Fig. 1

a Illustration of the simulation setup for the serrodyne OFS and b the sawtooth phase modulation with period \({\mathrm{T}}_{0}={1/\mathrm{f}}_{0}\). c Output optical spectrum for modulation frequency \({\mathrm{f}}_{0}\) = 0.1 MHz. The blue spectrum corresponds to an ideal sawtooth with infinitely small falling time. The yellow lines appear in the case of sawtooth with finite falling time (0.05 \({\mathrm{T}}_{0}\)). d The electrical spectrum after the coherent detection. The sidebands in the electrical spectrum are created from the down-converted side-modes present in the optical spectrum around the frequency shifted carrier at \({\mathrm{f}}_{\mathrm{opt}}+{\mathrm{f}}_{0}\) s