Viavi is becoming an AI network tester
- Viavi is shifting from slow telecom spending toward data centers and aerospace and defense.
- In Q3 FY2026, NSE revenue was $321.5 million and OSP revenue was $85.3 million.
- Data center customers are now in the high 40s percent of NSE revenue, while service providers are in the mid-30s.
- Hyperscalers are buying more field instruments, which pulls an older product line into the AI buildout.
- The main question is whether the stock already prices in too much of this shift.
The pivot is getting real
Viavi used to lean much more on service providers, meaning telecom and cable companies that buy network test gear when they spend on their networks. That market can be slow and cyclical. The company is now moving toward data centers, aerospace and defense, and optical products.
The strongest proof is inside NSE, its larger segment. Management said data center customers are now in the high 40s percent of NSE revenue, service providers are moving toward the mid-30s, and aerospace and defense is a little over 15%. That means data centers could soon become about half of NSE.
A key surprise is field instruments. These are tools used in the field to test fiber and wireless networks. Hyperscalers, the giant cloud companies, are buying more of them to check the fiber networks that link data centers. Management said data centers could soon drive about 50% of the field instruments business.
The bear case is price and dependence. Viavi is tying its story to hot areas like AI and defense. If cloud spending cools, if wireless test stays weak, or if the Spirent deal does not settle into a steady run rate, the slower parts of the company become easier to see.
Test gear for hard networks
Viavi makes money by selling hardware, software, and services that help customers test, monitor, and secure complex networks and optical systems. Its tools are used in labs, factories, field work, data centers, wireless networks, defense systems, and anti-counterfeiting products.
The bigger segment is Network and Service Enablement, or NSE. It includes lab and production test tools for fast optical links, field instruments for network work, aerospace and defense products, and wireless infrastructure test gear.
The smaller segment is Optical Security and Performance, or OSP. It uses optical coating skills for security pigments, 3D sensing filters, and other optical parts. This segment can be useful, but parts of it depend on consumer electronics product cycles.
The model breaks if customer spending turns down. Data centers are growing fast now, but they are competitive and tied to AI capital spending. Service providers remain cyclical, wireless test is still sluggish, and OSP has customer concentration risk in 3D sensing.
Where the products fit
Fiber lab and production test
These tools test high-speed optical links used by data center ecosystem players. Viavi has products for 400G, 800G, and emerging 1.6T standards.
Field instruments
These are portable tools used to deploy and maintain fiber and wireless networks. Demand from hyperscalers is rising, and management said data centers could soon be about 50% of this business.
Aerospace and defense
This includes positioning, navigation, and timing products. Inertial Labs is outperforming expectations, helped by demand tied to drones and autonomous systems.
Wireless infrastructure test
These products test wireless network equipment. The market is weak today because major network equipment makers are spending slowly, but a turn would add another growth lever.
Anti-counterfeiting optical products
Viavi sells optical security products, including pigments for currency and other high-value documents. This gives OSP a market that is different from telecom and data centers.
3D sensing optical filters
These parts are used in consumer electronics, mainly facial recognition. The risk is that demand can move with one large customer's product cycle and volumes.
Two reported segments
Segment mix is based on Q3 FY2026 revenue: NSE was $321.5 million and OSP was $85.3 million. Within NSE, management said the data center ecosystem is in the high 40s percent of revenue, but that is not a separate reported segment.
What could go wrong
AI data center spending slows
High impact · Medium oddsData centers are becoming the main growth engine inside NSE. If cloud companies slow AI-related capital spending, Viavi could lose the growth driver that is covering up weaker legacy areas.
Spirent revenue normalizes below target
Medium impact · Medium oddsSpirent added $54.2 million of revenue in Q3 FY2026, helped by deal timing. The next test is whether the acquired business settles into a stable run rate near the stated annual target after pull-in effects fade.
Wireless test stays weak
Medium impact · High oddsWireless infrastructure test remains in a prolonged downturn. Management expects weakness at major network equipment makers to stay sluggish in the medium term.
OSP customer and product cycle risk
Medium impact · Medium oddsOSP grew 11.4% year over year in Q3 FY2026, helped by 3D sensing and anti-counterfeiting. But 3D sensing appears tied to a large customer and consumer electronics cycles, which can change fast.
Restructuring hurts execution
Medium impact · Medium oddsViavi announced a January 2026 plan to reduce its global workforce by about 5%. Cost cuts can help margins, but they can also hurt morale and slow product work if handled poorly.
In one breath
What does Viavi Solutions do?
Viavi sells test, measurement, and optical products. Customers use its tools to test data center links, telecom networks, wireless equipment, defense systems, and security products.
Why is Viavi linked to AI?
AI data centers need fast fiber links, optical modules, and reliable networks. Viavi sells lab tools and field instruments that help build and check those networks.
What is the biggest risk for VIAV stock?
The biggest risk is that the market pays for a data center and defense growth story before the proof is complete. A slowdown in AI cloud spending, weak wireless test demand, or a messy Spirent integration could pressure the thesis.