Measurement of the LED electroluminescence 3dB frequency at low currents

An analysis and estimation of measuring errors the 3dB frequency of the LED electroluminescence by the standard method at low excitation levels are presented. It is noted that when measuring the variable component of the LED emission power at low currents (up to 100 μA), errors predominate due to the nonlinearity of the LED watt-ampere characteristic and the influence of additive noise of the measuring circuits. It is shown that there is a value of the alternating current amplitude at which the total measurement error of the optical signal at low currents takes on a minimum value.