Introduction In recent years, most of the FTTH deployments have been based on industry standard technologies such as Gigabit Ethernet Passive Optical Network (GEPON) and Gigabit PON (GPON). The success of these deployments has led to significant innovation in both system architecture and the components that are used to build these systems, and the next […]
WDM System
Dual Stage EDFA with DCM Mid-Stage Access – DCM-optimized EDFA
Besides optical amplifiers, modern optical networks also require other components to be place along the link, such as the Dispersion Compensation Module (DCM) used to correct signal distortion due to Chromatic Dispersion of the transmission fiber. Since the attenuation of DCM can be quite large, in the range of 5 to 10 dB, additional amplification […]
Variable Gain EDFA – Large Dynamic Gain Range & Better Noise Figure Performance
In order to support different span lengths between Optical Amplifiers in a transmission link, as well as to provide for aging of the link, it is desirable for an optical amplifier to support as large as possible dynamic gain range, i.e. to allow the gain to be dynamically configured over a wide range. For a […]
Raman Fiber Amplifiers – Advancements to Long Haul Transmission
Introduction Raman Fiber Amplifier (RFA) is used to assiste optical transmission system design issues such as mid-span optically amplified distance, bandwidth enhancement. The RFA does not suffer from the limitations of Erbium-Doped Fiber Amplifier (EDFA) in that it can be integrated with the transmission fibers, and pumped at any wavelength to provide wide gain bandwidth […]
Advanced Optical Components – Optical Filter
Optical Filter is a device that selectively permits transmission or blocks a range of wavelengths. Optical filters are typically bandpass or band-reject (shown in the figures below). A bandpass optical filter allows a certain range of optical wavelengths to pass and attenuates the rest (left), while a band-reject optical filter attenuates a band of optical […]
Advanced Optical Components – WDM Multiplexer
WDM Multiplexer is a device that uses Wavelength Division Multiplexing (WDM) technology to combine different optical wavelengths from two or more optical fibers into just one optical fiber. This combining or coupling of the wavelengths can be very useful in increasing the bandwidth of a fiber optic system. WDM multiplexers are used in pairs: one […]