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Intensity Noise (intensity + noise)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

Numerical analysis of optical feedback phenomenon and intensity noise of fibre-grating semiconductor lasers

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2007
Moustafa Ahmed
Abstract This paper demonstrates numerical analysis of the dynamics and intensity noise of fibre-grating semiconductor lasers (FGSLs). The induced phenomenon of strong optical feedback (OFB) is analysed. The simulations are based on an improved time-delay rate equations model of a single-mode laser that takes into account the multiple round-trips of the lasing field in the fibre cavity. The analyses are performed in terms of the temporal trajectory of the laser intensity, bifurcation diagram and relative intensity noise (RIN). We explore influence of the fibre-cavity length on the dynamics and RIN. The results show that when the fibre cavity is short, the regime of strong OFB is characterized by either continuous-wave (CW) operation or periodic pulsation. The pulsation frequency is locked at the frequency separation of either the compound-cavity modes or the external fibre-cavity modes. The corresponding RIN level is close to or higher than the level of the solitary laser depending on pulse symmetry. When the fibre cavity is long, the laser exhibits unstable dynamics over wider range of OFB. Moreover, the strong-OFB pulsation becomes beating quasi-periodic at the relaxation oscillation frequency and the fibre-cavity mode-separation frequency. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Impact of the pump reflector in double-pass discrete Raman amplifiers

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2006
M. I. Md Ali
Abstract We present the experimental investigation of a counter-pumped double-pass discrete Raman amplifier with and without a pump reflector. The pump reflector is constructed with high-reflectivity fiber Bragg grating. Gain improvement is obtained as a result of pump recycling, in comparison to the conventional double-pass Raman amplifier. Noise-figure degradation is found for large signals in the proposed Raman amplifier due to the enhanced double-Rayleigh scattering and bidirectional pumping caused by the pump reflector. The impact of pump-to-signal relative intensity noise in the experimental work is minimized by utilizing Fabry,Perot pump lasers. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 777,779, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21473 [source]

1.55-,m surface-illuminated monolithically integrated balanced metal semiconductor metal photodetectors and coplanar waveguide

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2002
Amr M. E. Safwat
Abstract Two metal,semiconductor,metal (MSM) photodetectors are integrated monolithically with a coplanar waveguide transmission line to form a 1.55-,m surface-illuminated balanced photodetector. Illuminating the device with CW and taking the difference, the relative intensity noise (RIN) is suppressed by 9,10 dB. In balanced detection, a 7-dB enhancement in the intermodulation term compared to single detector is achieved. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 125,130, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10393 [source]