Fiber multimode laser with reduced noise

摘要

Applicants have discovered that the intermodal beat noise of a fiber multimode laser can be substantially reduced by providing the fiber with an output coupler of broadened bandwidth. In a preferred embodiment, a reduced-noise, high power light source comprises a cladding pumped fiber laser having a chirped output grating. Experiments show that increasing the output bandwidth from 0.254 to 0.577 nm reduces the relative intensity-to-noise ratio 10 dB in a Nd-doped fiber laser. Increasing the bandwidth from 0.2 nm to 0.3 nm in a Yb-doped laser similarly reduces the noise by 12 dB.