OneChip Photonics has announced E-PON transceivers that are based on monolithic photonic integrated circuits (PICs) in indium phosphide (InP). These are the first fully integrated optical access transceivers on the market, which may finally see the promise of low cost for a high-volume product that this technology promises.
OneChip’s design includes using lasers and receivers that support longer-distance transmission and larger splits than those currently used. These components have yet to be evaluated by subsystem vendors, so we will have to wait to see whether the hype is justified.
Promise of lower cost, higher performance
Monolithic integration is the path to low-cost and high-volume in optics. The access market has always been sensitive to price, so targeting it with low-cost technology is a sound strategy. Furthermore, this product promises better performance at a lower cost than the incumbent technology.
However, keep in mind that there have been a number of companies that have tried to develop similar products, but so far there have been no successful stories of integration for a high-volume, low-cost product in telecoms.
So what is so special about OneChip’s approach to photonic integration? Its approach fully integrates all the active and passive functions required for an optical transceiver on a single indium phosphide chip. There is no active alignment required due to its proprietary automated alignment technique on a silicon optical bench. Higher yields and a smaller footprint result in a lower-cost product. With its single-chip process it is able to integrate higher-performance lasers, which mean longer reach, higher split ratios and higher bit rates. Additionally, OneChip claims its pre-amplified detector design is a higher gain-bandwidth solution than the conventional avalanche photodiode.
OneChip’s products address both the optical line terminal and optical network unit subsystems with a single fiber data link. The OLT transceiver consists of a 1490nm continuous mode transmitter and a 1310nm burst-mode receiver. The ONU transceiver consists of a 1310nm burst-mode transmitter and a 1490nm continuous mode receiver. They can be operated at 1.25Gbps or 2.5Gbps in both the downstream and upstream direction.