READ ME File For Dataset 'Sub-nanosecond all-optically reconfigurable photonics in optical fibres' Dataset DOI: 10.5258/SOTON/D3537 Date that the file was created: June,2025 ------------------- GENERAL INFORMATION ------------------- ReadMe Author: Kunhao Ji, University of Southampton [ORCID ID:https://orcid.org/0000-0002-2300-5942] Date of data collection: from January 2023 to June 2025 Information about geographic location of data collection: University of Southampton, U.K. Related projects: Multimode light shaping: from optical fibers to nanodevices, Horizon 2020 ERC (No. 802682) Self-organization of light in multicore optical fibres: a route to scalable high-power lasers and all-optical signal processing, EPSRC(EP/T019441/1) Future communications hub in all-spectrum connectivity, EPSRC(EP/X040569/1) -------------------------- SHARING/ACCESS INFORMATION -------------------------- Licenses/restrictions placed on the data, or limitations of reuse: CC-BY Recommended citation for the data: This dataset supports the publication: AUTHORS:Kunhao Ji, David. J. Richardson, Stefan Wabnitz, Massimiliano Guasoni TITLE:Sub-nanosecond all-optically reconfigurable photonics in optical fibres JOURNAL:Nature Communications PAPER DOI IF KNOWN: -------------------- DATA & FILE OVERVIEW -------------------- This dataset contains: all originally measured and calcuated data for plotting figures within the article. [File list (filenames, directory structure (for zipped files) and brief description of all data files)] The figures are as follows: Fig. 3: Tuneable mode manipulation. Results in a bimodal fibre. This fibre is 0.4 meter long and supports one even mode M1 and one odd mode M2 (see Supplementary Information 1). a-c. Theoretical 2D maps of the output probe mode distribution computed from equation (4). The maps show the output probe power fraction coupled to mode M1 versus the BCB total peak power (horizontal axis) and BCB mode distribution (vertical axis, indicating the fraction of BCB power coupled to mode M1). These maps indicate how to set the BCB in order to manipulate the output probe, ensuring it reaches the desired mode distribution. The maps correspond to 3 examples with different input probe mode states, which are reported at the top of each panel. For example, in panel a the input probe mode state is characterized by 10% power on mode M1, 90% on mode M2, and a relative phase Δϕ_(in,12) between the two modes of 0.3 rad. d-f. Experimental (exp) and theoretical (theory) results for the same input probe mode states as panels a-c, but with a fixed BCB mode distribution (indicated at the top of each panel and corresponding to the red-dashed lines in panels a-c). Arbitrary output probe mode distribution can be achieved by tuning the BCB power. Specifically, in panel d, full conversion to mode M1 is achieved when the BCB peak power is ~ 8 kW (3.2 W average power). In contrast, the BCB in f is configured such that it results in almost no variation of the output probe mode distribution. The insets in panels d-f show the far-field intensities of the output probe for different values of BCB peak power PBCB. Error bars of ±3% are added to the measured relative power of each mode, which represents the estimated uncertainty of our mode decomposition algorithm. Fig. 4: Tuneable mode manipulation. Results in various commercially available three- and six-mode fibres. Experimental (exp) and theoretical (theory) results are shown for different combinations of input probe and BCB mode distributions (indicated at the top of each panel) in a three-mode PM1550-xp, a three-mode PMHN1, and a six-mode PM2000 (all 0.4 m long). The six panels illustrate distinct cases of probe reconfiguration. Error bars of ±3% indicate the uncertainty in the measured relative power of each mode. Note that panels a-d use line plots as they involve only three modes. In panels e,f, where six modes are involved, a bar chart is used instead to prevent excessive visual clutter. a,b. Results in PM1550-xp fibre; c,d. Results in PMHN1 fibre; e,f. Results in PM2000 fibre. Fig. 5: Tuneable reconfiguration in dual-core fibre. Three different instances are shown. The insets show the near-field intensities of the output probe at each core. a. The input probe launch condition is optimized such that the output probe power is entirely in core 1 when the BCB is off (power ratio core1/core2 = 100/0). After having appropriately fixed the BCB mode state, we increase the BCB peak power from 0 to 9 kW (0 to 3.6 W average power). We then observe that the core-to-core power ratio of the output probe transitions gradually from 100/0 to 50/50, enabling an all-optical, fully tuneable X/(100-X) power splitting. b. Differently from panel a, in this case the output probe core distribution is relatively uniform when the BCB is off (power ratio core1/core2 = 35/65). The output probe is then progressively redirected into core 1 as the BCB power increases, achieving an all-optically controlled combination. At 11 kW of BCB peak power, 92% of the output probe power is in core 1 (power ratio core1/core2 = 92/8). We estimate that full combination (100/0) could be achieved at ~14 kW peak BCB power (not available). c. In