Alexandros Maziotis

All-optical carrier recovery with periodic optical filtering for wavelength reuse in RSOA-based colorless optical network units in full-duplex 10Gbps WDM-PONs

Optically assisted downstream cancellation for wavelength reuse in WDM-PONs is demonstrated, allowing downstream extinction ratios up to 9 dB for symmetrical full-duplex data transmission at 10Gbps with RSOA-based ONUs. PON budgets of ~20dB can be reached.

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.

Silicon-on-Insulator Nanowire Resonators for Compact and Ultra-High Speed All-Optical Wavelength Converters

We present the development of application-specific silicon-on-insulator SOI nanowire ring and racetrack resonators designed to assist semiconductor optical amplifier (SOA)-based all-optical wavelength conversion. We demonstrate the fabrication of fix resonance racetrack resonators exhibiting coupling gaps as low as 160 nm and tunable ring resonators with coupling gaps <; 90 nm. The resonators are cascaded after commercial 40 Gb/s SOAs to realize chirp filtering of the optical data signals through high-resolution spectral sampling. We experimentally demonstrate inverted and non-inverted SOI resonator-assisted all-optical wavelength conversion at 40 Gb/s and 160 Gb/s with power penalties <; 3 dB.

An All-Optical Carrier Recovery Scheme for Access Networks With Simple ASK Modulation

We theoretically investigate and experimentally demonstrate a scheme for all-optical carrier recovery in loopback access networks that avoids orthogonal or complex modulation formats for the downstream or upstream signals. The applied technique is based on a passive resonating circuit that is capable of recovering the optical carrier of the amplitude-shift-keyed downstream signal for remodulation with a reflective modulator as upstream transmitter enabling full-duplex 10 Gb/s operation. The scheme is compared with alternative pattern suppression techniques based on optical gain saturation and electro-optical feed-forward injection for the stringent requirements of next-generation access networks, namely, an extended loss budget and high upstream data rates. Operation at downstream modulation depths of ~3 dB is reported with the feed-forward approach, while higher modulation depths of up to 9 dB are demonstrated with the all-optical carrier recovery technique, for which the dependence on longer sequences of consecutive identical bits is investigated. Finally, the feasibility of the all-optical downstream cancelation technique for optical access networks is evaluated in a wavelength division multiplexed passive optical network, showing full-duplex transmission with margins of at least 9 dB.

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.

Wavelength reuse in a colourless ONU with all-optical clock recovery for full-duplex dense WDM PONs

In this paper, an approach of a colourless ONU comprised by a Fabry-Pérot filter and a Semiconductor Optical Amplifier for all-optical clock recovery of the downstream signal, followed by a Mach-Zehnder modulator as the upstream modulator is experimentally demonstrated. The all-optical clock recovery performs data erasure allowing for efficient wavelength reuse of the downstream signal for upstream remodulation. Operation at a full-duplex 10 Gb/s symmetrical data rate and 20 dB loss budget is demonstrated over fiber spans of 50 km with achieved power margin of ∼8 dB.

Colorless ONU With All-Optical Clock Recovery for Full-Duplex Dense WDM PONs

We propose a colorless optical network unit (ONU) comprised of a Fabry-Pérot filter (FPF) and a semiconductor optical amplifier (SOA) for all-optical clock recovery of the downstream signal, followed by a Mach-Zehnder modulator (MZM) as the upstream modulator. The all-optical clock recovery performs data erasure allowing for efficient wavelength reuse of the downstream signal for upstream remodulation. Operation at a full-duplex 10-Gb/s symmetrical data rate and 20-dB loss budget is demonstrated over fiber spans of 50 km.

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.