Ultrafast mode-locked fiber lasers for high-speed OTDM transmission and related topics

Abstract

Ultrashort optical pulse sources in the 1.5-μm region are becoming increasingly important in terms of realizing ultrahigh-speed optical transmission and signal processing at optical nodes. This paper provides a detailed description of several types of mode-locked erbium-doped fiber laser, which are capable of generating picosecond-femtosecond optical pulses in the 1.55-μm region. In terms of ultrashort pulse generation at a low repetition rate (∼100 MHz), passively mode-locked fiber lasers enable us to produce pulses of approximately 100 fs. With regard to high repetition rate pulse generation at 10-40 GHz, harmonically mode-locked fiber lasers can produce picosecond pulses. This paper also describes the generation of a femtosecond pulse train at a repetition rate of 10-40 GHz by compressing the output pulses from harmonically mode-locked fiber lasers with dispersion-decreasing fibers. Finally, a new Cs optical atomic clock at a frequency of 9.1926 GHz is reported that uses a regeneratively mode-locked fiber laser as an opto-electronic oscillator instead of a quartz oscillator. The repetition rate stability reaches as high as 10 −12 -10 −13 .

Ultra-high-speed OTDM transmission technology

“…Pulse sources used for high-bit-rate transmission experiments include modelocked laser diodes (MLLD) either external cavity devices, e.g., Refs [21][22][23] or monolithically integrated devices, e.g., Refs [24,25], mode-locked fiber lasers (MLFL), e.g., Refs [26][27][28], mode-locked solid-state lasers (MLSL) [29], and CW lasers externally modulated (pulse carving), e.g., by an electroabsorption modulator (EAM), e.g., Refs [30,31]. For WDM/OTDM applications, a multiwavelength pulse source is of particular interest.…”

An experimental method for pulse-width measurement in partial positions of an ultrashort-pulsed beam

“…The rapid development of ultrashort laser pulses have opened up the way for micromachining 1,2 , pump-probe spectroscopy 3,4 , surgical operation 5,6 , and optical fiber communications 7,8 . The measurement of the spatial or temporal intensity profile of ultrashort pulses is now a standard procedure in ultrafast optics laboratories.…”

High common mode rejection ratio InP 90° optical hybrid in ultra-broadband at 60 nm with deep-rigded waveguide based on × 4 MMI coupler*

“…Owing to the quadrature phase shift keying (QPSK) modulation technique, the real-time coherent optical transmission systems greatly reduce the transmission loss per bit, thereby improving the data transmission efficiency. [1][2][3][4][5][6][7][8][9][10] Besides, the coherent transmission system offers the more choices of the data transmission rates which are selected by software. [11][12][13][14] Therefore, the real-time coherent optical communication technology has been universally recognized as a preferable choice to improve the transmission speed up to 400 Gb/s and more in the industry.…”