Broad-band high-repetition-rate source for spectrally sliced WDM

Abstract

Abstract-A uniform 35-nm-wide spectrum is generated by broadening the output from a 2.5-GHz mode-locked femtosecond fiber laser in dispersion shifted fiber. The obtained spectrum is suitable for spectral slicing and wavelength-division-multiplexed applications. The spectral broadening in dispersion shifted fiber is optimized as a function of the launched pulse chirp parameter.Index Terms-High-repetition-rate mode-locked laser, modelocked fiber laser, optical fiber dispersion, optical fiber nonlinearity, pulse propagation in optical fiber, spectral slicing wavelengthdivision multiplexing, wavelength-division multiplexing. BROAD-BAND transmitters with multigigahertz data rates operating in the 1550-nm fiber-optic communications band are key enabling technologies for future wavelength and time division multiplexed (wavelength-division multiplexing and time-division multiplexing) networks. As the number of wavelength channels and data rates grow, using a separate stabilized source for each channel may become less practical. The individual CW sources must be tuned and aligned with the specific wavelength grid of the system. The use of a single, high repetition rate mode-locked erbium-doped fiber (EDF) laser simplifies wavelength stabilization and provides a potentially attractive alternative since its broad output spectrum can be partitioned into a large number of WDM channels [1], [2]. The wavelength channels are selected by passive filtering which facilitates the addition of new channels, and minimizes the affect of wavelength drift on system performance [3], [4]. In comparison with broadened incoherent sources such as those based on amplified spontaneous emission or supercontinuum generation, mode-locked sources do not suffer from beat noise between different portions of the spectrum within a channel, which can limit transmission capacity [5]- [7]. The coherence of the mode-locked source can be used to increase the channel information capacity by techniques such as those used in codedivision multiple-access (CDMA) networks [8]. Even higher bitrates per channel can be achieved by time multiplexing the short transform limited (picosecond) pulses generated in each of the spectrally sliced channels.In this letter, we report the generation of a uniform and flat, 35-nm-wide spectrum centered at 1549 nm from a 2.5-GHz repetition rate, femtosecond fiber laser. For channel

Harmonic Mode-Locked Fiber Laser based on Photonic Crystal Fiber Filled with Topological Insulator Solution

“…The high repetition rates of passively mode-locked fiber lasers with subnanosecond to picosecond pulses have potential applications in many fields, including high speed optical communication, optical frequency metrology [4,5]. As an important technique to increase the pulse repetition rate, the relevant harmonic mode locking (HML) fiber lasers have been a growing research region.…”

Toward higher-order passive harmonic mode-locking of a soliton fiber laser

“…This is a very simple way to multiply the repetition rate up to the GHz range without needing to reduce the fiber cavity length to impractical levels or requiring any active GHz modulators. This kind of optical source would be useful for applications in wavelength division multiplexing (WDM) communication via post-spectral broadening [7] or astronomical frequency combs via post-amplification [8] provided that the repetition rate can be sufficiently increased and the stability is guaranteed. So far, nonlinear polarization rotation (NPR) has been adopted as the primary means of achieving passive H-ML in Yb [9], doubleclad Yb [10], Er:Yb [11], and double-clad Er:Yb fibers [12,13].…”

Highly stable MXene (V2CTx)-based harmonic pulse generation

“…Compared with the fundamental state, harmonic mode-locking state can achieve higher repetition rate pulses. High repetition rate pulse can be widely used in the fields of fiber sensing [40], optical communications [41], frequency comb [42], etc. So far, there are rare reports on the harmonic mode-locking fiber laser based on MXene.…”