It is a book written by an engineer for engineering students. All topics are addressed in the most simple and intuitive as possible, while avoiding over-simplification; see for example the masterly treatment of mode-locked ("mode locking"). Only an elementary knowledge of electromagnetism and quantum mechanics few basics is required; so the book can be read with profit by every student from a BAC + 3, but it can also benefit the much higher levels of students and professionals. Unusually, there is also a book of corrected exercises, written by colleagues of Pr. Svelto and which completes this work.