In times where traditional curricula are questioned and multidisciplinarity is encouraged, optics -- in its broadest sense -- is playing a very privileged role. In this paper we wish to illustrate this statement by analyzing how optics is infiltrating many related basic disciplines and many coming- of-age technologies, making it an exciting new field. By tempting to answer the questions: What is teaching? What is optics? What are called other disciplines? we show how we strive to meet the expectations of students, industry and research labs. We report on our experience of teaching optics to small classes of electrical engineers and applied physicists, allowing to provide them with skills and insights much broader than the purely technical ones.