The QTekLaser™ 619 nm Fiber Laser is a precision-engineered source for quantum technologies, including quantum networking and tin (Sn) vacancies. Using sum-frequency generation (SFG), it delivers up to 100 mW of stable, coherent 619 nm light in a compact 3U 19" rack-mount chassis with an IoT-enabled control interface, combining laboratory-grade performance with industrial reliability.
Need a different wavelength? The 619 nm system is one configuration of our sum-frequency (SFG) platform covering 609–706 nm. We routinely build custom wavelengths across this range. Tell us your target line.
The wavelength range of QTekLaser™ products can be further extended using the nonlinear process of sum-frequency generation (SFG). This architecture is illustrated in figure 2. The two fundamental lasers are usually made of different gain fiber amplifiers. The extended wavelength values are summarized in the blue-shaded cells of table 1. This method achieves high power at certain wavelengths.
Figure 2. QTekLaser™ sum-frequency generation (SFG) fiber laser system. The frequency sum mixer is integrated into the product.
SFG Output Wavelength Matrix
SF-AMP-Tm2 (865 – 1030 nm)
SF-AMP-Yb (1012 – 1112 nm)
SF-AMP-Er (1530 – 1610 nm)
SF-AMP-Tm (1730 – 2060 nm)
SF-AMP-Yb (1012 – 1112 nm)
466 – 535 nm
506 – 556 nm
SF-AMP-Er (1530 – 1610 nm)
553 – 628 nm
609 – 658 nm
765 – 805 nm
SF-AMP-Tm (1730 – 2060 nm)
576 – 687 nm
638 – 722 nm
812 – 904 nm
865 – 1030 nm
Table 1. Wavelength extension of QTekLaser™ products via nonlinear frequency conversion. The red-shaded cells represent second-harmonic generation (SHG) and the blue-shaded cells sum-frequency generation (SFG).
QTekLaser™ lasers comply with Federal Regulations (21 CFR Subchapter J, Part 1040) as administered by the Center for Devices and Radiological Health and are certified to IEC 60825-1:2014 standards.
It is the end user's responsibility to ensure that no significant light is retroreflected back into QTekLaser™ systems as this can degrade performance and potentially damage the lasers. To prevent this, the use of an external optical isolator is strongly recommended. Damage due to retroreflected light is not covered under warranty.
It is the end user's responsibility to ensure that no significant light is retroreflected back into QTekLaser™ systems as this can degrade performance and potentially damage the lasers. To prevent this, the use of an external optical isolator is strongly recommended. Damage due to retroreflected light is not covered under warranty.
Figure 7. Tunability: Frequency vs. Seed Laser Temp. 619 nm fiber laser
Tunability Wavelength vs. Seed Laser Temp.
Figure 8. Tunability: Wavelength vs. Seed Laser Temp. 619 nm
Tunability Frequency vs. Seed Laser Current
Figure 9. Tunability: Frequency vs. Seed Laser Current 619 nm
Tunability Wavelength vs. Seed Laser Current
Figure 10. Tunability: Wavelength vs. Seed Laser Current 619 nm
Optimal SFG temperature vs. Wavelength
Figure 11. Optimal SFG temperature vs. Wavelength 619 nm
Frequency Modulation via the SMA port
Figure 12. Frequency Modulation via the SMA port 619 nm
Quantum Networking
Quantum networks rely on exquisitely controlled, low-noise optical signals to transmit quantum states (e.g. single photons, entangled photons) over fibers or free-space links. The 619 nm fiber laser from QTekLaser™ offers a compelling light-source solution for quantum networking platforms that exploit visible-wavelength transitions (for instance, in certain quantum memories, frequency converters, or quantum repeaters).
Key Benefits in Quantum Networking
High coherence — With a linewidth below 2 MHz, the 619 nm output supports long coherence times and low phase noise, critical for maintaining quantum phase relationships and ensuring high-visibility interference between remote nodes.
Low relative intensity noise (RIN) — The design delivers RIN better than –130 dBc/Hz (above 10 kHz), which helps suppress amplitude fluctuations that would otherwise degrade quantum bit error rates.
Power stability & reliability — The system offers <1% power variation over time, enabling stable link budgets and predictable behavior in long-duration experiments.
Fiber-coupled polarization-maintaining (PM) output — The PM630 fiber output with FC/APC connector ensures polarization purity and easy fiber integration, which is important for polarization-encoded qubits or coupling into downstream optics.
Compact, rack-mount form with IoT control — In a 3U, 19″ chassis with forced-air cooling, and integrated IoT-enabled interface, the laser is well suited for deployment in laboratory racks or quantum network nodes.
Sum-frequency generation (SFG) architecture — By internally converting from two seed lasers via SFG, the laser can deliver a stable visible wavelength without requiring external non-linear modules, simplifying system assembly and reducing alignment sensitivity.
Use Cases & Scenarios
Frequency conversion / quantum transduction — In many quantum networks, one needs to convert photons between telecom bands and visible or near-visible wavelengths (for atomic or solid-state quantum memories). The 619 nm source can serve as a pump or intermediate wavelength in sum-/difference-frequency conversion modules.
Quantum memory addressing / readout — Some quantum memory media (e.g. SnV) have transitions near 619 nm; the laser can be used to address, excite, or read out states in these systems.
Inter-node synchronization / calibration — The laser may be used to generate reference or calibration signals among nodes, enabling phase locking, channel stabilization, or alignment verification.
Interferometric quantum protocols — In quantum key distribution (QKD) or entanglement distribution over interferometers, the high coherence and low noise characteristics support high visibility and low decoherence.
Spec Highlights for Quantum Networking Applications
Parameter
Value
Why It Matters for Quantum Networking
Wavelength
619 nm
Matches visible transitions or acts as intermediate pump
Output power
Up to 100 mW
Sufficient headroom for conversion, splitting, or coupling losses
Linewidth
2 MHz
Supports coherent interference, long coherence length
RIN
< –130 dBc/Hz (≥ 10 kHz)
Minimizes amplitude noise that can degrade quantum SNR
Power stability
< 1% drift
Ensures stable link performance over time
Polarization extinction ratio
≥ 18 dB
Maintains polarization fidelity for polarization-encoded qubits
Output format
PM fiber (PM630, FC/APC)
Easily integrates with fiber-based quantum systems
Form factor
3U rack-mount, IoT interface
Convenient deployment in quantum network racks or nodes
