Hello, everyone!
Today I'm going to share with you the OXC solution.
The optical cross-connect (OXC) was a huge topic in optics at the turn of the millennium. Startups such as Xros and Client were building 1,000-port OXCs (or photonic switches) and being bought for billions of dollars in some cases. But the large-scale OXC trend fizzled when modest port-count 1×2 and 1×4 ROADMs proved to be the right solution to the wavelength routing challenges of that time.
Evolution of CDC ROADMs
Over the past decade, ROADMs have evolved to incorporate more of the functionality of an OXC, including greater levels of automation, flexibility and scale. With the latest iteration of ROADM technologies, the “OXC” term is coming back in vogue. By adding greater automation and agility to the photonic layer, the commercial introduction of colorless, directionless and contentionless (CDC) ROADMs set this trend in motion.
Conventional ROADMs enable optical express routing (or bypass) at intermediate nodes along a route but are limited by manual wiring and connecting at the endpoints. Colorless node architectures automate the assignment of add/drop wavelength functionality such that any wavelength (or color) can be matched to any port at an add/drop site. Directionless nodes allow any wavelength to be routed to any direction served by a node without physical rewiring. Twin 1×20 wavelength-selective switches (WSSes) were key enabling technologies for colorless and directionless ROADM nodes. They replaced multiplexers and passive splitters in the design and shifted from optical loss-heavy broadcast-and-select to more efficient route-and-select transmission.
The third component of the CDC ROADM is contentionless functionality. Even with colorless and directionless functions, a ROADM network may still have limitations that require manual intervention when two wavelengths of the same color converge at the same WSS drop structure at the same time, causing wavelength-blocking.
Adding an MxN switch on the drop side of the ROADM node addresses the challenge. But the current-generation multicast switches are made from a combination of power splitters and modest port-count 1xN space switches. They are bulky, power-hungry, heavy on optical loss and costly relative to colorless/directionless alone. As a result, uptake of full CDC functionality by operators has been far more limited than the CD-only combination. Without a true contentionless architecture, full automation with no restriction is not possible.
The good news for the industry is that a new generation of MxN switches has come to market for the drop-side structures that replace the early multicast version with a route-and-select architecture based on WSSes. Moving from broadcast-and-select to route-and-select add/drop eliminates the need for drop-side erbium-doped fiber amplifier (EDFA) arrays — a major culprit increasing space, power consumption and costs.
More Challenges
The CDC innovations described above — including the route-and-select MxN WSSes — are produced by ROADM manufacturers and will be used by systems suppliers to build large-scale optical nodes capable of routing hundreds of terabits of optical traffic. But beyond the CDC functionality, there is another challenge to be addressed. In large hub sites, the proliferation of ROADM nodes leads to fiber management challenges. In these large sites, thousands of interconnected ROADM fibers must be manually managed and physically moved, but this process is manual, time-consuming and prone to human error. The connectivity also consumes significant footprint in the central office.
As optical switching nodes scale upward, there is an increasing need for optical backplane connectivity. Moving fiber connectivity to the optical backplane eliminates the potentially thousands of fiber connections that can be made between large-scale optical elements. An optical backplane that eliminates external fiber connections saves on space, eliminates human error in connecting fibers, and — combined with new-generation MxN WSS components — enables fully automated routing of wavelengths at a massive scale.
Huawei OXC solution: New-generation Optical Switching for Tomorrow's Networks
Fiber is an environmentally friendly medium, using 60% to 75% less energy than copper. Based on this, we’ve developed all-optical backplane technology that allows us to print over 1,000 optical fibers on an optical backplane the size of an A4 sheet of paper. In turn, we’ve used the backplane to create a series of OXC products that reduce equipment room footprint by 90% and realize power consumption savings of 60%.
OXC has helped solve a host of issues such as uneven network traffic, insufficient equipment room resources, and excessive space used by traditional ROADM solutions in equipment rooms. By forming an optical cube network, this new connection method for network sites can meet the demands of large broadband, low latency, and low-energy consumption networks.
For information about Huawei OXC products, click the following link:
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