The purpose of this project is to see the different nature and types of laser and nonlinearrnoptics. Both laser and non-linear optics are the fruits of nineteenth century.rnGenerally, this paper summarizes the operation and application of laser and non-linearrnoptics. Upon irradiation with laser light of specific wavelengths and intensities optical fibersrnand bulk glasses undergo relatively slow (minutes to hours) changes, which result in newrnoptical phenomena that were not present before irradiation. One of these phenomena isrnSecond Harmonic Generation.rnParticularly in the first part of this project, from the meaning of laser to the type andrnuses of laser is going to be investigated.rnIn the second part, the non-linear optics, which is entirely related, to laser will bernexamined