Introduction to Photonics | Session 5 | Problem Solving | NPTEL

Good afternoon everyone. Today we are going to have a uh problem solving session uh for the introduction to photonics. This is a live session five and we are going to discuss about few uh things about the optical system including the lazing and uh cavity effect. So and optical amplification. So optical amplification uh there were there are so

many uh uh concepts uh involved in this uh particular topic. So we are going to discuss one by one including the lazing which is also uh amplification of light. So [clears throat] starting with this uh big uh theme which is optical amplification the physics of information across oceans. So uh we know that the while the light

or the uh wavelength of 1550 nanometer which is in IR telecom wavelength propagating through the optical fiber has the attunation of 0.2 uh decibel per kilometer. So it means that even pure ultra [clears throat] ultra pure silica glass experiences inherent optical signal loss or due to the relay scattering and absorption. So uh it

means that the uh signal loss of 20 decibel which is approximately 90 uh more than 98%. um uh has the uh only capability to travel the signal capability to travel up to 100 km and the uh power reduction is when the factor of 100. So uh what do we need to do to uh

uh compensate this loss? So here there uh uh amplification must be done to transmit the uh signal with the uh lossless form or less attenated form. So to uh to do this uh what we have to do is we need to amplify the uh telecom signal and how it can be done it can be done by

the amplifier and in the optical signal there is a different phenomena to uh have such kind of amplification where the anatomy of the EDFA comes into picture. What is EDFA? EDP is nothing but the ERBM doped fiber amplifiers host the quantum reaction inside the transmission code. Uh to understand this you can assume that the telecom signal