Methods and apparatus for reducing noise in optical apparatus comprising a delay line by utilizing a plurality of wavelength specific delay lines to delay an input waveform such as a pulse rather than a single delay line. In a preferred embodiment an apparatus is configured to generate an optical waveform by distributing an input optical waveform among a plurality of environmentally isolated legs, wherein each leg contributes to the generated optical waveform by reflecting back at least a portion of light distributed to the leg, and the distribution among the plurality of legs is at least partially wavelength dependent.