Measurement technique of phase aberration induced by fiber Bragg gratings

In this letter, we demonstrate a new method to accurately measure the phase aberration induced by optical elements with a frequency dependent intensity transfer function. The method is based on an amplitude modulation of a tunable laser. The complex transfer function of the measured element can be accurately calculated when the ratio between the modulation frequency and the frequency step size of the tunable laser is an integer number. Our measurement technique might be important for measuring the dispersion and the phase aberration induced by fiber Bragg gratings.