title: Suppressing Rayleigh backscatter and code noise from all-fiber digital interferometers.
abstract: We configure an all-fiber digital interferometer to eliminate both code noise and Rayleigh backscatter noise from bidirectional measurements. We utilize a sawtooth phase ramp to upconvert code noise beyond our signal bandwidth, demonstrating an in-band noise reduction of approximately two orders of magnitude. In addition, we demonstrate, for the first time to our knowledge, the use of relative code delays within a digital-interferometer system to eliminate Rayleigh-backscatter noise, resulting in a noise reduction of a factor of 50. Finally, we identify double Rayleigh-backscatter noise as our limiting noise source and suggest two methods to minimize this noise source.
authors.forename: Silvie
authors.initials: S
authors.lastname: Ngo
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Shaddock
authors.forename: Terry G
authors.initials: TG
authors.lastname: McRae
authors.forename: Timothy T-Y
authors.initials: TT
authors.lastname: Lam
authors.forename: Jong H
authors.initials: JH
authors.lastname: Chow
authors.forename: Malcolm B
authors.initials: MB
authors.lastname: Gray