Evidence of ultra low microwave additive phase noise for an optical RF link based on a class--a semiconductor laser.
The additive RF phase noise of a microwave photonics link is measured using, as the optical source, a semiconductor laser operating in the class-A regime. The relative intensity noise of this laser being below the shot noise relative level, the phase noise floor of the link is shown to be shot noise limited, -152 dBc/Hz in our experimental conditions. As a result, the phase noise floor evolves as the inverse of the detected photocurrent, pushing the limits of performance to the availability of high power photo-detectors. Below 6 kHz from the carrier frequency at 3GHz, some noise, in excess with respect to the shot noise limit, is observed but remains lower than -110 dBc/Hz at 100 Hz offset frequency. This residual noise originates mainly from environmental noise and can be reduced by isolating the laser from acoustic/electromagnetic perturbations.
Baili
Ghaya
G
Thales Research & Technology France, RD 128, 91767 Palaiseau Cedex, France.
Alouini
Mehdi
M
Malherbe
Thierry
T
Dolfi
Daniel
D
Huignard
Jean-Pierre
JP
Merlet
Thomas
T
Chazelas
Jean
J
Sagnes
Isabelle
I
Bretenaker
Fabien
F