ADIABATIC COUPLERS - DESIGN RULES AND OPTIMIZATION

Explicit analytic design rules are derived for both 3 dB and full adia batic couplers, The design rules are in excellent agreement with numer ical calculations using the beam propagation method (BPM), It is shown that the length scaling for 3 dB couplers compared to full couplers m akes the former more difficult to design, The design for each case is optimized to obtain the upper limit of performance and a comparison is carried out between two different design geometries for both 3 dB and full adiabatic couplers.