Stabilization of Semiconductor Lasers

Abstract

Chaos and instabilities are not only the effects in semiconductor lasers with external perturbations. Semiconductor lasers are also strongly stabilized by external perturbations under appropriate parameter conditions. Optical injection from a different laser is a typical example of laser stabilizations. Other examples are weak or strong optical feedback, phase-conjugate optical feedback, grating optical feedback, and optoelectronic feedback. The longitudinal and transverse modes, frequency, power, and polarizations of semiconductor lasers are stabilized by external perturbations. Stabilizations are especially important in newly developed semiconductor lasers (VCSELs, broad-area semiconductor lasers, laser arrays, and so on), since these lasers involve instabilities even in their solitary oscillations. In this chapter, stabilization and control of semiconductor lasers are discussed based on rather simple configurations of external perturbations. Other than these examples, we present laser stabilizations using photonic structures and quantum-dot structures for newly developed lasers. The control methods introduced here may not be chaos control discussed in the previous chapter, but they are closely related to the ideas of dynamic and chaos controls in semiconductor lasers.