In this paper, we presents the characterization technique of high-speed optoelectronics devices based electrical and
optical spectra, which is as important access to the devices performance as the prevalent vector network analyzer (VNA)
sweeping method. The measurement of additional modulation of laser and frequency response of photodetector from
electrical spectra, and the estimation of the modulation indexes and the chirp parameters of directly modulated lasers
based on optical spectra analysis, are given as examples.
Various high-speed laser modules are fabricated by TO-Packaged processes, such as FP laser modules, DFB laser
modules, and VCSEL modules. Furthermore, the resonance among the circuit elements provides an approach to
compensating the TO packaging parasitics, and improving the frequency response of the devices. The detailed
equivalent circuit model is established to investigate both the laser diode and packaging comprehensively. The small-signal
modulation bandwidths of the TO packaged FP laser, DFB laser and the VCSEL modules are more than 10, 9.7
and 8 GHz, respectively.
An ultra-wide-band frequency response measurement system for optoelectronic devices has been established using the optical heterodyne method utilizing a tunable laser and a wavelength-fixed distributed feedback laser. By controlling the laser diode cavity length, the beat frequency is swept from DC to hundreds GHz. An outstanding advantage is that this measurement system does not need any high-speed light modulation source and additional calibration. In this measurement, two types of different O/E receivers have been tested, and 3 dB bandwidths measured by this system were 14.4GHz and 40GHz, respectively. The comparisons between experimental data and that from manufacturer show that this method is accurate and easy to carry out.
An extended subtraction method of scattering parameters for characterizing laser diode is introduced in this paper. The intrinsic small-signal response can be directly extracted from the measured transmission coefficients of laser diode by the method. However the chip temperature may change with the injection bias current due to thermal effects, which causes inaccurate intrinsic response by our method. Therefore, how to determine the chip temperature and keep the laser chip adiabatic is very critical when extracting the intrinsic response. To tackle these problems, the dependence of the lasing wavelength of the laser diode on the chip temperature is investigated, and an applicable measurement setup which keeps the chip temperature stable is presented. The scattering parameters of laser diode are measured on diabatic and adiabatic conditions, and the extracted intrinsic responses for both conditions are compared. It is found that the adiabatic intrinsic responses are evidently superior to those without thermal consideration. The analysis indicates that inclusion of thermal effects is necessary to acquire accurate intrinsic response.