An Truong Nguyen

Binary-to-Quaternary ASK Encoding in the Optical Domain With Semiconductor Optical Amplifiers

Quaternary amplitude-shift-keying signal is all-optically generated from binary signals exploiting gain compression in two semiconductor optical amplifiers. The scheme is suitable for phase-control-free all-optical digital-to-analog conversion. Only two semiconductor amplifiers, a single optical filter, and no assist probe light are required for 2-bit operation. In addition, the input wavelength is preserved at the output of the device. Dynamic operation is experimentally demonstrated. The quality of the level-converted signal is confirmed by the high Q -factor of the output eye diagrams.

All-Optical Digital Circuits Exploiting SOA-Based Loop Memories

All-optical digital circuits based on loop memories are demonstrated. These circuits are a variable optical buffer, an optical random access memory, an optical shift register, and an optical linear feedback shift register. Buffers are employed in network nodes to solve the contentions without loosing information. Shift registers are used for error detection and correction techniques. Linear feedback shift registers are employed for generation of pseudo-random bit sequences, data scrambling, and encryption/decryption of information in secure communication systems. Since the role of optical processing is gradually increasing within the communication systems, the possibility to store information directly in the optical domain can lead to a systems simplification and to a performance improvement. In order to make the schemes suitable for practical applications, optical integration is necessary. The use of semiconductor optical amplifier as gain element into the memory loop allows all the proposed schemes to be integrated.

All-Optical Gated Wavelength Converter-Eraser Using a Single SOA-MZI

We propose and experimentally demonstrate an original scheme for simultaneous all-optical wavelength conversion and data erasing under an optical gate signal, suitable for on-off keying (OOK) signals. This function is obtained in a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) exploiting nonlinear interaction between a continuous data stream and an optical gate signal at a different wavelength. In correspondence of the gate signal, a burst of data from the optical stream is converted at the optical gate wavelength and, at the same time, cancelled at the input stream wavelength. Fast switching time enabling selective wavelength shifting on a data stream at 10 Gb/s without any bit loss is demonstrated. Error-free operation with 0.2-dB power penalty for the wavelength-preserved output data and 1.8 dB for the shifted data is reported.

Novel Architecture for a Photonics-Assisted Radar Transceiver Based on a Single Mode-Locking Laser

A novel solution for the optical generation of radio-frequency signals for coherent radars is proposed, which exploits the same mode-locking laser of the photonic-assisted radar receiver. The scheme, which is based on the concept of shifting the frequency of a laser mode, exploits a commercial optical in-phase/quadrature modulator to allow using a single mode-locking laser for both the radar transmitter and receiver, making the solution attractive for immediate and practical implementation in photonics-assisted transceivers.

All Optical Add and Drop Multiplexing Node for Hybrid Topology Networks

A new concept for all optical add and drop multiplexing (OADM) node is presented. The node is meant to act as gateway node between optical network segments that exhibit diverse properties in terms of multiplexing systems, granularity and modulation formats. The general architecture of the mentioned OADM node is presented, showing that the node is able to act as a “language translator” between network segments based on OTDM and WDM systems exploiting different modulation formats to transport data streams (RZ-OOK and NRZ-DPSK respectively). The design and experimental demonstration of a first prototype of an OADM node that is able to convert a NRZ-DPSK data signal coming from the WDM stream into a RZ-OOK signal, to drop one channel from the OTDM stream and insert the converted signal into the released time slot are presented.

Multicasting in WDM-PON using cross-gain modulation in semiconductor optical amplifier

Using cross gain modulation in a semiconductor optical amplifier (SOA), we experimentally demonstrate a novel scheme to provide broadcasting service in a colorless WDM-PON system. Due to simple structure, it offers intrinsic stability and cost-effective solution for multicasting in WDM-PON.

Fine granularity ROADM node testbed for OTDM and WDM based subnetworks towards 100 Gbps interconnection and beyond

New concept, architecture and prototype for ROADM gateway node are proposed. The ROADM acts as a “translator” between network segments based on OTDM and WDM systems exploiting different modulation formats to transport data streams.

Power optimization for intensity and time jitter characterization in optical frequency multiplication and time multiplexing

Intensity and time jitter characterization in optical frequency multiplication and time multiplexing is theoretically described. The power constraints are experimentally measured for a 10 to 20 GHz optical frequency multiplication system.