is used in combination with a Fiber Bragg Grating (FBG) to generate intensity modulated UWB signal for downstream transmission. A bi-directional link having a data rate of 1.25 Gbps was demonstrated over a 25 km Single Mode Fiber (SMF) to a single BS. The downstream optical carrier is re-used for upstream by combining the two orthog- onal signals of the downstream carrier at a polarizer which results in an un-modulated optical carrier. An adaptive UWB signal generation and transmission at a data rate of 625 Mbps using doublet pulses is experimentally demonstrated in [7]. An inverse mono-cycle pulse is generated by directly modu- 123