Splitters and Couplers
Splitters and Couplers
What needed? to combine signals and/or to split them multiple ways up to 1000x 1000 for WDM LANs three important characteristics Return Loss: the amount of power that is reflected and thus lost Insertion LoSs: the amount of signal lost in the total transit through the device Excess Loss additional loss of a device over and above the loss required by theory
What needed? • to combine signals and/or to split them multiple ways. • up to 1000x1000 for WDM LANs • three important characteristics – Return Loss:the amount of power that is reflected and thus lost. – Insertion Loss:the amount of signal lost in the total transit through the device. – Excess Loss:additional loss of a device over and above the loss required by theory
Resonant Coupling Cladding Glass Port 1 Port 2 Gap-5 microns Port 4 Port 3 Sngle mode cores Coupling Length power will oscillate from one fibre core to the other
Resonant Coupling power will oscillate from one fibre core to the other
Single-Mode Propagation Cladd Core Cladding Part of wawe extends to cadang Field Amplitude EJe sp Fibre Fibre Fibre Cladding Core Cladding
Single-Mode Propagation
Theory Equations △β R dr/dz-joR=-jKS dS/dz+ joS =-jKR AH=R exp(-joz) A、=Sexp(z tuning coefficient:8=(β、-P1 Coupling coefficient: K
Theory • Equations： dR/dz- jdR = -jKS; dS/dz+ jdS = -jKR • Am =R exp(-jdz); • An= S exp(jdz) • Detuning coefficient：d=(bn-bm )/2 • Coupling coefficient: K