Materials. Lower than expected yields drove our disappointing silicon carbide gross margin in the third quarter. Specifically, a power failure limited our silicon carbide substrate growth yield. The resulting lower production volume translated into lower overhead absorption. We have fully resolved the power failure. Our silicon carbide growth yields are very close to plan and production volumes are increasing with, we expect, an over 50% sequential increase in our silicon carbide revenue in our fourth quarter.
Networking. Lower than expected Datacom gross margin accounted for over 50% of the total adverse impact. Specifically, lower transceiver yields was the primary issue. We have implemented a number of corrective actions, have started to see meaningful improvement in yield, and expect to attain our targeted yield by the time we exit the first quarter of fiscal 2025.
Lasers. Lower than expected gross margin in our Lasers segment was primarily due to a number of one-off inventory provisions related to portfolio adjustments. We do not expect these to recur.
Unchanged Long-Term Outlook; Growth Bias. Our longer-term outlook for improved margin structure and strong secular growth in all of our markets remains unchanged, driven by both an eventual recovery in end market demand and the impact of AI along with other significant drivers discussed at greater length below.
We are not waiting for improved end market demand to drive enhanced profitability. We have already implemented actions across virtually all of our businesses in a drive for enhanced operating efficiency as measured by return on sales.
As discussed in our second quarter fiscal 2024 Shareholder Letter and at greater length below, some of these actions require significant time, effort, innovation, and investment to have meaningful impact. These include our digital transformation and facilities consolidation including consolidation of multiple fabs (which are part of our Enterprise Transformation Program) as well as our Asia Pacific Center of Excellence for materials, optics, and lasers where we are expanding our footprint to accommodate our long-term growth in the Philippines, Malaysia, Vietnam, and Singapore. We think the near-term cost of these actions will yield meaningful long-term return in the form of significant improvement in our cost structure and operating efficiency, which in turn we expect will benefit both our margin structure and our competitiveness and thereby our revenue growth and our profitability.
In addition, our diversification across product, technology, customer, and regional markets allows us to redeploy capital and people from low or declining returns to higher-return market opportunities. Almost by definition, the initial “investment” phase of such a shift typically entails lower gross margin, which eventually is followed by margin uplift as the investments and learning begin to translate into targeted yields, BOM costs and cycle times, enhanced operating efficiency, greater revenue volume, and increased overhead absorption.
Near-Term Focus on Execution; Increased FY24 Revenue Outlook Driven by Strong AI-Driven Datacom Demand. We have increased the lower end of our fiscal 2024 revenue guidance. We are now guiding for $4.62 – 4.70 billion versus our previous guidance of $4.55 – 4.7 billion. Underlying our revised outlook, the third quarter reinforced our confidence in the outlook for our Datacom vertical (which is within our Communications market) driven by AI-related datacenter builds by webscale, other cloud internet content providers (ICPs), and companies that supply them.
For the fourth quarter of fiscal 2024, we are forecasting 5% sequential revenue growth and almost 13% sequential non-GAAP EPS growth over the third quarter (at the midpoint of guidance). The expected revenue growth is driven primarily by the strength in our AI-related Datacom transceiver and silicon carbide businesses.
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