Fiber Optics

Sources, Modulators, and Detectors For Fiber-Optic Communication Systems Part 11

Dark Current Semiconductor diodes can pass current even in the dark, giving rise to dark current that provides a background present in any measurement. This current comes primarily from the thermally generated diffusion of minority carriers out of the n and p regions into the depleted junction region, where they recombine. The current-voltage equation for […]

Optical Fiber Amplifiers

INTRODUCTION The development of rare-earth-doped fiber amplifiers has led to dramatic increases in the channel capacities of fiber communication systems, and has provided the key components in many new forms of optical sources and signal processing devices. The most widely used fiber amplifiers are formed by doping the glass fiber host with erbium ions, from […]

Fiber-Optic Communication Links (Telecom, Datacom, and Analog) Part 1

INTRODUCTION There are many different applications for fiber-optic communication systems, and each has its own unique performance requirements. For example, analog communication systems may be subject to different types of noise and interference than digital systems, and consequently require different figures of merit to characterize their behavior. At first glance, telecommunication and data communication systems […]

Fiber-Optic Communication Links (Telecom, Datacom, and Analog) Part 2

LINK BUDGET ANALYSIS: OPTICAL POWER PENALTIES Next, we will consider the assembly loss budget, which is the difference between the transmitter output and receiver input powers, allowing for optical power penalties due to noise sources in the link. We will follow the standard convention in the literature of assuming a digital optical communication link which […]

Fiber-Optic Communication Links (Telecom, Datacom, and Analog) Part 3

Jitter Although it is not strictly an optical phenomenon, another important area in link design deals with the effects of timing jitter on the optical signal. In a typical optical link, a clock is extracted from the incoming data signal which is used to retime and reshape the received digital pulse; the received pulse is […]

Solitons in Optical Fiber Communication Systems Part 1

INTRODUCTION To understand why optical solitons are needed in optical fiber communication systems, we should consider the problems that limit the distance and/or capacity of optical data transmission. A fiber-optic transmission line consists of a transmitter and a receiver connected with each other by a transmission optical fiber. Optical fibers inevitably have chromatic dispersion, losses […]

Solitons in Optical Fiber Communication Systems Part 2

SLIDING FREQUENCY-GUIDING FILTERS As one can see, the excess gain prevents one from taking a full advantage of guiding filters. By using the sliding frequency-guiding filters,35 one can essentially eliminate the problems associated with the excess gain. The trick is very simple: The transmission peak of each guiding filter is shifted in frequency with respect […]

Solitons in Optical Fiber Communication Systems Part 3

WAVELENGTH-DIVISION MULTIPLEXED DISPERSION-MANAGED SOLITON TRANSMISSION One of the advantages of DM transmission over classical soliton transmission is that the local dispersion can be very highwhich efficiently suppresses the four-wave mixing from soliton-soliton collisions in WDM. Consider the timing jitter induced by collisions in the non-pulse-overlapped DM transmission. The character of the pulse collisions in DM […]

Tapered-Fiber Couplers, Mux and Demux (Fiber Optics)

INTRODUCTION Fiber-optic couplers, including splitters and wavelength-division multiplexing (WDM) components, have been used extensively over the last two decades. This use continues to grow both in quantity and in the ways in which the devices are used. The uses today include, among other applications, simple splitting for signal distribution and wavelength multiplexing and demultiplexing multiple […]

Fiber Bragg Gratings (Fiber Optics)

INTRODUCTION A fiber Bragg grating (FBG) is a periodic variation of the refractive index of the fiber core along the length of the fiber. The principal property of FBGs is that they reflect light in a narrow bandwidth that is centered about the Bragg wavelength, XB, which is given by XB = 2NeHA, where A […]

← Previous Entries

Next Entries →