READ ME File For Dataset 'Mode attraction, rejection and control in nonlinear multimode optics' Dataset DOI: 10.5258/SOTON/D2810 Date that the file was created: October,2023 ------------------- GENERAL INFORMATION ------------------- ReadMe Author: Kunhao Ji, University of Southampton [ORCID ID:https://orcid.org/0000-0002-2300-5942] Date of data collection: from November 2021 to May 2023 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) -------------------------- 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, Ian Davidson, Jayanta Sahu, David. J. Richardson, Stefan Wabnitz, Massimiliano Guasoni TITLE:Mode attraction, rejection and control in nonlinear multimode optics 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. Mode rejection in the DCF. Mode decomposition of output FS in the DCF fibre (1 m long) for different launching conditions (experiments(exp): dots; simulations(simu): lines). The bottom images show the far-field intensities of the output FS for 3 distinct values of BCB power. The input FS is coupled to different combinations of SMe and SMo (see relative power of input FS on the top of each panel) and launched with fixed power of 3.75 kW,6.5 kW and 6.2 kW in a, b, c respectively. If the input BCB is coupled to SMo (a), then the output FS rejects SMo and is therefore mainly coupled to SMe. When the BCB power =5.1kW, ~90% of the output FS power is coupled to SMe. Consequently, the output FS far-field exhibits one single lobe and resembles the mode SMe-FF of Fig.2b, corresponding to in-phase combination of the cores. On the contrary, if the input BCB is coupled to SMe (b, c), then the output FS undergoes rejection of SMe and is therefore mainly coupled to SMo . When the BCB power = 5.6kW, ~81% and 98% of the output FS power is coupled to SMo in cases b and c, respectively. Consequently, the output FS far-field exhibits two distinct symmetric lobes and resembles the mode SMo-FF of Fig.2b, corresponding to out-of-phase combination of the cores. Fig. 4. Robustness and control of mode rejection. Input FS and BCB are linearly polarized and launched with ~ 5kW peak power in the DCF. a, Mode decomposition of the output FS for off/on BCB. The input FS is coupled to a combination of the two supermodes, whereas the input BCB is coupled to SMe. FS and BCB are co-polarised. The fibre is perturbed 5 different times. Each time, the perturbation consists in compressing or bending the fibre with different levels of intensity and in different points. For each perturbation, the mode decomposition of the output FS is computed, and the output FS far-field intensity is imaged when the BCB is either turned off or on. When BCB is on, robust rejection of SMe occurs in the output FS (<10% power in all 5 cases). b, Mode decomposition and far-field intensity of the output FS as a function of the relative angle α between the polarisation orientations of the input FS and the BCB. The far-field with BCB off is reported for comparison. Fig. 5. Mode rejection in the TCF. Mode decomposition of the output FS in the homemade TCF (40 cm long) for 3 different launching conditions, and comparison with numerical simulations. The input FS is coupled to different combinations of guided supermodes SM1,2,3 (see relative power of input FS on the top of each panel) and launched with fixed power of 4.23 kW, 4.23 kW and 4.33 kW in panels a, b, c respectively. The input BCB is mainly coupled to SM1(a), SM2(b) or SM3(c). We observe almost full rejection of SM1 and SM2 in a and b, respectively, when the BCB has ~ 6.2kW(a) or 4.5kW(b) peak power. Rejection of SM3 reported in c is instead less effective. Nevertheless, we observe a clear trend of rejection in line with numerical simulations, indicating that full rejection maybe achieved by increasing the total power of FS and/or BCB. Fig. 6. Mode rejection in the 6-mode fibre (PM-2000 from Thorlabs, 1 m long). The input FS is coupled to different combinations of modes and launched with fixed power of 4.00 kW, 4.10 kW and 3.20 kW in panels a, b, c respectively. The input BCB is mainly coupled either to LP01(a, b) or LP11b(c). Fig. 7. Comparison between the dynamics of the output FS and the output BCB in the home-made DCF. In the case of panel a, the input FS is launched with fixed power of 5.05 kW, whereas the BCB power is variable (see horizontal axis). In the case of panel c, the input BCB is launched with fixed power of 5.05 kW, whereas the FS power is variable (see horizontal axis). Panel b shows the far-field intensities. The input FS is a combination of ~60% SMe and ~40% SMo , whereas the input BCB is coupled to SMo. Consequently, the output FS undergoes rejection of SMo as illustrated in panel a. On the other hand, the output BCB does not undergo rejection, as illustrated in panel c. Indeed, the mode content of the output BCB in stationary regime strictly depends on the fibre parameters and the input FS, which is in general arbitrary. In this example, because the fibre is bimodal and the Kerr coefficients are almost identical, then the output BC reaches a state orthogonal to the input FS (~40% SMe and ~60% SMo) when the 2 beams have the same power (5.05 kW, see green dashed line in panel c). Fig. 8. Preliminary experiments of all-optical mode control. Differently from Figs.3-7, where the input BCB is coupled to one single mode leading to mode rejection, now the input BCB is coupled to a combination of modes (see relative power of input FS and BCB on the top of panels a and b). The bottom images show the far-field intensities of the output FS when the BCB power is either 0 W or 6.6 kW. The input FS is almost identical in panels a and b, and consequently the corresponding output FS is almost identical in the two cases when BCB is turned off (see the far-field with BCB=0 W in panels a and b). On the contrary, the input BCB is different in panels a and b. We see that different mode distributions of the input BCB give rise to different mode distributions of the output FS (see the far-field with BCB=6.6 KW in panels a and b). These results seem to suggest that, by properly setting the input BCB, the output FS could be shaped on demand in time and space. Error bars of ±3% were added to the measured relative power of each mode, which represents the estimated uncertainty of our mode decomposition algorithm. -------------------------- 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.