Optical demultiplexer circuit and demultiplexer device and optical wavelength division multiplex circuit

Abstract

An optical demultiplexer to reduce the number of expensive dispersion compensators when compensating secondary dispersion during demultiplexing. By providing optical circulators, dispersion compensators, and optical filters that reflect specified wavelengths and transmit wavelengths other than the specified wavelengths from among the outputs of the dispersion compensators, and causing specified wavelengths to make round trips of the dispersion compensators, the dispersion volume of the dispersion compensators is reduced.

1 . An optical demultiplexer, comprising: 
 a dispersion compensator to receive multiplexed light and to disperse the received multiplexed light at a predetermined dispersion value;    a first reflecting and transmitting device, coupled to an end of the dispersion compensator which does not receive the multiplexed light, to reflect light having a specified wavelength and to transmit light having a wavelength other than the specified wavelength so as to demultiplex the wavelength light from the multiplexed light,    wherein the light having the specified wavelength is reflected through the first reflecting and transmitting device such that the light having the specified wavelength passes through the dispersion compensator a plurality of times.    
   
   
       2 . An optical demultiplexer as recited in  claim 1 , wherein the first reflecting and transmitting device reflects light having a plurality of specified wavelengths and transmits light having wavelengths other than the plurality of specified wavelengths.  
   
   
       3 . An optical demultiplexer device, comprising: 
 an optical multiplexer circuit including, 
 a dispersion compensator having one of an input or an output end connected to a transmission line; and  
 an optical filter provided in the transmission line, connected to another end of the dispersion compensator opposite the one of the input or output end, to reflect light having a specified wavelength and to transmit light having a wavelength other than the specified wavelength so as to demultiplex the wavelength from a multiplex wavelength light, said light having the specified wavelength being reflected through the optical filter to pass through the dispersion compensator.  
   
   
   
       4 . An optical demultiplexer device, comprising: 
 a dispersion compensator unit provided in a transmission line to receive multiplexed light, the dispersion compensator unit having a first and second end; and    a filtering unit coupled to the second end of the dispersion compensator unit to reflect light having a specified wavelength and to transmit light having a wavelength other than the specified wavelength, said light having the specified wavelength being reflected through the filtering unit to pass through the dispersion compensator at least two times so as to demultiplex the wavelength from a multiplex wavelength light.