8 - Pulse Shaping

Abstract

This chapter discusses the techniques applied to compress or shape pulses in amplitude and phase. While the shaping of ns and ps pulses can be achieved by electronically driven pulse shapers, such as the electro-optic modulators, all the optical techniques have to be applied for the fs pulse shaping. The optical pulse compression is the optical analogue of a well-established technique for the shaping of radar pulses. It is achieved by a two-step process. In the first step, a phase modulation is impressed on the pulse. The next step is the Fourier transform analog of the first one. The drawback of using bulk materials as a nonlinear medium is the strong nonlinear behavior of the frequency modulation and the poor pulse quality after compression. The self-phase modulation (SPM) is associated with self-lensing if the transverse beam profile is not uniform. Thus, the achievable spectral broadening is limited. The chapter concludes by discussing the pulse compression by the optical single-mode fiber, which leads to the production of linearly chirped output pulses.