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Fp laser vs dfb laser.
Dfb laser is with higher production cost and suitble for long distance transmission.
Distributed feedback laser selects only one principal wavelength in fp laser spectrum.
Fabry perot laser diodes are lasers whose mirrors are simply the flat cleaved surfaces at the ends of the laser chip.
It is more precise compare to fp laser type.
Distributed feedback dfb laser diodes are lasers that have a grating structure in the cavity that produces multiple reflections throughout the cavity.
Their operating wavelength threshold current and forward voltage are also different.
Shen 1electrical and electronic engineering the university of hong kong hong kong china people s republic of introduction.
Eventually a red shift occurs to a higher gain mode leaving a gap in the tuning range.
In this tutorial we will quickly explain what is a dfb.
Fp lase are mainly used for low rate short distance tramission.
While the spectral width of the fp laser is relatively wide it is a multi longitudinal mode laser.
Comparison of fp vcsel and dfb laser diode in optical transmission for mr rf coil array c.
Yuan and g.
Chart from reference 3.
The spectral width of the dfb laser is generally narrow is a single longitudinal mode with distributed negative feedback.
Following are the characteristics of this dfb laser type.
Optical fiber transmissions of using direct modulation and external modulation for multi receiver array have been applied to remove the cable cross.
The fp laser spectral width is relatively wide is a multi longitudinal mode lasers.
In summary fp and dfb lasers working principles are different.
This is a fatal mode hop if the desired wavelength exists within the gap.
For example the tramission distance is generally within 20 km the speed is generally within 1 25 g and the fp is divided into two wavelengths 1310 nm 1550 nm.
Typical tuning curve of a dfb laser 3.
It has output power capability much lower than fp laser type.
A distributed feedback laser dfb is a type of laser diode quantum cascade laser or optical fiber laser where the active region of the device contains a periodically structured element or diffraction grating the structure builds a one dimensional interference grating bragg scattering and the grating provides optical feedback for the laser this longitudinal diffraction grating has periodic.
The main difference can be got by the form between the fp and dfb laser is that the spectral width is different.
