Measure the Insertion Loss of a Fiber Optic Component | Thorlabs Insights

Insertion loss measures the drop in optical power caused by the addition of a device to a fiber optic network. All sources of optical loss contribute to a device's insertion loss, including reflections, absorption and scattering due to intrinsic material properties, micro- and macrobending losses, split ratios, splice loss, and connector loss.
A single-ended insertion loss measurement is demonstrated. In this approach, a reference cable is attached to the source, and then the power at the cable's output is measured. Next, a mating sleeve is used to attach the component under test to the reference cable. The optical power at the selected output port of the component is measured. The insertion loss is calculated by first taking the ratio of this power reading to the power measured at the reference cable output, and then expressing the ratio in terms of decibels (dB).

The single-ended insertion loss measurement includes the loss from coupling light into the device, which is often mostly due to the misalignment of the fiber cores in the mating sleeve. However, this measurement does not include the same type of loss that occurs when coupling the light output from the device into the next leg of the fiber optic network. Note also that the insertion loss is wavelength dependent and will differ for each combination of device input and output ports selected for the measurement. This is due to the differences in split ratio, bend loss, absorption, scattering, reflections, and all other individual sources of attenuation along the optical path between the two ports.

0:00 - Introduction
0:28 - Overview of the Insertion Loss Measurement
1:11 - The Setup Used to Measure Insertion Loss
2:28 - Making the Insertion Loss Calculation Easier
4:16 - Insertion Loss of a Fiber Patch Cable Measured
7:05 - Insertion Loss of a 50/50 Fiber Coupler Measured

Components used in this demonstration include:
- S3FC1550 Fiber-Coupled Laser Source: https://www.thorlabs.com/newgrouppage...
- ADAFCB3 Mating Sleeve: https://www.thorlabs.com/newgrouppage...
- S154C Optical Power Sensor: https://www.thorlabs.com/newgrouppage...
- PM400 Optical Power Meter: https://www.thorlabs.com/newgrouppage...
- TW1550R5A1 50:50 Fiber Coupler: https://www.thorlabs.com/newgrouppage...
- Single Mode Fiber Patch Cable: https://www.thorlabs.com/newgrouppage...

For more photonics how-to videos, visit https://www.thorlabs.us/newgrouppage9....