OFC 2010: Talk already moves beyond 100G

40G and 100G is everywhere at OFC/NFOEC this year. There are enough products now for deployment to begin. Although 100-Gbps links should begin deployment this year, there’s already talk of moving beyond 100G. As I explained in “Complex modulation comes to optical fiber,” long-haul links will employ DP-QPSK (dual polarization quadrature phase-shift keying) modulation to get 4×25-Gbps transmissions on a single wavelength using existing 10-Gbps fibers. 40-Gbps Ethernet is also coming online.

Engineers have been speculating on the modulation technique to increase transmission rates. Terms such as 8PSK (phase-shift keying) and 16-QAM (quadrature amplitude modulation) are bouncing around the halls of the San Diego Convention Center. 16-QAM, another technology developed for digital RF communications, produces four bits per baud by combining phase and amplitude modulation. PSK uses phase modulation only, and QPSK produces two bits per baud.

For short and medium haul links, I’m hearing 64-QAM and even 256-QAM. Long-haul links have too much signal loss to support these techniques, but who knows what the future will bring?

Read about new products from Tuesday, March 23 here.