A Brillouin and Rayleigh distributed sensor comprising: a first laser source to emit a first laser beam; a second laser source to emit a second laser beam; a photodiode to acquire a beat frequency between the first laser beam and the second laser beam, wherein the beat frequency is used to maintain a predetermined offset frequency shift between the first laser beam and the second laser beam, wherein the predetermined offset frequency shift is relative to a predetermined frequency of either the first laser beam or the second laser beam; a modulator to modulate the first laser beam, wherein the modulated first laser beam is to be injected into a device under test, i.e. DUT; a coherent receiver to acquire a backscattered signal from the DUT, wherein the backscattered signal results from the modulated first laser beam injected into the DUT, and wherein the coherent receiver is to use the second laser beam as a local oscillator to determine Brillouin and Rayleigh traces with respect to the DUT based on the predetermined offset frequency shift between the first laser beam and the second laser beam by further using a polarization beam splitter of the coherent receiver to receive the backscattered signal, and divide the backscattered signal into two different polarization states including a first polar state and a second polar state that are the same as first and second polar states of the second laser beam, wherein a divided portion of the backscattered signal corresponding to the first polar state is to be mixed with the second laser beam at the first polar state, and a divided portion of the backscattered signal corresponding to the second polar state is to be mixed with the second laser beam at the second polar state to determine the Brillouin and Rayleigh traces with respect to the DUT. a first laser source to emit a first laser beam; a second laser source to emit a second laser beam; a photodiode to acquire a beat frequency between the first laser beam and the second laser beam, wherein the beat frequency is used to maintain a predetermined offset frequency shift between the first laser beam and the second laser beam, wherein the predetermined offset frequency shift is relative to a predetermined frequency of either the first laser beam or the second laser beam; a modulator to modulate the first laser beam, wherein the modulated first laser beam is to be injected into a device under test, i.e. DUT; a coherent receiver to acquire a backscattered signal from the DUT, wherein the backscattered signal results from the modulated first laser beam injected into the DUT, and wherein the coherent receiver is to use the second laser beam as a local oscillator to determine Brillouin and Rayleigh traces with respect to the DUT based on the predetermined offset frequency shift between the first laser beam and the second laser beam by further using a polarization beam splitter of the coherent receiver to receive the backscattered signal, and divide the backscattered signal into two different polarization states including a first polar state and a second polar state that are the same as first and second polar states of the second laser beam, wherein a divided portion of the backscattered signal corresponding to the first polar state is to be mixed with the second laser beam at the first polar state, and a divided portion of the backscattered signal corresponding to the second polar state is to be mixed with the second laser beam at the second polar state to determine the Brillouin and Rayleigh traces with respect to the DUT. receive the backscattered signal, and divide the backscattered signal into two different polarization states including a first polar state and a second polar state that are the same as first and second polar states of the second laser beam, wherein a divided portion of the backscattered signal corresponding to the first polar state is to be mixed with the second laser beam at the first polar state, and a divided portion of the backscattered signal corresponding to the second polar state is to be mixed with the second laser beam at the second polar state to determine the Brillouin and Rayleigh traces with respect to the DUT.