Calculate back facet reflectivity from measured laser output power

[dhirhe]

Hi Every one,

I measured optical output power from both laser facets, front facets emits 120 mW and back facets 10 mW. Assuming front facets reflectivity of 30%(for cleaved facets). What will be the reflective of back facets? Please suggest formula and reference this problem.

 

[UltrafastPED]

This external cavity (ECL) tutorial may provide some insight:
http://www.thorlabs.de/tutorials.cfm?tabID=24960

Here is an abstract for "Method of Determining Semiconductor- Laser Facet Reflectivity after Reflectance Modification": http://www.nsa.gov/research/tech_transfer/fact_sheets/laser_facet_reflectivity.shtml