Polarization insensitive all-fiber mode-lockers functioned by carbon nanotubes deposited onto tapered fibers

Abstract

The authors demonstrate a nonblocked all-fiber mode locker operated by the interaction of carbon nanotubes with the evanescent field of propagating light in a tapered fiber. Symmetric cross section of the device with the randomly oriented nanotubes guarantees the polarization insensitive operation of the pulse formation. In order to minimize the scattering, the carbon nanotubes are deposited within a designed area around the tapered waist. The demonstrated passively pulsed laser has the repetition rate of $7.3\mathrm{MHz}$ and the pulse width of $829\mathrm{fs}$ .