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1535 nm vs 1550 nm laser rangefinder modules — does the wavelength difference matter?

Both sit in the same eye-safe window: water absorbs the beam in the cornea before it reaches the retina, so the accessible-emission limit is far higher than at 905 nm. In practice the choice is driven by what the supplier can actually deliver consistently, not by 15 nm of wavelength. What matters to an integrator is the pulse energy the module can emit at the stated class, the detector material and its noise floor, and whether the range figure was measured at a stated target and visibility.

Matching modules from the catalogue

Model	Wavelength	Published range	Accuracy	Mass	Interface
LRF1829C	1535 nm	23 km	±2 m	400 g	RS-422
LRF1830C	1.54 µm	23 km	±2 m	400 g	UART + RS-422
LRF1525C	1.54 µm	15 km	±2 m	400 g	RS-422
LRF1221C	1.54 µm	12 km	±2 m	275 g	RS-422
LRF1222C	1.54 µm	12 km	±2 m	335 g	RS-422
LRF1831C	1535 nm	12 km	±2 m	410 g	RS-422

The conditions behind those numbers

LRF1829C — a) Under line-of-sight conditions, with visibility not less than 26 km and humidity not greater than 50% (at 30 °C), the ranging distance for a vehicle target (3 m × 3 m) is ≥ 18,000 m. b) Under line-of-sight conditions, with visibility not less than 30 km and humidity not greater than 50% (at 30 °C), the ranging distance for a target with diffuse reflectance not less than 30% (6 m × 6 m) is ≥ 23,000 m.
LRF1830C — ≥23,000 m to a 6 × 6 m diffuse target, reflectance ≥30%; line of sight; visibility ≥30 km; relative humidity ≤50% at 30 °C
LRF1525C — 4m × 6m Objective ≥15 km
LRF1221C — 4m × 6m Objective ≥12 km
LRF1222C — Reference target(2.3m × 2.3m) ≥12 km
LRF1831C — a) Under line-of-sight conditions, with visibility not less than 15 km and humidity not greater than 80% (at 30 °C), the ranging distance for Target 1 (5 m × 15 m) is ≥ 6,500 m. b) Under line-of-sight conditions, with visibility not less than 15 km and humidity not greater than 80% (at 30 °C), the ranging distance for a target with diffuse reflectance not less than 30% (20 m × 20 m) is ≥ 12,000 m.

Full detail and the manufacturer's original wording: 1535 nm vs 905 nm · all 59 range conditions · filter the catalogue yourself

Questions people ask about this

Is 1535 nm the same as 1550 nm?

In the eye-safety argument yes, both are absorbed before the retina. They are different emission lines; treat the datasheets as separate and compare the measured condition, not the label.

Which one reaches further?

Range depends on pulse energy, receiver aperture and detector noise, not on the 15 nm gap. Two modules at the same wavelength can differ by kilometres for those reasons.

Why do integrators care at all?

Because detector and optics availability differs between the two lines, and that decides lead time and second-source options.

Send the requirement, not a part number Target size, reflectance, required range, mass budget, interface, quantity. Two candidates and their limiting factor come back. Email specs@erdilrf.com All answers

Figures transcribed from manufacturer pages on 2026-10-26. Conditions are quoted verbatim; nothing here extrapolates a range to a target the manufacturer did not test.