The test utilized Infinera's new 500 Gigabit/s (500G) photonic integrated circuits (PICs), each integrating five 100G channels. Infinera believes the field test represents a significant step toward the future commercialization of PIC-based optical systems for coherent 100G transmission, aimed at expanding total fiber capacity and significantly reducing the cost of photonic integration systems. 
The field test involved Infinera's 500G PICs transmitting and receiving a 100G channel over a 1,348 km production route between Denver and Dallas on XO's national fiber optic network. The route consists of a 100G-ready WDM ILS line system, designed to deliver scalable fiber capacity exceeding 8 Terabits/s. During the field test, the 100G channel was transmitted using PM-QPSK modulation, and coherent detection was used at the receiver to establish error-free, repeater-free transmission over ultra-long distances. Infinera believes this was the first demonstration of coherent 100G transmission using the fully integrated 500G optical PICs in both the transmitter and receiver, including the use of local oscillators integrated within the PIC receiver.