LASER WITH TUNABLE OUTER CAVITY AND METHOD FOR USING SAME

摘要

Provided in embodiments of the present invention are a laser with tunable outer cavity and a method for using the same, wherein the laser with tunable outer cavity comprises a gain chip, a collimating mirror, a wavelength selecting element, and an optical path difference generating optical passageway; a cavity surface of the gain chip is located in a focal plane of the collimating mirror; the wavelength selecting element is located between the collimating mirror and the optical path difference generating optical passageway; light beams emitted from the cavity surface of the gain chip are collimated by the collimating mirror to form parallel beams which are sent to the wavelength selecting element; the wavelength selecting element filters the parallel beams from the collimating mirror and then sends them to the optical path difference generating optical passageway; the optical path difference generating optical passageway splits the parallel beams entering the optical path difference generating optical passageway into at least two branch beams, and reflects each of the branch beams in the incident direction to the gain chip, wherein the optical path difference generating optical passageway is capable of adjusting the optical path difference between the optical paths of the branch beams. Since the optical path difference generating passageway serves to roughly select mode without the need for precious control and adjustment, the process of wavelength tuning and selecting is made easier.