Major deployments of Fiber to the Home (FTTH) networks are now underway in both North America and Japan, and such deployments are also accelerating in China and Europe. Most of these deployments utilize “Passive Optical Network” (PON) configurations, as shown in the figure below, which combine the fibers from up to 32 (or sometimes 64) end users into a single fiber at the splitter cabinet, which is up to 20 km distant from the access hub, which is often located at a central office. This network architecture greatly simplifies fiber deployment and management.

Passive Optical Network Architecture
There are three key optical modules required for these PON systems (see diagram above):

1) an optical network unit (ONU) transceiver at the subscriber premise (a Subscriber Unit)

2) an optical line terminal (OLT) transceiver at the access hub which handles traffic from 32 subscribers (a Line Unit)

3) a passive optical device, either a splitter or a multi-channel filter, which combines the 32 end-user fibers at a splitter cabinet into the one fiber which continues to the access hub.

In addition, there are currently three different international standards for such PON systems: BPON, GPON and GEPON.

A Subscriber Unit Biplexer combines the upstream (send) and downstream (receive) data functions. A Subscriber Unit Triplexer adds the downstream video receive function to the Biplexer data functions. NeoPhotonics fully serves the FTTH market by manufacturing all three of these types of PON modules for all three main standards (BPON, GPON and GEPON) and which we sell in North America, Japan and China. Furthermore, we have begun to migrate these products to designs based on our PIC integration technology in anticipation of additional major market growth.

FTTH Subscriber Unit Transceivers
One of the key elements of all FTTH systems is the Subscriber Unit transceiver, which is located on the subscriber’s premises and provides the interface between the subscriber and the network. Depending on whether the FTTH system has an analog video overlay wavelength, the Subscriber Unit must separate two or three wavelengths, provide upstream and down stream data transmission (Biplexer) and, in some cases, an additional downstream analog video optical channel (Triplexer). The Subscriber Unit is deployed at each customer premise.

NeoPhotonics manufactures a portfolio of Biplexer and Triplexer transceivers for FTTH “triple play” (data, voice and video over the same network) applications. These Subscriber Unit transceivers are placed at the customer premise and feature duplex operation over a single-fiber, which reduces system cost and simplifies network design and fiber management. Biplexer transceivers are a key part of our FTTH product portfolio, and NeoPhotonics shipped more than 2 million Biplexer transceiver components for FTTH applications. NeoPhotonics offers Biplexer transceivers suitable for all PON network standards and for all variations of fiber penetration, whether to the node, curb, business, multi-unit dwelling, or single family home. NeoPhotonics line of GPON transceivers includes both Biplexer and Triplexer modules. The Triplexer module includes an integrated high-end video receiver designed to meet stringent industry requirements.

FTTH Optical Line Unit Transceivers
In addition to our Subscriber Unit transceivers, NeoPhotonics manufactures a complete line of Line Unit transceivers for the access hub side of FTTH deployments. Line Unit transceivers are more complex than Subscriber Unit transceivers, since each Line Unit transceiver must communicate with up to 32 Subscriber Unit transceivers.

FTTH Outside Plant Splitters and Multi-Channel Filters
The second key to the efficiency of PON systems for FTTH is the passive element which combines the signals from multiple subscribers onto one fiber. In current systems this is done by power splitters. Advanced systems are being developed which provide an individual wavelength to each end user, and replace the power splitter with an PIC-based multi-channel athermal filter, known in the industry as an athermal Arrayed Waveguide Grating (AWG).

We manufacture a portfolio of PIC-based 8, 16, 32 and 64 channel power splitters and have introduced PIC-based multi-channel athermal filters designed for out-door installations, which feature industry leading optical performance and are used in a wide range of telecom applications. We also provide PIC-based power splitters which can combine the analog video overlay signal wavelength with the digital signal wavelengths, thus cost-effectively supporting Subscriber Unit Triplexer deployments.