oh i thought it was data you acquired. NIrx software allows you to do it. I found this converter online: NITRC: NIRx2nirs: A NIRx to .nirs data converter: Tool/Resource Info but it seems it requires a .sd file.
I worked with this dataset in the past; and tried to ask the information to the authors but they never replied to my emails...
If you want to analyse the data, my best suggestion is to download the .mat files and use the following script to import into brainstorm :
shin_import.m (8.7 KB)
You will need to replace lines at the begening to indicate the path to your data nirs_data_folder, eeg_data_folder, the number of subject you want to import n_subject and the name of the protocol in Brainstorm (protocol_name).
If I remember well what I did, it should import both EEG and NIRS (already as concentration).
In the mean time, I will process with the importation of the NIRx file in case you get access to this .SD file 