Marios Bougioukos

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.

All-Optical RZ-to-NRZ Conversion of Advanced Modulated Signals

A generic scheme for return-to-zero (RZ) to nonreturn-to-zero (NRZ) format conversion of optical signals is analyzed. It relies on a simple delay interferometer with frequency periodicity twice as high as the input symbol rate and a subsequent optical band-pass filter. Simulation results at 40 Gbaud indicate the compatibility of the technique with a variety of advanced modulation formats. RZ-to-NRZ conversion of 40 Gb/s differential phase shift keying signals is experimentally demonstrated with 1.5 dB power penalty compared to the back-to-back measurement.

DPSK Regeneration at 40 Gb/s and Beyond Using a Fiber-Sagnac Interferometer

We analyze the experimental demonstration of a phase-incoherent regeneration scheme for differential phase-shift keying signals at 40 Gb/s. The scheme is based on decoding of the input signal by a 1-bit delay interferometer and subsequent optical remodulation using a fiber-Sagnac interferometer. Power penalty improvement up to 3 dB is reported for phase, amplitude, and amplified spontaneous emission noise loaded signals. Simulation results are in agreement with the experimental findings, and reveal the capability of extending the method at ultrahigh data rates.

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.

Experimental demonstration of an all-optical packet forwarding gate based on a single SOA-MZI at 40 Gb/s

We present a new forwarding-gate scheme using a single SOA-MZI. We show a bi-stable behavior with a 13.6 dB extinction-ratio and rise and fall times below 30ps. Error-free operation is achieved at 40 Gb/s.

Agile photonic integrated systems-on-chip enabling WDM terabit networks

The ICT-APACHE research project is focusing on the development of cost-effective, compact, scalable and agile integrated components capable of generating, regenerating and receiving multi-level encoded data signals for high capacity (>100 Gb/s) WDM optical networks. APACHE technology relies on InP active, monolithic chips, hybridly integrated on silica-on-silicon planar lightwave platforms in order to achieve cost-efficiency, high yield, low power consumption and device scaling beyond the level commercially available today. The APACHE integration approach is implemented in a two-dimensional plan, horizontally and vertically, in order to enable multi-functionality and increased capacity, respectively. The final goal of the APACHE project is the fabrication of integrated arrays of transmitters, receivers and regenerators that will operate with 100 Gb/s OOK, DPSK and DQPSK modulated signals, allowing for 1 Terabit/s on-chip capacity. In this paper, we will review the latest results from the system-level characterization of the developed components and will outline the roadmap for future endeavours.

Phase-Incoherent DQPSK Wavelength Conversion Using a Photonic Integrated Circuit

We investigate the performance of a large-scale, silica-on-silicon photonic integrated circuit for multiformat signal processing, and we experimentally demonstrate wavelength-conversion of (differential) quadrature phase-shift keying [(D)QPSK] signals. The circuit exploits phase-incoherent techniques to decode the input signal and to phase remodulate two phase-shift-keying components before combining them in a common QPSK output stream. Error-free wavelength conversion with 4-dB power penalty is reported at 44 Gb/s.

Phase-incoherent DPSK regeneration using a fiber-sagnac interferometer

We experimentally demonstrate for the first time phase-incoherent regeneration of DPSK signals based on fiber-Sagnac interferometer. Power penalty improvement of phase-, amplitude- and ASE-noise loaded signals up to 3 dB is reported at 40 Gb/s.

0.87 Tbit/s 160 Gbaud dual-polarization D8PSK OTDM transmission over 110 km

The feasibility of transmitting 0.87 Tbit/s dual polarization D8PSK-OTDM over 110 km is, for the first time, demonstrated along with 0.44 Tbit/s single polarization D8PSK-OTDM over 220 km in conventional 55-km span SMF+DCF link.

Multi‐Format All‐Optical Regeneration at 40 Gb/s Based on SOA‐MZI

We present all‐optical regeneration at 40 Gb/s for On‐Off Keying (OOK) and Differential Phase‐Shift Keying (DPSK) signals using a multi‐functional Semiconductor Optical Amplifier (SOA) based Mach‐Zehnder Interferometer (MZI). Error free operation for both circuits was achieved indicating that this device can be used effectively as a regenerator for both OOK and DPSK modulation formats.