Asymmetric chirped fiber Bragg grating for diode laser of fiber amplifier

A method to amplify seed light having a seed wavelength, the method comprising:

• generating pump light with a laser diode, the pump light having a pump wavelength different from the seed wavelength, the laser diode having a front facet with a front reflectivity;
• coupling the pump light from the front facet of the laser diode with an optical fiber segment having a fiber Bragg grating, the fiber Bragg grating having a length and having a plurality of refractive index variations, the refractive index variations having a chirped period changing spatially along the length of the fiber Bragg grating;
• locking the pump light of the laser diode to the pump wavelength by reflecting at least a portion of the pump light back to the front facet using the fiber Bragg grating, the refractive index variations in the chirped period having a first reflectivity for a short wavelength region of the fiber Bragg grating, the first reflectivity being shifted asymmetrically from a central wavelength region of the fiber Bragg grating, being greater than a second reflectivity of the central wavelength region, and being greater than a third reflectivity of a long wavelength region, wherein the fiber Bragg grating has a center wavelength in the central wavelength region, the center wavelength being at a center of the fiber Bragg grating, and the fiber Bragg grating has a peak wavelength in the short wavelength region offset from the central wavelength, wherein the offset is greater than 0.2 times a full-width half maximum (FWHM) of a combined reflectivity bandwidth of the fiber Bragg grating for the first reflectivity, the second reflectivity, and the third reflectivity;
• transmitting the seed light and at least a portion of the pump light to a doped fiber;
• and
• amplifying the seed light by interacting the pump light with the doped fiber.