Optical waveguide terminators with doped waveguides

Abstract

Disclosed herein are methods, structures, apparatus and devices for the termination of unused waveguide ports in planar photonic integrated circuits with doped waveguides such that free-carrier absorption therein may advantageously absorb any undesired optical power resulting in a significant reduction of stray light and resulting reflections.

1 . A method for enhancing the operational characteristics of a photonic integrated circuit, 
       said photonic integrated circuit including:
 one or more used ports and one or more unused ports; 
 
       said method comprising the step of:
 terminating one or more unused ports of the photonic integrated with a doped waveguide such that internal reflections and stray light is reduced when light traverses the one or more used ports. 
 
     
     
         2 . The method according to  claim 1  further comprising the step of:
 modifying a used port of the photonic integrated circuit such that the photonic integrated circuit includes an additional unused port; and 
 terminating the additional port with a doped waveguide. 
 
     
     
         3 . The method according to  claim 1  wherein said doped waveguide terminator is n-doped having an electron concentration of 1E19-5E20 and exhibits a length of 20 micrometers to 1.5 mm. 
     
     
         4 . The method according to  claim 1  wherein said doped waveguide terminator includes both doped and undoped portions. 
     
     
         5 . The method according to  claim 1  wherein said doped waveguide is doped at different concentrations at different parts of the waveguide. 
     
     
         6 . An optical waveguide terminator comprising:
 a length of doped waveguide being optically connected to an unused port of a photonic integrated circuit.   
     
     
         7 . The terminator of  claim 6  wherein said doped waveguide terminator is n-doped having an electron concentration of 1E19-5E20 and exhibits a length of 20 micrometers to 1.5 mm. 
     
     
         8 . The terminator of  claim 7  which includes both doped and undoped portions. 
     
     
         9 . The terminator of  claim 8  wherein said doped waveguide is doped at different concentrations at different parts of the waveguide. 
     
     
         10 . A method for enhancing the operational characteristics of a photonic integrated circuit, said photonic integrated circuit including one or more used ports, said method comprising the step of:
 modifying a used port of the photonic integrated circuit such that the photonic integrated circuit included an unused port; and   terminating the unused port of the photonic integrated with a doped waveguide.   
     
     
         11 . The method of  claim 10  wherein said doped waveguide terminator is n-doped having an electron concentration of 1E19-5E20 and exhibits a length of 20 micrometers to 1.5 mm. 
     
     
         12 . The terminator of  claim 11  which includes both doped and undoped portions. 
     
     
         13 . The terminator of  claim 12  wherein said doped waveguide is doped at different concentrations at different parts of the waveguide.