the waveform however control of only the amplitude or only the phase may be sufficient depending on the application hence in some cases only the polarization controllers or only the phase shifters may be needed the optical waveform may then be passed to a waveform amplifier such as an erbium doped fiber amplifier edfa to amplify the signal other waveform manipulation common in the art may also be performed e g noise reduction and would be clear to those skilled in the art since polarization controllers and fiber stretchers may be inserted between the fbgs without having to break the fiber the dynamic waveform shaping system described above may retain light in a continuous splice free fiber which may serve to lessen or minimize possible insertion loss this system may operate in the frequency domain and may be capable of shaping pulses at high repetition rates owing to its all fiber configuration this system may have an advantage over the free space slm systems in terms of insertion loss since the pulse shaping may be carried out in a continuous fiber insertion loss may be lessened or minimized and thus the system may be scaled up to control many spectral lines for higher temporal resolution and better shape control physical disturbance or temperature variation on the fiber may introduce polarization and phase fluctuation to the waveform simply enclosing the fbgs might not be sufficient to stabilize the waveform sufficient stability may be achieved using an insulator material around the fbgs the insulator material may additionally insulate the polarization controllers.