Single Frequency Laser diodeS

Single frequency laser diode is a specialized type of laser that emits light at a single, highly stable wavelength. Unlike typical laser diodes that might produce light over a broader spectrum, single frequency laser diodes are designed for applications that require a very narrow linewidth and high spectral purity. This makes them ideal for a variety of advanced technological applications, including cold atom spectroscopy, Raman spectroscopy, interferometry, and tunable diode laser absorption spectroscopy (TDLAS).

TOPTICA EAGLEYARD offers different kinds of laser types as single frequency laser diodes. Our portfolio of comprises a variety of different laser and package designs like Distributed feedback lasers (DFB lasers), distributed Bragg reflector lasers (DBR lasers), RWS (Rich Waveguide Stability) lasers and our miniECL.

DFB Laser Diodes

DFB Laser Diodes Distributed Feedback (DFB) lasers are a prominent type of single frequency laser diode. They are engineered to maintain a single longitudinal mode, ensuring that the laser operates at a single frequency. This is achieved through the integration of a grating structure within the laser’s active region. The grating provides feedback by reflecting light only at the desired wavelength, while other wavelengths are suppressed, ensuring that the laser operates in a single mode. DFB lasers are highly valued for their ability to produce a stable, narrow linewidth, which is crucial for applications requiring precise frequency control. The inherent design of the DFB laser diode eliminates the need for external components to stabilize the frequency, making it a compact and reliable option for many single frequency applications. Especially for industrial applications with a demand for higher volumes and low costs we designed stabilized ridge waveguide lasers (RWS lasers). The design of the RWS laser is derived from DFB lasers and allows wider tolerances in the manufacturing process which enables a higher yield and thus a reduction of costs. In contrast to the RWS lasers our extended cavity lasers (ECDL) are aiming at very demanding spectroscopic application. Our miniECL products are available for various wavelengths and achieve a linewidth of 100 kHz. The integration into a hermetically sealed standard 14 pin butterfly package makes the miniECDL robust and easily usable.

DBR Laser Diodes

Another important technology in the realm of single frequency laser diodes is the Distributed Bragg Reflector (DBR) laser. Similar to DFB lasers, DBR lasers also utilize a grating structure to achieve single frequency operation. However, the key difference lies in the placement of the grating. In DBR lasers, the grating is located outside the active region, at one or both ends of the laser cavity. This configuration allows the DBR laser to achieve a similar narrow linewidth as DFB lasers.

RWS Laser Diodes

RWS laser is a word creation by TOPTICA EAGLEYARD – is stands for “Rich Waveguide Stabilized” and uses the same chip material, design and technology as classical DFB lasers – but at half the costs. RWS lasers are specifically developed for industrial usage, mainly for interferometry and users that are very cost-sensitive. RWS lasers can make projects become reality when a small linewidth is required while an exact target wavelength is not needed. The RWS lasers guarantee a mode-hop free range when operating conditions are set ideally. The RWS laser is available at 780 nm – a sweet spot for high performance of the laser and good sensitivity of silicium Si detectors that are available at very low costs compared to other wavelengths making our RWS laser a real ‘cost-saver’.

miniECL

Another specialty is the miniECL of TOPTICA EAGLEYARD. In contrast to the RWS lasers our extended cavity lasers (ECDL) are aiming at very demanding spectroscopic application. The very compact design of the ECDL comprising a gain chip with an external grating enables the integration into a 14 pin butterfly package with integrated beam collimation. The high integration into the standard package makes the miniECL suitable for the use in the lab as well as for the integration into industrial products enabling the mounting on printed circuit boards. Our miniECL products are available for various wavelengths and achieve a linewidth of 100 kHz and a SMSR of typ. 50 dB. Like the laser types mentioned before the miniECL requires no readjustments of the laser cavity because of the robust design, the high mechanical stability of the resonator and the hermetically sealed package with integrated thermoelectric cooler.

Advantages of Single Frequency Laser Diodes

Single frequency laser diodes offer several significant advantages over broader spectrum laser diodes, making them the preferred choice for many high-precision applications. These advantages include:

Narrow Linewidth: The narrow linewidth of single frequency laser diodes results in a reduction in phase and frequency noise, which is critical for applications that require precision measurements.
High Spectral Purity: Single frequency laser diodes produce light with excellent spectral purity and high side-mode suppression ratio (SMSR).
Stability: The ability of single frequency laser diodes to maintain stable output power due to a low mode partition noise.

The narrow linewidth of these lasers leads to a reduction in phase noise, making them ideal for a variety of precision measurements. Their ability to maintain stable single-frequency operation over time and temperature changes also makes them highly reliable for long-term use in critical applications. Moreover, the compact design of single frequency laser diodes, especially when compared to larger systems that might require external stabilization components, makes them suitable for integration into various devices where space is at a premium. This compactness, combined with their high efficiency and low power consumption, makes single frequency laser diodes an excellent choice in many photonic applications.