Resonant cavity photodetectors have been shown to provide wavelength selectivity and to decouple the quantum efficiency from the transit time component of the bandwidth.However,there is still a tradeoff between the quantum efficiency and the spectral response linewidth in that it is intrinsically difficult to obtain a narrow linewidth (<2 nm) with an acceptable quantum efficiency by using this structure.In this paper we analyze a novel structure that utilizes an inclined mirror in a three mirror cavity and discuss the way to realize it.This approach has the advantage that the quantum efficiency is decoupled from the bandwidth and the linewidth.Our calculations show that a linewidth of 2 nm and a quantum efficiency over 50% can be achieved simultaneously.In addition,the spectral peak can be tuned over a wide range by changing the material refractive index in the filtering sub cavity of the device.