Triple-Junction Laser Diodes


The new SemiNex triple junction laser diode makes use of 3 monolithic semiconductor laser junctions that produce over 100 watts peak power at 1550nm and pulsed conditions. It delivers 3X more optical power compared to a single junction laser diode with 1W/A slope efficiency. With a low operating voltage the wall plug efficiency of a triple junction laser diode can be 2X higher at high driving current than a comparable diode in the market place.


SemiNex offers triple junction laser diodes in several configurations for various customer needs and applications. The selection of aperture widths includes 50μm, 95μm, 180μm, and 350μm, and the standard cavity length covers both 1.5mm and 2.5mm. SemiNex provides triple junction laser diodes in several packaging and submount configurations such as Chip-on-Carrier, TO9, and TO56. Samples and production units are available for delivery. The product matrix of Triple Junction laser diodes for 10nsec short pulsed conditions can be found here and those for 150nsec pulsed conditions can be found here.


(I) LiDAR for autonomous vehicles and drones, and industrial applications

For the past ten years LiDAR manufacturers have taken two laser approaches for time-of-flight LiDAR systems: 905nm laser diodes or 1550nm fiber lasers. The 1550nm fiber lasers are impractical for mass market deployment because of their size, cost, and complexity. Typical time-of-flight LiDAR systems using multi-junction 905nm lasers are limited to a range of 100 meters due to a low eye-safety acceptable emission limits (AEL) of International Electrotechnical Commission (IEC) regulations. Neither of these past approaches meets the automotive industry goals of 200 meters, eye-safe, or cost effective LiDAR to enable mass deployment in high-speed autonomous vehicles.

The new SemiNex triple junction laser diode at 1550nm enables eye-safe, high-power, longer-range over 250m, lower cost LiDAR solutions for autonomous vehicles at high speed. It delivers 80X more photons, 27X stronger detection, and 3X longer detection distance compared to a 905nm laser diode in an automotive LiDAR. A major challenge with the existing LiDAR technology for autonomous vehicles has been to find a cost-effective semiconductor laser diode that can provide high peak power at eye-safe wavelengths for long range applications. Operating at 1550nm, the SemiNex Triple Junction laser diode provides 3X the peak power of a single emitter thus improving the resolution and penetration effectiveness in bad weather while remaining eye-safe. It can be operated at pulse widths between 2ns and 150ns at 200kHz to 400kHz pulse repetition rate.

Our Feature Article in the November 2021 issue of Laser Focus World describes the benchmark details of our Triple Junction laser diode at 1550nm outperforming 905nm for long range LiDAR.

(II) Range finding and targeting applications

Infrared lasers are popular with the military for targeting and range finding applications. Infrared spectrum is preferred as laser target designators, which are used with precision-guided munitions to guide munitions, because light from an infrared laser cannot be seen by the human eyes. Same as range finding, the 1550nm infrared laser is adopted predominantly due to the eye-safe requirement. 

The SemiNex Triple Junction laser diodes deliver the highest power available to the market place, where the detection range and eye safety are both critical. Small form-factor packaging such as TO9 and TO56 are available for easy design-in and drop-in replacement into the existing systems.  

Further Reading

Laser Diodes
Infrared Lasers
Medical Lasers
SemiNex Technology