A multilayer optical fiber coupler for coupling optical radiation between
an optical device and an optical fiber, including a first layer that has
a fiber socket formed by photolithographic masking and etching to extend
through said first layer, and a second layer bonded to the first layer.
The first layer may comprise substantially single-crystal silicon. An
optical fiber is inserted into the fiber socket to align the optical
fiber precisely within the fiber socket. In one embodiment the optical
fiber is a single mode fiber, and an optical focusing element formed on
the second layer is aligned with the core of the single mode fiber. The
second layer may comprise glass having an index of refraction that
approximately matches the index of the optical fiber, and an optical
epoxy is used to affix the optical fiber into the fiber socket and fill
the gaps between the end face of the fiber and the second layer.
Embodiments are disclosed in which an optical device such as a VCSEL or
photodetector is bonded to the second layer. Alternative embodiments are
disclosed in which the optical device is incorporated into the second
layer. Advantages include reduced cost due to batch fabrication
techniques, and passive alignment of the optical fiber.