DAS · Gen 3 / 4 / 4.5 / 5 · DAS generations & selection guide

Compare generation 3/4/4.5/5 configurations to select a suitable product.

DAS Technology Generations and Product Selection

DAS Technology Generations and Product Selection

This document organizes architecture and selection differences using the generation definitions in the source product materials. Generations 1–3 are historical platforms; Generations 4, 4.5 and 5 are current platforms with OEM/ODM options. Performance follows the model-specific datasheet.

Rayleigh-intensity Φ-OTDR with a single I(z,t) signal and no dedicated polarization diversity; susceptible to coherent fading. Distributed event detection with a lower frequency around 10 Hz. Early intensity-based DAS for basic event detection.

Rayleigh-intensity Φ-OTDR with a single I(z,t) signal and no dedicated polarization diversity; susceptible to coherent fading. Distributed event detection with a lower frequency around 10 Hz. Early intensity-based DAS for basic event detection.

Single-frequency direct-detection phase DAS with phase correlation/differencing to improve intensity-response nonlinearity; fading suppression remains limited. Moves from event presence to quantitative phase measurement, with a lower frequency around 10 Hz.

Single-frequency direct-detection phase DAS with phase correlation/differencing to improve intensity-response nonlinearity; fading suppression remains limited. Moves from event presence to quantitative phase measurement, with a lower frequency around 10 Hz.

Single-frequency coherent I/Q using a local oscillator, 90-degree optical hybrid and complex demodulation with basic polarization compensation. Improves weak-signal sensitivity, dynamic range and audio reconstruction; lower frequency around 1 Hz.

Single-frequency coherent I/Q using a local oscillator, 90-degree optical hybrid and complex demodulation with basic polarization compensation. Improves weak-signal sensitivity, dynamic range and audio reconstruction; lower frequency around 1 Hz.

Coherent multi-pulse interference and fusion suppress coherent fading through complementary pulse information, without independent X/Y optical diversity. Lower frequency 0.1 Hz and improved long-range continuity. DAS-UL10(30/50/100), with Lite, Pro and Plus+ engineering configurations.

Coherent multi-pulse interference and fusion suppress coherent fading through complementary pulse information, without independent X/Y optical diversity. Lower frequency 0.1 Hz and improved long-range continuity. DAS-UL10(30/50/100), with Lite, Pro and Plus+ engineering configurations.

Coherent multi-pulse fusion with software polarization diversity. Digital quality assessment, selection and weighting reduce polarization-related fading without X/Y optical diversity hardware. Lower frequency 0.1 Hz. DAS-UL10(A30/A70) for enhanced long-range monitoring.

Coherent multi-pulse fusion with software polarization diversity. Digital quality assessment, selection and weighting reduce polarization-related fading without X/Y optical diversity hardware. Lower frequency 0.1 Hz. DAS-UL10(A30/A70) for enhanced long-range monitoring.

Three frequency bands and orthogonal X/Y optical diversity form six internal complex-signal branches. Adaptive phase-aligned weighted complex-vector fusion addresses coherent and polarization fading. Listed lower frequency is 0.01 Hz. DAS-UL10(N30/N70) targets weak vibration, high fidelity and ultra-low-frequency applications.

Three frequency bands and orthogonal X/Y optical diversity form six internal complex-signal branches. Adaptive phase-aligned weighted complex-vector fusion addresses coherent and polarization fading. Listed lower frequency is 0.01 Hz. DAS-UL10(N30/N70) targets weak vibration, high fidelity and ultra-low-frequency applications.

Selection boundaries

Six internal demodulation branches are not six external sensing channels. Lower frequency, bandwidth and range depend on fiber, sampling, gauge length and SNR; 0.001 Hz is not a specified value here. Generation names or star ratings without common tests do not establish cross-vendor performance rankings.

Frequency range depends on fiber length, scan rate, gauge length and SNR. The 100 kHz upper limit applies only to short-range configurations with adequate high-speed sampling, not simultaneously across a 30–100 km fiber. Conventional per-point temporal sampling must satisfy the Nyquist criterion with anti-aliasing margin.

Applications and further reading

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