Innolume developed 4-mm-long Quantum Dot DFB lasers with ultranarrow spectral line.

We have recently developed Quantum Dot-based DFB laser chips with length of 4 mm for O-band. The increased chip length enhances the laser resonator finesse and maximal achievable optical power. As a result, record-narrow spectral line was achieved with full width at half maximum (FWHM) of only 120 kHz. In order to resolve such small linewidth, the self-heterodyne technique was used. The line shape is fitted by Voigt function accounting for inhomogeneous and homogeneous contributions. While the former one is low due to the suitable laser design, the latter one benefits from the low alpha-factor characteristic for active medium based on quantum dots. Stabilization of the laser emission with active feedback would allow to reduce the linewidth further down to tens of Hz. 

These devices can be used in any applications requiring highly reliable semiconductor lasers with excellent emission characteristics and especially in applications with strict requirements on laser coherence, such as LIDARs or coherent data transmission.

Our team is working on introduction this model into series.