| 摘要 |
PURPOSE:To obtain the direction of the time axis of the waveform of a light pulse to be measured, by measuring the autocorrelation waveforms of the light pulse to be measured with respec to both of a state wherein a medium whose wavelength dispersion characteristic is known is inserted in a light path and a state wherein said medium is not inserted. CONSTITUTION:The Fourier transform fE(omega) of the complex amplitude E(t) of the electric field of a light pulse L to be measured is measured according to the known method using a waveform memory device 17 ad a computer 18. The Fourier transform fE'(omega) of the electric field E'(t) of a light pulse when a medium 31 whose wavelength dispersion characteristic T(omega) is inserted in the light path of the light pulse L to be measured is also measured in the same way. By utilizing that there is the relation of phi'(omega)=phi(omega)+theta(omega) between phases phi(omega), phi'(omega) and theta(omega) of fE, fE', and T, the codes (positive or negative) of phi, phi' indifinite in a conventional measuring method, that is, the time axial directions of E, E' are determined. When the instantaneous frequency change (charp) of the light pulse is linear, the time axis directions of E, E' can be also determined from the change in the time width of the light pulse caused by the presence of the medium. |
