MOPA Parameter Explorer

On a MOPA fiber laser, frequency and pulse width are the two parameters that control what colour appears on stainless steel. Unlike power or speed, they don't just make marks brighter or faster — they determine the thickness of the oxide layer the laser builds, and that thickness is what produces colour. This tool helps you understand what each combination tends to produce, so you can make better decisions before you start testing.

Choose your frequencyUse the slider to dial in your target frequency in kHz.
Select your pulse widthPick one of the 17 real JPT M7 waveforms — these are your actual options in LightBurn.
See what colours to expectThe result panel shows which colours you can expect on stainless steel at that combination.
JPT M7 only. This tool is calibrated for JPT M7 MOPA fiber laser sources (20W–100W), which are the source inside most ComMarker, OMTech, Monport, and Cloudray MOPA machines. Other sources (Raycus, MAX, IPG) have different waveform sets. Results are approximate starting points — always verify on your own machine and material.

Step 1 — Frequency

Frequency (kHz)
i
200 kHz

Step 2 — Pulse Width

Q-Pulse Width (ns)
i

These are the 17 real waveforms in a JPT M7 — not a continuous range. If you enter a value between two of these in LightBurn, your laser rounds to the nearest one.

Select a pulse width above to see what colours to expect on stainless steel.

Colours you can expect on stainless steel

Approximate starting points only — actual results depend on your machine's wattage, lens size, surface finish, and focus. Always run a material test to dial in for your specific setup.

Your selected parameters
Frequency —
Q-Pulse Width —
Effect zone —
About this tool

How the JPT M7 parameter system works

The JPT M7 MOPA source has 17 real pulse waveforms — CW (continuous wave) plus 16 discrete pulse widths from 2 ns to 500 ns. These aren't arbitrary numbers: each waveform shapes how energy is delivered per pulse, which changes the oxide layer that forms on stainless steel, which changes the colour you see.

Frequency and pulse width on a MOPA laser are independently adjustable — this is what separates MOPA from a standard Q-switched fiber laser, which has a fixed pulse width you can't change. That independence is exactly what makes colour marking possible across a wide palette.

The colour tendency hints in this tool are cross-referenced against real recipe data from the MOPA Colour Reference Chart and community-verified settings. They are honest starting points, not guarantees. Material finish, machine wattage, lens size, and focus all affect the final result.

This tool covers JPT M7 sources only. If you're on a Raycus or MAX source, your waveform options will be different — check your machine's documentation for the correct waveforms.

Common questions
5 questions
What does frequency actually do to the colour?
Frequency controls how many pulses per second hit the material. At higher frequencies (300 kHz and above), you're delivering many short bursts — each carrying less energy individually. This creates thin, precise oxide layers that produce blues, purples, and some greens. At lower frequencies (under 100 kHz), each pulse is more powerful and lingers longer, producing thicker oxide layers associated with golds, yellows, and eventually browns and blacks. The relationship isn't perfectly linear — pulse width interacts with it — but frequency is the coarser dial and pulse width is the finer one.
Why are there only 17 pulse width options?
The JPT M7 laser source uses pre-set waveforms — specific pulse shapes stored in its firmware. There are 17 of them: CW (continuous wave, used for deep engraving) and 16 discrete pulse durations from 2 ns to 500 ns. If you enter a value in LightBurn that falls between two of these — say, 7 ns — your laser will round to the nearest waveform (in this case 6 ns or 9 ns). The chips in this tool show the real options so you're always working with values your hardware actually supports.
What's the difference between this and the Colour Reference Chart?
The MOPA Colour Reference Chart gives you 15 complete, tested recipes — specific combinations of frequency, pulse width, speed, power, and line interval that have been verified to produce named colours on stainless steel. It's the "what settings do I use to get blue?" answer.

This Parameter Explorer works the other direction: "I'm thinking of using 300 kHz and 5 ns — what's that likely to produce?" It's a learning and exploration tool, not a recipe list. Use both together: explore here, then verify with the Reference Chart recipes on your machine.
Does this work for titanium or other metals?
The colour tendency hints in this tool are calibrated for stainless steel, which is the most common material for MOPA colour marking and the best-documented. Titanium also produces colour through oxide layer interference, and the parameter ranges have some overlap — but the exact colours at a given frequency/pulse width combination are different on titanium. Brass produces colour in a narrower range. For now, treat the results here as stainless-steel specific and test separately on other metals.
My colours still aren't coming out right — what else affects the result?
Frequency and pulse width are the primary colour controls, but several other factors influence the final result: speed (faster = less energy per mm, affecting oxide depth), line interval (tighter spacing = more energy overlap), focus (exact focal point matters more for colour than for engraving), surface finish (brushed vs polished vs matte steel all produce different results at the same settings), and steel grade (304 and 316 behave differently). If colours look washed out or inconsistent, check out the guide Why Stainless Steel Takes Colour from a MOPA Laser for a systematic troubleshooting approach.

Jason Mills

Builder of MOPA Color Studio. Based in Ontario, Canada. Verified settings on a 30W JPT M7 MOPA fiber laser. All tools on this site are free, require no account, and are built to help MOPA laser users get results faster.