![]() ![]() Another method for measuring chromatic dispersion is the interferometric method using a Mach–Zehnder interferometer with a fiber under test in one arm and a reference fiber in the other arm. Such a measurement requires a very long fiber length with significantly cumulated chromatic dispersion to see a series of nulls in the frequency modulations to retrieve the chromatic dispersion information. The effect gives the AM response a characteristic shape which can be analyzed to determine the chromatic dispersion at a particular wavelength. As the chromatic dispersion changes the relative phase of the sidebands of modulated signals, with an intensity modulated signal, the chromatic dispersion converts AM to frequency modulation (FM). Another method is called baseband amplitude modulation response. When an optical source is modulated by a sinusoidal wave, the propagation delay can be evaluated by the relative phase retardation of the received radio frequency (RF) signal and the chromatic dispersion can be calculated from the derivative of the group delay over wavelength. One method is modulation phase shift method. As a result, more sensitive measurement techniques have been developed. km) at 1550 nm, for a time domain measurement, it would require a picosecond-level pulse width and an optical bandwidth greater than 100 GHz for the receiver in order to detect the pulse broadening at 1 km length, which is challenging.Since for a standard single-mode fiber, the chromatic dispersion is around 17 ps/(nm Various chromatic dispersion measurement methods have been developed primarily for single-mode fibers. By measuring the group delays over different wavelengths, the data can yield the chromatic dispersion of each mode over the wavelength window. Although the sampling is highly under-sampled for the whole fiber link, through proper treatment of the data, we can de-alias the signals and obtain accurate values of the group delays of each mode. The inverse Fourier transform of the measured complex transfer function is used to determine the group delays for each mode of the fiber. Using a vector network analyzer, the measurement instrument obtains the complex transfer function of fiber transmission. The method is applied to all three types of fibers through one measurement methodology uniformly. In this paper, a simple and robust measurement method for chromatic dispersion measurement of single-mode fibers, polarization-maintaining fibers, and few-mode fibers is presented using a frequency domain instrument and a vector network analyzer. These methods are often subject to some limitations. In the literature, measurement techniques were also developed to characterize few-mode fibers and multi-mode fibers. Chromatic dispersion is an important fiber attribute affecting transmission performance over optical fibers. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |