A directly modulated 1.55-μm buried-heterostructure passive feedback laser exhibits a high modulation bandwidth of up to 34 GHz at moderate distributed-feedback (DFB) section currents between 20 and 60 mA. A very flat frequency response and a low alpha parameter have been demonstrated in the small signal modulation analysis. The device has open eyes at data rates of 25 and 40 Gb/s with reduced frequency chirp.

We discuss experimentally and numerically the dynamical behavior of a novel integrated semiconductor laser subject to multiple optical feedback loops. The laser's structure consists of distributed feedback section coupled to a waveguide, an air gap section and two phase sections. It is found that the laser, due to the multiple feedback loops and under certain operating conditions, displays chaotic behaviors appropriate for chaos-based communications. The synchronization properties of two unidirectionally coupled (master-slave) systems are also studied. Finally, we find numerically the conditions for message encryption/extraction using the multiple-feedback lasers.

We propose a novel architecture for implementing a dual-frequency lidar (DFL) exploiting differential Doppler shift measurement. The two frequency tones, needed for target velocity measurements, are selected from the spectrum of a mode-locked laser operating in the C-band. The tones’ separation is easily controlled by using a programmable wavelength selective switch, thus allowing for a dynamic trade-off among robustness to atmospheric turbulence and sensitivity. Speed measurements for different tone separations equal to 10, 40, 80, and 160 GHz are demonstrated, proving the system’s capability of working in different configurations. Thanks to the acquisition system based on an analog-to-digital converter and digital-signal processing, real-time velocity measurements are demonstrated. The MLL-based proposed architecture enables the integration of the DFL with a photonic-based radar that exploits the same laser for generating and receiving radio-frequency signal with high performance, thus allowing for simultaneous or complementary target observations by exploiting the advantages of both radar and lidar.

A multiflow transponder in flex-grid optical networks has recently been proposed as a transponder solution to generate multiple optical flows (or subcarriers). Multiflow transponders support high-rate super-channels (i.e., connection composed of multiple corouted subcarriers contiguous in the spectrum) and sliceability; i.e., flows can be flexibly associated to the incoming traffic requests, and, besides composing a super-channel, they can be directed toward different destinations. Transponders supporting sliceability are also called sliceable transponders or sliceable bandwidth variable transponders (SBVTs). Typically, in the literature, SBVTs have been considered composed of multiple laser sources (i.e., one for each subcarrier). In this paper, we propose and evaluate a novel multirate, multimodulation, and code-rate adaptive SBVT architecture. Subcarriers are obtained either through multiple laser sources (i.e., a laser for each subcarrier) or by exploiting a more innovative and cost-effective solution based on a multiwavelength source and micro-ring resonators (MRRs). A multiwavelength source is able to create several optical subcarriers from a single laser source. Then, cascaded MRRs are used to select subcarriers and direct them to the proper modulator. MRRs are designed and analyzed through simulations in this paper. An advanced transmission technique such as time frequency packing is also included. A specific implementation of a SBVT enabling an information rate of 400 Gb/s is presented considering standard 100 GbE interfaces. A node architecture supporting SBVT is also considered. A simulation analysis is carried out in a flex-grid network. The proposed SBVT architecture with a multiwavelength source permits us to reduce the number of required lasers in the network.

We report electronic generation of optical Nyquist pulses using an arbitrary waveform generator (AWG) followed by a Mach Zehnder modulator (MZM), providing a simple, highly stable and flexible technique to perform photonic sampling. Here, we demonstrate the generation of 10 GHz periodic optical Nyquist pulses by synthesizing both all-positive and alternate positive-negative electrical pulse trains using a 25 GHz bandwidth AWG. Biasing the MZM at null ensures the meeting of the Nyquist ISI-free criterion in the optical domain and allows for pulse compression. Moreover, we report the first photonic sampling and demodulation of 1 Gbaud 16- and 32-QAM signals up to 22.5 GHz using 10 GHz optical Nyquist sampling pulse trains.