New optical interface standard aims at 5G
Article By : Larry Desjardin
The latest test-industry standard, the Optical Data Interface and how it might find additional use is explained.
By now, you may have seen the announcement from the AXIe Consortium, the VITA trade organization, and six companies endorsing a new standard called the Optical Data Interface (ODI).
ODI is a new high-speed interface for instrumentation and embedded systems. It breaks speed and distance barriers by relying on optical communication between devices, over a standard pluggable optical fiber. With speeds up to 20 GBytes/s from a single optical port, and speeds up to 80 GBytes/s through port aggregation, ODI is designed to address challenging applications in 5G communications, mil/aero systems, high-speed data acquisition, and communication research.
Figure 1 shows a storage and playback system using ODI, the Optical Data Interface standard. Since ODI is a pluggable interface, any product can become ODI-enabled, regardless of form factor. A test system controller configures each device to enable ODI transmission through its standard interface. In the figure above, data is streamed over the ODI link from the digitizer to the storage unit. Alternately, it could stream to a DSP processor. The recorded data may be played back by sending the recorded data stream to the AWG over the second ODI link.
Figure 1. ODI provides a high-speed optical link between test instrumentation and DSP or storage devices. Source: Modular Methods.
How ODI works
Let me explain how ODI works. But first, it’s time for full disclosure. I’m not an unbiased observer when it comes to ODI. In fact, I’m the chairman of the AXIe Technical Committee that created the standard. I’m an unapologetic advocate of open systems, and I believe this standard is the right standard at the right time to address a multitude of vexing instrumentation and embedded system challenges.
Here’s the problem.
When you take a look at a number of emerging applications, such as 5G communication or phased-array radar, the aggregate bandwidth needed to transfer IQ data grows very rapidly. Whether you are creating or testing these applications, the solutions require very high data bandwidths between measurement and processing blocks. It is easy to calculate 15 GBytes/s needed, and that’s just for a single channel. At these speeds, electrical communications links can’t extend across a backplane, mush less a racked system. The electrical signals quickly dissipate, and the connectors create large reflections, creating signal-integrity problems that make interoperability difficult. Plus, the speeds are only going to get faster.
With optical links, the interoperability, bandwidth, and distance issues simply disappear. You can connect instruments 100 meters away if needed, so there is no issue of interconnect distance within a rack.
That is what the ODI standard delivers—an open system method of connecting a fiber-optic data link between two devices, regardless of their physical format, regardless of manufacturer. The ODI standard is designed around a standard optical connector, which may be placed anywhere on any device. Therefore, ODI works equally well with all product formats, whether AXIe, PXI, LXI, VPX, or a traditional bench instrument design. It works equally well with instrumentation and embedded systems, such as those found in mil/aero applications. Through the standardized ports, ODI enables high-speed continuous communications between instruments, processors, storage, and embedded devices. Though the standard itself is sponsored by the AXIe Consortium, it is open to all vendors, without license fees or royalties.
Let’s take a look at the technology.
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