methods and apparatus for generating a frequency comb and for its use in analyzing materials and in telecommunications . the frequency comb is generated by passing pulsed light from a laser through an optical fiber having a constriction . the frequency comb comprises a plurality of monochromatic components separated in frequency by a substantially constant frequency increment . the monochromatic components are used to probe materials for analysis . in preferred embodiments , the materials are dna , rna , pna and other biologically important molecules and polymers . optical responses are observed and used to analyze or identify samples . in telecommunication applications , the individual monochromatic components serve as carriers for individual communication channels that can carry information of any of a variety of types , such as voice , data and images .