Optical injection locking and switching of transistor oscillators

Abstract

In this letter we describe a novel approach of achieving injection locking of solid-state oscillators. This is done by taking an external driving signal to modulate a GaAlAs cw injection laser and then guiding the modulated light output in a fiber waveguide to illuminate the active solid-state component in the oscillator circuit. Experiments were carried out with silicon transistor oscillators with frequency ranging from below 1 kHz up to 1.8 GHz. Optical injection locking was observed not only at fundamental frequencies, but also at various subharmonics with less tolerance in frequency deviation. It is also possible to achieve switching and locking simultaneously in these oscillators.