OPTICAL FREQUENCY LINEAR CHIRP VARIABLE UNIT

摘要

An optical frequency linear chirp variable unit employing a dielectric multilayer film mirror not requiring alignment of optical axis every time when the amount of chirp is varied. The optical frequency linear chirp variable unit comprises two dielectric multilayer film mirrors (2, 2) arranged in parallel with the dielectric multilayer film mirror surfaces (2a) facing each other, and a movable mirror (4) arranged in a space (3) formed between the dielectric multilayer film mirrors (2, 2). The movable mirror (4) reflects an incident light (5) entering obliquely from one end of the space (3) formed between the dielectric multilayer film mirrors (2, 2) and reflected a plurality of times to the direction of one end (3a) in parallel with the dielectric multilayer film mirror surface (2a) in an incident plane (7) determined by the incident light (5) and the surface normal (6) to the dielectric multilayer film mirrors (2). The movable mirror (4) is movable inward of the incident plane (7) in parallel with the dielectric multilayer film mirror surface (2a), and an amount of chirp to be added is varied by advancing or retracting the movable mirror (4) in that direction.