Infinera Corp of Sunnyvale, CA, USA, a vertically integrated manufacturer of digital optical transport networking systems incorporating its own indium phosphide-based photonic integrated circuits (PICs), says that it has achieved two industry-first milestones for coherent technologies that increase the capacity and reach of optical transport networks to the next level.
The first drives optical transmission technologies to 100 gigabaud (GBaud), and the second enhances modulation technology to 1024QAM (quadrature amplitude modulation). These new technologies are designed to deliver the highest possible capacity on a single wavelength for varied distances, helping operators to extract the best performance from their optical transport networks.
“Infinera uniquely uses vertical optical integration to extract maximum performance from the optical transport network,” comments Andrew Schmitt, lead analyst at Cignal AI. “The new levels of performance in baud rate and modulation schemes for terabit wavelengths exhibited at ECOC are a good example of how this approach can eventually result in production solutions with greater capacity and reach.”
Optical transport networks enable cloud-based services to reach users around the world, and rely on three axes for increasing transmission performance:
- Baud rate (at which modulation symbols are sent): The typical deployed baud rate is 32GBaud with the quadrature phase-shift keying modulation carrying 4 bits per baud, resulting in 100 gigabits per second of transmission. While industry optoelectronics are moving to 66GBaud development demonstrations, Infinera claims to be first to showcase 100GBaud using 32QAM to achieve a single-wavelength 1 terabit per second (Tb/s) data rate using multi-channel indium phosphide (InP)-based photonic integrated circuits (PICs) integrated with electronic driver and amplifier application-specific integrated circuits. This result was presented at the European Conference on Optical Communications (ECOC 2017) in Gothenburg, Sweden (18-20 September).
- Modulation scheme (converting bits to symbols): At ECOC, Infinera showcased the higher-order modulation scheme of 1024QAM using advanced constellation shaping algorithms and Nyquist subcarriers, allowing wavelengths to be spaced close to each other to maximize the data rate for a certain reach. The Infinera test bed used 66GBaud at 1024QAM to reach 1.32Tb/s, yielding spectral efficiency of 9.35 bits per second per hertz over 400km (an industry first).
- Channel count (implementing multiple parallel wavelengths on a single module to create a coherent super-channel): As baud rates increase, placing optical components closer together on an integrated chip reduces component size and power while increasing reliability.
Baud rate and modulation scheme have been addressed by the industry for some time, with Infinera now setting new milestones for each. The firm says that its PIC technology uniquely enables high-channel-count coherent super-channels. These technologies indicate the next level of capacity and reach achievable in the years to come, it adds.
“Infinera is delivering optical engines at a faster cadence to help operators achieve exceptional capacity and reach performance on their transport network infrastructures,” says co-founder & president Dr Dave Welch. “As 5G wireless and cable video services take off, Infinera offers significant value to transport network operators by designing industry-first solutions.”