Tunable multichannel filter in a photonic crystal containing semiconductor photonic quantum well

A tunable multichannel filter in the finite photonic crystal (PC) containing photonic quantum well (PQW) as a defect is proposed. The symmetric structure (AB) ^P(CD) ^Q(BA) ^P and the asymmetric structure (AB) ^P(CD) ^Q(AB) ^P are considered in this work. Here, the host PC of (AB) ^P is made of Si for layer A and of SiO ₂ for layer B. In the PQW, (CD) ^Q, C also is Si, but D is an extrinsic semiconductor, n-type silicon (n-Si). With the use of n-Si, it is found that both structures can function as a tunable multichannel filter in the infrared region. The number of channels is equal to Q + 1 in the symmetric structure, whereas it is Q for the asymmetric one. The positions of multiple resonant peaks can be tuned by the variation in the impurity concentration of n-Si. The proposed filter could be used to design the wavelength division multiplexer filter that is of technical use in optical communications.