Stabilized multi-frequency light source and method of generating synthetic light wavelengths

PCT No. PCT/EP95/03237 Sec. 371 Date Feb. 19, 1997 Sec. 102(e) Date Feb. 19, 1997 PCT Filed Aug. 16, 1995 PCT Pub. No. WO96/06472 PCT Pub. Date Feb. 29, 1996The invention concerns the generation of synthetic light wavelengths in which light from a first light source (D1) is coupled into a common light path section (LG1) and its average frequency value (+E,ovs nu +EE 1) is locked with a resonant frequency ( nu 1) of the Fabry-Perot resonator (R). The light from a second light source (D2) is coupled into the common light path section (LG1) and its average frequency value (+E,ovs nu +EE 2) is set in order to reach a subsequent resonant frequency ( nu 2) of the Fabry-Perot resonator (R) and be locked therewith. A beat frequency ( DELTA nu 12), which is measured by electronic counters whilst a corresponding measured frequency value (f12) is prepared, is formed between the frequencies ( nu 1, nu 2) of the light from the two light sources (D1, D2). The light from at least one further light source (Di) is coupled into the common light path section (LG1) and its average frequency value (+E,ovs nu +EE i) is first adapted to the average frequency value (+E,ovs nu +EE 1 or +E,ovs nu +EE 2) of one of the above light sources (D1, D2) and then altered until it reaches a pre-determined resonance of the Fabry-Perot resonator (R) and is locked therewith, the number (k1) of resonances passed through being counted. The beat frequency ( DELTA nu 1i or DELTA nu 2i) between the frequency ( nu 1 or nu 2) of the light from the selected light source (D1 or D2) and from the further light source (Di) is calculated as the product (k1x DELTA nu 12 or k1+1x DELTA nu 12) of the beat frequency ( DELTA nu 12) between the frequencies ( nu 1, nu 2) of the light from the first and second light sources (D1, D2) and the number (ki or k1+1) of resonances passed through.