Optical waveguides play a crucial role in applications such as waveguide lasers, frequency converters, and supercontinuum generation. Among various fabrication methods, femtosecond laser writing emerges as one of the most efficient techniques for fabricating waveguides in transparent dielectric materials. This study primarily involves femtosecond laser direct machining induced refractive index modifications and femtosecond laser enhanced wet etching. This study provides a comprehensive review of the principles and recent advancements in femtosecond laser enhanced wet etching for optical waveguide fabrication. Key topics include the mechanisms of selective etching, the waveguide fabrication process, the influence of fabrication parameters on etching efficiency, and the applications of fabricated waveguides. Furthermore, the study addresses current challenges and potential solutions in using femtosecond laser enhanced wet etching for hollow-channel waveguide fabrication and discusses the future development of this promising technique.