Homogeneous glass samples with different compositions 42 (P2O5)center dot 40 (ZnO)center dot(16-x)(K2O)center dot 2 (Bi2O3)center dot x(Cu2O) (where x = 1, 2 and 3 mol%) were prepared by conventional melt-quenched technique under controlled conditions. The structure of the prepared glass samples was investigated by X-ray diffraction. Optical properties (transmittance and reflectance) of the glasses were measured in the wavelength range 200-900 nm. The optical band gap energy of the investigated glasses with 1, 2 and 3 mol% Cu2O was estimated from absorption data using the Mott and Davis relation and found to be 2.33, 2.45 and 2.53 eV, respectively. The mechanism of optical absorption was found to be direct. The band tail width was also estimated and found to lay in the acceptable range. Refractive index, absorption coefficient, extinction coefficient and real/imaginary parts of dielectric constants were calculated. Further to this, some theoretical investigation of the spectral problems was carried out. The investigation was based on finite difference method.