Photonics Wafer Laser Trimming Solution

It enables precise correction of fabrication deviations directly at the wafer level, providing a scalable approach for high-volume silicon photonics manufacturing.

Through controlled material modification, wafer laser trimming allows accurate tuning of critical photonic components such as Mach–Zehnder interferometers and microring resonators without introducing thermal drift or additional process complexity.

By improving phase accuracy, device yield, and process reliability, this technology helps semiconductor fabs transition silicon photonics and co-packaged optics (CPO) from R&D environments to scalable production for next-generation AI and data-center infrastructure.

What Is Laser Trimming ?

Our Photonics Wafer Laser Timming Solution is set to boost overall throughput in photonics components manufacturing by correcting process errors at wafer level. The Trimming Solution uses a fiber laser connected to a multi-function head which integrates focussing optics, 2D beam pointing and a high-resolution vision camera, the complete set of functionalities for fast response and precision.

How Does Laser Trimming Work?

Step 1- Wafer loading and initial measurement

The silicon photonics wafer, containing numerous fabricated PICs with inherent manufacturing variations, is securely loaded onto a high-precision positioning stage within the trimming system. Each PIC (die) or a specific component on the die, is electrically and optically probed. Its actual spectral response and the resulting phase error are measured against the target design value. This determines the precise correction required.

Step 2 – Localization of target area for correction

A high-magnification vision system precisely locates the target area on the waveguide for trimming. The stage moves the wafer to position the defective circuit component directly under the laser focus.

Step 3 – Laser Beam Contacless correction and Final Verification

The short-pulsed laser beam is delivered to the specific section of the waveguide that requires correction. The laser pulses interact with the material of the waveguide, causing a localized, permanent, and highly controlled change in the material’s internal structure. After trimming, the circuit’s spectral response is measured again to confirm the phase shift has corrected the device to the design specifications, turning a “Known Bad Die” into a “Known Good Die (KGD).”

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Trimming Sequence

Trimming Measurement Sequence

Laser Trimming Key Benefits

Femtum laser trimming solution significantly increase the manufacturing yield for high-precision components, particularly Photonic Integrated Circuits (PICs). It acts as a post-fabrication “fix” that allows manufacturers to precisely and permanently correct performance variations, such as phase errors in optical waveguides, that result from unavoidable manufacturing tolerances.

Permanent phase accuracy

Permanently corrects phase shifts, ensuring stable device performance without active tuning.

Higher yield and recovered dies

Recovers out-of-spec devices, improving wafer yield and reducing scrap in photonic manufacturing.

Lower power consumption

Reduces reliance on thermal phase shifters, lowering power budgets and simplifying design.

Laser Trimming by Circuit Type

MZI Trimming (Mach-Zehnder Interferometer)

During fabrication, small process variations can introduce phase imbalance between the two arms of a Mach–Zehnder interferometer, degrading device performance. Our approach is to apply a highly localized laser exposure to permanently correct this imbalance after fabrication.

By selectively modifying the optical path length in one arm of the MZI, the phase difference is precisely adjusted until the device returns to its intended operating point. The correction is performed with optical feedback, ensuring accuracy and repeatability.

Learn more about Photonics Integrated Circuit Trimming

Manufactured

Corrected

Manufactured

Corrected

Ring Resonator on SiN

Fabrication variations can cause silicon microring resonators to shift away from their target resonance wavelength, impacting device performance and yield. Our process enables precise, post-fabrication correction of these wavelength offsets.

A highly localized laser exposure is applied near the microring to permanently adjust its effective refractive index, fine-tuning the resonance back to its designed wavelength. Optical feedback ensures accurate and repeatable trimming without altering the device geometry.

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High-Precision Laser Trimming Solutions for Photonics Wafers

What Is Laser Trimming ?

How Does Laser Trimming Work?

Step 1- Wafer loading and initial measurement

Step 2 – Localization of target area for correction