Optical fibers and optical fiber devices with total dispersion greater than material dispersion

Abstract

Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP 02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

1 . Optical waveguide supporting an optical signal in a higher order propagating mode (HOM) comprising a length of all-solid glass fiber wherein the total dispersion of said HOM is greater than the material dispersion of the waveguide and has a value less than +50 ps/nm-km.  
   
   
       2 . The optical waveguide of  claim 1  wherein the waveguide is a few mode fiber.  
   
   
       3 . The optical waveguide of  claim 2  wherein the dispersion of the waveguide has a value greater than zero.  
   
   
       4 . The optical waveguide of  claim 2  wherein the slope of the dispersion is positive.  
   
   
       5 . The optical waveguide of  claim 2  wherein the slope of the dispersion is negative.  
   
   
       6 . The optical waveguide of  claim 2  wherein the dispersion has a turnover region.  
   
   
       7 . The optical waveguide of  claim 2  wherein the HOM is LP 02   
   
   
       8 . An optical device comprising the optical waveguide of  claim 1  combined with a mode converter for converting a lower order mode to said HOM.  
   
   
       9 . The optical device of  claim 8  wherein the mode converter is a long period grating.  
   
   
       10 . The optical device of  claim 8  wherein the mode converter is a phase plate.  
   
   
       11 . The optical device of  claim 8  further including a mode converter for converting the HOM to a lower order mode.  
   
   
       12 . Optical device comprising: 
 a) a first length of all-solid glass optical fiber, the optical fiber having a core and a cladding wherein said core supports a first mode,    b) a mode converter for converting light in the first mode to light in a second, higher order, mode (HOM)    c) a second length of all-solid glass optical fiber, the second length of all-solid glass optical fiber having a core and a cladding wherein the HOM propagates in the core of the second length of all-solid glass optical fiber, and further wherein the total dispersion of said HOM is greater than the material dispersion of the waveguide and the effective index of the HOM is different from that of any other mode propagating in the said core by at least 0.0001.    
   
   
       13 . The optical waveguide of  claim 12  wherein the waveguide is a few mode fiber.  
   
   
       14 . The optical waveguide of  claim 13  wherein the dispersion of the waveguide has a value greater than zero.  
   
   
       15 . The optical waveguide of  claim 13  wherein the slope of the dispersion is positive.  
   
   
       16 . The optical waveguide of  claim 13  wherein the slope of the dispersion is negative.  
   
   
       17 . The optical waveguide of  claim 13  wherein the dispersion has a turnover region.  
   
   
       18 . The optical waveguide of  claim 13  wherein the HOM is LP 02    
   
   
       19 . An optical device comprising the optical waveguide of  claim 12  combined with a mode converter for converting a lower order mode to said HOM.  
   
   
       20 . The optical device of  claim 19  wherein the mode converter is a long period grating.  
   
   
       21 . The optical device of  claim 19  wherein the mode converter is a phase plate.  
   
   
       22 . The optical device of  claim 19  further including a mode converter for converting the HOM to a lower order mode.