Fiber arrays
As mentioned, optical fibers are mostly used as multi-channel fiber ribbons. To align these fiber ribbons with the optical couplers on silicon photonic chips, the number of channels and pitch of the fiber ribbon must precisely match the number of channels and the pitch of the coupler on the chip. Therefore, fiber ribbons are typically aligned within V-grooves formed in glass blocks (e.g., Pyrex) or silicon blocks to maintain precise spacing between individual fibres. Each fiber is placed in a separate V-groove, and a cover glass (Lid) is applied and secured with an adhesive. This assembly is known as a fiber array unit (FAU). The fabricated FAU is then polished at an appropriate angle using a mirror finish to match the configuration of the photonic chip's optical couplers.
There are two standard pitches for fiber spacing in FAUs: 127 µm and 250 µm. The overall width of the FAU is determined by the number of fiber channels.
Depending on the optical coupler type and the form of the photonic chip, a fiber array unit without a lid is also required. A detailed explanation of the application of a lidless fiber array will be provided later when discussing optical couplers.
Comments
Post a Comment