The 1535 nm erbium glass laser serves as the mainstream eye-safe laser ranging light source on the current market. Its core advantages include Class 1 eye safety, strong atmospheric penetration, long detection range and robustness against harsh weather conditions. It is widely adopted in security protection, unmanned aerial vehicles, meteorological observation and other scenarios.

I. Working Principle of 1535 nm Eye-Safe Erbium Glass Lasers

Self-developed and self-produced 1535 nm eye-safe erbium glass lasers from RealLight are mainly deployed in medium-to-long distance ranging. They feature wide operating temperature range (-40~70℃), temperature-control-free operation, low power consumption, compact size and eye safety.

1535 nm erbium glass lasers and 905 nm diode lasers complement each other in the marketplace. 905 nm lasers are primarily used for measurement scenarios within 2–3 km, while 1535 nm lasers target applications beyond 3 km, with a maximum detection range exceeding 30 km. As 1535 nm laser technology advances and costs decline, such lasers are gradually competing with 905 nm lasers in certain short-range ranging scenarios. In comparison, 905 nm laser radiation tends to focus on the retina and requires strict power control, whereas 1535 nm lasers are eye-safe and capable of higher single-pulse energy for extended ranging distance.

The 1535 nm erbium glass laser adopts a 940 nm diode laser as the pump source, delivering high efficiency and compact form factor. Erbium glass acts as the gain medium, and spinel functions as the passive Q-switch crystal. The central wavelength of the 940 nm pump source shifts with temperature changes. Benefiting from the broad absorption peak of erbium glass, sufficient pump light absorption can be maintained across -40~70℃, which enables temperature-control-free operation over a wide temperature range for erbium glass lasers.

Figure 1 Schematic Diagram of 1535 nm Eye-Safe Erbium Glass Laser

II. Working Principle of Laser Ranging

1535 nm erbium glass lasers applied for laser ranging adopt the Time-of-Flight (ToF) method for distance measurement. The principle is illustrated below:

The laser emits a laser pulse; a PD receives the laser signal and triggers the TDC timer to start timing. Most laser light passes through a beam expander to reduce divergence angle and irradiate the surface of the target object. Part of the reflected light travels back along the original optical path, passes through the receiving system and is detected by an APD. The signal instantly commands the TDC timer to stop timing. The round-trip flight time of laser light is thereby obtained. Given the known speed of light, the distance between the observer and the target can be calculated using the formula **L=C×T/2**.

Figure 2 Schematic Diagram of Laser Rangefinder

III. Product Features and Advantages of RealLight 1535 nm Erbium Glass Laser Series

Key specifications of RealLight 1535 nm erbium glass laser series are listed below:

– Single pulse energy: Full coverage from 10 μJ to 2 mJ

– Pulse width: 3~10 ns

– Repetition frequency: 1 Hz – 5 kHz

– Peak power: Up to 40 kW ~ 150 kW

– Operating temperature range: -40~70℃

– Minimum divergence angle: ≤0.5 mrad

– Energy stability: RMS ≤3%

RealLight 1535 nm erbium glass laser series features compact fully sealed structure with dust and moisture resistance. The lightest model weighs merely 3 g with ultra-miniature dimensions, enabling direct replacement of 905 nm lasers for laser ranging. Strict high-low temperature tests verify stable output of RealLight 1535 nm erbium glass lasers under extreme environments. Selected models can be matched with beam expander antennas, greatly lowering the difficulty of complete machine development and shortening your development cycle. All products of RealLight 1535 nm erbium glass laser series support customized development according to customer requirements.

Figure 3 RealLight 1535 nm Eye-Safe Erbium Glass Laser

All core components and manufacturing processes of RealLight 1535 nm laser series are independently controllable with full domestic supply chain. Customization of pulse energy, repetition frequency and packaging form is available. Driven by the continuous development of lidar and ranging industry, RealLight has introduced automated production lines with an annual production capacity of more than 100,000 units, guaranteeing excellent product consistency and strong mass delivery capability. The company provides high-performance domestically-produced light source solutions for laser ranging, lidar, security monitoring and other fields.

Figure 4 Production Workshop of RealLight 1535 nm Eye-Safe Erbium Glass Laser

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