this example, the output power ratio goes from 15/85 when BCB is off to 85/15 when the BCB peak power is ~10 kW. Full switching (0/100 to 100/0) could be achieved with ~18 kW BCB peak power (not available). d. Temporal evolution of output probe power at the two cores measured by the oscilloscope when the BCB is off (power ratio core1/core2 = 35/65). e. Temporal evolution of output probe power at the two cores measured by the oscilloscope at 5 kW BCB peak power. The power ratio shifts to 65/35. The oscilloscope also detects the BCB reflection, with the 2 ns delay corresponding to the time of flight of light in the fibre. Fig. 6: Tuneable reconfiguration in three-core fibre. Our ability to implement all-optical probe reconfiguration extend to fibres with more than 2 cores. This figure illustrates all-optical operations in a 0.4m long TCF. The insets show the near-field intensities of the output probe at each core. a. Output probe core distribution simulated via equations (1) and (2), with linear and nonlinear coefficients estimated from the fibre parameters (see Supplementary Information 1). In this simulation, the BCB mode state is as follows: 5% of power in mode 1, 30% in mode 2, 65% in mode 3, and all modes in-phase. The probe power can be arbitrary low. By adjusting the BCB peak power from 0 to 50 kW we can either equalize the output probe power in the 3 cores (see black spot) or combine most of the output probe power in core 1 (blue spot), core 2(red spot) or core 3 (green spot). b-d. Experimental results in the TCF. Each panel corresponds to different launch conditions of the input probe. In each case, the BCB is optimized to achieve relevant operations for a BCB peak power of ~7kW (i.e. 2.8 W average power, the maximum we are able to couple into the TCF). In panel b, the output probe is almost equally split across the 3 cores. In panel c, the probe is mainly redirected to a single core (core 3). In panel d, we achieve power swapping between core 1 and core 2. Fig. 7: Remote characterization of the input probe. Experimental results (bars) and corresponding best theoretical fits (red-dashed lines) showing the output probe power fraction coupled to mode M1 versus BCB peak power in a 0.4-m long bimodal fibre (DCF, see Supplementary Information 1). Panels a-c correspond to different input probe mode states and BCB mode distributions, measured experimentally and reported on the top of each panel. The best theoretical fit is calculated from equation (4), assuming the same input probe and BCB relative powers and optimizing the input probe relative phase to minimize the least squares difference with experimental data. Note that in all the 3 cases the estimated optimal least-squares value Δϕ ̃_(in,12)^ (0.06 rad, 5.72 rad, 1.26 rad in panels a, b, c respectively) is close to the measured Δϕ_(in,12) (0.3 rad, 5.7 rad, 1.2 rad in panels a, b, c respectively). This demonstrates our ability to detect from remote the relative phase of the input probe modes by analysing the output probe response to the BCB. Note that the larger error in panel a is due to the large power imbalance among the two input probe modes (92% and 8%, respectively). Fig. 8. Illustration of linear and nonlinear probe regimes a-b. Mode distribution of the output probe (a) and output BCB (b) versus the BCB peak power when the probe is in a strong nonlinear regime (peak power fixed to 10 kW). The output probe is asymptotically attracted to the mode state orthogonal to the input BCB, and vice versa. c-d. Mode distribution of the output probe (c) and output BCB (d) versus the BCB peak power when the probe is in linear regime (peak power fixed to 10 mW). The output probe mode distribution oscillates sinusoidally as a function of the BCB power, whereas the BCB mode distribution is unchanged. -------------------------- METHODOLOGICAL INFORMATION -------------------------- Description of methods used for collection/generation of data: The data include different kinds of formats, for instance, the beam profile imgages were collected with a CCD camera; the evolution of the mode contents is measured by applying mode decomposition method; the related simulation data are calculated with our numerical tools to double-check with the experimental results. Methods for processing the data: The data were processed with Matlab. Software- or Instrument-specific information needed to interpret the data, including software and hardware version numbers: Excel, matlab, python, etc. Standards and calibration information, if appropriate: N/A. Environmental/experimental conditions: In the lab at the Optoelectronic Research Centre. Describe any quality-assurance procedures performed on the data: N/A. People involved with sample collection, processing, analysis and/or submission: N/A. -------------------------- DATA-SPECIFIC INFORMATION -------------------------- Number of variables: details are given in each tab of the datafile. Number of cases/rows: details are given in each tab of the datafile. Variable list, defining any abbreviations, units of measure, codes or symbols used:details are given in each tab of the datafile. Missing data codes: N/A. Specialized formats or other abbreviations used: N/A.