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.