US 12,034,482 B2
Accurate measurement for guided acoustic-wave Brillouin scattering
Fatih Yaman, Princeton, NJ (US); Eduardo Mateo Rodriguez, Tokyo (JP); Shinsuke Fujisawa, Princeton, NJ (US); Hussam Batshon, Monroe, NJ (US); Kohei Nakamura, Tokyo (JP); Takanori Inoue, Tokyo (JP); Yoshihisa Inada, Tokyo (JP); and Takaaki Ogata, Tokyo (JP)
Assigned to NEC Corporation, Tokyo (JP)
Filed by NEC Laboratories America, Inc., Princeton, NJ (US)
Filed on Jun. 1, 2021, as Appl. No. 17/336,280.
Claims priority of provisional application 63/141,068, filed on Jan. 25, 2021.
Claims priority of provisional application 62/704,927, filed on Jun. 3, 2020.
Prior Publication US 2022/0278748 A1, Sep. 1, 2022
Int. Cl. H04B 10/2537 (2013.01); G01H 9/00 (2006.01); H01S 3/067 (2006.01); H01S 3/10 (2006.01); H01S 3/16 (2006.01); H01S 3/30 (2006.01); H04B 10/073 (2013.01); H04B 10/61 (2013.01)
CPC H04B 10/2537 (2013.01) [G01H 9/004 (2013.01); H01S 3/06716 (2013.01); H01S 3/10061 (2013.01); H01S 3/1608 (2013.01); H01S 3/302 (2013.01); H04B 10/073 (2013.01); H04B 10/615 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An arrangement providing for the accurate measurement for guided acoustic-wave Brillouin scattering (GAWBS), said arrangement comprising:
a coherent optical receiver having a local oscillator input port and a signal port;
a length of polarization maintaining (PM) optical fiber in optical communication with the coherent receiver LO port;
a length of an optical fiber under test (FUT) in optical communication with the coherent receiver signal port;
a continuous-wave (CW) laser in optical communication with the PM optical fiber and the FUT; and
a calibrating laser (Laser-cal) in optical communication with the FUT;
said arrangement configured such that light is output from the Laser-cal and light is output from the CW laser;
the light output from the CW laser is split into two beams, one beam directed into the PM optical fiber and the other beam directed into the FUT;
the light output from the Laser-cal is combined with the CW laser beam directed into the FUT;
the coherent receiver receives light from the CW laser at its LO port and the combined Laser-cal output light and CW light at its signal port;
the light received at the LO port and combined light received at the signal port is detected by a plurality of photodetectors and photodetector output signals resulting therefrom are subsequently filtered by respective bandpass filters;
the filtered output signals are digitized through the effect of an analog to digital converter (ADC); and
GAWBS measurements are determined from digitized output signals of the ADC; wherein the coherent receiver includes a hybrid which receives the LO port light and the signal port light;
wherein the hybrid is configured to receive the LO port light and the signal port light and generate four separate outputs each of which overlaps the signal and the LO in two orthogonal polarizations (X, Y) and for each polarization overlaps them in two quadratures, in-phase and 90-degrees out-of-phase (I, Q).