A lidar comprising: a laser having a first frequency-modulated laser radiation and a second frequency-modulated laser radiation; a first waveguide coupled to the laser, wherein the first frequency-modulated laser radiation and the second frequency-modulated laser radiation are transmitted by the laser into the first waveguide; a second waveguide (32; 56); a filter (18; 50, 52, 54) coupled between the first waveguide and the second waveguide (32; 56), wherein the filter (18; 50, 52, 54) is configured to couple and pass the first frequency-modulated laser radiation through the filter (18; 50, 52, 54) to the second waveguide (32; 56), and is configured to not couple or pass the second frequency-modulated laser radiation through the filter (18; 50, 52, 54) to the second waveguide (32; 56); wherein the second frequency-modulated radiation continues on the first waveguide and is used to illuminate an object; and a photodetector coupled to the second waveguide; wherein: the first frequency-modulated laser radiation comprises a linearly chirped ramp modulation v 1m; and the second frequency-modulated laser radiation comprises a linearly chirped ramp modulation v 2m; and wherein the second waveguide (32; 56)is arranged to receive a waveform that comprises a scattered radiation of v 2m from said object, shifted by a Doppler shift f D caused by a velocity of the object, so that the received waveform is v 2m + f IF ± f D; wherein the photodetector is arranged to mix the linearly chirped ramp modulation v 1m with the received waveform v 2m + f IF ± f D to produce a beat frequency Δv + f IF ± f D, where Δv = v 1m - v 2m; and wherein f IF = BΔt T where Δ t = 2 L / c, L is a distance to the object, c is a speed of the light, B is a bandwidth or range of frequency modulation, and T is a period of frequency sweeping. a laser having a first frequency-modulated laser radiation and a second frequency-modulated laser radiation; a first waveguide coupled to the laser, wherein the first frequency-modulated laser radiation and the second frequency-modulated laser radiation are transmitted by the laser into the first waveguide; a second waveguide (32; 56); a filter (18; 50, 52, 54) coupled between the first waveguide and the second waveguide (32; 56), wherein the filter (18; 50, 52, 54) is configured to couple and pass the first frequency-modulated laser radiation through the filter (18; 50, 52, 54) to the second waveguide (32; 56), and is configured to not couple or pass the second frequency-modulated laser radiation through the filter (18; 50, 52, 54) to the second waveguide (32; 56); wherein the second frequency-modulated radiation continues on the first waveguide and is used to illuminate an object; and the first frequency-modulated laser radiation comprises a linearly chirped ramp modulation v 1m; and the second frequency-modulated laser radiation comprises a linearly chirped ramp modulation v 2m; and wherein the second waveguide (32; 56)is arranged to receive a waveform that comprises a scattered radiation of v 2m from said object, shifted by a Doppler shift f D caused by a velocity of the object, so that the received waveform is v 2m + f IF ± f D; wherein the photodetector is arranged to mix the linearly chirped ramp modulation v 1m with the received waveform v 2m + f IF ± f D to produce a beat frequency Δv + f IF ± f D, where Δv = v 1m - v 2m; and wherein f IF = BΔt T where Δ t = 2 L / c, L is a distance to the object, c is a speed of the light, B is a bandwidth or range of frequency modulation, and T is a period of frequency sweeping. L is a distance to the object, c is a speed of the light, B is a bandwidth or range of frequency modulation, and T is a period of frequency sweeping.