In this thesis, strategies to efficiently control nonlinear dynamical properties of semiconductor lasers with delayed optical feedback are successfully applied and accomplished. Based on this possibility, it is demonstrated how nonlinear dynamics can be harnessed for the realization of coherence controlled sources and encrypted communications based on chaotic carriers. Semiconductor lasers (SLs) with delayed optical feedback can exhibit intriguing dynamical phenomena. Therefore, these delay systems have become established experimental systems for studying fundamental nonlinear dynamics phenomena, comprising high-dimensional broadband chaotic emission dynamics. Nevertheless, with regard to the functionality of technical applications of SLs, feedback induced instabilities often represent a severe problem, so that much effort has been undertaken to suppress such instabilities. The opposite approach, asking whether the complex dynamical behavior of these systems can also be harnessed for applications remained barely treated so far. To give an answer to this question represented the gist of this thesis. With this aim, the emission properties of SLs with optical feedback have been intensively studied with the focus on regimes of chaotic emission. It is exemplified how the obtained knowledge about the nonlinear dynamical behavior of these systems can be utilized for tailoring the emission properties of SLs. This result represents a cornerstone of the presented work, since in fact it facilitates realization of new applications which are based on chaotic light. To substantiate this finding, a tailored SL light source is presented for which the coherence length can be tuned in a range between 8 m and 130 m. Such a light source can be implemented in modern ranging measurement technology, e.g., in chaotic LIDAR systems. As a second example, it has been studied whether it is possible to synchronize SL-systems that exhibit broadband, high-dimensional chaotic dynamics. The presented results give evidence that excellent synchronization can be achieved. Even more, it is verified that the revealed synchronization properties can be successfully utilized for realization of functional cryptographic communication systems. Hence, both examples highlight the potential of applied nonlinear dynamics for realization of novel practical applications for SLs.