We have studied operator algebraic approach to super conformal field theory with S. Carpi and R. Longo. It is known that the super Virasoro algebras have discrete series of representations for central charges less than 3/2. We have realized the super Virasoro nets of operator algebras for these cases as coset nets and obtained a classification result by studying their extensions. Together with general theory we have established, we also use the classification technique of modular invariants given by Gannon and Walton.