Embedded optical micro/nano-fibers for stable devices

Abstract

We present a technique to embed silica micro and nanofibers in low-index material (Teflon) using an inexpensive and straightforward fabrication process based on spin coating. The optical properties of the silica micro/nano-fibers have been investigated when they are bare or completely or partially embedded. Optical degradation occurs in bare fibers with diameters smaller than twice the wavelength of the guided light, thus making protection through embedding necessary. Our results also show that completely embedded fibers do not degrade over a long time, while partially embedded fibers can preserve the large evanescent waves without undergoing considerable degradation, which would be further reduced or even become negligible with functional overlayers. The results represent a step forward toward the development of durable and stable devices based on optical micro/nano fibers.

Optical microfibers and nanofibers

“…Besides, to bestow the as-fabricated MNFs with greater versatilities, a number of post-fabrication techniques including micromanipulation [13,85], plastic bend [13], coating [24,29], embedding [44,45,[86][87][88][89][90] and fusion splicing [47,56,80,81] of MNFs have been investigated in the past years. Also, a variety of novel structures, such as MNFs with panda core to maintain polarization [91], elliptical cross-sections for high birefringence [76], or suspended cores to isolate surface contamination and contact leakage [92][93][94] have been also reported.…”

Photonic nano-device for optical signal processing

“…Lou et al [26] have reported a technique to embed silica micro-and nanofibers in low-index material (Teflon) by using an inexpensive and straightforward fabrication process based on spin coating. Their results showed that the optical properties of completely embedded fibers do not degrade over a long time, while partially embedded fibers can preserve the large evanescent waves without undergoing considerable degradation, which represent a step forward toward the development of durable and stable devices based on MNOF.…”

“…on the other hand, MNOF with small size will undergo mechanical and optical degradations. The degradations are more prominent as the MNOF becomes thinner and thinner [26]. Thus, some techniques are necessary to prevent MNOF from degradations such as embedding MNOF in low-index material.…”

Micro/nanofiber optical sensors

“…Various MNF-based photonic devices [23][24][25][26][27][28][29][30][31][32] have been reported, among which MNF resonators [23][24][25][26][27] and interferometer [33] are particularly useful for sensing applications. For robust and stable operation, the MNF assembly can be embedded in low refractive index substrates [34,35]. In addition, MNFs have been used for coupling light in and out of other sensing structures such as liquid-core optical ring-resonators [36], microdisks [37], and microspheres [38,39].…”