Slow and fast light is becoming a wide research field driven by an extensive effort to implement this new technology in real applications. Coherent population oscillations in semiconductor optical amplifiers constitute one of the most promising approaches, in particular for the processing of optically carried microwave signals, which includes the control of tunable true time delays and RF phase shifts.We studied theoretically and experimentally the available tunable delays and phase shifts and the associated bandwidths for a microwave photonics link including a semiconductor optical amplifier. We analyzed the influence of the coherent population oscillations on the dynamic range of the link.The understanding of the underlying physical mechanisms led us to propose new architectures in order to overcome the identified limitations of the components. We show how up-converted coherent population oscillations enable to get rid of the intrinsic limitation of the carrier lifetime (500 MHz), leading to the generation of true time delays at any high frequencies in a single semiconductor device. We demonstrated tunable delays up to 389 ps at 16 GHz, with an instantaneous bandwidth of 360 MHz.Lastly we demonstrate how to conceive a RF phase shifter up to 180 degrees at high frequency by forced coherent population oscillations. This effect replaces the enhancement of the coherent population oscillations by gain-index coupling effect, revealed by an optical filter. We used this principle, which enables to achieve a tunable phase shift up to 162 degrees at 2,2 GHz, in order to conceive an optoelectronic oscillator at 2,2 GHz. The frequency of this oscillator is fast tunable over 6 MHz by changing the current of the semiconductor amplifier.
