Laser Opto-Electronic Oscillator and the Modulation of a Laser Emission

Abstract

The autonomous optoelectronic generator (OEO) is considered in the chapter as a source of low-noise oscillations. Differential equations are considered and methods with OEO modulation with direct and external modulation are analyzed. The complexity of both approaches is related to the non-standard way of description of the nonlinear method modulation for the internal (direct) structure and the utilization of the specific Mach-Zehnder modulator for the first stage on external modulation. The purpose of the presentation is to consider the main features of OEO as a low-noise generator. This includes consideration based on the study of differential equations, the study of transients in OEO, and the calculation of phase noise. It is shown that different types of fibers with low losses at small bending radii can be used as a FOLD in OEO. The important role of the choice of a coherent laser for OEO with a small spectral line width is shown. The prospects of using structured fibers with low losses at bends of less than 10 mm in OEO are described. The results of modeling dynamic processes in OEO with direct modulation are presented.

Phase and amplitude fluctuations of oscillations in laser optoelectronic oscillator

“…Several experimental direct modulation the LOEO images were investigated, which worked at frequencies of 8 to 10 GHz and had quantum-sized lasers as a laser source, which worked at a wavelength of 1300 and 1550 nm, the optical fiber lengths were 60 to 4400 m 14 , 15 , 17 , 18 . The maximal output power of optical emission for used laser diodes formed about 10 to 30 mW.…”

“…Several experimental direct modulation the LOEO images were investigated, which worked at frequencies of 8 to 10 GHz and had quantum-sized lasers as a laser source, which worked at a wavelength of 1300 and 1550 nm, the optical fiber lengths were 60 to 4400 m. 14,15,17,18 The maximal output power of optical emission for used laser diodes formed about 10 to 30 mW. Using in OEO of the highly coherent laser with the phase noise less than −50 to 70 dB∕Hz (at the 10 kHz offset) is the condition of OEO small phase noises less than −110 dB∕Hz at the 10 kHz offset.…”

“…[8][9][10] The large number of publications on experimental investigations of low phase noise LOEO and other methods of RF oscillation generation are explained by the relevance of the topic. [15][16][17][18][19][20][21] At present, in large-dimension models of laser LOEO with external radiation modulation by Mach-Zender modulator with the fiber-optical delay line (FODL), the low phase noise level of −140 to −150 dB∕Hz is achieved on the 10 GHz generation frequency at 1 kHz offset from a carrier. 22 Experimental and theoretical investigations of the power spectral density (PSD) of the laser oscillator phase noise described in Ref.…”

“… – 10 The large number of publications on experimental investigations of low phase noise LOEO and other methods of RF oscillation generation are explained by the relevance of the topic 15 – 21 …”