Optical Amplifiers

100 nm bandwidth flat-gain Raman amplifier – Average power model

Optical System - Figure 8 Counter-propagating pump

This lesson shows the performance of the Average power model in analysis of the 100 nm bandwidth Raman amplifier with multiwavelength backward pump. The parameters considered are close to these used in the experiment of [1]. The same experimental situation has been modeled by means of Average power model in [2].  As is well known one…

Flattening the gain of broadband Raman amplifier with multipump configuration

Optical System - Figure 4 Optimized pump power spectrum

In this lesson, we will use the gain flattening type of optimization to optimize the pump powers for flattening the gain of a Raman amplifier.  Fiber Raman amplifiers are recently getting much more attention in WDM systems due to their greatly extended bandwidth and distributed amplification with the installed fiber as gain medium [1]. It has…

Optimizing the pump power and frequencies of Raman amplifiers for gain flatness

Optical System - Figure 5 Output power spectrum after the optimization

In this example, we show that the Gain Flattening type of optimization can be used to design multi-wavelength pumped Raman amplifiers with a flattened gain. Given amplifier specifications such as signal level, required gain profile, and number of allowed pump channels, the optimization procedure can generate a combination of pump wavelengths and input powers that…

Raman Amplifier – Dynamic Model

Optical System - Figure 1 Project Layout for analysis of the Raman gain

This lesson demonstrates generating the transients based on add-drops in signals in a Raman amplifier. In this example, we simulate a counter-pumped Raman amplifier for a small number of signals. Then the results are compared with the ones found in the literature. The project consists of a simple model as shown in Figure 1.   Figure 1: Project Layout…

SOA Gain Saturation – Gaussian Pulses

Optical System - Figure 12 SOA amplified internal loss Gaussian pulse signal

Amplification of ultra-short optical pulses in SOA produces considerable spectral broadening and distortion due to the non-linear phenomenon of self-phase modulation. The physical mechanism behind SPM is gain saturation, which leads to intensity-dependent changes of refractive index in response to variations in carrier density. Signal-gain saturation in SOA is caused by a reduction of the…

SOA Gain Saturation – Comparison with Experimental Results

Optical System - Figure 5 Time and frequency domain of initial and amplified pulses

This lesson applies the results from SOA gain saturation—Gaussian pulses for interpretation of the experimental results on the amplification of Gaussian pulse with SOA obtained in [1]. The aim of [1] was to report the first investigation of the spectral characteristics of pulse amplification in SOA.  Parameters of SOA given in the paper are:  …

SOA Gain Saturation – Chirped and Super Gaussian Pulses

Optical System - Figure 1 SOA parameters

This lesson continues to study the effect of gain saturation induced self-phase modulation on the amplification of optical pulses. We will concentrate on the pulses with different shape and initial frequency shift. The chirped Gaussian input pulses are the pulses which are usually produced from directly modulated semiconductor lasers.   As in SOA gain saturation—Gaussian…

SOA Gaussian Pulse – Gain Recovery

Optical System - Figure 1 SOA parameters

In the previous three lessons, we assumed that the input pulse was much shorter than the carrier lifetime. When the pulse width becomes comparable to the carrier lifetime, the saturated gain has time to recover during the pulse. The recovery effect influences the shape and spectrum of the amplified pulse.   This lesson studies this…

SOA Pulse Compression

Optical System - Figure 10 Shape and spectra of pulses with 3, 30, and 60 mW peak power

This lesson applies the results from SOA gain saturation—Gaussian pulses to analyze the possibility for compression of weak picosecond pulses. As mentioned in SOA gain saturation—Gaussian pulses, one of the main results of the gain saturation induced self-phase modulation in SOA is the formation of positive chirp of the pulse in the process of amplification.…

SOA as a Wavelength Converter (FWM)

Optical System - Figure 1 Two multiplexed CW signals

This lesson demonstrates the application of traveling wave SOA as a wavelength converter using the four-wave mixing effect. Four-wave mixing (FWM) is a nonlinear effect that takes place when two waves (signal and pump) at different wavelengths are injected into an SOA. A third optical field is generated at the device output, with frequency Wc =…