Maria Spyropoulou

SOA-MZI-Based Nonlinear Optical Signal Processing: A Frequency Domain Transfer Function for Wavelength Conversion, Clock Recovery, and Packet Envelope Detection

We present analytic expressions for the frequency-domain transfer function of semiconductor optical amplifier Mach-Zehnder interferometric (SOA-MZI) switches that employ a single optical control signal and a continuous wave input optical beam. Our analysis relies on first-order perturbation theory approximations applied both to the SOA response as well as to the SOA-MZI characteristics, yielding a frequency response that enables a qualitative insight into the different SOA-MZI operational regimes. The final transfer function expression is utilized for the analysis and evaluation of the multifunctional potential of SOA-MZI switches, concluding with the necessary conditions for supporting a number of completely different SOA-MZI-based nonlinear signal processing applications that have been demonstrated experimentally: wavelength conversion, packet envelope detection (PED), and clock recovery (CR). The theoretically obtained operational conditions are in close agreement with experimental observations, showing that SOA-MZIs can serve as functional circuit elements in applications with different requirements depending on its operational parameters: as low-pass filtering devices with cut-off frequencies in the megahertz regime or in the multi-gigahertz regime, and as resonant modules resembling band-pass filtering structures. The validity of our theoretical SOA-MZI frequency-domain system model is further confirmed by its successful incorporation in a Fabry-Perot assisted SOA-MZI subsystem, demonstrating PED and CR operations through the exploitation of typical systems theory tools.

40 Gb/s NRZ Wavelength Conversion Using a Differentially-Biased SOA-MZI: Theory and Experiment

We present theoretical and experimental performance analysis of 40 Gb/s Non-Return-to-Zero (NRZ) All-Optical Wavelength Conversion (AOWC) using a differentially-biased SOA-MZI. A frequency domain transfer function model for both the standard single-control SOA-MZI-based AOWC and for the differentially-biased SOA-MZI is analytically derived, exploiting first order perturbation theory techniques and showing that only the differentially-biased scheme can yield an almost flat low-pass filtering response enabling wavelength conversion at 40 Gb/s. The theoretically obtained results are also confirmed through experiments that demonstrate successful 40 Gb/s AOWC functionality for NRZ data signals only when a differentially-biased SOA-MZI configuration is employed, whereas an error-floor is obtained when 40 Gb/s NRZ AOWC with the standard single-control SOA-MZI scheme is attempted. The 1.7 dB negative power penalty obtained by the differentially-biased SOA-MZI architecture confirms its enhanced regenerative properties and its potential for extending 40 Gb/s optical transparent network dimensions by means of cascaded 2R AOWC stages.

Field Experiments With a Grooming Switch for OTDM Meshed Networking

Field experiments of 42.7/128.1 Gb/s wavelength-division multiplexed, optical time-division multiplexed (WDM-OTDM) transmultiplexing and all-optical dual-wavelength regeneration at the OTDM rate are presented in this paper. By using the asynchronous retiming scheme, we achieve error-free bufferless data grooming with time-slot interchange capability for OTDM meshed networking. We demonstrate excellent performance from the system, discuss scalability, applicability, and the potential reach of the asynchronous retiming scheme for transparent OTDM-domain interconnection.

Field trial of WDM-OTDM transmultiplexing employing photonic switch fabric-based buffer-less bit-interleaved data grooming and all-optical regeneration

We report, for the first time, a field trial of a novel 42.7Gbps/128.1Gbps WDM/OTDM grooming node, and confirm node interoperability and the data integrity of asynchronous retiming.

Simulation of Multiwavelength Regeneration Based on QD Semiconductor Optical Amplifiers

In this letter, we examine the performance of a multiwavelength 2R regenerator based on the cross-gain modulation effect in quantum-dot semiconductor optical amplifiers. Extensive numerical simulations have been performed to investigate the device parameters and operating conditions of the proposed subsystem. All-optical regeneration of two input channels at 40 and 160 Gb/s are illustrated.

