Design of monolithic distributed Bragg reflector-integrated photodiode using a tapered waveguide with InP and polymer cladding layer

•Generally, the bandwidth and quantum efficiency of the photodiode are mutually constrained. A photodiode with a small active area and a thin absorber layer will result in a broadband covering from dc to sub-terahertz, while leading to difficulty in optical coupling and low quantum-efficiency. For this reason, we propose a monolithic distributed Bragg reflector (DBR) integrated photodiode using a tapered waveguide with InP and polymer cladding layer for achieving a high-efficiency bandwidth product.•In the proposed photodiode, a DBR mirror is formed at the end of the waveguide, thereby increasing the effective absorption length of the device. Furthermore, to reduce coupling loss and enhance the optical power confinement ability of the waveguide, the InP and polymer cladding layers are formed under and on top of the core layer, respectively.•The efficiency bandwidth product of the proposed structure can be improved by 38% compared to the structure without DBR end-mirror and cladding layer.•The proposed structure can also be applied to different photodetector designs. We propose a monolithic distributed Bragg reflector (DBR) integrated photodiode using a tapered waveguide with InP and polymer cladding layers for achieving a high efficiency bandwidth product. In the proposed photodiode, a DBR mirror is formed at the end of the waveguide, thereby increasing the effective absorption length of the device. Furthermore, to reduce the coupling loss, the InP and polymer cladding layers are formed under and on top of the core layer, respectively. Consequently, the mutual tradeoff between the bandwidth and quantum efficiency of the photodetector could be alleviated.