Computationally efficient dynamical analysis of optically driven injection-locked GaAs FET oscillators

A computer-aided simulation technique for the dynamical analysis of a class of GaAs FET optically-driven injection-locked oscillators (ODILO´s) is presented. By combining a measurement-derived nonlinear model of the illuminated transistor with a phasor-domain analysis method, a first-approximation - but phenomenologically complete - differential model of the synchronized oscillator is derived. Since amplitude and phase of waveform evolutions are directly addressed and evaluated in a stroboscopic-time scale, the calculation of the transient response to modulated input signals can be done in a more user-friendly and computationally efficient manner than possible through conventional time-domain approaches. Furthermore, as shown by the simulation and experimental results presented, the calculation of locking bandwidth and other figures of merit of the ODILO is also fast and accurate, thus suggesting the use of the proposed approach in the development of dedicated CAD-tools for the design and optimization of high-speed data-links employing this new opto-electronic components.