 中文
	  
	English
	
	  
    中文
	  
	English
	
 
		In recent years, WDM technology mainly in two directions toward the ultra-long-r
 
		At present, the main use EPON optical access network, or GPON, both up and down
 
		WDM metro and long-haul wavelength division due to the different needs of differ
 
		EPON + LAN: IP services and CATV signals are transmitted to the user at home by