Passive fiber alignment arrangement for coupling to nano-taper optical waveguides
View Patent ↗An arrangement for providing passive alignment between an optical fiber and the “tip” of a nanotaper coupling waveguide (the nanotaper formed within the SOI layer of an SOI-based optoelectronic arrangement). The arrangement includes a separate fiber carrier support element, including a longitudinal V-groove for supporting the fiber and an alignment feature formed parallel thereto. The SOI structure is formed to include an associated alignment slot, so that as the fiber carrier is positioned over and attached to the SOI structure, the alignment feature and alignment slot will mate together and provide passive alignment of the optical fiber to the nanotaper waveguide tip.
1. An arrangement for providing passive optical alignment between an optical fiber and a nanotaper coupling waveguide formed in an SOI structure, the coupling arrangement comprising
a fiber carrier support member including a fiber-holding groove formed along a top surface thereof and at least one alignment feature disposed offset from said fiber-holding groove and separated therefrom by a predetermined distance, the fiber carrier support member further comprising a beveled edge along the top surface, disposed such that the fiber-holding groove is disposed between the beveled edge and the at least one alignment feature; and
an SOI structure including a surface silicon layer including the nanotaper coupling waveguide, an oxide layer and a silicon base layer, said SOI structure further comprising a cavity region formed through said surface silicon layer, said oxide layer and into said silicon base layer so as to expose a tip portion of the nanotaper coupling waveguide, and at least one alignment slot formed through said surface silicon layer, said oxide layer and into said silicon base layer and separated therefrom by the predetermined distance separating the fiber-holding groove and the at least one alignment feature, wherein the fiber carrier support member is positioned over the SOI structure such that an optical fiber disposed within the fiber-holding groove protrudes into the SOI structure cavity region and the at least one alignment feature protrudes into and mates with the at least one alignment slot.
2. An arrangement as defined in claim 1 wherein the fiber-holding groove of the fiber carrier support member comprises a V-groove.
3. An arrangement as defined in claim 1 wherein the at least one alignment feature comprises a first alignment feature having a predetermined length L and the associated first alignment slot comprises a length greater than L, such that upon positioning of the fiber carrier support member over the SOI structure the first alignment feature may be translated along the length of the first alignment slot until contact between the vertical walls thereof is achieved.
4. An arrangement as defined in claim 1 wherein the fiber carrier support member comprises a plastic material.
5. An arrangement as defined in claim 4 wherein the fiber carrier support member comprises an injection-molded plastic component.
6. An arrangement as defined in claim 1 wherein the cavity region and the alignment slot within the SOI structure are formed using a deep reactive ion etch (DRIE) process.