1. Introduction
Fiber-Optical CATV systems play an integral part in distribution infrastructure, owing to their broad
bandwidths and longer reach properties to provide high quality video signals to subscribers [1], [2].
Additionally, to satisfy the tremendous demand of handheld devices, radio over fiber (ROF) technique
which integrates the advantages of both optical and wireless communications is highly promising for
satisfying such requirements as well [3]–[9]. As a result, fiber-optical CATV in combination with ROF
technology has received growing interest, owing to its ability to provide both wireline and wireless
connectivity in a cost-effective structure [10], [11]. To achieve this objective, a hybrid network structure
in [12], [13] is developed to use an external intensity modulator to generate wireline and wireless
signals simultaneously. Despite the directness and simplicity of this combining scheme, the wireless
signal in that scheme is modulated in the nonlinear region due to the existence of the wireline signal.
Therefore, nonlinearity of the external modulator and interchannel interference between wireline and
wireless signals will significantly limit the overall transmission performance. To overcome the drawback,
two laser sources and two optical ultra-narrow band filters are deployed in the [10] to individually
service the CATV and wireless signals transmissions through a common trunk fiber. However, the cost
of deploying multiple laser diodes and optical ultra-narrow band filters in that system will significantly
limit its applications. Instead, the optical carriers in the [11] are generated by a single distributed
feedback laser (DFB) diode and then utilizing three optical ultra-narrow band filters and external
intensity modulator to select and modulate the downstream signals with three individual optical
carriers. In this case, a single DFB could be utilized to service multiple downstream transmissions with