Panagiotis Zakynthinos

All-Optical 3R Burst-Mode Reception at 40 Gb/s Using Four Integrated MZI Switches

We demonstrate an all-optical retime, reshape, reamplify (3R) burst-mode receiver (BMR) operating error-free with a 40-Gb/s variable-length asynchronous optical data packets that exhibit up to 9-dB packet-to-packet power variation. The circuit is completely based upon hybrid integrated Mach-Zehnder interferometric (MZI) switches as it employs four cascaded MZIs, each one performing a different functionality. The 3R burst-mode reception is achieved with the combination of two discrete all-optical subsystems. A reshape, reamplify BMR employing a single MZI is used first to perform power equalization of the incoming bursts and provide error-free data reception. This novel approach is experimentally demonstrated to operate error-free, even for a 9-dB dynamic range of power variation between bursty data packets and for a wide range of average input power. The obtained power-equalized data packets are then fed into a 3R regenerator to improve the signal quality by reducing the phase and amplitude jitter of the incoming data. This packet-mode 3R regenerator employs three MZIs that perform wavelength conversion, clock extraction, and data regeneration for every packet separately and operates at 40 Gb/s, exhibiting rms timing jitter reduction from 4 ps at the input to 1 ps at the output and a power penalty improvement of 2.5 dB

Enabling Tb/s Photonic Routing: Development of Advanced Hybrid Integrated Photonic Devices to Realize High-Speed, All-Optical Packet Switching

We present recent advances in photonic integration introduced by integration-related European research project IST-MUFINS. The contribution of the project in the progress of a functional photonic integration is outlined, from device fabrication to device application focusing on photonic routing using multielement photonic chips. Specifically, we report on the transition from single-element to multielement photonic devices with the fabrication of hybrid integrated arrays of optical switches exploiting and upgrading the silica-on-silicon hybrid photonic integration. We demonstrate how the enhanced processing power and capacity of these components can be exploited to implement key functionalities required in next-generation fully integrated terabits per second photonic routers.

A 40 Gb/s 3R Burst Mode Receiver with 4 integrated MZI switches

We demonstrate for the first time a 40 Gb/s all-optical 3R burst-mode receiver error-free operation for 9,3 dB power fluctuation between short bursty packets. It consists of a sequence of four integrated MZI switches.

Simple intradyne PSK system for UDWDM-PON

An enhanced homodyne coherent system for ultra-dense WDM-PON is demonstrated, using conventional DFB, coupler instead of 90° hybrid and digital signal processing, achieving improved sensitivity and phase noise tolerance.

An SOA-MZI NRZ Wavelength Conversion Scheme With Enhanced 2R Regeneration Characteristics

We present a novel scheme for all-optical nonreturn-to-zero (NRZ) wavelength conversion with enhanced 2R regenerative characteristics. It employs a hybridly integrated semiconductor optical amplifier Mach-Zehnder interferometer using bidirectional data injection and an additional external continuous-wave signal for differentially biasing the interferometer arms, optimizing gain and phase conditions during the switching functionality. Experimental verification of its superior 2R regenerative capabilities are demonstrated for 10-Gb/s NRZ data signals.

40 Gb/s 2R Burst Mode Receiver with a single integrated SOA-MZI switch.

We demonstrate a novel scheme for 2R burst mode reception capable of operating error-free with 40 Gb/s variable length, asynchronous optical data packets that exhibit up to 9 dB packet-to-packet power variation. It consists of a single, hybrid integrated, SOA-based Mach-Zehnder Interferometer (SOA-MZI) with unequal splitting ratio couplers, configured to operate as a self-switch. We analyze theoretically the power equalization properties of unequal splitting ratio SOA-MZI switches and show good agreement between theory and experiment.

Monolithic GaAs Electro-Optic IQ Modulator Demonstrated at 150 Gbit/s With 64QAM

We report on the experimental demonstration of a GaAs IQ modulator. The device consists of two “nested” Mach-Zehnder modulators for the inphase and quadrature component and is operated at a symbol rate of 25 GBd. Using QPSK, 16QAM, 32QAM and 64QAM, data rates of up to 150 Gbit/s were encoded on a single carrier in one polarization. The individual Mach-Zehnder modulators, and hence, the IQ-modulator have an electro-optic 3 dB bandwidth of 27 GHz and a 6 dB bandwidth larger than 35 GHz. The extinction ratio of the Mach-Zehnder exceeds 20 dB. The devices exhibit small footprint of 2 mm × 40 mm and can be integrated on large-area GaAs wafers using high-yield fabrication processes while providing performance similar to established lithium niobate devices.

A tunable continuous wave (CW) and short-pulse optical source for THz brain imaging applications

We demonstrate recent advances toward the development of a novel 2D THz imaging system for brain imaging applications both at the macroscopic and at the bimolecular level. A frequency-synthesized THz source based on difference frequency generation between optical wavelengths is presented, utilizing supercontinuum generation in a highly nonlinear optical fiber with subsequent spectral carving by means of a fiber Fabry‐Perot filter. Experimental results confirm the successful generation of THz radiation in the range of 0.2‐2 THz, verifying the enhanced frequency tunability properties of the proposed system. Finally, the roadmap toward capturing functional brain information by exploiting THz imaging technologies is discussed, outlining the unique advantages offered by THz frequencies and their complementarity with existing brain imaging techniques.

Cascadability Performance Evaluation of a New NRZ SOA-MZI Wavelength Converter

We evaluate the cascadability performance of a new semiconductor optical amplifier (SOA) Mach-Zehnder interferometer-based nonreturn-to-zero wavelength converter in a loop experiment. We use the bidirectional data injection control scheme with an additional continuous-wave signal to optimize the gains and phases imparted by the SOAs. The scheme has been shown to be capable of eight cascaded, error-free wavelength conversions at 10 Gb/s.

Enabling transparent technologies for the development of highly granular flexible optical cross-connects

Flexible optical networking is identified today as the solution that offers smooth system upgradability towards Tb/s capacities and optimized use of network resources. However, in order to fully exploit the potentials of flexible spectrum allocation and networking, the development of a flexible switching node is required capable to adaptively add, drop and switch tributaries with variable bandwidth characteristics from/to ultra-high capacity wavelength channels at the lowest switching granularity. This paper presents the main concept and technology solutions envisioned by the EU funded project FOX-C, which targets the design, development and evaluation of the first functional system prototype of flexible add-drop and switching cross-connects. The key developments enable ultra-fine switching granularity at the optical subcarrier level, providing end-to-end routing of any tributary channel with flexible bandwidth down to 10Gb/s (or even lower) carried over wavelength superchannels, each with an aggregated capacity beyond 1Tb/s.