A New Method for Measuring the Frequency Response of Broadband Optoelectronic Devices

A new and simple method based on the frequency-sweep method for measuring the frequency response of broadband optoelectronic devices is demonstrated. The electro-absorption modulator (EAM) can function as both modulator and receiver with the same frequency response. With this property, the frequency responses of a distributed feedback (DFB) laser at different bias currents were measured from dc to 20 GHz by the method. The results were quite identical with the results measured by the frequency-sweep method with broadband photodetector. Besides, the measurement bandwidth is not limited by the bandwidths of the devices, and the results are not influenced by the bandwidths of the EAM or other devices.