Environmentally stable optical fiber mode-locked laser generating device having an achromatic quarter wave plate

摘要

An Environmentally stable optical fiber mode-locked laser generating device having an achromatic quarter wave plate is disclosed. An optical fiber unit is formed of a polarization maintaining (PM) optical fiber, and a Bragg grating is formed on a first region from one end in direction to the other end, a gain material is doped on a core of a remaining second region. An optical coupling unit provides a pump laser input to one end of the optical fiber unit, and outputs a laser input from the optical fiber unit. A lens unit converts a laser output from the other end of the optical fiber unit and focuses the laser on a certain regime. A polarization control unit includes an achromatic quarter wave plate (AQWP) which is disposed between the lenses constituting the lens unit and made by laminating two quarter wave plates (QWPs) such that fast-axes of the QWPs are orthogonal to each other, and controls mode-locking of the laser and spectral bandwidth by adjusting an angle of the AQWP with respect to a fast-axis or a slow-axis of the optical fiber unit. A saturable absorbing unit saturably absorbs and reflects the laser passed through the second lens, resulting in mode-locking.

主权项

1. An optical fiber mode-locked laser generating device, comprising:
a first pump laser generating unit for generating a pump laser with a predetermined wavelength; an optical fiber unit having an optical fiber of which a first region is formed of a Bragg grating from one end of an optical fiber in direction to the other end and of which a second region, the remaining part of the optical fiber, is doped with a gain material in a core of the optical fiber; a first optical coupling unit for providing a pump laser input from the pump laser generating unit to one end of the optical fiber unit, and outputting a mode-locked laser input from the optical fiber unit; a lens unit including a first lens configured to generate a parallelized laser by changing a path of the laser output from the other end of the optical fiber, and a second lens configured to focus the parallelized laser passed through the first lens on a certain area by changing a path of the parallelized laser; a polarization control unit including an achromatic quarter wave plate (AQWP) which is disposed between the first lens and the second lens and made by laminating two quarter wave plates (QWPs) such that a fast-axis of one QWP is orthogonal to a fast-axis of the other QWP, and controlling polarization of the parallelized laser and spectral filtering bandwidth by adjusting an angle of the AQWP with respect to a fast-axis or a slow-axis of the optical fiber unit; and a saturable absorbing unit saturably absorbing and reflecting the parallelized laser passed through the second lens.