A device, comprising: a ring laser comprising an optical ring which forms a positive optical feedback loop that comprises at least one optical gain medium operable to sustain optical oscillations and to produce laser light; an optical modulator coupled in the optical ring and operable to modulate the laser light in response to a control signal to produce a modulated laser beam; an opto-electronic feedback loop comprising an optical portion operable to receive a portion of light from the optical ring, a photodetector operable to convert the received portion of light into a detector signal, an RF filter to filter the detector signal to produce a filtered detector signal, and an electrical portion operable to produce the control signal from the filtered detector signal, wherein the opto-electronic feedback loop is structured to form a positive feedback loop having a total loop gain greater than a total loop loss and sustaining an oscillation at a frequency equal to the modulation frequency of the optical modulator in modulating the laser light in the optical ring and the opto-electronic feedback loop and the optical ring are correlated in gain and in phase with each other, wherein the laser light is a pulsed output; an optical splitter to split the received portion of the light from the optical ring into a first beam and a second beam; a first optical delay path to receive the first beam; a second optical delay path to receive the second beam, wherein the first and second optical paths have different optical delays, wherein the photodetector is coupled to receive the first and second beams, at orthogonal polarizations, from the first and second optical delay paths to produce the detector signal; and a dispersion compensation element (119; 310) coupled in the optical ring, the dispersion compensation element operable to compensate for optical dispersion in the optical ring, the optical ring having an optical path to achieve an optical mode spacing in the optical ring such that the spurious mode in the detector signal caused by an optical mode that does not coincide with an oscillation mode of the opto-electronic feedback loop is outside the bandwidth of the RF filter and so is not included in the filtered detector signal, while maintaining a desired low phase noise level and a high cavity quality factor for each of the optical ring and the opto-electronic feedback loop. a ring laser comprising an optical ring which forms a positive optical feedback loop that comprises at least one optical gain medium operable to sustain optical oscillations and to produce laser light; an optical modulator coupled in the optical ring and operable to modulate the laser light in response to a control signal to produce a modulated laser beam; an opto-electronic feedback loop comprising an optical portion operable to receive a portion of light from the optical ring, a photodetector operable to convert the received portion of light into a detector signal, an RF filter to filter the detector signal to produce a filtered detector signal, and an electrical portion operable to produce the control signal from the filtered detector signal, wherein the opto-electronic feedback loop is structured to form a positive feedback loop having a total loop gain greater than a total loop loss and sustaining an oscillation at a frequency equal to the modulation frequency of the optical modulator in modulating the laser light in the optical ring and the opto-electronic feedback loop and the optical ring are correlated in gain and in phase with each other, wherein the laser light is a pulsed output; an optical splitter to split the received portion of the light from the optical ring into a first beam and a second beam; a first optical delay path to receive the first beam; a second optical delay path to receive the second beam, wherein the first and second optical paths have different optical delays, wherein the photodetector is coupled to receive the first and second beams, at orthogonal polarizations, from the first and second optical delay paths to produce the detector signal; and a dispersion compensation element (119; 310) coupled in the optical ring, the dispersion compensation element operable to compensate for optical dispersion in the optical ring, the optical ring having an optical path to achieve an optical mode spacing in the optical ring such that the spurious mode in the detector signal caused by an optical mode that does not coincide with an oscillation mode of the opto-electronic feedback loop is outside the bandwidth of the RF filter and so is not included in the filtered detector signal, while maintaining a desired low phase noise level and a high cavity quality factor for each of the optical ring and the opto-electronic feedback loop.