- #1
fisico30
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fastest modulation: laser diode vs LED...
Hello Forum,
in the telecomm industry, the most common and economical form of modulation is direct modulation, acting on the current operating LEDs or diode lasers.
Using an external intensity modulator (OOK), like a super fast chopper, the process of modulation and source characteristics (carriers recombination) are independent.
Will LED pulses generated with an external intensity modulator be of poorer quality, after a certain limit chopping speed, compared to the laser diode pulses? If so, why? Is it due to the different coherence properties of the two sources, the laser and the LED?
Theoretically, It would seem that light pulses from either a laser or LED would be comparable (eye diagram), no matter how high the OOK speed, if we used an external modulator...
(LEDs have lower coherence properties, both spatial and temporal, due the broader linewidth, less directionality and power density)
thanks,
fisico30
Hello Forum,
in the telecomm industry, the most common and economical form of modulation is direct modulation, acting on the current operating LEDs or diode lasers.
Using an external intensity modulator (OOK), like a super fast chopper, the process of modulation and source characteristics (carriers recombination) are independent.
Will LED pulses generated with an external intensity modulator be of poorer quality, after a certain limit chopping speed, compared to the laser diode pulses? If so, why? Is it due to the different coherence properties of the two sources, the laser and the LED?
Theoretically, It would seem that light pulses from either a laser or LED would be comparable (eye diagram), no matter how high the OOK speed, if we used an external modulator...
(LEDs have lower coherence properties, both spatial and temporal, due the broader linewidth, less directionality and power density)
thanks,
fisico30