OFC 2026 was held a couple of weeks ago, and since then, I have had a chance to reflect on what was shown and what I saw from the perspective of an Optical Transport industry analyst. The simple conclusion is that the next direction for optical networking is to scale up in density.

100 Gbps ZR/ZR+ is officially a market

I should clarify this headline. 100 Gbps ZR/ZR+ QSFP28 pluggable optics have been shipping for revenue since 4Q 2023, and shipments have ramped nicely. However, the only supplier of the DSP (Digital Signal Processor) was a co-developed product from Coherent Corp and Adtran. So, technically, it was only one supplier. This changed during OFC when two additional suppliers—Cisco Acacia and Arycs Technologies—announced plans to begin shipping their 100 Gbps ZR/ZR+ pluggable with in-house DSPs in mid-2026. Now there are three DSP suppliers, introducing competition and giving customers a choice. It “feels” more like a market. I should add that in the IPoDWDM and Disaggregated WDM report, we forecast that 100 Gbps ZR/ZR+ optical pluggable modules will grow steadily for many years to come.

 

1.6 Tbps ZR/ZR+ pluggable optics were announced… before 800 ZR/ZR+ volume shipments started

This is the environment we are in right now—things are moving fast, and development cycles are shortening. The good news is that Cisco Acacia announced it has ramped 800 Gbps ZR/ZR+ DSP production, shipping 25,000 DSPs to date, which is a lot compared to other 800 Gbps ZR/ZR+ suppliers. But to put this in perspective, the cumulative shipments for 400 Gbps ZR/ZR+ pluggable optics to date for the industry, per our ZR/ZR+ optical pluggable shipment tracker, are closer to 1.7 million (FYI Cisco Acacia has stated they shipped 750 thousand 400 Gbps DSPs to date, where most were used for ZR/ZR+ optics). So, 800 Gbps ZR/ZR+ is just starting to ramp in production.

The vendors that announced plans to sell 1.6 Tbps ZR/ZR+ optical plugs in an OSFP form factor based on DSPs using a 2 nm foundry process were 1Finity, Ciena, Marvell, and Nokia. The timeline was a little vague, but I believe 1.6 Tbps ZR/ZR+ plugs will be generally available before the end of 2027, with samples as early as 4Q 2026. A couple of items to point out: 1) 1Finity will use a 3^rd party DSP, and 2) Cisco Acacia did not make any announcements about 1.6 Tbps optics at OFC. So, I am guessing the company is waiting until ECOC in September.

 

Nokia laid out its anywhere, anyplace, and anybody product strategy

“Anywhere, anyplace, and anybody” is my own interpretation of Nokia’s optical product strategy after listening to the company’s announcements. Nokia held an analyst event at OFC where the company presented all the new products it has in the pipeline. Personally, I liked seeing all the products it has in development, but it could be overwhelming to hear it all at once in under 60 minutes. Luckily, for me, the OFC analyst event was the fourth Nokia meeting I had with them, where they presented these product ideas, so I understood more of the details that the company executives didn’t have time to explain during the event. In summary, Nokia presented the following new products:

• Four new coherent DSPs (Huron, Superior, Ontario, and Pacific) are planned. Not one or two, but four! The key here is that three of the four are being developed simultaneously, using the same 2 nm base structure and logic. In other words, the cost to develop two of them (Superior and Ontario) is a fraction of the cost to develop Huron. Nokia’s objective is to create cost and performance-optimized DSPs for applications that include 3.2 Tbps coherent-lite for campus, 1.6 Tbps ZR/ZR+ pluggable for metro and DCI, and 2.4 Tbps high-performance for long-haul and subsea. And while not explicitly stated, to meet the differing needs of their wide customer base (CSPs, cloud providers, enterprises/public). So, basically, DSPs for anywhere, anyplace, and anybody. There wasn’t much said about Pacific, but I believe it will be a high-performance, 3.2 Tbps-capable DSP operating at 400 Gbaud and will likely be productized later than the first three.
• All the pluggable optics (QSFP and OSFP) and embedded line cards needed to house the new DSPs in different shapes and forms.
• Double-sided pluggable transponder. The idea is simple: combine the client optical transceiver and the coherent optical transceiver into a single pluggable module. One use case for this is to convert CPO grey light to colored light.
• Multi-rail in-line amplifier (ILA). It wasn’t clear what variations the company would offer, but they stated that the highest-density configuration would be 160 rails per rack. The system will begin sampling mid-2026.
• A Full Band Transponder (also called a full spectrum transponder) that encloses all the client ports, coherent transponder components, and mux/demux into one line card module that fits in an existing GX chassis, delivering a single fiber output with multiple wavelengths. Nokia plans to offer variations of this module with different options and optical engines.

