One of the essential QTekLaser technologies is the optical-fiber-based amplifiers that can amplify a milli-watt optical signal up to hundred-watt power while maintaining low noise and high reliability. These merits are critical to the laser applications in the rapidly growing quantum industry, which includes but is not limited to quantum sensing, quantum computing, and quantum communication. This type of amplifier is based on the physics that some special optical fibers, when being optically pumped, can be good optical gain media, through which a weak laser signal within a certain wavelength range can be amplified substantially. These special fibers and their amplification bandwidth are Yb-doped fiber with an amplification wavelength range of 1010 - 1090 nm, Er-doped fiber with a range of 1529 – 1615 nm, and Tm-doped fiber with a range of 1680 – 2060 nm.
QTekLaser has developed recipes to make multi-stage fiber amplifiers that can amplify a 10 – 20 mW input signal up to:
Within these specifications, the amplifiers are compatible with both broad-linewidth (GHz) and narrow-linewidth (<10 kHz) seed lasers without suffering from the stimulated Brillouin scattering (SBS) effect. Carefully selected low-noise electronics boards drive the amplifiers so that no significant noise is added to the amplified signals. This selection process is crucial to keep the residual intensity noise (RIN) of the laser small. To meet the 24/7 operation needs of the quantum industry, we enhance the long-term reliability of our lasers by incorporating a good thermal management design, vibration-resistant packaging, and a stage-by-stage interlock system. All readouts of monitor sensors inside the laser system can be accessed via TCP/IP protocols.
QTekLaser amplifiers work with various kinds of seed lasers. They can be economic semiconductor diode lasers with mega-hertz laser linewidth, robust fiber lasers with kilo-hertz linewidth, or expensive cavity-locked ultra-stable lasers with hertz-level linewidth. Based on customer requirements, we can recommend the best options and integrate them into the laser system as illustrated in figure 1.
QTekLaser offers laser systems with extended wavelength range by combining nonlinear frequency conversion technologies. One of the common processes is second-harmonic generation (SHG), through which we achieve significant laser power at the visible and NIR regime (see wavelength values in the red-shaded cells of table 1). This laser architecture is illustrated in figure 2. With the development of periodic poled crystal technology and the associated waveguide technology, nonlinear frequency conversion has become a powerful tool to extend the application scope of fiber lasers. For QTekLaser products, the max power of the converted laser light is constrained by the damage threshold of commercially available nonlinear crystals, which is typically several tens of watts.
Additionally, the wavelength range of QTekLaser products can be further extended using another nonlinear process, sum frequency generation (SFG). This laser architecture is illustrated in figure 3. 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 is one of the most important ways to achieve high power at certain wavelengths.
