Optical Sources – LED and Laser Diodes

Jun 21 • Notes • 3014 Views • 3 Comments on Optical Sources – LED and Laser Diodes

Optical Sources – LED and Laser Diodes

LED STRUCTURE
– They can be seen glowing green, yellow or red in vehicles, telephones, cameras.
– They are inexpensive and highly reliable light sources.
– The LED used in optical communications are much smaller and emit in the infrared region

MATERIALS:-
– Semiconductor-based light sources are about the size of a grain of salt.
– It allows efficient coupling of the light output in small diameters of fibers.
– They are compatible with integrated-circuit electronics because of its semiconductor structure.

MODULATION OF LED
– It is used for producing a light level which is proportional to some signal.
– The signal can then be send through a fiber optic cable and detected on the other end.
– Then a device produces a current proportional to the input voltage of the applied signal.
– This can be done with the help of an op-amp that acts as a voltage-to-current converter.

 

LASER DIODE:-
– They are the optical sources used in fiber communication systems.
– The four types of lasers are the Fabry-Perot (FP) laser, the distributed-feedback (DFB) laser, tunable lasers and the vertical cavity surface-emitting laser (VCSEL).

EXPECTED QUESTIONS WITH ANSWERS

1) WHAT IS LED AND WHAT ARE THE MATERIALS USED IN LED?

Ans:- – They can be seen glowing green, yellow or red in vehicles, telephones, cameras.
– They are inexpensive and highly reliable light sources.
– The LED used in optical communications are much smaller and emit in the infrared region

MATERIALS:-
– Semiconductor-based light sources are about the size of a grain of salt.
– It allows efficient coupling of the light output in small diameters of fibers.
– They are compatible with integrated-circuit electronics because of its semiconductor structure.

2) HOW IS LED MODULATED?

Ans:- MODULATION OF LED
– It is used for producing a light level which is proportional to some signal.
– The signal can then be send through a fiber optic cable and detected on the other end.
– Then a device produces a current proportional to the input voltage of the applied signal.
– This can be done with the help of an op-amp that acts as a voltage-to-current converter.

3) WHAT ARE LASER DIODE?

Ans:- – They are the optical sources used in fiber communication systems.
– The four types of lasers are the Fabry-Perot (FP) laser, the distributed-feedback (DFB) laser, tunable lasers and the vertical cavity surface-emitting laser (VCSEL).

 

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