Stretcher fiber and module

A stretcher fiber, comprising:

• a core region having a radius r1, a refractive index n1, and a positive refractive index difference Δn1 with respect to an outer cladding region having an outer radius r0 and a refractive index n0, where Δn1 is equal to n1−n0,
• an inner trench region surrounding the core region, the trench region having an outer radius r2, a refractive index n2 less than n0, and a negative refractive index difference Δn2 equal to n2−n0,
• a ring region surrounding the trench region, the ring region having an outer radius r3, a refractive index n3 greater than n0, and a positive refractive index difference Δn3 equal to n3 - n0,
• an outer trench region surrounding the ring region, the outer trench region having an outer radius r4, a refractive index n4 less than n0, and a negative refractive index difference Δn4 equal to n4−n0,
• the outer cladding region surrounding the outer trench region,
• wherein the values of r0, r1, r2, r3, r4, Δn1, Δn2, Δn3, and Δn4 are structured to provide the stretcher fiber with a relationship between dispersion and wavelength, wherein the stretcher fiber β2and β3/β2curves have a shape and wavelength range matching those of a selected compressor module,
• wherein β2 is the second derivative of the stretcher fiber's propagation constant β with respect to angular frequency ω:
• β
• 2
• =
• ⅆ
• 2
• ⁢
• β
• ⅆ
• ω
• 2
• ,
• and
• wherein β3 is the third derivative of the selected fiber's propagation constant β with respect to angular frequency ω:
• β
• 3
• =
• ⅆ
• 3
• ⁢
• β
• ⅆ
• ω
• 3
• .