Enhanced VCSEL performance by optical injection locking for analog and digital applications

In this paper, we have thoroughly investigated the locking phenomena within the entire locking range and useful injection regimes are identified for communication applications. The enhanced laser performance can be attained in a wide injection parameter space, demonstrating the robustness of this technique. An upper bound of the resonance frequency improvement was found also using rate equation analysis. And a direct measurement on chirp confirms the usefulness of this technique for large signal modulation. In conclusion, we have demonstrated the frequency response enhancement with the injection locking technique. A flat, enhanced S21 can be achieved with a high injection power and large wavelength detuning. This is highly desirable for both analog and digital modulation. Furthermore, the direct chirp measurement of the VCSEL confirms that injection-locking technique can effectively reduce the laser chirp and can be readily applied to digital modulation applications.