Depending on the application, the wavelength and can be very important.  In Multimode applications the most common wavelength is 850 nano-meters. For high speed applications a VCSEL or Vertical-Cavity Surface-Emitting Laser is used due to it’s low cost and high speed.

In Singlemode the most common wavelength is 1310 nano-meters. Typically a Fabre Perot laser is used for applications under 15 KM. For longer distances of up to 80 + KM a 1550nm DFB or Distributed Feedback laser is used. Over long distances, dispersion or the spreading of the laser light becomes a factor. A DFB laser typically has a tighter optical spectrum and higher optical power so distances of over 80 KM can be reached.

Since DFB lasers have a tighter spectrum and are much more stable over temperature, they are ideal for CWDM optical multiplexing. Up to 18 DFB lasers in varying wavelengths from 1271 nano-meters up to 1611 nano-meters can be multiplexed with a 20 nano-meter spacing on one fiber. Due to the tight spectrum and temperature stability, the lasers maintain there assigned wavelength and do not bleed into one another.   Further details on fiber transport solutions, please click here.

FAQ, Tech Talk with Jim Jachetta FAQ, fiber, laser, multimode, singlemode