Ultra low phase noise in multigigahertz oscillations of injection tracked DFB lasers

Injection of cw-light from a single-mode laser into the cavity of a second one with a frequency detuning outside the locking range leads to output power oscillations of the injected laser. The oscillation frequency and the extinction ratio can be controlled by the amount of injected power and the frequency detuning between the two noninteracting lasers. Thus a continuous tunability of the oscillation frequency is possible far frequencies ranging from < 10 GHz to > 100 GHz. A further advantage of such injection tracked oscillations is the low phase noise. Additionally the oscillations can be synchronized with external frequencies or a system clock by sideband injection locking.