ABSTRACT
An extinction-based compact InGaAsP/InP waveguide variable optical attenuator
(VOA) with electrically modulated bend loss is demonstrated. Injection of carriers is
utilized to modify the effective index of the waveguide bent section. The p-i-n
semiconductor waveguide layer structure is discussed. Signal propagation at multiple
bias conditions is simulated and the attenuator performance is calculated and
compared to that of a straight waveguide attenuator. The device exhibits attenuation
better than 15 dB for both TE and TM polarizations. 3-dB attenuation is achieved at
an applied current of ~ 12 mA which is less than half the current required by a
comparable straight waveguide attenuator.