Advancement in using tapered coupler instead of lensing for low-loss integration of disparate photonic devices
Silicon photonics can now be more efficiently connected to mainstay low index contrast fiber thanks to a breakthrough by Chiral Photonics scientists.
In a recently issued patent, Chiral Photonics researchers describe the photonics behind their tapered coupler device, the Helica TC. The Helica TC consists of two concentric cores and a cladding. While the two cores have low index contrast, the outer core and the cladding have high contrast. At input the low index contrast cores facilitate low-loss connectivity to standard fibers. The fiber then tapers down over its length, eliminating the inner core by the output end. At the output end then, high index contrast enables low-loss connectivity to high index contrast structures such as planar waveguides.
This interconnect exploits a dual-core fiber design to allow light from a conventional low numerical aperture fiber to be efficiently endface-coupled into another waveguide with smaller mode field dimensions and higher numerical aperture. By permitting index-matching compounds to be used between the coupler and waveguide and eliminating the need for microlens-based coupling and air gaps, the Helica TC affords uniquely low loss and system stable integration. The technology supports both polarizing and polarization maintaining coupler variations.
High index contrast structures within photonic integrated circuits or planar lightwave circuits (PICs and PLCs) form the basis for a large fraction of the recent worldwide innovation in integrated optics. Via highly efficient lasers, extremely sensitive sensors, and waveguides moving vast amounts of data through small radius bends, these faster, smaller, and power-conserving PICs and PLCs promise to advance everything from consumer electronics to personal computing. PICs and PLCs stand to bring more sensitive and less invasive biomedical diagnostics, feed ever more information to wireless devices, and refine industrial processes from drug development to navigation systems.
Chiral Photonics released the Helica TC in late 2007. Developers of next-generation optoelectronics already employ it to couple standard fiber to planar waveguide devices and photonic nanostructures, as well as in other research. “We believe this is a significant enabling technology for planar nanophotonics and in the field of high index contrast photonics more generally,” said Victor Kopp, Chiral Photonics’ Director of R&D. “In addition to the endface and evanescent coupling devices we are currently supplying, we plan to use this technology to introduce a passive alignment solution for board-to-board and chip-to-chip interconnects.”
Chiral Photonics
