30 Gbit/s PAM4 transmission using an 8-GHz directly modulated multi-section laser.

This paper describes the characterization of a novel directly modulated multi-section laser with a master-slave configuration. Amplitude and phase noise measurements show relative intensity noise values of around -150 dB/Hz and a 3-dB linewidth of around 3 MHz. The laser's suitability for optical access networks, enabled by the chirp reduction from the external injection locking, is shown by demonstrating unamplified 30 Gbit/s C-band transmission over 25 km and 50 km of single mode fiber using PAM4, as well as 30 Gbit/s PAM4 and PAM8 amplified transmission over 75 km.

Nonlinear effects induced in the normalized ion density in a linear trap system for a large ion cloud.

In this work, we design, by means of a non-neutral plasma method, a linear trapping model for large ion clouds, which will become the core of an atomic clock. We first obtain the geometry and electromagnetic characteristics of the ion trap. We then perform a systematic analysis describing the main parameters of the ion cloud such as size, secular frequency, and ion number per unit length of temperature. The most appropriate operation point of the ion trap in a set of these specific parameters is evaluated, and a thorough discussion is performed about how minor perturbations introduced in these parameters affect, in a nonlinear response, the performance of the trapping system in sensibility, heating, and radiofrequency potential.

Modeling of racetrack-resonator add-drop filters with arbitrary nonlinear directional couplers.

In this Letter we employ the general coupled-mode equations of the nonlinear directional coupler and demonstrate that the switching characteristics of prototypical nonlinear racetrack-resonator structures may differ considerably from those obtained when the standard, generally incorrect, coupled-mode equations are used.