Gill Parvinder Kaur, Kukin Aleksei, Marom Dan M
Opt Lett. 2024 Jul 15;49(14):3946-3949. doi: 10.1364/OL.528786.
On-chip optical sensors using ring- and disk-resonators have many potential sensing applications, yet robust and efficient fiber-to-chip coupling and the differing form factor between the two pose deployment challenges. To resolve this, we 3D-printed a ring-resonator onto the tip of a dual-core fiber and demonstrate its use as a remote temperature sensor. The fiber-tip optical circuit is fabricated using direct laser writing (DLW) with two-photon absorption photopolymer material IP-Dip, forming micrometer-scale waveguide cores having a refractive index of 1.53 with a surrounding air cladding. We connect the two-fiber cores by a printed bus-waveguide, utilizing total internal reflection mirrors, allowing light launched into one core to be guided back to the other core. Furthermore, a DLW printed racetrack resonator evanescently coupled to the bus waveguide (Q ∼ 3000) imposes spectral dips on resonance wavelengths. Light sent down into one core is interrogated upon return from the second core, all from the distal end of the sensor. When the sensing end's temperature is varied, we find a sensitivity of 78 pm/K, due to the polymer's thermo-optic index variation. The ring-resonator could be functionalized for other sensing applications.
使用环形和盘形谐振器的片上光学传感器有许多潜在的传感应用，但强大且高效的光纤到芯片的耦合以及两者不同的外形尺寸带来了部署挑战。为了解决这个问题，我们在双芯光纤的尖端3D打印了一个环形谐振器，并展示了其作为远程温度传感器的用途。光纤尖端光学电路是使用直接激光写入（DLW）和双光子吸收光聚合物材料IP-Dip制造的，形成了微米级的波导芯，其折射率为1.53，周围是空气包层。我们通过印刷总线波导连接两个光纤芯，利用全内反射镜，使射入一个芯的光被引导回另一个芯。此外，一个与总线波导倏逝耦合的DLW印刷跑道形谐振器（Q ∼ 3000）在谐振波长上产生光谱凹陷。射入一个芯的光在从第二个芯返回时被检测，所有这些都来自传感器的远端。当传感端的温度变化时，由于聚合物的热光指数变化，我们发现灵敏度为78 pm/K。该环形谐振器可用于其他传感应用的功能化。
