Measurement of the spin-orbit coupling interaction in ring-core optical fibers

Abstract

Ring-core optical fibers have been designed to carry orbital angular momentum modes. We demonstrate the imaging of these modes, individually identifying modes separated temporally by only 30 ps. A single-pixel camera operating in the short-wave infrared detection range is used to image the 1550 nm wavelength optical modes. With this technique, examination of these optical modes can be performed with significantly higher temporal resolution than is possible with conventional imaging systems, such that the imaging of modes separated by spin-orbit coupling is achieved and evaluated. Deconvolution is required to separate the instrument response from the optical mode signal, increasing the clarity and temporal resolution of the measurement system.

High resolution spectral metrology leveraging topologically enhanced optical activity in fibers

“…In this vortex fiber, Δ n eff scales as (see Eq. ( 2 )), due to the combined effect of SOI (factor of ) and the interaction of the optical field with the index inhomogeneity of the fiber 45 . As such, ORD birefringent strength, α , scales with mode order, as demonstrated in Fig.…”

“…An additional benefit of the ORD wavemeter is that the vortex fiber can support multiple OAM modes of differing ℒ simultaneously, making it ideal for multiplexing functionalities. ORD birefringent strength, 𝛼, scales as ℒ 2 in these fibers 24 [see Eq. 2], as demonstrated in Fig.…”

“…Over the course of 5 minutes we measured the OA angle [see Fig. The spin-orbit interaction splitting of effective index between SOa and SOaa vortex fiber modes, ∆𝑛 𝑒𝑓𝑓 , has an OAM modal dependence proportional to ℒ 2 in these vortex fibers 24 [see Eq. 2], as determined by perturbative theory 12 .…”

“…Whereas the interaction length for these other cases is limited between μm and cm, vortex fibers can support km-length propagation 23 . Another advantage is that ∆𝑛 𝑒𝑓𝑓 scales as ℒ 2 in these vortex fibers 24 [see Eq. 2], due to the combined effect of SOI (factor of ℒ) and the interaction of the optical field with the index inhomogeneity of the fiber (∫ 𝐹 2 (𝑟) 𝜕∆𝑛(𝑟) 𝜕𝑟 𝑑𝑟 ∝ ℒ).…”