Ultracompact, all-passive optical 90 degrees -hybrid on InP using self-imaging

Abstract

A miniature (300- mu m*1750- mu m), all-passive 90 degrees -hybrid in GaInAsP/InP multimode waveguide is realized using self-imaging. Excellent performance (splitting ratio of 97:99:104: 99, low on-chip insertion losses <or=1 dB, only +or-3 degrees deviation from phase quadrature) and polarization-insensitive behavior at lambda /sub 0/=1.523 mu m was obtained. Experiments confirm simulations that predict that the splitting ratio and the IF phase relationships are much less sensitive to the coupler length than the insertion loss, thereby adding to the robustness of multimode interference devices.<<ETX>>