How to Precisely Connect Light Chips to Optical Fibers

This patent describes a clever way to accurately align tiny light-emitting components inside a photonic chip with an external optical connector, using a built-in alignment mark and a viewing hole.

What it covers

This patent describes an optical apparatus that precisely connects a photonic integrated circuit (PIC) to an optical interface unit. The PIC has a light emitter that sends light through its material to the optical interface unit, which is attached to the PIC's bottom side (claim 1). To ensure perfect alignment, the PIC includes a special "alignment feature" on its top side, which is built at a known, fixed distance from the light emitter (claim 1). A small "hole" extends from the top side of the PIC down to the bottom, allowing a clear view of this alignment feature from the same side where the optical interface unit connects (claim 1). This setup allows for very accurate positioning of the optical interface unit relative to the light emitter. For example, when manufacturing, a camera could look through the hole to see the alignment feature and then precisely place the optical interface unit based on its known offset from the light emitter. The patent also mentions a heat spreader layer around the optical interface unit to manage heat (claim 10).

What it doesn't cover

• —Does not cover alignment methods where the alignment feature is not offset by a predetermined distance from the light emitter (claim 1).
• —Does not cover systems where the alignment feature is viewed from the same side as the light emitter, rather than through a hole from the opposite side (claim 1).
• —Does not cover optical apparatuses that lack a hole extending from the first side to provide a line of sight to the alignment feature (claim 1).
• —Does not cover systems where the optical interface unit is not connected to the second side of the photonic integrated circuit (claim 1).
• —Does not cover alignment techniques that do not involve a heat spreader layer surrounding the optical interface unit (claim 10).

The clever bit

The novelty lies in creating an alignment feature directly on the PIC's top surface, offset by a precise, predetermined distance from the light emitter, and then providing a viewing hole through the PIC to see this feature from the bottom. This allows for highly accurate, "self-referenced" alignment during assembly, even when the light emitter itself is hidden.

Why it matters

Photonic integrated circuits are crucial for high-speed data communication, sensing, and computing. Accurately connecting these tiny light-based chips to external optical fibers or lenses is a significant manufacturing challenge. This patent addresses that by providing a robust, repeatable method for precise alignment and thermal management, which is essential for reliable and high-performance photonic systems. This precision helps reduce signal loss and improve the efficiency of light transmission, impacting industries relying on optical data transfer.

Real-world examples

• 1.High-speed optical transceivers in data centers
• 2.Fiber optic communication modules
• 3.Lidar systems for autonomous vehicles
• 4.Optical sensors for medical diagnostics
• 5.Quantum computing interconnects