Optical signal demultiplexing device and optical signal demultiplexing method

Abstract

An optical signal demultiplexing device includes a demultiplexing unit that receives an optical signal multiplexed by an optical time-division system and a synchronization pattern, and demultiplexes the optical signal based on the synchronization pattern. The optical signal demultiplexing device also includes a pulse-width increasing unit that makes optical signals demultiplexed by the demultiplexing unit generate chirp, and increases the pulse widths of the optical signals generating the chirp by passing the optical signals through a wavelength dispersion medium.

1 . An optical signal demultiplexing device comprising:
 a demultiplexing unit that receives an optical signal multiplexed by an optical time-division system and a synchronization pattern, and demultiplexes the optical signal based on the synchronization pattern; and   a pulse-width increasing unit that makes optical signals demultiplexed by the demultiplexing unit generate chirp, and increases the pulse widths of the optical signals generating the chirp by passing the optical signals through a wavelength dispersion medium.   
   
   
       2 . The optical signal demultiplexing device according to  claim 1 , wherein the pulse-length increasing unit passes the demultiplexed optical signal through an LN waveguide, and changes a refractive index of the LN waveguide, to generate the chirp in the optical signals. 
   
   
       3 . The optical signal demultiplexing device according to  claim 1 , wherein the pulse-width increasing unit generates the chirp in the optical signals in such a manner that the demultiplexed optical signals are passed through a wavelength conversion element, the wavelength conversion element is irradiated by light a wavelength of which is periodically changed and on which a wavelength conversion is to be performed to change a conversion amount of the wavelength concerning the optical signals. 
   
   
       4 . The optical signal demultiplexing device according to  claim 3 , wherein the pulse-width increasing unit collectively passes the optical signals in which the chirp is generated by the wavelength conversion element through the dispersion medium to increase the pulse widths, and demultiplexes the optical signals that pass through the dispersion medium. 
   
   
       5 . The optical signal demultiplexing device according to  claim 1 , further comprising:
 an electric-signal converting unit that increases the pulse width of the optical signal and converts the optical signal, whose pulse width is increased, into an electric signal, and   a demultiplexing unit that extracts the synchronization pattern of the multiplexed optical signal from the electric signal obtained by a conversion by the electric-signal converting unit, to demultiplex the optical signal based on the synchronization pattern.   
   
   
       6 . An optical signal demultiplexing method comprising:
 receiving an optical signal multiplexed by an optical time-division system and a synchronization pattern, and demultiplexing the optical signal based on the synchronization pattern;   making the demultiplexed optical signals generate chirp; and   increasing the pulse widths of the optical signals generating the chirp by passing the optical signals through a wavelength dispersion medium.   
   
   
       7 . The optical signal demultiplexing method according to  claim 6 , wherein the chirp is generated in the optical signals in such a manner that the demultiplexed optical signal is passed through an LN waveguide and a refractive index of the LN waveguide is changed. 
   
   
       8 . The optical signal demultiplexing method according to  claim 6 , wherein the chirp is generated in the optical signals in such a manner that the demultiplexed optical signals are passed through a wavelength conversion element, the wavelength conversion element is irradiated by light a wavelength of which is periodically changed and on which a wavelength conversion is to be performed to change a conversion amount of the wavelength concerning the optical signals. 
   
   
       9 . The optical signal demultiplexing method according to  claim 8 , wherein the increasing includes collectively passing the optical signals in which the chirp is generated by the wavelength conversion element through the dispersion medium to increase the pulse widths, and demultiplexes the optical signals that pass through the dispersion medium. 
   
   
       10 . The optical signal demultiplexing method according to  claim 6 , further comprising:
 increasing the pulse width of the optical signal and converting the optical signal, whose pulse width is increased, into an electric signal; and   extracting the synchronization pattern of the optical-division multiplexed optical signal from the electric signal, to demultiplex the optical signal based on the synchronization pattern.