October 2, 2011
Single-mode fiber is a type of fiber optic cable through which only one light signal can travel at a time.
October 2, 2011
There are 2 major differences one color code. single mode will be white or yellow. multimode will be black or tan. 2nd the hole in the connector ferrel for the fiber. fiber is 125 microns. in a single mode connector the opening is 126 microns. multimode is 127/128.Single Mode cable is a single strand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. Single Mode Fiber with a relatively narrow diameter, through which only one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber.
September 30, 2011
Next generation access (NGA) is a replacement for existing communications access networks that will deliver unlimited broadband services.
September 30, 2011
A 90° optical hybrid is a six-port device that is used for coherent signal demodulation for either homodyne or heterodyne detection. It would mix the incoming signal with the four quadratural states associated with the reference signal in the complex-field space. The optical hybrid would then deliver the four light signals to two pairs of balanced detectors.
September 30, 2011
The commercial feasibility of a coherent system for optical signal transmission was first investigated around 1990 as a means to improve a receiver’s sensitivity. In contrast to existing optical direct-detection system technology, an optical coherent detection scheme would detect not only an optical signal’s amplitude but phase and polarization as well. With an optical coherent detection system’s increased detection capability and spectral efficiency, more data can be transmitted within the same optical bandwidth. Moreover, because coherent detection allows an optical signal’s phase and polarization to be detected and therefore measured and processed, transmission impairments which previously presented challenges to accurate data reception, can, in theory, be mitigated electronically when an optical signal is converted into the electronic domain.
September 30, 2011
Six-port hybrid devices have been used for microwave and millimeter-wave detection systems since the mid-1990s and are a key component for coherent receivers. In principle, the six-port device consists of linear dividers and combiners interconnected in such a way that four different vectorial additions of a reference signal (LO) and the signal to be detected are obtained. The levels of the four output signals are detected by balanced receivers. By applying suitable base-band signal processing algorithms, the amplitude and phase of the unknown signal can be determined.