Graded-index Circular Core Research Articles

Design, fabrication, and characterization of a highly nonlinear few-mode fiber

We present the design, fabrication, and characterization of a highly nonlinear few-mode fiber (HNL-FMF) with an intermodal nonlinear coefficient of 2.8 (W·km)−1, which to the best of our knowledge is the highest reported to date. The graded-index circular core fiber supports two mode groups (MGs) with six eigenmodes and is highly doped with germanium. This breaks the mode degeneracy within the higher-order MG, leading to different group velocities among corresponding eigenmodes. Thus, the HNL-FMF can support multiple intermodal four-wave mixing processes between the two MGs at the same time. In a proof-of-concept experiment, we demonstrate simultaneous intermodal wavelength conversions among three eigenmodes of the HNL-FMF over the C band.

Polymer parallel optical waveguide with graded-index rectangular cores and its dispersion analysis

A low-loss and high-bandwidth polymer parallel optical waveguide with graded-index (GI) rectangular cores is fabricated for high-speed and high-dense optical interconnections. We demonstrate that the near-parabolic index profile formed in the rectangular-shaped core GI waveguide exhibits superior properties similar to those of GI circular core waveguides we previously reported. In particular, we focus on the modal dispersion in the GI polymer waveguides with rectangular cores by showing experimental results. In this paper, the GI rectangular cores are fabricated using the preform method. However, conventional photo-lithography and imprinting processes are viable to fabricate a similar waveguiding structure, by which fabrication of a printed circuit board embedding this waveguide would become feasible.

High-Density 2$\,\times\,$4 Channel Polymer Optical Waveguide With Graded-Index Circular Cores

We propose to introduce a densely aligned 2times4 channel polymer parallel optical waveguide with graded-index circular cores for board-level optical interconnection, which is fabricated using the preform method. It is verified that this novel waveguide has sufficiently low loss (0.028 dB/cm at 850 nm and 0.061 dB/cm at 980 nm) and high bandwidth, due to the specific characteristic of the graded-index profile. This paper discusses insertion loss sensitivity to the displacement of the launched beam, various inter-channel crosstalk properties, and inter-channel skew, taking into account the real implementation of waveguides on printed circuit boards, especially for high-speed optical interconnects.

Polymer waveguide with 4-channel graded-index circular cores for parallel optical interconnects

A polymer waveguide with 4-channel graded-index circular cores is fabricated by the preform method. Very low loss (0.028 dB/cm at a wavelength of 850 nm) and high bandwidth (83 Gbps for 1 m, estimated) properties are experimentally demonstrated by the new waveguide for the first time. By densely aligning the cores during the preform fabrication, a waveguide with a pitch size of 56 mum and a core diameter of 50 mum is obtained, which is expected to be utilized in high-speed and high-density parallel optical interconnections.