In Step 5, concept of DWDM, which as we discussed in Step 4, was just introduced, evolved to have possibilities to transmit multiple wavelengths to in both directions using same fiber:
This way, all cost of building the cable and equipment infrastructure were decreased.
Best way to show such a concept is FTTH passive networks, or PON – we have 2 types of these – GPON and GEPON (EPON).
In such networks, we use 3 wavelenghts, to send various services over same fiber – 1550 nm is used for the CATV signal, and 1490/1310 nm are used for PON itself.
In this article, which discussed CATV overlay over PON you might get more details on this topic.
Scheme in this case will look anything like this:
Now, you can see that to mix 3 wavelenghts and to send them over single fiber, CATV EDFA is used, more details on CATV EDFA can be found here.
You’ve sure heard about “Triple Play” so this is it – Voice + Internet + TV is triple play.
Current ONU & ONT range we have, offers not only Voice, TV and Internet (Ethernet) on same unit, but even wifi router access and nowadays we call such units as HGU ONT’s – Home Gateway Units.
Figure 3: 4 x Fast Ethernet + Voice FXS POTS + WiFi + CATV GPON ONT HGU type access unit
Testimonials
Lomoveishiy – Finland
I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!
