4: Getting the conditions right
(a) Comparison of theory (red) and experiment (blue) for the squeezing of a 126 femtosecond pulse in a 6.4 metre long fibre. The x-axis is the input energy (in soliton units) and the y-axis is the noise power (relative to the shot-noise level). Squeezing occurs for values of the input energy between about 0.78 and 1.11.
(b) Predicted squeezing (see colour bar) as a function of input energy and asymmetry of the interferometer (y-axis). The shot-noise level is shown by the thick black line and squeezing occurs in the region inside this line. The dashed line represents the asymmetry used in (a). Preliminary experiments have confirmed that a larger asymmetry will lead to even more noise reduction (From Schmitt et al.)