Wavelength division multiplexing passive optical network system

Abstract

Disclosed is a wavelength division multiplexing passive optical network (WDM PON) system in which an optical signal outputted from a central office is injected into a Fabry-Perot laser diode (F-P LD) as the light source of an optical network unit, so that the output wavelength of the optical network unit is injection-locked at the same wavelength as that of the optical signal outputted from the central office, thereby enabling the optical network unit to output an optical signal having the same wavelength as that of the optical signal outputted from the central office. In accordance with this system, it is possible to transmit and receive forward and backward data at the same wavelength by the unit of channels. Since inexpensive F-P LDs are used as respective light sources of the central office and optical network units, it is possible to efficiently and economically implement a WDM PON system.

1 - 13 . (canceled)  
     
     
         14 . A bus type wavelength division multiplexing passive optical network (WDM PON) system including a central office, and a remote node connected to the central office via a single optical fiber while being connected to a plurality of optical network units via optical fibers, respectively, 
 wherein the central office generates optical signals of N different wavelengths, multiplexes the generated optical signals through a multiplexer, transmits the resultant multiplexed optical signal to the remote node through the single optical fiber, receives a multiplexed optical signal from the remote node, and demultiplexes the received multiplexed optical signal through a demultiplexer, thereby detecting data generated from the optical network units; and    wherein the remote node includes bi-directional add/drop elements connected to respective optical network units, thereby establishing a bus type distribution network, each of the bidirectional add/drop elements drops an optical signal having a selected wavelength from optical signals of N different wavelengths inputted to an input port thereof, to a drop port thereof in accordance with a reflection operation thereof, and transmits the optical signals of the remaining wavelengths through an output port thereof, while reversibly reflecting an optical signal having the selected wavelength inputted to the drop port toward the input port to output the reflected optical signal to the central office.    
     
     
         15 . The bus type WDM PON system according to  claim 14 , wherein the multiplexing/demultiplexing operation of the central office is carried out in the same manner in both cases in which optical signals travel in forward and backward directions, respectively.  
     
     
         16 . The bus type WDM PON system according to  claim 14 , wherein each of the add/drop element is a WDM thin film filter having an input port, an output port, and a drop port, the WDM thin film filter dropping an optical signal having a selected wavelength from optical signals of N different wavelengths inputted to the input port thereof, to the drop port thereof in accordance with a reflection operation thereof, and transmitting the optical signals of the remaining wavelengths through the output port thereof, while reversibly reflecting an optical signal having the selected wavelength inputted to the drop port thereof toward the input port.