Optically modulated MEMS scanning endoscope

This letter presents a novel configuration of a microelectrical-mechanical system (MEMS) scanning endoscope that is actuated by external optical modulation. Light at a wavelength in the 1550-nm range is used to modulate a scanning MEMS mirror. The instrument also provides for the delivery of a second beam at a wavelength of 1310 nm, commonly used for medical diagnostic applications such as optical coherence tomography. The two wavelengths are combined with using a wavelength-division-multiplexing filter and launched into a single-mode fiber. This novel approach provides for the operation of a scanning endoscope without the need for directly powering up the scanning element. In this way a less hazardous apparatus for in vivo diagnosis is possible. The design of the module and MEMS scanning mirror is discussed. A fabricated module is demonstrated in which a MEMS mirror scans at the resonant frequency of 350 Hz, generating an optical scanning angle of 8 degrees.