J. Phys. Colloques
Volume 42, Numéro C8, Décembre 1981Troisième Symposium sur les Etalons de Fréquence et la Métrologie / Third Symposium on Frequency Standards and Metrology
|Page(s)||C8-463 - C8-472|
J. Phys. Colloques 42 (1981) C8-463-C8-472
PHASE-COHERENT FREQUENCY SYNTHESIS SUITABLE FOR DIRECT FREQUENCY MEASUREMENTS UP TO 30 THzE. Bava, A. Godone et A. De Marchi
Istituto Elettrotecnico Nazionale "Galileo Ferraris", Torino, Italy
Great advances have been made in the recent years in the field of phase-coherent frequency synthesis into the infrared region of the electromagnetic spectrum. Most important are the improvements achieved in the phase noise of the reference oscillators, in the modulation and control capabilities of important intermediate oscillators such as optically pumped FIR lasers, and in general in the understanding of the problems to be dealt with, both of noise level and of multiplication efficiency. In this paper a short review is given of the progress occurred in the field in the last years, and a projection is attempted for the ultimate possibilities of the techniques presented. The importance of reaching the 30 THz region with a coherent signal is discussed in view of a coherent frequency scale from VHP to the infrared.