  Quantum Key Distribution (QKD) can guarantee security for practical indoor
optical wireless environments. The key challenges are to mitigate artificial
lighting and ambient light at the receiver. A new spectral region for QKD is
proposed and an ideal QKD link model is simulated with experimental ambient
light power measurements. Simulation, modelling, and analysis indicates that
the carbon dioxide and water absorption band (1370 nm) is a new wavelength
region for QKD operation in indoor optical wireless environments. For a
feasible QKD link, approximately 20 dB of signal to noise ratio (SNR) is
required and a maximum quantum bit error rate (QBER) of 11% when using the BB84
protocol. Links in the new spectral region with a FOV of several degrees are
feasible, depending on available components.
