Coupling Loss (dB) @ O1 : -10 Log(O1/(O1+O2)) Coupling Loss (dB) @ O2 : -10 Log(O2/(O1+O2))
Insertion Loss: Excess Loss + Coupling Loss + Polarizaton Effects (Single mode only)
Uniformity (dB): Maximum Insertion Loss - Minimum Insertion loss
Directivity (dB): -10 Log ( I2 / I1 ) (With all outputs terminated for zero reflection)
Return Loss (Back reflection) Return loss is loss of signal when light that is reflected back along the path of transmission, from either the coupling region, the connector or a terminated fiber.
Polarization (Single mode only) and Thermal stability Maximum change in coupling ratio through all polarization orientations and/or specified temperature ranges.
Definition of singlemode Wavelength Division Multiplexer / Demultiplexer terms
Insertion Loss : Excess Loss + Coupling Loss at Wave1 and Wave2
Isolation (dB) The optical power separation in channel O1 and O2 between the specified wavelengths. Assumes input levels are the same for each wavelengths.