| CPC H04B 10/2537 (2013.01) [H01S 3/302 (2013.01); H04B 10/2916 (2013.01); H04B 10/07 (2013.01); H04B 10/61 (2013.01)] | 12 Claims |

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1. An arrangement for measuring guided acoustic Brillouin scattering (GAWBS) noise comprising:
a first laser configured to emit first laser light and a second laser configured to emit second laser light;
a first length of optical fiber that optically connects the first laser light to a first port of a coherent receiver;
a second length of optical fiber that optically connects the second laser light to a second port of the coherent receiver; and
a third length of optical fiber that optically connects the first length of optical fiber to the second length optical fiber such that a portion of the first laser light is redirected to the second length of optical fiber wherein it is mixed with the second laser light resulting in mixed laser light;
a fiber under test (FUT) that receives the mixed laser light from a section of the second length of optical fiber such that it is directed to the second port of the coherent receiver via another portion of the second optical fiber; and
the coherent receiver that generates 4 beating signals from light signals received at the first and second ports;
wherein the arrangement is configured to suppress a large carrier using band-pass filters and further configured such that the second laser light emitted from the second laser is outside of a GUIDED ACOUSTIC BRILLOUIN SCATTERING (GAWBS) window and both polarization components of GAWBS are simultaneously measured.
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