Insertion loss and return loss are two important data to evaluate the quality of many passive fiber optic components, such as fiber optic patch cord and fiber optic connectors, etc.

In telecommunications, insertion loss is the loss of signal power resulting from the insertion of a device in a transmission line or optical fiber and is usually expressed in dBs. Insertion loss (IL) is a measure of attenuation,  but is a more precisely defined term. For instance, attenuation can include loss due to the source and load impedances not matching, but is not included in insertion loss since this is a loss that was already present before the "insertion" was made.

If the power transmitted to the load before insertion is PT and the power received by the load after insertion is PR, then the insertion loss in dB is given by,

    10 \log_{10} {P_\mathrm T \over P_\mathrm R}

In metallic conductor systems, radiation losses, resistive losses in the conductor as well as losses in the surrounding dielectric all reduce the power. Line terminations play an important part in insertion loss because they reflect some of the power. All of these effects can be conceptually modelled as various elements which make up the equivalent circuit of the line.

In an optical fiber system, insertion loss is introduced by things such as Fiber Optic Pach Cables, Fibre Optic Pigtails, fiber optic connectors, splices, and couplers.

According to industry standard, Ultra PC polished fiber optic connectors return loss should be more than 50dB,Angled polished generally return loss is more than 60dB. PC type should be more than 40dB.

During the fiber optic products manufacturing procedure, Exfiber have professional equipment to test the fiber optic products insertion loss and return loss, our products are 100% tested on each single piece before shipment, and they are fully compliant or exceed the industry standard.