Spiros Mikroulis

Investigation of a SMF-MMF Link for a Remote Heterodyne 60-GHz OFDM RoF Based Gigabit Wireless Access Topology

A simple single-mode fiber/multimode fiber (SMF-MMF) 60-GHz radio over fiber scheme using a conventional central launching technique at 1550 nm is proposed and experimentally evaluated. The system targets cost-efficient Gigabit wireless access using already installed indoor MMF fed by a passive optical network topology. A complete characterization of the composite SMF/MMF/SMF optical medium is presented, in terms of coupling loss, power stability, and chromatic and modal dispersion. A robust multiband orthogonal frequency-division multiplexing optical single-side-band technique, employing envelope detector scheme, is used as to address the performance limitations imposed by the simple SMF-MMF coupling scheme, chromatic dispersion degradation, and phase noise owing to ordinary long-wavelength lasers. A characterization of the system is performed and a 3.84-Gb/s transmission is demonstrated over a scheme including 17.5-km SMF and 250-m MMF.

Bandwidth Compressed Waveform for 60-GHz Millimeter-Wave Radio Over Fiber Experiment

A bandwidth compressed waveform termed spectrally efficient frequency division multiplexing (SEFDM) is experimentally demonstrated in a 60-GHz millimeter-wave (mm-wave) radio-over-fiber scenario to increase transmission data rates without changing signal bandwidth and modulation format. Experimental results show the advantages of SEFDM and confirm that the bit rate of SEFDM signals can be substantially higher than that of orthogonal frequency-division multiplexing (OFDM) signals. Experimentally, a 2.25 Gbit/s 4QAM OFDM signal is transmitted through 250 m of OM-1 multi-mode fiber and then it is optically up converted to 60 GHz band at the photodiode before delivery to a mm-wave antenna for transmission over a 3 meter wireless link. The work demonstrates that when the OFDM signal is replaced by an SEFDM signal using the same modulation format and occupying the same bandwidth, the bit rate can be increased, by a factor of up to 67%, to 3.75 Gbit/s at the expense of a 3-dB power penalty. Additionally, a bandwidth compressed 4QAM SEFDM is shown to outperform an 8QAM OFDM of the same spectral efficiency, thereby verifying that a lower order modulation format may replace a higher order one and achieve performance gain.

First demonstration of a spectrally efficient FDM radio over fiber system topology for beyond 4G cellular networking

In this work, a spectrally efficient frequency division multiplexing (SEFDM) scheme based on radio over fiber (RoF) technology is proposed for the first time, so as to address next generation wireless data traffic demands on a cost, energy & spectrally efficient way. A proposed radio over fiber topology for beyond 4G deployment is addressed and a proof-of-concept SEFDM long term evolution (LTE) type radio over multimode fiber transmission is successfully demonstrated at 36Mb/s.

DWDM-PON/mm-Wave wireless converged Next Generation Access Topology using coherent heterodyne detection

A radio-over-fibre system using coherent optical heterodyne detection scheme is proposed, to achieve seamless integration of a photonic Remote Antenna Unit (RAU) into a Next Generation Dense Wavelength Division Multiplexed Passive Optical Network (NG DWDM-PON). The proposed scheme significantly simplifies the optical mm-wave generation and data recovery as it doesnt require any high-bandwidth modulator at the central office or high-frequency Local Oscillators (LOs) at either the central office or the customer unit; or optical phase-locking techniques to generate the mm-wave wireless signal. A proof-of-concept transmission utilizing 1 Gb/s On-Off Keying is experimentally demonstrated.

Cost-efficient DWDM-PON/Mm-Wave wireless integration using coherent radio-over-fiber (CRoF)

This work aims to investigate the performance of millimetre wave (mm-wave) broadband wireless access for seamless integration with the (ultra-dense) WDM infrastructure. By using two uncorrelated lasers at the coherent receiver, a simple implementation is obtained, which can additionally be improved, if thermally uncooled lasers are used. Although such asynchronous receiver design is mildly affected by laser phase noise, it suffers from the wavelength drift that occurs between the uncooled laser sources. Also, there are performance penalties due to high laser line-width when complex modulation formats are used for transmission. In this work, we analyze the performance of heterodyne based optical receivers, using OOK and multilevel modulation formats.

Comparison of OFDM standards for 60GHz SMF-MMF radio over fiber links

A simple, single mode fiber/ multimode fiber (SMF-MMF) 60GHz radio over fiber scheme using a conventional central launching technique at 1550nm is experimentally evaluated under various indoor OFDM standards at a 5Gb/s bit rate.

Practical demonstration of spectrally efficient FDM millimeter-wave radio over fiber systems for 5G cellular networking

This work reports the first demonstration of spectrally efficient frequency division multiplexed (SEFDM) signal transmission based on mm-wave radio over fiber (RoF) technology. Such systems aim to satisfy the beyond 4G (5G) demands of low cost, low energy, millimeter-wave carrier frequencies and high spectral efficiency. The proposed radio over fiber topology, using passive optical network (PON) infrastructure and low-cost multimode fiber (MMF), is analyzed and a proof-of-concept SEFDM radio over 250m OM-1 MMF transmission with a 3m 60GHz wireless link is successfully demonstrated. Different systems are demonstrated, at raw data rates up to 3.7 Gb/s, showing SEFDM spectrum saving up to 40% relative to OFDM.

Evaluation of OOK and OFDM on an SMF-MMF-SMF Link Targeting a PON/60-GHz Topology for Beyond 4G

In this letter, an integrated passive optical network/ millimeter wave (mm-wave) wireless topology is addressed, focusing on mm-wave for beyond 4G in building extension and small-cell mobile backhaul/fronthaul. A simple single-mode fiber/multi-mode fiber (MMF) scheme using conventional central launching or an offset coupling technique is proposed. An experimental study comparing the above coupling schemes is performed using a 1.2-Gb/s ON-OFF keying (non-return to zero) transmission and 60-GHz photonic up-conversion or 5 Gb/s at 60-GHz carrier multiband orthogonal frequency division multiplexing (MB-OFDM) both propagating over OM-1 MMF.

Wavelength shift tolerance of a heterodyne detection scheme for cost-efficient DWDM-PON / 60 GHz wireless integration

Radio-over-fiber systems employing remote antenna units (RAUs) based on coherent optical heterodyne detection of two phase uncorrelated lasers and envelope detection have been recently demonstrated. By using two uncorrelated lasers, this system concept allows simple implementation that can additionally be improved, if thermally uncooled lasers are used. Although such asynchronous receiver design is mildly affected by the laser phase noise, it suffers from the wavelength drift that occurs between the uncooled laser sources. Also, there are performance penalties due to high laser line-width when complex modulation formats are used for transmission. In this work, we analyze the performance of heterodyne based optical receivers, using OOK and multilevel modulation.

Investigation of a cost-efficient PON/mm-wave converged access topology using multimode fiber feeds

In this work, a PON/mm-wave converged topology using single-mode fiber (SMF) to multimode fiber (MMF) feeds is addressed supporting 60-GHz indoor wireless access, standard PON and a 60-GHz wireless bridge providing a virtual PON extension. Proof-of-concept experiments are performed using a 1.2-Gb/s OOK (NRZ) transmission over SMF-MMF-SMF link without or including 60-GHz photonic up-conversion to be used on a wireless link (PON bridge) and fiber post-transmission, or 5 Gb/s at 60-GHz carrier MB-OFDM transmission over SMF-MMF-SMF link co-existing with a 1.2-Gb/s OOK (NRZ) signal.