Quasi-CW Fiber Lasers

IPG Photonics' quasi continuous wave (QCW) fiber

lasers produce peak power 10 times greater in

pulsed versus CW mode and are ideal for the

replacement of conventional flashlamp-pumped

YAG lasers used in spot welding, seam

welding & drilling. The QCW Series fiber

lasers can be retrofitted into most

existing systems. These compact

units are substantially more

cost-effective than lamp-pumped

YAG lasers due to >30% wall-plug

efficiencies and maintenance-

free operation.

Quasi-CW Fiber Lasers
The Last Replacement Part you will EVER Need for your YAG Laser

First in the world IPG's Quasi-CW fiber lasers are available for requalifying existing lamp-pumped processes at IPG’s application facilities and applications labs. IPG's QCW Series also features a highly cost-effective OEM module.


Retrofit services, including engineers familiar with system integration, are available to help customers replace older production lasers with energy-efficient fiber lasers from IPG.

Features of Quasi-CW Lasers

Maximum Peak Power  = 10x Average Power Wall-plug Efficiency >30% 
Outstanding Pulse Power/ Energy Stability Pulse Duration* 0.05-50 ms
Internal Pulse Generator/ Pulse shaping Single-mode or Multi-mode

* Minimum pulse duration is 10 microseconds upon request. Please contact your IPG representative.

Q-switched fiber lasers are capable of providing pulse energies in the mJ range, but for materials processing applications requiring multiple Joules of pulse energy at multi-kilowatt peak powers IPG has developed the unique Quasi-CW Fiber Lasers. These fiber lasers occupy the space between kW class CW fiber lasers and Q-switched pulsed lasers.  They are very similar to kW class fiber lasers with one notable difference: their peak power during ON time is up to tenfold higher than their average power in pure CW mode of operation. Thus, these lasers can provide tens of joules of energy over a long pulse, from 50 microseconds to 50 milliseconds.

Another important note is that although the same peak and average power could be obtained by modulating IPG's kW-class power ytterbium lasers, the QCW lases are significantly cheaper, providing affordable high peak power in several 100 Watt to a few kW average power range.


Individual Quasi-CW Fiber laser pulses can be modulated with analog control to achieve the optimal temporal pulse shape or pulse train for any particular application: 

  • Multi-pulse for drilling
  • Ramp up for pre-cleaning
  • Enhanced spike for high reflectivity materials
  • Remove porosity or shrinkage pipe in center of weld
  • Ramp down pulse used for reducing cracking on crack sensitive materials

The availability of true single-mode beam mode quality combined with very high pulse energy has never before been achieved in a competitively priced laser. 


Flat-top beam profile is optimal for many applications. YLM modules and YLR rack-mounted units are available with both single-mode and multi-mode feed fibers, YLS systems are available with multi-mode feed fibers starting from 50 micron core.


True single-mode beam mode quality



Flat-top beam multi-mode beam mode

Choice of delivery fibers: 50, 100, 200 or 300 micron core

  • no lamp replacement
  • compact
  • 10x energy efficient, > 30 % wall-plug efficiency
  • temporal pulse-shaping
  • no free space optics, all fiber design
  • thermally and mechanically robust
  • not a fiber delivered laser - FIBER laser
  • choice of delivery fibers: single-mode, multi-mode or flat top
  • red aiming diode 
YLR-QCW Ytterbium fiber laser







YLM modules:

OEM & Integrator 

YLR 19" rack-mountable units:

compact user-friendly interface

YLS systems:

kW class industrial rugged design

  YLM-QCW module  YLR-QCW   YLS-QCW system
Interface Analog/ RS-232 / Ethernet Touchscreen front panel,  RS-232, Digital I/O, Analog Control

Standard: LaserNet, Digital I/O, Analog Control

Optional: DeviceNet, Profibus or Ethernet

  Average Power, W Peak Power, W

Enclosure Dimensions

(W × D × H), mm

Feed Fiber
YLM-150/1500-QCW-AC  150 1500  256 × 435 × 148 Single-mode fiber to
LC-8 connector
YLR-150/1500-QCW-AC  448 × 502 × 177
YLM-200/2000-QCW-AC 200 2000 336 × 435 × 148
YLM-300/3000-QCW-AC 300 3000 336 × 435 × 148 50, 100 or 200 μm fiber
 to LC-8 connector
YLR-300/3000-QCW-AC 448 × 504 × 266 
YLM-450/4500-QCW-AC 450 4500 416 × 566 × 148
YLR-450/4500-QCW-AC 448 × 680 × 286
YLM-450/4500-QCW-WC 411 × 509 × 85
YLR-450/4500-QCW-WC 448 × 680 × 177
YLS-600/6000-QCW-AC 600 6000 775 × 800 × 550 
YLS-600/6000-QCW-WC 411 × 509 × 85
YLS-900/9000-QCW-WC 900 9000

1000 × 800 × 550


850 × 800 × 1100

100, 200 or 300 μm fiber
to HLC-8 connector

YLS-1200/12000-QCW-WC 1200 12000
YLS-1500/15000-QCW-WC 1500 15000
YLS-1800/18000-QCW-WC 1800 18000
YLS-2000/20000-QCW-WC 2000 20000

-AC and -WC are air-cooled and water-cooled models, repectively.

Higher or lower powers are available upon request. Please contact your IPG representative.

Single-mode YLM-QCW and YLR-QCW models are available up to 2.5 kW peak QCW power. 

Maybe the Most Flexible Laser Ever Fiber Laser Micromachining in High-volume Manufacturing

TWI (Cambridge, UK) endorses IPG's Quasi-CW fiber lasers

TWI endorses IPG QCW fiber lasers for spot welding, cutting, seam welding and drilling applications

TWI is one of the world’s foremost independent research and technology organizations, with expertise in materials joining and engineering processes as applied in industry.

QCW fiber lasers Wavelength, nm  Beam Mode Modulation Frequency

Output Power,

average/peak, W 

DLM-QCW 895  Multi-mode
up to 10 Hz

300/3000 and 600/6000

1070±5 Single-mode  0-50 kHz 75/750 to 200/2000
Multi-mode 150/1500 to 600/6000
YLS-QCW Multi-mode 0-5 kHz 600/6000 to 2400/24000*
YLS-QCW-AMB 1070 ±2 Multi-mode


* Higher output powers are available upon request.


Drilling Cutting
Spot Welding Batteries
Seam Welding Medical Devices
Microwelding Computer Components
Application Note _05_ Cutting with Long Pulse Fiber Lasers YLR 150_1500-QCW-AC Application Note #15: Temporal Pulse Shaping of Millisecond High Pulse Energy Fiber Lasers

QCW Fiber Laser Receives 2010 Prism Award for Photonics Innovation

Category of Industrial Lasers

The Quasi Continuous Wave pulsed fiber laser replaces the aging population of inefficient flash lamp-pumped solid state lasers with much smaller and longer lasting diode pumped devices. Plus, it has 30% rather than 3% wall-plug efficiency.

For your convenience, we have sales offices in many locations. Here you can contact our Sales Force, request literature, ask us a question.