Abstract: A low-loss comb-generating optical cavity including an optical amplifier and a microwave-driven electro-optic modulator crystal, produces a comb of optical frequency sidebands having spectral lines equally spaced around the frequency of an input laser beam incident on the comb-generating cavity. The comb-generating cavity includes an input mirror movable along the beam propagation direction, and a fixed position output mirror located at time synchronous distances of both the input laser wavelength and modulation wavelength. The comb-generating cavity and its microwave driven modulator are in resonance with the input laser beam, and provide iterative or recirculating beam action that transfers the input optical frequency of the laser, sideband by sideband, to remote and precisely known comb frequencies offset from, and centered on, the input laser frequency.