Aldo Righetti

Impact of Rayleigh backscattering on Stimulated Brillouin Scattering threshold evaluation for 10 Gb/s NRZ-OOK signals

We experimentally verified a decrease of stimulated Brillouin scattering threshold for 10 Gb/s NRZ-OOK signals with respect to theoretical predictions. We relate this reduction to Rayleigh backscattering interaction with Stokes backscattered spectrum. BER curves are shown.

100-Gb/s polarization multiplexed DQPSK transmission with automatic polarization stabilization

Increasing Ethernet data traffic has decreed the need for 100 Gb/s Ethernet (100GE) transport solutions. The scientific community widely recognizes that differential quadrature phase-shift-keying (DQPSK) format together with polarization multiplexing (POLMUX) is the best candidate to achieve 100-Gb/s bit rate [1]. DQPSK alone halves the symbol rate, increasing the chromatic dispersion (CD) and polarization mode dispersion (PMD) tolerance; POLMUX allows to further halve the symbol rate. Thus, by using 25-Gbaud POLMUX DQPSK, 100-Gb/s capacity is achieved with high CD and PMD tolerance.

Narrow Linewidth and Compact External-Cavity Lasers for Coherent Optical Communications

In this chapter, the activities related to external-cavity laser development executed in CPqD will be presented in detail. The target application is high-speed and high-order modulation formats optical systems for telecom. Using cavity design techniques, a narrow linewidth and high output power laser suitable for manufacturing is presented. It is presented the operation principle of the tunable mirror which is used as channel selector for the external cavity. Experimental results of a fixed-wavelength prototype are presented, showing optical output power above 16 dBm, Side-mode Suppression Ratio (SMSR) of 60 dB, and linewidth around 75 kHz. The cavity shows good stability for long-term high-temperature storage.