摘要
A new approach to measure the second order correlation function g (2) and the coherence time was investigated. The g (2) was calculated from the photon pair time interval distribution by direct numerical self-convolution with the high order correction. The accuracy of this method was examined using an optical fiber based Hanbury-Brown-Twiss interferometer with a pseudo-thermal light source. We found that the significance of the high order correction is related to the factor I¯τ c , which is the overlapping of the photon wave packets. A novel technique was also demonstrated to measure the coherence time τ c of a light source using the random phase modulation. This method is more suitable for a weak light source with a long coherence time using a simple experimental setup.