Travelling Wave-Semiconductor Optical Amplifier (TWSOA) based 1.55 µm inline detectors are analyzed for their bandwidth characteristics under simultaneous amplification mode. Four different configurations of inline detector are considered for this study and they are full length, short length, multisection and optimum differential electrode based detector configurations. From the numerical solutions of rate equation, it is found that the short length configuration provides a bandwidth of 3 GHz and responsivity of 1650 V/W at − 20 dBm input power, compared to full length and multisection configurations. Optimum differential configuration has the best responsivity characteristics of 3600 V/W at 100 mA at − 20 dBm input power and provides two fold improvement in detection voltage than the best scheme reported earlier. However the bandwidth saturates for higher powers. For applications which demands greater responsivity with considerable bandwidth, the optimum differential configuration could be used. Applications those require higher dynamic bandwidth characteristics, the short length configuration and multi electrode configuration could be useful. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.