The new structure under consideration is similar to a double velocity avalanche transit time (DOVATT) diode. DOVATT is basically a heterojunction IMPATT diode which consists of one avalanche zone followed by two drift zones having different scattering limited velocities. Recent studies have shown that the structure can be used efficiently as a detector in optical communication systems. The new detector has been given the name photo-DOVATT. The present paper examines the noise behaviour of the device. A quantitative study of the noise generated caused by randomness of multiplication process in the avalanche zone of an InP/InGaAsP photo-DOVATT has been carried out. It is observed that the device shows less noise voltage and higher signal to noise ratio (SNR) compared with other existing avalanche photodiodes.