A method may comprise: generating an optical frequency comb; applying a filter in a first configuration to the generated optical frequency comb to select a first frequency of the optical frequency comb, wherein, in the first configuration, the first frequency aligns with a first pass-band of the filter, and a second frequency of the optical frequency comb does not align with a second pass-band of the filter; altering the filter to a second configuration to shift the first pass-band and the second pass-band to a shifted first pass-band and a shifted second pass-band; and applying the altered filter to the generated optical frequency comb to select the second frequency of the optical frequency comb, wherein the second frequency aligns with the shifted second pass-band of the filter, and the first frequency of the optical frequency comb does not align with the shifted first pass-band of the filter.