nokia

Support for the Nokia Bell Labs multi-span (OFDR) DAS formats.

These are written by the Nokia Bell Labs interrogator used on the Ocean Observatories Initiative Regional Cabled Array (2025-2026). There are two variants: an extension-less binary file framed by OFDR1MAGIC holding chunks of 32 time samples for every channel, and downsampled_*.h5 files holding a single data dataset ordered (distance, time).

When the recorder masked parts of the fiber (its masked spans add up to the stored channel count), each span is its own patch, keyed by its position (“0”, “1”, …); otherwise the file is one patch starting at 0 m.

Data are raw phase in radians. Per the dataset’s readme, absolute times lag real time by several seconds, by an amount the metadata cannot recover; the reader does not correct this. The dataset’s reference code converts the phase to strain rate by multiplying it by 1.55e-6 / (4 * pi * 1.4677 * 0.78) / (Tp / Npulses) / gauge_length, where Tp and Npulses are the file’s acquisition parameters.

Examples

import dascore as dc
from dascore.utils.downloader import fetch
spool = dc.spool(fetch("nokia_ofdr_1"))
len(spool)

Classes

Name	Description
NokiaOFDRH5V1	Support for the downsampled Nokia multi-span HDF5 files, version 1.
NokiaOFDRV1	Support for the Nokia multi-span binary format, version 1.

Modules

Name	Description
core	Core module for the Nokia Bell Labs multi-span (OFDR) formats.
utils	Utilities for the Nokia Bell Labs multi-span (OFDR) formats.