Frequency-domain measurement of carrier escape times in MQW electro-absorption optical modulators

Frequency-domain measurement of carrier escape times in reverse-biased multiple-quantum wells (MQW´s) is proposed and demonstrated. Measurement and analysis of opto-to-electrical (OE) frequency response give the escape times of both electrons and holes with excellent time resolution. Using this technique, we measured escape times in an InGaAs-InAlAs MQW electro-absorption modulator and estimated the carrier density in the wells during optical input. This measurement can clarify the optical saturation effect in optical devices such as MQW electro-absorption modulators.