Nanotube Based Nonlinear Fiber Devices for Fiber Lasers

In this paper, we review the optical properties of carbon nanotubes (CNTs) and describe how those properties have been used for the implementation of various nonlinear fiber optic applications. Early studies on the optical properties of CNTs in the late 1990s revealed that these materials exhibit high third order susceptibility and a broadband saturable absorption with a sub-picosecond response time. Such ultrafast, highly nonlinear optical response means that they can be employed for noise suppression and for the mode-locking of fiber lasers, and, in addition, their high third order nonlinearity holds great promise for the implementation of various other nonlinear fiber optic devices such as wavelength converters based on four wave mixing. In this review, we discuss the various methods that have been considered for the integration of CNTs in optical systems, highlight the advantages and limitations of using the saturable absorption of carbon nanotubes for the passive mode-locking of fiber lasers and discuss the current status of CNT saturable absorbers in the state of art fiber laser technologies.