How to measure Optical Return Loss?

How to measure Optical Return Loss? : In this article, we will discuss about optical return loss. We will try to find out what is optical return loss, why it happens and how it can be measure. Is it necessary to measure optical return loss for deployment of transmission systems? In this article we will try to know all such issues.

According to the technical point of view optical return loss can degrade the stability of the laser source and it can be directly increase the bit error rate (BER). So it must be measure or taken into consideration the optical return loss during system installation or system upgrade processes. Whenever we talk about optical return loss, we also talk about back reflection.So now we will discuss little bit about back reflection.

How to measure ooptical return loss?

Optical Return Loss

What is Back Reflection?

We can say that amount of light reflected back from an optical component of a transmission link (e.g. connector, mechanical splice) is called the back reflection. It measured by the ratio of the reflected power (Pr) to the incident power (Pi) at a particular point, infect It is the logarithmic ration of Pr to Pi. It is also called reflectance.

R= 10 log Pr/Pi

What is Optical return Loss?

Optical return loss indicates total accumulated light back to source with telecommunications link. This return Light is caused by various physical phenomena such as many Connector back-Reflections, Rayleigh back-scattering, diffusion etc.

The optical return loss defined as the logarithmic ratio between the transmitted power and the received power (back-reflection + back scattering) at the fiber origin. It is expressed in positive decibels (dB).

Optical return loss = 10Log Pe/Pi

High the value of the lower the reflected power and the smaller the effect of the reflection on the active transmission elements: 60 dB is better than 40 dB Optical return loss.

Some OTDRs are available that can measure the amount of reflecting light automatically by clicking one cursor just in front of the reflection, an icon available on the top of ODTR an another cursor at the top of the reflection and by pressing the appropriate button on the control panel.

Higher levels of Optical return loss will reduce some broadcast performance Link. Analog transmission system and very high speed digital transmission Systems can be sensitive to Optical return loss.It means high Optical return loss degrade the reformance of link.