Frequently Asked Questions about Fiber Lasers

1. I’m currently using lamp-pumped YAG lasers in my application. What advantages would switching to fiber lasers offer me?

  • Electrical efficiency of greater than 30% wall-plug efficiency vs. 1.5% to 2% for lamp-pumped YAG
  • Cost savings from no replacement of flash lamps: Long life telecom grade single emitter diodes lifetimes greater than 100,000 hours used in fiber lasers vs. flash lamps
  • Fixed spot size and spot profile at all power levels
  • Maintenance-free or low maintenance operation
  • Minimal spare parts
  • Air-cooled or minimal cooling requirements
  • Substantial reduction in laser footprint
  • Longer working distance
  • No requirement for alignment
  • No warm-up/instant on

2. Where do I purchase beam delivery components for fiber lasers?
All of the third-party manufacturers of beam delivery components now offer beam delivery with plug and play compatibility for fiber lasers. IPG can supply you with a list of manufacturers.

3. Can I use my existing YAG beam delivery components?
In general yes, however you may require an adapter to accept the IPG fiber connector. In some instances you may want to increase the focal length to take full advantage of the processing advantages that fiber lasers offer.

4. Can these lasers be integrated to my current work cell?
Yes. Fiber laser have a wide choice of industrial interfaces and can be easily interfaced to standard industrial controls.

5. Are there integrators that can supply my company with a turn-key system?
Yes. There are many who have successfully provided turn-key systems with fiber lasers for several years. IPG can supply a list of integrators and OEMs that can provide a turn-key solution.

6. Do fiber lasers come with a warranty?
IPG offers the longest warranty in the industry: the standard warranty for fiber lasers is for a full 2 years after purchase. IPG also offers extended warranties for up to 8 years. Contact your sales person for details.

7. Where do I go to see if fiber lasers can meet my requirements?
IPG has extensive application development facilities in Oxford, Massachusetts; Detroit, Michigan; Santa Clara, CA; Burbach, Germany; and Yokohama Japan. In addition various institutes and universities in North America, Europe and Asia are available for advanced research in applications development with fiber laser technology.

8. Your competition claims that back-reflection is a problem with fiber lasers. Is this true?
These statements come from people not familiar with fiber laser technology. Our multi-kilowatt low mode fiber lasers are not susceptible to back reflection issues if the appropriate delivery fiber is utilized. With single-mode lasers they in most cases do not have a problem, unless highly reflective materials are processed. However, if the back reflection is too high, the units sense the reflection and automatically shut down. The addition of an isolator eliminates this issue. IPG have numerous units in the field cutting and welding highly reflective material such as copper and aluminum on a production basis.

9. Why do other manufactures quote lower life times on their diode bars?
Diode bars (AKA as monolithic laser diode arrays) are made up of multiple emitters arranged in parallel in one crystal. Because of the high heat density in the junction area and strong thermal crosstalk between the emitters comprising the bars diode arrays must be mounted on copper with soft solder (Indium) and be water-cooled. High-speed and high pressure water flow through tiny gold coated channels in the copper (called micro-channel coolers) provides aggressive cooling. However the water in the system must be kept extremely clean and be PH neutral as these channels are prone to failure due to cavitations and erosion in a relatively short period of time. Keeping water quality to the specification is extremely challenging task in any, especially in industrial, environment. Copper heatsink and diode bar semiconductor are very dissimilar materials, including coefficient of thermal expansion. Under real world operating conditions, frequent on-off cycles, the performance of bars tends to deteriorate much faster than under constant driving current which bar manufacturers use mostly to characterize their devices.

The other source of frequent bars’ failure is in the semiconductor diode bar itself; lifetime of the bar is usually determined by the reliability of its “weakest” emitter. In order to improve performance and to boost heatsinking bars are often get attached to micro-channel coolers with high heat conductive soft solder, indium. Under high driving current operation indium is known to migrate through bar metallization into semiconductor material thus causing its sudden instantaneous failure.

Many manufacturers of diode bars pro rate the warranty based on hours used. Regarding IPG single emitter diodes, they are mounted on a heat sink with the same coefficient of thermal expansion as the diode chip. IPG uses telecom-qualified hard solder which is free of electro-migration defect. Depending upon the size of the fiber laser, IPG diodes are either air-cooled with high speed fans or are water-cooled through stainless steel pipes beneath the heat sink. There is no contact with water coolant. The diode light is delivered via fiber and is delivered directly to the active medium and spliced thus eliminating an air to active medium interface that can be a source of contamination. The life of the single emitter diodes is directly related to the current they are operated at. All industrial IPG fiber laser diodes are run at a current level where the predicted end of life (MTBF) is > 100,000 hours of operation. IPG Photonics diodes are not pro-rated and are covered for the complete warrantee period of the fiber laser or amplifier.

