DFB vs DBR (or vs VCSEL vs other semiconductor lasers)

[Laserenthusiast]

Hi everyone!

I’ve been reading into semiconductor lasers and came across DFB and DBR lasers and while I understand, superficially, the difference between them, I fail to find an application or necessity that would absolutely need a DBR laser and couldn’t be done with a DFB laser or VCSEL or other type of semiconductor laser.

Anyone have some knowledge they’d like to share on this?

Thank you!

[kecked]

https://www.photodigm.com/difference...ied%20grating.

google is your friend

[sgdbr1550]

The primary advantage of a DBR laser over a DFB or VCSEL is its inherent wavelength tunability. DBR lasers designed for optical fiber communications can tune across the entire C-band, making them them attractive as source laser for wavelength-division-multiplexed transmission. WDM systems can transmit upwards of a hundred or more channels of information simultaneously over a single fiber, and a multi-section DBR laser can tune to any of those channel's wavelengths by appropriately adjusting reflector tuning currents and phase section current. In contrast, a DFB or VCSEL typically has just a single current to control optical power, and limited tuning through temperature around a nominal wavelength fixed by the grating or epilayer design.