Physics Journal of the Indonesian Physical Society
FREQUENCY_DIFFERENCE MEASUREMENT OF 22 THZ SEPARATED LASERS USING SECOND HARMONIC OF OPTICAL FREQUENCY COMB
Bambang Widiyatmoko and Rietje Yunaningsih
Research Center for Physics, Indonesian Institute of Sciences, Kompleks Puspiptek Serpong, Tangerang 15314
Frequency difference between 0.78 micrometer and 0.826 micrometer diode lasers has been measured using second harmonics of optical frequency comb (SH-OFC) pumped by wide span fundamental comb at 1.55 micrometer. A periodically poled lithium niobate with period of 19 micrometer and 21.4 micrometer was exploited for second harmonic generation. The span of SH-OFC for different PPLN length is also examined by beat signal measurement. It shown that the span is increased by shorter PPLN but the beat signal to noise ratio (S/N) is decreased. The difference frequency between two laser was calculated from measured beat frequency was 22.057 THz. The signal to noise ratio of the beat signal was 32dB. We estimate that the 50THz frequency-difference can be measure using this method.