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Single-Emitter Diodes

Single-Emitter Diodes

What is a Laser Diode?

What is a Laser Diode?

Laser diodes are semiconductor devices that use electricity to emit laser light. Laser diodes are remarkably energy efficient and reliable but are only capable of emitting up to a few hundred Watts of output power. As a result, the majority of industrial semiconductor, diode, and fiber lasers rely on multiple diodes to “pump” laser light through a pump coupler before using optics to emit a controlled beam as a final output.

The architecture of how these laser diodes are coupled and pumped has a dramatic effect on the reliability and efficiency of the final laser. A unique diode technology platform allows IPG fiber lasers to achieve higher output powers and superior beam quality than alternative fiber lasers.

What Are Single-Emitter Diodes?

There are various methods of combining laser diode power employed by industrial laser manufacturers. A common method is to combine multiple emitters along a large area chip known as a bar, bar stack, or monolithic laser diode array, with the number of diode emitters on a single bar varying from approximately 10 to 100. Although the precise details vary by approach, the bar architecture forces each diode to share a common electrical current source and thermal management system. Thermal and electrical crosstalk greatly limits bar lifetimes and places severe constraints on their performance — the lifetime of a bar or bar stack is generally limited by its weakest emitter or an unreliable microchannel water cooling system.

IPG Diodes Offer Superior Performance

  • Individual Emitter Output Power

  • Coupling Efficiency

  • Continuous Wave MTBF

  • Quasi-Continuous Wave MTBF

  • Energy Efficiency (In Fiber)

Bar Diodes

  • Individual Emitter Output Power1 to 2 W

  • Coupling Efficiency50 to 75%

  • Continuous Wave MTBF5,000 to 10,000 hours

  • Quasi-Continuous Wave MTBF2,000 to 5,000 hours

  • Energy Efficiency (In Fiber)25 to 35%

IPG Single Emitter Pump

  • Individual Emitter Output Power6 to 10+ W

  • Coupling Efficiency90 to 95%

  • Continuous Wave MTBF>200,000 hours

  • Quasi-Continuous Wave MTBF>200,000 hours

  • Energy Efficiency (In Fiber)50 to 60%

Single-emitter diodes serve as independent, individual pumping elements for a laser source. IPG fiber lasers use a distributed single-emitter pump architecture that is free of the drawbacks of bar pumping. Unlike with bars, the failure of any number of single-emitter diodes does not affect the performance and reliability of the remaining diodes. This scalable, modular design enables IPG to build lasers that require virtually zero maintenance and have any number of redundant diode pumps to ensure continuous reliable laser performance over the longest lifetimes in the industry. The addition of more diodes also greatly increases energy efficiency by requiring less from each individual diode. The exceptionally high reliability and efficiency of IPG single-emitter diode pump technology is proven in our laboratories and substantiated by the famous field reliability of IPG lasers.

IPG Diodes Power The World's Most Efficient Lasers

IPG Diodes Power The World's Most Efficient Lasers

A dedication to innovative diode architectures and rigorous quality requirements enables the creation of the most energy efficient lasers on the market today. Learn more about the technology behind IPG high-efficiency fiber lasers.

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Fabrication of IPG Diodes

IPG is one of the largest diode manufacturers in the world — many megawatts of rated diode power roll out of IPG facilities annually. IPG diodes are manufactured using telecom-proven technology and processes and each wafer is qualified to rigorous standards. An insistence on using only the highest quality diodes is a critical part of ensuring that IPG fiber lasers offer the longest lifetimes and highest energy efficiencies on the market. Manufacture of single-emitter diodes involves a number of intricate steps to create the final semiconductor device.

(1) wafer growth (2) photolithography & etching (3) metallization (4) die separation (5) bonding & packaging (6) testing & characterization (7) integration & final assembly


1. Wafer Growth: Using molecular beam epitaxy (MBE), wafers are loaded into the process chamber where multiple layers or depositions are deposited onto the wafer. An iterative process is used to deposit p-type and n-type materials to create the p-n-junction. When driven by an electrical current, a lasing condition can occur at this junction.

2. Photolithography and Etching: Photolithography is a process used to define patterns on the wafer to define different regions of the wager. A photoresist is applied and then exposed through a mask to create precise patterns. An etching process is then used to remove the unwanted semiconductor materials based on the defined patterns. The MBE and photolithography steps are an iterative process which can be used to build up multiple layers and define the individual die on the wafer substrate.

3. Metallization: Metal contacts are added to the wafer to allow electrical connection to the p-type and n-type regions, which will include lasing when voltage is applied.

4. Die Separation: This process involves cutting the wafer into individual die prior to packaging.

5. Bonding and Packaging: Individual die are then packaged into a diode pump module which may include a plurality of die along with associated optical elements to direct the output into a fiber. The package is sealed to protect the diode assembly from environmental factors like dust and other contaminants.

6. Testing and Characterization: Rigorous burn-in and testing is performed to ensure that the module meets strict quality and performance characteristics.

7. Integration and Final Assembly: These pump diodes are then assembled with additional components, such as an active fiber and control electronics, to create a full laser source. Power is easily scaled using fiber combining techniques to allow multiple pump diodes to operate together within the laser source. By creating segregated groups of pump diodes and advanced fiber designs, advanced technologies like Adjustable Mode Beam are possible.

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Whether you have a project in mind or just want to learn more about IPG fiber laser technology, a laser expert is ready to help.