Current programmable photonic integrated circuits (PICs) are volatile and suffer from high optical signal losses – both of which prevent them from maintaining their programmed state. A team of researchers has now succeeded in fabricating meter-scale single-mode photonic waveguides that boast optical losses of only 0.03 dB/cm.
The researchers also used their waveguides to construct optical true delay lines (OTDLs), which are important components of many photonic devices – including future quantum information processors and sensors.
Lithium niobate on insulator (LNOI) has recently emerged as an attractive substrate material for PICs, and it shows promise for making circuits with lower losses, higher density, and greater tunability than previous devices. The researchers have used a new technique called photolithography-associated chemo-mechanical etching (PLACE). The technique can produce smooth, meter-long photonic waveguides on the LNOI that can be integrated with micro-electrodes, which allow the devices to be tuned electro-optically at a later stage.