The correct answer is False.
Nonlinear effects in optical fibers are small. This is because the refractive index of the fiber is very close to unity, and the nonlinear coefficient is very small. As a result, the nonlinear effects only become significant at very high intensities.
The nonlinear effects in optical fibers can be divided into two categories: self-phase modulation and cross-phase modulation. Self-phase modulation is the change in the phase of a light wave as it propagates through the fiber due to its own intensity. Cross-phase modulation is the change in the phase of one light wave as it propagates through the fiber due to the intensity of another light wave.
Both self-phase modulation and cross-phase modulation can be used to generate new frequencies, such as harmonics and subharmonics. They can also be used to control the propagation of light in the fiber, such as by creating solitons.
However, the nonlinear effects in optical fibers can also be a problem. They can cause distortion of the transmitted signal, and they can limit the power that can be transmitted through the fiber.
To minimize the nonlinear effects in optical fibers, the fiber is typically made with a low nonlinear coefficient. The fiber is also typically operated at a low intensity.