Femtosecond optical modulation measurements of the 3 dB bandwidth of 1.3 /spl mu/m InAsP lasers

Summary form only given. We describe a method to obtain the frequency response of semiconductor laser diodes that employs optical instead of electrical modulation. The technique uses the output of a femtosecond Optical Parametric Oscillator to excite the laser diode, biased above threshold, through a window placed on the top p-side of the laser. The laser emission coming from one of the facets passes through an optical isolator and is launched into an optical fiber, which guides the signal to the input of a 26 GHz photodetector. The detector output is connected to an HP 8561 Spectrum Analyzer. The signal at the spectrum analyzer consists of a discrete number of lines separated by a frequency equal to the OPO repetition rate, 81 MHz. The frequency response of the laser is obtained by measuring the amplitude of each of the harmonics with a narrow Intermediate Frequency (IF) bandwidth, thereby reducing the noise floor.