Koheras HARMONIK H63

Koheras HARMONIK H63 – 630 nm range high-power fiber laser

Are you looking for a high-power laser in the 624-644 nm range for conversion into the UV wavelengths required for Rydberg excitation of strontium, lithium, cesium, or helium? Or perhaps a high-power alternative to 633 nm HeNe lasers?

Discover our Koheras HARMONIK fiber laser systems!

The Koheras HARMONIK are single-frequency, mode-hop-free, and ultra-stable fiber lasers. Engineered for high-power and narrow-linewidth light at precise atomic transitions, they are perfect for quantum applications.

Experience excellence with Koheras HARMONIK lasers, ideal for quantum computing, sensing, metrology, and communications. Featuring a robust single-frequency design, low phase and intensity noise, high OSNR, and industrial-grade reliability.

Key Features

Up to 10 W output power

Sub-kHz linewidth

Ultra-low frequency and intensity noise

Wide wavelength tuning

Excellent beam quality, M2 < 1.1

Fiber delivery option

Want to know more?

Get in touch with one of our Koheras laser experts and learn more

Industrial reliability

We know that uptime is important to you. Our Koheras fiber lasers are inherently stable. They are reliable, alignment-free, and maintenance-free. You can mount them in a rack or place them upside down, they just do their job. Others even trust our Koheras lasers enough to send them into space. And should you need support, we have a team of dedicated engineers ready to help.  

15,000 Koheras lasers have been installed in demanding industrial applications for decades. Now, they are ready to assist you in your quantum research.  

Unique fiber delivery system 

Do you want to mount the laser system in a rack? No problem. With the unique fiber delivery system, you can get light wherever you want. The fiber delivery solution handles high power, preserves the low-noise laser properties, and delivers single-mode light at all wavelengths.  

Fast wavelength modulation

The systems are equipped with easy and user-friendly fast wavelength modulation. This feature is typically used to lock the laser to an external stable reference — such as an atomic transition line or interferometer — to obtain even higher wavelength stability than provided by the free-running laser.

The HARMONIK systems offer a 15 GHz mode hop-free tunability with a 10% power change.

Thermal tuning

All Koheras fiber lasers are equipped with thermoelectric temperature controllers (TECs).

The TECs stabilize the operation of the laser and make it insensitive to environmental temperature fluctuations. The TECs also make it possible to tune the center wavelength by changing the operating temperature of the laser.

At standard room temperature (around 20-30°C or 68-86°F) the laser can be thermally tuned to an industry-leading 500 pm.

Looking for a Titanium-Sapphire substitute?

You can successfully replace Ti:Sapphire lasers with Koheras HARMONIK fiber laser systems to get a stable alternative with high power and a narrow linewidth.

More details on noise and linewidth

If you want more details about phase noise, spectral linewidth, frequency stability, or how to wavelength tune your Koheras laser, we have some application notes for you.

Laser phase noise is a frequency-domain view of the noise spectrum around the laser signal. Read more about phase noise in single-frequency lasers.

Spectral linewidth is a measure of the spectral content of the laser light. Read more about linewidth measurement methods.

The laser’s frequency stability is often described in terms of its spectral linewidth. However, this term lacks detail about the laser frequency noise which is often critical in laser applications. Read the analysis of the laser frequency stability using beat-note measurement.

The wavelength of the laser is controlled by the temperature and strain of the DFB cavity. Learn how to tune your Koheras laser.


Choose model:
Center wavelength1) [nm]
Standard wavelength [nm]
Laser emission
Beam quality
M2 < 1.1
Output power2) [W]
> 10
Linewidth [kHz]
< 20
RIN peak [MHz]
≈ 1
RIN level @ peak [dBc/Hz]
< -100
RIN level @ 10 MHz [dBc/Hz]
< -140
Long term stability (peak-peak, 1h @25°C)3)  [%]
< 10
Optical S/N (50 pm res.) [dB]
> 70
Polarization / PER [dB]
> 20
Min. thermal wavelength tuning range [pm]
± 140
Total thermal wavelength tuning range [pm]
Fast wavelength modulation range [GHz]
> 8
Fast wavelength modulation [kHz]
Up to 20
Pump unit(s) size for 19” rack system [U]
Number of frequency conversion modules4)

1) Center wavelength is selectable within the specified range.
2) Shot noise-limited > 5 Mhz.
3) After a 10-20 minute warm-up.
4) Delivered as tabletop modules(s).

Weight [kg]


Power supply requirements
100-240 VAC, 50-60 Hz
Digital interface
Ethernet 10/100
Monitor output, standard
Monitor output, optional 1)

1) 2.5 m high power, single mode fiber delivery