In recent years, exploratory endomicroscopic examinations have become prevalent.1 Indeed, bronchoscopy, colonoscopy, laryngoscopy, etc., are used to detect diseases as early as possible. The technique used is mainly miniaturized confocal microscopy terminated by an optical fiber for in vivo imaging deep inside organs. But it is still highly limited by the low level of beam penetration, high level of photodamage, and the only accessible mean of contrast, linear fluorescence. Consequently, surgeons appeal to physicists to convert this limited linear endomicroscope to a nonlinear one to obtain a higher penetration depth, reduced photo damage, and several complementary means of endogenous contrasts. The real time and direct study of cellular structure constituents, operation, and dysfunction without resorting to a surgical act is actually a clinical need. Thus, nonlinear high-resolution fiber imaging of in vivo organs or living animals at cellular or subcellular resolution has become progressively widespread over the last 20 years.2,3 Multiphoton endomicroscopy allows nonlinear imaging contrast through endogenous second-harmonic generation (SHG) and two-photon fluorescence (TPF). Due to its flexibility and deep penetration depth, multiphoton endomicroscopy has the potential to replace invasive tissue excision or surgical biopsy by soft in vivo optical biopsy. Today, no endomicroscopic system is available to be commercialized because of several challenges.