10. How can you be so confident that your diodes have this life-time?
IPG Photonics tests 100% of their diodes before they are certified for a laser or amplifier. Duration of the test generally is longer than 1,500 hours when diodes are operated at stressed conditions, greatly elevated temperature and current. If the diodes pass this test with no drop off in power they are certified for usage in our devices. Whether the diode is used for a 10 kW fiber laser for materials processing or a broad band fiber amplifier for telecom, similar procedures are followed. IPG is now the largest manufacturer of single emitter multi-mode diodes with the most extensive diode test facility in the world. This is also backed up with over 650 multi-kilowatt fiber lasers now in production applications with many in operation over 5 years.

11. Why is IPG fully vertically integrated?
There are three main reasons:

  • Many of the components used by IPG are not available on the open market or do not meet the stringent requirements required for high power fiber lasers.
  • Vertical integration allows IPG to better optimize components for our unique systems, to respond quickly to customer requests and to bring product to market rapidly.
  • Finally, it allows IPG to closely control cost to maximize the benefit to our customers.

12. How do you focus a fiber laser?
It is quite simple. With a fiber laser the procedure is to image the output of the fiber on the work piece. The spot size is equal to the fiber diameter x the magnification ratio of your collimator and final focus lens. For example, if the fiber diameter is 50 microns and you use a 60 mm focal length collimator and a 300 mm final focus lens the final spot size is SS= 50x 300/60= 250 microns. The fiber diameter, collimator and final focus lenses can all be changed to obtain the appropriate spot size. The spot size will not vary as a function of power over the complete dynamic range of 5% to 105% of rated power. With a single mode laser the spot size at the work will be Gaussian and with a low order mode laser top hat.

13. Can the same fiber laser both cut and weld?
The same fiber laser can do cutting, welding, drilling and cladding. Many customers have purchased a fiber laser with a 2-way, 4-way or 6-way beam switch. For example, one leg will have a 100 micron fiber for cutting, a 200 micron for welding and 400 or higher for cladding or annealing. The power can be changed to a different level and switched to a new delivery fiber in a matter of milli-seconds. Delivery fiber can support multiple work stations of up to 200 meters apart.

14. Why are fiber lasers more efficient than other solid state and gas lasers?
The answer is simple – the design of fiber lasers generates less heat and manages the heat they generate effectively. The quantum defect (that is the difference between pump and emission energy) is lesser for a Ytterbium diode-pumped fiber laser (pumped at 980 nm) than a Nd:YAG diode pumped laser (pumped at 808 nm). Also, the optical to optical conversion efficiency of fiber laser is typically 70-80%, as compared with approximately 4% for lamp pumped YAGs, and approximately 40% for diode-pumped YAGs and disk lasers. Because the light is always contained in a fiber, there are no additional sources of the loss inside the laser cavity.

15. How much can I save if I switched to fiber lasers?
Users can save significant savings from using fiber lasers in their production. The amount you can save depends upon many things including your current process, materials, production environment, electrical and labor costs. Here are some of the savings:

a. Higher Wall-plug Efficiency: Fiber lasers have unrivaled efficiency when compared to existing conventional laser technologies:

Type Wall-plug Efficiency
Fiber Laser Ytterbium (Yb) 30%+
Lamp-pumped YAG 1.5-2%
Diode-pumped YAG 10-20%
Disc 15-25%
CO2 5-15%

 

b. Cooling: The efficiency of the fiber laser also contributes to lower cooling requirements, which contributes to lower electrical usage. Lower power fiber lasers require only air-cooling. Higher power fiber laser require water-cooling that is generally more simple and less costly than for equivalent alternative laser technologies. Cooling also depends upon your particular production environment.

c. Consumables/Replacement Parts: Because of the highly efficient design of fiber lasers (better thermal management) and the use of telecom-grade single emitter pump diodes in our fiber lasers, you can save on replacement parts (such as lamps and diode bars), labor and production down time. Many lamps and diode bars used in YAGs have estimated lifetimes of 2,000 hours and 20,000 hours, respectively. These are a fraction of the MTBF of IPG’s single emitter diodes of > 100,000 hours which mean that for the life of the fiber laser, you should not have to replace the diodes. In the all solid-state fiber-to-fiber design of IPG’s lasers, you save even further because there are no optics to adjust or maintain, such as resonators mirrors, crystals, fluids and filters, as in conventional lasers.

d. Maintenance: Fiber lasers require no or low maintenance, depending on the output powers and other factors, as compared to conventional lasers. There are no optics to align and no warm up-times, as well as consumables/replacement parts. As a result, you can save substantial sums on maintenance.

e. Capital costs: With fiber lasers, the same laser can cut, weld and drill, allowing you to lower your investment costs as compared to purchasing and maintaining different lasers and laser systems for each of these functions.

 

16. How large is IPG?

  • IPG was the 4th largest maker of laser sources at the end of 2007 (measured by total sales)
  • As a result of the growing acceptance of IPG’s all solid-state fiber lasers across numerous industries and applications, IPG’s sales grew 32% in 2007 to $189 million from $143 million in 2006
  • IPG has over 400,000 sq. feet of manufacturing space in the US, Germany, Italy and Russia
  • IPG has sales and service centers in the US, Germany, UK, Italy, Russia, Japan, China, Korea and India. Contact us
  • IPG has over 1,500 employees
  • IPG is listed on the NASDAQ Global Market under the symbol “IPGP”