Ultra-stable Master Laser

The laser systems offered by iXblue have been initially developed for our own use to operate our commercial Quantum Sensors, namely the Absolute Quantum Gravimeter and our cold-atom clock. The USML laser is a master laser whose frequency is stabilized on an atomic transition using saturated absorption spectroscopy. Our laser systems are equipped with dedicated electronics, on-board computer and power supply to offer:

• ultra-low noise laser light
• agile and precise frequency control
• Industry-grade integration and remarkable robustness
• user-friendly operation

Because integration, robustness and reliability were the key drivers for our developments, the laser systems proposed by iXblue are based on C-band optical telecom seed lasers. The laser light at telecom wavelength, like 1560 nm, is then amplified and frequency-doubled to generate the required wavelength.

These laser systems can integrate an ultra-low noise microwave synthesizer, upon request.

This laser system is also available without the frequency-stabilization module.

The seed module

The current version of our laser system can include a DFB laser diode or an ECDL as a seed laser. We developed dedicated ultra low-noise electronics to achieve outstanding spectral features.

The amplification module

A specific EDFA architecture was developed for these laser systems. Strong R&D efforts were conducted to optimize several key parameters such as Amplified Spontaneous Emission (ASE), wall-plug efficiency, polarization characteristics, and power stability.

The frequency doubling module

Second harmonic generation is obtained with a PPLN waveguide crystal qualified for high power operation. This component also offers a very high conversion efficiency which loosens constraints on power requirements and management of thermal effects.

The frequency-stabilization module

The frequency of the laser is stabilized on an atomic transition thanks to an optimized saturated absorption spectroscopy technique. Our design is based on a heated and magnetically shielded gas cell, and includes specific ultra low-noise frequency-lock electronics. This allows to keep the laser frequency locked on the atomic transition over several months. In addition, the locking of the laser frequency is automated and does not require any optimization from the user.

The laser system developed by iXblue relies on the use of lasers operating at 1560 nm. This approach therefore gives access to a wide variety of high performance fibered optical components, originally developed for high-bit-rate optical communication systems. Thanks to the technological efforts conducted over the last 20 years by the telecom industry, these components present unique features:

• fibered components: no optical alignment required
• remarkable optical and electrical performances
• compliance with Telcordia qualification procedures (extended temperature range)
• high reliability (lifetime > 50 000 h).

Installation time: 10 minutes (no optical alignment, no mechanical assembly, no manual adjustment required prior to operation)

Auto-lock: the frequency locking of this master is automated and managed by the on-board computer. No manual adjustment required.

Robustness: the frequency lock remains locked for month without any action required from the user. It is robust with regard to temperature variations and vibrations.

Software: Dedicated and user-friendly data acquisition and system controller software
Automated starting procedure
Automated self-calibration procedures
Remote access and real-time data retrieval

Small footprint: the laser system is integrated within 19’’ rack and features an output fiber whose length can be of several meters.

Option: this laser system is also available without the frequency-stabilization module.

The laser systems provided by iXblue feature state-of-the-art optical performances that meet the stringent demand of cold-atom physics and atom interferometry. On the optical domain, careful measurements show a typical linewidth of 50 kHz at 780 nm and a typical frequency stability of the different slave lasers of 50 kHz rms over days.

In terms of atomic performances, we are able to characterize on the Absolute Quantum Gravimeter that atomic temperatures as low as 2 µK can be obtained with ILS780 laser series. We also conclude that the number of atoms trapped in the MOT is stable within a few percent over months.

After several years of industrialization of USML lasers, iXblue is able to commit to excellent performance to sustain the most ambitious R&D projects and product developments.