A method for temperature or strain determination, the method comprising: maintaining a predetermined offset frequency shift between a first laser beam and a 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; modulating the first laser beam, wherein the modulated first laser beam is to be injected into a device under test; acquiring a backscattered signal from the DUT, wherein the backscattered signal results from the modulated first laser beam injected into the DUT, and wherein the second laser beam is to be used as a local oscillator; determining, based on the acquired backscattered signal from the DUT, a Brillouin trace for the DUT based on a coherent detection at a relatively low frequency, wherein predetermined offset frequency shift for determination of the Brillouin trace is selected from a range of approximately 10.0 GHz to approximately 13.0 GHz; determining, based on the Brillouin trace, a Brillouin frequency shift and a Brillouin power for the DUT to implement an absolute referencing of a Rayleigh reference trace, wherein the Brillouin frequency shift is determined by fitting distributed Brillouin spectra, the Brillouin power is determined based on application of an integration operation to the distributed Brillouin spectra, and the absolute referencing of the Rayleigh reference trace is implemented based on the Brillouin frequency shift and a ratio of the Brillouin power and the Rayleigh power, and a Rayleigh trace is acquired by setting the first laser beam and the second laser beam to an offset frequency shift within a range of approximately 100.0 KHz to approximately 1.0 GHz; determining, in a subsequent acquisition, relative to the Rayleigh reference trace, a further Brillouin frequency shift and a Rayleigh frequency shift; and determining, by combining the further Brillouin frequency shift and the Rayleigh frequency shift, a temperature or a strain associated with the DUT. maintaining a predetermined offset frequency shift between a first laser beam and a 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; modulating the first laser beam, wherein the modulated first laser beam is to be injected into a device under test; acquiring a backscattered signal from the DUT, wherein the backscattered signal results from the modulated first laser beam injected into the DUT, and wherein the second laser beam is to be used as a local oscillator; determining, based on the acquired backscattered signal from the DUT, a Brillouin trace for the DUT based on a coherent detection at a relatively low frequency, wherein predetermined offset frequency shift for determination of the Brillouin trace is selected from a range of approximately 10.0 GHz to approximately 13.0 GHz; determining, based on the Brillouin trace, a Brillouin frequency shift and a Brillouin power for the DUT to implement an absolute referencing of a Rayleigh reference trace, wherein the Brillouin frequency shift is determined by fitting distributed Brillouin spectra, the Brillouin power is determined based on application of an integration operation to the distributed Brillouin spectra, and the absolute referencing of the Rayleigh reference trace is implemented based on the Brillouin frequency shift and a ratio of the Brillouin power and the Rayleigh power, and a Rayleigh trace is acquired by setting the first laser beam and the second laser beam to an offset frequency shift within a range of approximately 100.0 KHz to approximately 1.0 GHz; determining, in a subsequent acquisition, relative to the Rayleigh reference trace, a further Brillouin frequency shift and a Rayleigh frequency shift; and determining, by combining the further Brillouin frequency shift and the Rayleigh frequency shift, a temperature or a strain associated with the DUT.