A simple method using photocurrent and power transmission for measuring the absorption coefficient in electroabsorption modulators

A simple method of measuring the absorption coefficient in an electroabsorption modulator is important to both material characterization and device optimization. A variation of the photocurrent-optical-transmission method proposed by T.H. Wood (1986) for the absolute measurement of the absorption coefficient in both waveguide and planar modulators, is presented and illustrated with experimental data. The method given in this work is more accurate, does not require a guess of the absorption coefficient, and is not sensitive to the assumed form of the internal quantum efficiency. A method is also given for the measurement of the optical filling factor in waveguides.<>