Long wavelength generation in optical fiber

A supercontinuum light source comprising a pump light source arranged to emit pump light and a nonlinear fiber having a core arranged to receive the pump light, where said pump light and nonlinear fiber are arranged so that a supercontinuum comprising infrared wavelengths is generated in said nonlinear fiber from said pump light, said nonlinear fiber being a step-index fiber and having a dispersion profile, wherein said core comprises fluoride glass comprising InF3 and has a core diameter smaller than 7 μm and a numerical aperture of more than 0.26, and wherein the dispersion profile comprises:

• a. a zero dispersion wavelength ZDW equal to or longer than 1600 nm,
• b. a positive peak value at a peak wavelength longer than said zero dispersion wavelength ZDW, and
• c. a minimum value of dispersion Dmin at a minimum wavelength longer than 2 μm,
• wherein said nonlinear fiber is transparent at a wavelength longer than 3 μm, and
• wherein said pump light is arranged to comprise energy at one or more preferred pump wavelengths which are longer than said zero dispersion wavelength ZDW by 150 nm or more, whereby said dispersion profile causes a soliton red-shift that occurs when said supercontinuum is generated in said nonlinear fiber to be most accelerated at wavelengths at which Raman based soliton energy loss and an increasing mode field diameter cause the soliton red-shift to slow down, thereby overcoming said soliton red-shift slow down and enabling the soliton red-shift to continue to longer infrared wavelengths.

A supercontinuum light source comprising a pump light source arranged to emit pump light and a nonlinear fiber having a core arranged to receive the pump light where said pump light and nonlinear fiber are arranged so that a supercontinuum comprising infrared wavelengths is generated in said nonlinear fiber from said pump light, said nonlinear fiber having a dispersion profile, wherein said core comprises fluoride glass comprising InF3 and comprises PbF2 in a concentration of less than 30 mol %, but more than 1 mol %, and wherein said nonlinear fiber is a step-index fiber and the dispersion profile comprises:

• a. a zero dispersion wavelength ZDW equal to or longer than 1600 nm, and
• b. a positive peak value at a peak wavelength longer than said zero dispersion wavelength ZDW, and
• c. a minimum value of dispersion Dmin at a minimum wavelength longer than 2 μm,
• wherein said nonlinear fiber is transparent at a wavelength longer than 3 μm, and
• wherein said pump light is arranged to comprise energy at one or more preferred pump wavelengths which are longer than said zero dispersion wavelength ZDW by 150 nm or more, whereby said dispersion profile causes a soliton red-shift that occurs when said supercontinuum is generated in said nonlinear fiber to be most accelerated at wavelengths at which Raman based soliton energy loss and an increasing mode field diameter cause the soliton red-shift to slow down, thereby overcoming said soliton red-shift slow down and enabling the soliton red-shift to continue to longer infrared wavelengths.

A supercontinuum light source comprising a pump light source arranged to emit pump light and a nonlinear fiber having a core arranged to receive the pump light wherein said pump light and nonlinear fiber are arranged so that a supercontinuum comprising infrared wavelengths is generated in said nonlinear fiber from said pump light, said nonlinear fiber having a dispersion profile, the dispersion profile comprising:

• a. a zero dispersion wavelength ZDW equal to or longer than 1600 nm,
• b. only one zero dispersion wavelength ZDW shorter than 2 μm,
• c. a positive peak value at a peak wavelength longer than said zero dispersion wavelength ZDW, and
• d. a minimum value of dispersion Dmin at a minimum wavelength longer than 2 μm,
• wherein said nonlinear fiber is a step-index fiber and is transparent at a wavelength longer than 3 μm, wherein said core of said nonlinear fiber comprises fluoride glass comprising InF3, and wherein said pump light is arranged to comprise energy at one or more preferred pump wavelengths which are longer than said zero dispersion wavelength ZDW by 150 nm or more, whereby said dispersion profile causes a soliton red-shift that occurs when said supercontinuum is generated in said nonlinear fiber to be most accelerated at wavelengths at which Raman based soliton energy loss and an increasing mode field diameter cause the soliton red-shift to slow down, thereby overcoming said soliton red-shift slow down and enabling the soliton red-shift to continue to longer infrared wavelengths.

A supercontinuum light source comprising a pump light source arranged to emit pump light and a nonlinear fiber having a core arranged to receive the pump light wherein said pump light and nonlinear fiber are arranged so that a supercontinuum comprising infrared wavelengths is generated in said nonlinear fiber from said pump light, said nonlinear fiber having a dispersion profile, the dispersion profile comprising:

• a. a zero dispersion wavelength ZDW equal to or longer than 1600 nm,
• b. a positive peak value at a peak wavelength longer than said zero dispersion wavelength ZDW, and
• c. a minimum value of dispersion Dmin at a minimum wavelength longer than said peak wavelength,
• wherein the dispersion is non-negative at said minimum wavelength, and wherein said nonlinear fiber is a step-index fiber and is transparent at a wavelength longer than 3 μm, wherein said core of said nonlinear fiber comprises fluoride glass comprising InF3, and wherein said pump light is arranged to comprise energy at one or more preferred pump wavelengths which are longer than said zero dispersion wavelength ZDW by 150 nm or more, whereby said dispersion profile causes a soliton red-shift that occurs when said supercontinuum is generated in said nonlinear fiber to be most accelerated at wavelengths at which Raman based soliton energy loss and an increasing mode field diameter cause the soliton red-shift to slow down, thereby overcoming said soliton red-shift slow down and enabling the soliton red-shift to continue to longer infrared wavelengths.