Antonello Vannucci

Serial 100 Gb/s connectivity based on polymer photonics and InP-DHBT electronics.

We demonstrate the first integrated transmitter for serial 100 Gb/s NRZ-OOK modulation in datacom and telecom applications. The transmitter relies on the use of an electro-optic polymer modulator and the hybrid integration of an InP laser diode and InP-DHBT electronics with the polymer board. Evaluation is made at 80 and 100 Gb/s through eye-diagrams and BER measurements using a receiver module that integrates a pin-photodiode and an electrical 1:2 demultiplexer. Error-free performance is confirmed both at 80 and 100 Gb/s revealing the viability of the approach and the potential of the technology.

Strip-Loaded High-Confinement Waveguides for Photonic Applications

Sol-gel is a promising deposition technique for the fabrication of silica-on-silicon photonic components. Silica-titania compositions provide large index differences, and thus strong mode confinement, and are suitable hosts for Er-doped optical amplifiers. We have developed channel waveguides based on phosphosilicate strip loads over high index titania-doped guiding layers. Here we demonstrate that low propagation loss (0.3 dB/cm) can be obtained in such guides at optical communication wavelengths. Alumina co-doped guiding layers are shown to inhibit OH retention without causing titania segregation, and reduced humidity during spinning is shown to be necessary to achieve low propagation losses.

Strip-loaded sol-gel waveguides : Design and fabrication

Sol-gel is one of the most attractive techniques for production of silica-on-silicon integrated optical devices. In fact, it combines low cost with flexibility and ease of doping; thus, nonlinear and active compounds can be effectively included in the silica matrix. Here, the feasibility of applying the sol-gel technique to the realization of an erbium-doped optical amplifier is reported on, operating in the third telecommunication window. In particular, the development of an optimum strategy for the design and fabrication of a guiding structure in the strip-loaded configuration is described. Design optimization results, as well as fabrication results and measured characteristics, are described and discussed.Sol-gel is one of the most attractive techniques for production of silica-on-silicon integrated optical devices. In fact, it combines low cost with flexibility and ease of doping; thus, nonlinear and active compounds can be effectively included in the silica matrix. Here, the feasibility of applying the sol-gel technique to the realization of an erbium-doped optical amplifier is reported on, operating in the third telecommunication window. In particular, the development of an optimum strategy for the design and fabrication of a guiding structure in the strip-loaded configuration is described. Design optimization results, as well as fabrication results and measured characteristics, are described and discussed.

A method for microwave characterization of LiNbO 3 modulators

A procedure to extract the S-parameters of both the active section and the input and output coplanar tapers of Mach-Zehnder modulators is proposed. The S-parameters of the three sections of the modulator have been successfully extracted up to 30 GHz from measurements and EM simulations performed on proper test structures.

A high-resolution integrated optical spectrometer with applications to fibre sensor signal processing

An integrated optical device has been developed to realize the instrumentation for the processing of the optical signal such as those from fibre optic Bragg grating sensors (FBG) embedded in composite materials. The optical circuit integrates on X-cut an acousto-optical TE - TM converter included between two crossed polarizers, in order to realize a tunable high-resolution optical filter. The design and fabrication process parameters and solutions adopted with the aim of obtaining very-high-resolution filters ( FWHM < 0.45 nm at 1300 nm) are discussed. The device has been demonstrated to allow the polarization-independent spectrum analysis of in-fibre optical radiation, exploiting the heterodyne detection of the optical signals from the output of the acousto-optical tunable filter. The application as instrumentation for the processing of optical signals from such sensors is described and the experimental results are presented for the monitoring of static and dynamic deformations of composite material structures such as those in which the FBG sensors have been embedded.

Multi-100 GbE and 400 GbE Interfaces for Intra-Data Center Networks Based on Arrayed Transceivers With Serial 100 Gb/s Operation

We demonstrate a 2 × 100 Gb/s transmitter and a 4 × 100 Gb/s receiver as the key components for multi-100-GbE and 400-GbE optical interfaces in future intradata center networks. Compared to other approaches, the two devices can provide significant advantages in terms of number of components, simplicity, footprint, and cost, as they are capable of serial operation with nonreturn-to-zero on-off keying format directly at 100 Gb/s. The transmitter is based on the monolithic integration of a multimode interference coupler with two Mach-Zehnder modulators on an electro-optic polymer chip, and the hybrid integration of this chip with an InP laser diode and two multiplexing and driving circuits. The receiver on the other hand is based on the hybrid integration of a quad array of InP photodiodes with two demultiplexing circuits. Combining the two devices, we evaluate their transmission performance over standard single-mode fibers without dispersion compensation and achieve a BER of 10-10 after 1000 m and a BER below 10-8 after 1625 m at 2 × 80 Gb/s, as well as a BER below 10-7 after 1000 m at 2 × 100 Gb/s. Future plans including the development of tunable 100 GbE interfaces for optical circuit-switched domains inside data center networks are also discussed.

\(2 \times 100\) -Gb/s NRZ-OOK Integrated Transmitter for Intradata Center Connectivity

We demonstrate an integrated transmitter that can generate two 100-Gb/s optical channels with simple nonreturn-to-zero-ON-OFF keying format. The transmitter is based on the combination of an ultrafast electro-optic polymer platform for the photonic integration and the optical modulation with ultrafast InP-double heterojunction bipolar transistor electronics for the multiplexing and the amplification of the 100-Gb/s driving signals. Through error-free transmission of 2 × 80-Gb/s signals over 1 km of SMF and transmission of 2 × 100-Gb/s signals over 500 m of single-mode fiber with error performance way below the forward error correction limit, we reveal the potential of the approach for parallel 100-GbE optical interfaces in small footprint transceivers for intradata center networks.

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.

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.

Passive and electro-optic polymer photonics and InP electronics integration

Hybrid photonic integration allows individual components to be developed at their best-suited material platforms without sacrificing the overall performance. In the past few years a polymer-enabled hybrid integration platform has been established, comprising 1) EO polymers for constructing low-complexity and low-cost Mach-Zehnder modulators (MZMs) with extremely high modulation bandwidth; 2) InP components for light sources, detectors, and high-speed electronics including MUX drivers and DEMUX circuits; 3) Ceramic (AIN) RF board that links the electronic signals within the package. On this platform, advanced optoelectronic modules have been demonstrated, including serial 100 Gb/s [1] and 2x100 Gb/s [2] optical transmitters, but also 400 Gb/s optoelectronic interfaces for intra-data center networks [3]. To expand the device functionalities to an unprecedented level and at the same time improve the integration compatibility with diversified active / passive photonic components, we have added a passive polymer-based photonic board (polyboard) as the 4th material system. This passive polyboard allows for low-cost fabrication of single-mode waveguide networks, enables fast and convenient integration of various thin-film elements (TFEs) to control the light polarization, and provides efficient thermo-optic elements (TOEs) for wavelength tuning, light amplitude regulation and light-path switching.