US 12,392,810 B2
Device for wide-band spectral analysis of a signal of interest
Hugues Guillet De Chatellus, Saint Martin d'Heres (FR)
Assigned to CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and UNIVERSITE GRENOBLE ALPES, Saint Martin d'Heres (FR)
Appl. No. 18/039,205
Filed by CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and UNIVERSITE GRENOBLE ALPES, Saint Martin d'Heres (FR)
PCT Filed Dec. 3, 2021, PCT No. PCT/EP2021/084245
§ 371(c)(1), (2) Date May 26, 2023,
PCT Pub. No. WO2022/122594, PCT Pub. Date Jun. 16, 2022.
Claims priority of application No. 2012783 (FR), filed on Dec. 7, 2020.
Prior Publication US 2023/0417810 A1, Dec. 28, 2023
Int. Cl. H04B 10/64 (2013.01); G01J 3/12 (2006.01); G01R 23/165 (2006.01)
CPC G01R 23/165 (2013.01) [G01J 3/1256 (2013.01); H04B 10/64 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A wideband device (D) for the spectral analysis of a signal of interest comprising:
a source(S) designed to generate said signal of interest (Si);
an optical splitter element (ES) designed to spatially split said signal of interest into a first signal (V1) and a second signal (V2);
a first frequency-shifting optical cavity (DBDF, BDF1) comprising a first frequency shifter (AOM1) designed to shift the optical frequency of the first signal by a first frequency f1 per round trip in said first cavity, said first cavity having a first trip time τ1;
a second frequency-shifting optical cavity (DBDF, BDF2) comprising a second frequency shifter (AOM2) designed to shift the optical frequency of the second signal by a second frequency f2 per round trip in said second cavity, said second cavity having a second trip time τ2;
the first and the second optical cavity being designed such that a maximum number of round trips of said signal in the first and the second cavity is equal to predetermined N;
a detector (PD) designed to coherently detect the first signal (W1) transmitted by the first cavity and the second signal (W2) transmitted by the second cavity and generate a photocurrent (Tr) proportional to a luminous intensity detected by said detector, a low-pass filter (LP) designed to filter frequencies of the photocurrent that are lower than min (f1/2, f2/2),
a processor (UT) configured to compute a square modulus of the photocurrent filtered by said low-pass filter, from which a temporal representation of frequency information of said signal of interest is determined, said frequency information being:
a real part of a fractional Fourier transform of said signal of interest, an order of said fractional Fourier transform being set by the value f1×τ1−f2×τ2 when the first cavity and the second cavity are configured to verify the condition f1×τ1+f2×τ2, modulo 1 or
a power spectrum of said signal of interest when the first cavity and the second cavity are configured to verify the condition f1×τ1=f2×τ2 modulo 1.