A single photon is an indivisible quantum of energy. Most quantum information processing protocols require a single photon source. A robust method to generate single photons is spontaneous parametric down conversion (SPDC). This is a second order optical effect, where a photon (pump) incident on a nonlinear crystal is converted into two photons (signal and idler), obeying the energy and momentum conservation laws. Down conversion refers to the fact that the signal and idler will have a frequency lower than the pump photon. Since the detection of one photon heralds the presence of another, these are called heralded single photons. Attaching an orbital angular momentum (OAM) to these photons provides an infinite number of orthogonal states, which could be used to encode more information. These photons generated by SPDC, having an OAM value are called twisted heralded single photons. This lab is involved with using OAM degree of freedom along with polarisation and other degrees of freedom such as time bin and path for implementing various information processing protocols covering quantum communication, quantum sensing and quantum computation.