Cleaning and Care: PROFAs are all-glass and, therefore, can be cleaned with alcohol much like a bare fiber tip. Care must be taken to avoid breaking or chipping the tip as any damage to the tip will likely cause the device to be unusable.
Alignment, Coupling and Packaging: The device is aligned similarly to other micro-optic devices, e.g. similar to working with lensed fibers. Using the PROFA, the most efficient and stable coupling is achieved by butt coupling the device to the waveguide. Often customers will use index matching liquids or adhesives but this is not required.
PROFA standard products are rigid fiber optic couplers. This product is often used in probing. However, in packaging, when attaching to a die, we typically use a PROFA with a flexible tip. This flexibility enables the PROFA-die interface to be mechanically decoupled from the package. We have developed processes and materials for packaging that may vary, depending on the application needs.
Chiral Photonics will be very supportive in transferring the materials knowledge and process knowledge to our customers. There is a fair amount of customization with regard coupling that depends on the design (e.g. channel count, mode field size, SM vs. PM, die edge design and quality) and the application needs. Therefore, we strongly suggest that we work with the customer initially to package the device at Chiral Photonics. After we have done that and the customer has received and is satisfied with the packaging, we can transfer the details of materials and process, if desired, so that the customer can take it in-house and just order the couplers and do the packaging themselves. Ideally, after the customer is satisfied with the initial package, we will be happy to host the customer at Chiral Photonics to see how we packaged the device hands-on. Alternately, we can document the packaging process and materials and make that available to the customer.
Rough Alignment: PROFA2Ds are typically provided with a fiducial marking relative to the numbered channels of the array. This can be used to achieve rough alignment of the PROFA.
Fine Alignment: A five axis stage with at least 1 micron resolution is typically used for XYZ motion as well as angular alignment. The needed stage resolution will depend on the mode field sizes one is working with and the application. A general rule of thumb is 10% of the mode field diameter, or 1 µm for a standard 10 µm PROFA2D. Fine alignment is typically done actively, using two outer channels of the array.