What makes fiber optic networks and FTTH specially the trend for the access network while carriers are deploying the 4G, going to 5G faster than ever?

There is no limitaation on the bandwidth and its deployment is cheap .

FTTH is more cheaper option than Microwave or Legacy copper access networks in the sense of OPEX. The passive nature of FTTX gives advantave over other access technologies in the following criteria:

1-Minimum maintance

2-Rapid ROI

3-Long time span

4-Virtually unlimited bandwidth (limited by the active equipments in exchange only)

5-Zero electrical power consumption footprint over the full fiber trace (No amplifiers required in between)

6-Very long haul distance (up to 40Km) from nearest exchange.

Therefore the FTTX is having the full advantage for investment over other technologies.

Right now the 4G equipment by major vendors are working via dark fibers to ensure full utilization of media bandwidth which will be easier to integrate with the new 5G systems as fiber is having the best link budget and lowest media losses.