Patent ID: 8600705

Claim:
A method for measuring efficiency of an optical device, comprising: calculating, by a light measurement unit, a power of emission light from the optical device by irradiating an excitation stimulus on the optical device; extracting, by an operation unit, a power of a reference excitation stimulus at which a variation of recombination coefficients in a quantum well of the optical device with respect to a variation of carrier concentration in the quantum well of the optical device becomes minimum; calculating, by the operation unit, an internal quantum efficiency of the optical device at the power of the reference excitation stimulus; and calculating, by the operation unit, an internal quantum efficiency of the optical device at powers of various excitation stimuli from the internal quantum efficiency of the optical device at the power of the reference excitation stimulus, wherein the excitation stimulus is excitation light, the reference excitation stimulus is reference excitation light, and the various excitation stimuli are various excitation lights, wherein the extracting of the power of the reference excitation stimulus comprises extracting a power of reference excitation light at which a second order differential value of a second parameter (y) curve with respect to a first parameter (x) curve becomes minimum, and the first parameter (x) is √{square root over (P PL )}, and the second parameter (y) is P L /√{square root over (P PL )}, where the P L is the power of the excitation light, and the P PL is the power of the detected emission light.