A variety of digital subscriber loop (DSL) services, such as high-rate DSL (HDSL), asymmetric DSL (ADSL), very high-rate DSL (VDSL) and others, are generally referred to as xDSL services. The xDSL services share the same carrier with plain old
telephone service (POTS). POTS splitters are used to isolate the POTS service from the xDSL transceiver. POTS splitters generally have a low-pass filter to permit passing of the POTS service and a high-pass filter to permit passing of the xDSL service. An optical power splitter splits an optical signal into a plurality of optical signals, and is used as a key component of an optical subscriber network. A signal, containing a single channel or multiple channels, may be divided by a splitter and delivered to several different destinations. Phase splitters are circuits which generate multiple output signals of equal amplitude but different phases. Phase splitters are used for a variety of applications including single sideband modulators, image-reject mixers, and IQ
modulators and demodulators such as those used in quadrature phase shift keying (QPSK) or offset quadrature phase shift keying (OQPSK) modulation.
