|Wednesday, 25 October 2006|
A power divider is an essential component of any amplitude modulator constructed with optical waveguides which operates by interfering two-phase shifted guided waves. Powder dividers are used to take a signal at a common terminal and divide the signal among a series of signal paths while maintaining desired impedances at the common terminal and at all output terminals. Power divider circuits are used in radio frequency applications to split an input signal over two or more outputs so that the input signal can be processed in parallel in subsequent stages. The power level of the output signals of a power divider can be equal of weighted. Power combining techniques for radio frequency signals, including millimeter wavelength signals, have been accomplished in either a waveguide circuit or in a microstrip circuit. Power dividers have been made by forming transmission lines on microstrip structures using printed circuit boards. Power dividers have also been fabricated on ceramic substrates using screened on thick film conductors and dielectrics. Microwave power dividers are useful in a wide variety of instrumentation and system applications, such as feeding signals to multiple antennas. Microwave power dividers of various types are already known particularly for hollow-waveguide microwaves. Certain of the higher frequency bands in the microwave spectrum lead themselves to other types of waveguide. Coupled line dividers are often used in microwave applications for supplying power from an input port to a pair of output ports. Coupled line dividers, however, are not fully satisfactory because they require precise line gaps and spacings to achieve the desired power division. Power dividers can also be used to combine microwave signals by applying the signals to be combined to what would normally be considered the outputs of the divider. Combining signals in this manner is a popular way of obtaining higher output power from semiconductor signal sources.
RF power dividers can be classified into three categories: T-junction power divider, Wilkilson power divider, and Quadratue hybrid power divider. Among them, a particular power divider is selected according to desired characteristics. A Wilkinson circuit uses transmission lines at a characteristic impedance to convey signals to different ports. The ports are tied through resistors to a common node. The transmission lines may be anywhere from a quarter wavelength to a half wavelength in length. Optical power dividers are required in many types of optical communications networks, such as long haul networks, metropolitan networks, and access networks, as well as in optical multiplexers and switches of such networks. In modern fiber optic telecommunications, much reliance is being placed on the state of polarization of light signals. Network components or devices which function based upon the polarization of the light signal include fiber optic polarization tunable filters, depolarizers, binary polarization switch/modulators, polarization division multiplexers and many other polarization related fiber optic components. Many of these devices require fiber optic variable polarization beam splitters and/or combiners. An optical waveguide device includes an optical waveguide core through which an optical signal is transmitted by experiencing total internal reflection in the optical waveguide core, and a clad surrounding the optical waveguide core.