# What is the noise of the optical source?

## What is the noise of the optical source?

Laser noise arises from random fluctuations in the intensity of the optical signal. The two main noise contributors are fluctuations in light intensity, which comes from the laser diode, and interferometric noise, which arises because of multiple light reflections in the optical fiber.

What is optical noise?

Fiber-optic communication systems that use optical amplifiers are subject to optical noise, called amplified spontaneous emission (ASE) noise [25–27]. ASE noise is due to spontaneous emission of photons that adds optical noise to the signal during its amplification.

### What is noise figure in optical communication?

The noise figure F of an optical amplifier (e.g. a fiber amplifier or semiconductor optical amplifier) is a measure of how much excess noise the amplifier adds to the signal.

What is ASE noise?

Amplified spontaneous emission (ASE) or superluminescence is light, produced by spontaneous emission, that has been optically amplified by the process of stimulated emission in a gain medium. It is inherent in the field of random lasers.

## What is dark current noise in optical communication?

Dark current noise: When there is no optical power incident on the photodetector a small reverse leakage current still flows from the device terminals. This Dark current contributes to the total system noise and gives random fluctuations about the average particle flow of the photocurrent.

What is meant by modes in optical fiber?

Modes are the possible solutions of the Helmholtz equation for waves, which is obtained by combining Maxwell’s equations and the boundary conditions. These modes define the way the wave travels through space, i.e. how the wave is distributed in space. 657 define the most widely used forms of single-mode optical fiber.

### What are the types of noise?

The Four types of noise

• Continuous noise. Continuous noise is exactly what it says on the tin: it’s noise that is produced continuously, for example, by machinery that keeps running without interruption.
• Intermittent noise.
• Impulsive noise.
• Low-frequency noise.

What is noise types of noise?

of noise in data communication exist, and managing noise successfully requires the use of multiple techniques. Among the most common types of noise are electronic noise, thermal noise, intermodulation noise, cross-talk, impulse noise, shot noise and transit-time noise.

## Why is noise figure important?

Noise figure is a number by which the noise performance of a radio receiver, amplifier, mixer or other circuit block can be specified. The lower the value of the noise figure, the better the performance. Essentially the noise figure defines the amount of noise an element adds to the overall system.

What are the factors of noise?

There are three major characteristics that will affect the sound level at any location. They are traffic conditions, roadway configuration, and attenuation parameters.

### What is OSNR tolerance?

In an experimental environment where factors such as loss, dispersion, and non-linear effects are excluded, if the OSNR is less than the specified threshold, the pre-FEC BER will be excessively large and uncorrectable bit errors will be generated. The OSNR threshold in this case is called B2B OSNR tolerance.

What is EDFA what for it is used?

Erbium-Doped Fiber Amplifier (EDFA) is an optical amplifier used in the C-band and L-band, where loss of telecom optical fibers becomes lowest in the entire optical telecommunication wavelength bands. The use of EDFA has eliminated the need for such O-E and E-O conversion, significantly simplifying the system.

## Why is noise a problem in optical systems?

Optical systems, communication systems, and other systems that require sensitive electronic and optical measurements can suffer from a variety of noise sources. The challenge in dealing with these noise sources is to identify them from time domain and/or frequency domain measurements.

What can be done to reduce optical noise?

In the systems discussed earlier, optical noise is not accompanied with the optical signal that reaches the optical receiver, and therefore, BER can be reduced by increasing the level of signal optical power.

### Which is the correct unit of optical noise?

Since the unit of the signal average power is [W] and the unit of optical noise power spectral density is [W/Hz], the unit of OSNR should be [Hz], or [dB·Hz].

Which is the dominant noise in an optical filter?

Since SAE-ASE beat noise can be reduced by further reducing the bandwidth of the optical filter, the dominant noise in most of the long-distance optical systems employing multiple inline optical amplifiers are signal-ASE beat noise.

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