A High-Speed Multiwavelength Clock Recovery Scheme for Optical Packets

We present a novel scheme for high-speed multiwavelength clock recovery using a low finesse Fabry-Perot filter and a quantum-dot semiconductor optical amplifier. Performance evaluation based on extensive numerical analysis reveals that the proposed configuration can acquire clock from 40- and 160-Gb/s input data packet streams at four wavelengths with very short rise- and fall-times.

Tunable 100 Gbaud Transmitter Based on Hybrid Polymer-to-Polymer Integration for Flexible Optical Interconnects

We introduce a hybrid integration platform based on the combination of passive and electro-optic polymers. We analyze the optical and physical compatibility of these materials and describe the advantages that our hybrid platform is expected to have for the development of transmitters in terms of operation flexibility and speed. We combine our platform with InP electronics and develop a transmitter with 22-nm tunability in the C-band and potential for serial non-return-to-zero on-off-keying operation directly at 100 Gb/s. We investigate its transmission performance at 80 and 100 Gb/s using dispersion uncompensated standard single-mode fiber and demonstrate bit-error rate (BER) lower than 10-10 at 80 Gb/s after 1625 m, lower than 10-10 at 100 Gb/s after 500 m, lower than 10-9 at 100 Gb/s after 1000 m, and BER 10-7 at the same rate after 1625 m. We also employ the transmitter inside an experimental setup, which aims to emulate an optical circuit switched (OCS) domain of an intradata center network, and demonstrate at 100 Gb/s the way, in which its wavelength tunability can resolve contentions and improve the flexibility and the efficiency of the network. Finally, we outline our next plans, including the development of flexible and ultra-fast transmitters for coherent systems using the same polymer-to-polymer integration platform.

Study of a Multi-wavelength Regenerative subsystem based on Quantum Dot Semiconductor Optical Amplifiers at 40Gbps

For the first time to our knowledge we perform a study related with multi-wavelength 2R regeneration based on cross-gain modulation (XGM) operation at 40 Gbps using quantum-dot semiconductor optical amplifiers (QD-SOAs).

Multi-Flow Transmitter Based on Polarization and Optical Carrier Management on Optical Polymers

We propose a novel multi-flow transmitter concept capable of controlling the number, type, wavelength, and destination of the generated optical flows depending on the client traffic. The concept is based on the selection of the number of optical carriers per flow and the selection between single- and dual-polarization flows. We demonstrate the proof-of-concept combining two commercial In-Phase/Quadrature (IQ) modulators with two prototype polymer circuits, which integrate three tunable lasers for flexible wavelength allocation, four thermo-optic switches for flexible optical routing on-chip, and elements for polarization handling on-chip. We incorporate this transmitter inside an optical node, and we investigate one-flow scenarios with dual-carrier or dual-polarization quadrature phase shift keying (QPSK) modulation, and two-flow scenarios based on two independent QPSK signals. The transmitter and node configuration are controlled by a software-defined optics platform. We demonstrate dynamic operation at 28 GBd and error-free coherent transmission over 100 km of the standard single-mode fiber.

Multi-format all-optical processing based on a large-scale, hybridly integrated photonic circuit

We investigate through numerical studies and experiments the performance of a large scale, silica-on-silicon photonic integrated circuit for multi-format regeneration and wavelength-conversion. The circuit encompasses a monolithically integrated array of four SOAs inside two parallel Mach-Zehnder structures, four delay interferometers and a large number of silica waveguides and couplers. Exploiting phase-incoherent techniques, the circuit is capable of processing OOK signals at variable bit rates, DPSK signals at 22 or 44 Gb/s and DQPSK signals at 44 Gbaud. Simulation studies reveal the wavelength-conversion potential of the circuit with enhanced regenerative capabilities for OOK and DPSK modulation formats and acceptable quality degradation for DQPSK format. Regeneration of 22 Gb/s OOK signals with amplified spontaneous emission (ASE) noise and DPSK data signals degraded with amplitude, phase and ASE noise is experimentally validated demonstrating a power penalty improvement up to 1.5 dB.