Narrow-Linewidth 780-nm DFB Lasers Fabricated Using Nanoimprint Lithography

Purely Gain-Coupled Distributed-Feedback Bragg Semiconductor Laser Diode Emitting at 770 nm

“…The DFB lasers have a cavity length of 1 mm, with facet coating (high reflection >99%, antireflection <0.5%). The maximum CW power of the devices in single-longitudinal-mode operation is as high as 116.3 mW at 350 mA, which is better than that of the laterally coupled ridge-waveguide (LC-RWG) surface gratings of the DFB lasers (which is 28.9 mW), reported in [37], and better than commercial DBR lasers (which is 80 mW) [31]. An ECDL can get higher output power [37], even more than 700 mW.…”

Advances in narrow linewidth diode lasers

“…It was an ideal low-cost DFB laser technology solution, which made LC-DFB easier to integrate into large-scale optoelectronic devices. In 2018, Virtanen et al [2] from the University of Tampere in Finland proposed a narrow-linewidth DFB laser using a nanoimprinting technique to fabricate a third-order lateral surface grating combined with a ridge waveguide structure, achieving a wavelength of 780 nm and a laser power of 28.9 mW at 300 mA, a narrow linewidth output with SMSR > 40 dB, and a line width < 10 kHz; this technology is suitable for manufacturing low-cost miniaturized atomic clock pump modules.…”

“…In 2016, a high-quality quantum dot distributed feedback (DFB) semiconductor laser [1] was proposed by Kassel University in Germany, which successfully reduced the laser linewidth to 10 kHz. Subsequently, a side-coupled surface grating DFB laser was fabricated by nanoimprint technology at Tampere University, Finland; the laser power was 28.9 mW and the linewidth was less than 10 kHz [2]. In the field of external cavity feedback technology, the German FBH Institute proposed using a DFB laser chip and integrating it with the confocal Fabry Pérot cavity to form a resonant feedback resonator; for this laser, the output power was 50 mW and the Lorentz line width was only 15.7 Hz which is the highest recorded level in the world [3].…”

Spectral Linewidth vs. Front Facet Reflectivity of 780 nm DFB Diode Lasers at High Optical Output Power

“…Semiconductor-based distributed feedback (DFB) lasers with excellent spectral purity, high energy-conversion efficiency, high reliability, and large frequency modulation bandwidth are attractive candidates for this demand. Some previous studies on the performance of the lasers [8][9][10] had shown very promising results for application in quantum optics. Therefore, further development of this diode laser type needs to be done.…”