OPTICAL-FIBER INDEX TAPER-THEORETICAL ANALYSIS AND EXPERIMENT DEMONSTRATION

We discuss theoretical analysis of optical fiber taper with its refrac tive index gradually changing alone its propagation axis caused by pho tosensitivity. The numeric results for two different taper shapes in s tep-index fiber show that the couplings of fundamental mode to the ref lected mode and to high-order modes is relatively small provided the c hange is gradual. The fundamental mode has the capability of excellent transmission that can adjust itself adiabatically to the refractive i ndex change. The experiment demonstrates its effectiveness for optical interconnection with different mode-fields.