Alcatel-XFP optical modules can be plugged in on the FWLT-B board. By combining several wavelength profiles on the different TWDM ports of the FWLTB and using the corresponding optics, the aggregate throughput can go up to 40 Gbps (4 wavelength profiles, so 4 x 10 Gbps) in downstream direction and 40 Gbps (4 x 10 Gbps) or 10 Gbps (4 x 2.5 Gbps) in upstream on a single TWDM PON fiber.