MARCH 23, 2009 -- NeoPhotonics (search Lightwave for NeoPhotonics) has announced at the OFC/NFOEC conference and exposition in San Diego, CA, two new passive photonic integrated circuit (PIC)-based products that the company expects to become key enablers of the emerging "coherent" optical network transmission systems for 40- and 100-Gbps networks. Coherent signaling technology allows first 40 Gbps and then 100 Gbps to be transmitted over DWDM channels currently transmitting 10 Gbps.
The company's coherent mixer and DQPSK (differential quaternary phase-shift key) demodulator products provide for transparent phase decoding within each of the two major branches of coherent transmission systems emerging for 40 and 100 Gbps. The mixer product is an optical demodulator providing advanced demodulation to analyze the state of polarization (SOP) and optical phase of a phase-modulated signal relative to an externally supplied optical reference, enabling recovery of the phase-polarization constellation for dual polarization quaternary phase-shift keyed (DP-QPSK) data transmission. The mixer requires no power, operates across the C or L band, and is based on planar integration, utilizing lower-cost, high-volume semiconductor production methodologies.
DQPSK systems utilize delay-line interferometers (DLIs) to coherently mix the incoming signal with a delayed sample, thereby avoiding the need for an external optical reference. The DQPSK demodulator consists of two DLIs, providing in-phase and quadrature analysis of the phase-encoded signal. To accommodate the unpredictable and varying nature of the received signal polarization, the demodulator has been optimized to exhibit extremely low sensitivity to polarization variations.
"The rapid uptake of 40-Gbps transmission on the line side, and the anticipated move to 100 Gbps in the next couple of years, enables significantly greater utilization of already deployed DWDM channels, but at the same time places stringent requirements on the optical components required," says Tim Jenks, CEO of NeoPhotonics.
"These demodulators are precision assemblies of passive optical components and, since they are used on each channel rather than on each fiber, will be required in fairly large volumes with very tightly maintained specifications," says Ferris Lipscomb, vice president of marketing. "As such, they are ideal candidates for photonic integration, and especially planar waveguide integration."
NeoPhotonics is showcasing later this week at OFC/NFOEC in San Diego (March 24-26, in Booth #1126) a portfolio of MEMS- and PIC-based optical components, its line of telecom transceiver products in SFF, SFP and XFP form factors, and the new products for 40- and 100-Gbps coherent optical transmission systems.