Estimation of the optical loss in bent-waveguide superluminescent diodes by an analytical method^*

The optical loss in the bent region is one of the key features for bent-waveguide superluminescent diodes that affects the device performance greatly under some conditions. For the purpose of device fabrication and optimization, it will be helpful if this bend loss can be estimated. In this letter, we have derived an analytical formula which can be used to get the bend-loss coefficient by fitting the P–I curves of the devices. It is proved that the formula is successful in estimating the loss coefficients from the P–I curves simulated from a complicated quantum-dot device model. We expect this method could also be valid in estimating bend losses of actual devices.