 

Ciena kept things at the system level

Ciena announced several products under development but kept much of the coherent DSP activity under wraps (probably to spread its announcements out between OFC and ECOC). The products included:

• 6 Tbps ZR/ZR+ OSFP pluggable module for IPoDWDM. No comment was made on the DSP to enable it other than that it is a 2 nm DSP.
• 2 Tbps coherent-lite plug for campus. This may leverage the same DSP developed for 1.6 Tbps ZR/ZR+ as Ciena did for its 1.6 Tbps coherent-lite plug.
• RLS Hyper-rail, which is a multi-rail ILA. The company plans to offer 300 mm and 600 mm versions, as well as a 5 RU size to fit in existing ILA huts.
• Full Spectrum Transponder to house all the client ports, coherent transponder components, and mux/demux in a single unit that outputs all the wavelengths through a single fiber connector, enabling a rapid delivery for a full-fiber deployment.
• Early work on xPO modules was shown. I was surprised since the MSA was just announced, but I guess the advantage of xPO is that companies can use existing components to fill in the xPO form factor, but in a tighter configuration, since the xPO has liquid cooling.

 

Optical line systems are REALLY important

As transponder technology approaches Shannon’s Limit, spectral efficiency improvements do little to increase fiber capacity. The realization is that to add more capacity, more fibers will be needed, and each fiber pair requires an ILA every 80 km. In addition, cloud providers are building massive AI data centers that now need to scale-across hundreds of kilometers between data centers to form a larger virtualized AI factory. My discussion at OFC with some folks pointed to a need for 20 Pbps of capacity to connect the back-end of a GPU data center to another. This would convert to 390 fiber pairs when connecting 800 ZR+ optics at each end. The answer to this is a multi-rail system. If a rack unit supports 128 rails, three racks of multi-rail ILAs will be needed at each site.

During OFC, four companies announced multi-rail products: Coherent Corp., Ciena, Cisco, and Nokia. Three other companies (Molex, Ribbon, and Smartoptics) plan to look into developing a multi-rail system. Based on the timing of availability, I think commercial shipments of multi-rail products could begin in 2027.

 

Density is the Next Dimension

For decades, the method for scaling optical transport networks was to increase wavelength speeds (Mbps to Tbps) and the usable spectrum in a fiber (C-band to Super C and L-band). However, as we saw at OFC 2026, the next dimension is density—increasing the number of transponders and ILAs that fit in a cubic meter of space. This is the reason for some of the new product announcements:

• 1.6 Tbps ZR/ZR+ optics
• xPO form factor pluggable module
• Full Spectrum Transponder
• Multi-rail ILA

You can imagine. Combining all four product features into an optical network will increase the density by around 4 times.

• Put multiple 1.6 Tbps coherent optics inside a full-band/spectrum transponder unit. Use xPO modules for the client interface instead of 1.6 Tbps OSFP plugs, saving 75% of the front panel density.
• Connect the fiber coming out of the full-band/spectrum transponder to a multi-rail ILA that is 75% smaller than a traditional ILA unit.

Following OFC 2026, I think the new metric for an optical transport system’s efficiency will be volumetric density (Gbps-per-cubic meter) rather than spectral efficiency (Gbps-per-hertz).