Switchable multi-wavelength fiber laser based on modal interference

Abstract

A comb fiber filter based on modal interference is proposed and demonstrated in this paper. Here two cascaded up-tapers are used to excite the cladding mode, and a core-offset jointing point is used to act as an interference component. Experimental results show that this kind of structure possesses a comb filter property in a range of the C-band. The measured extinction ratio is better than 12 dB with an insertion loss of about 11 dB. A switchable multi-wavelength erbium-doped fiber laser based on this novel comb filter is demonstrated. By adjusting the polarization controller, the output laser can be switched among single-, dual-, and three-wavelengths with a side mode suppression ratio of better than 45 dB.

Tunable and Switchable Erbium-Doped Fiber Laser Using a Multimode-Fiber Based Filter

“…The wavelength fluctuation of the 1st and 2nd peak is 0.04 nm and 0.03 nm, and their power fluctuations are 0.46 and 0.32 dB, respectively, which shows good power uniformity and stability. The stable dual-wavelength operation could benefit from a polarization hole burning effect [11] and a deeply saturated spectral hole burning effect in the EDF [24] to effectively suppress the mode competition from the homogenous line broadening and cross-gain saturation in the EDF.…”

“…Due to the nature of the homogeneous broadening effect of the erbium doped fiber, it is challenging to achieve a stable multi-wavelength operation. Multiwavelength EDFLs have been demonstrated by using different schemes, for example, cascaded fiber Bragg gratings (FBGs) [1], four-wave-mixing of dispersion shifted fiber [2], nonlinear polarization rotation [3], and various fiber-optic interferometers (FOIs) [4][5][6][7][8][9][10][11][12][13][14][15][16]. Among them, much of the research attention has been recently paid to employ FOIs to generate multiwavelengths.…”

“…Among them, much of the research attention has been recently paid to employ FOIs to generate multiwavelengths. An FOI can be constructed with a pair of long period gratings (LPGs) [4], sandwich-structured single-mode fiber (SMF) driven by an acoustic transducer [5], a fiber loop mirror (FLM) incorporated with one or two sections of high birefringent fibers [6][7][8][9] or a combination with hollow-core Bragg fiber [10], and modal interference by using fiber tapers [11][12][13] or multimode fiber (MMF) [14,15].…”

“…Although the switchable function from single-to multi-wavelength is readily realized by adopting a polarization controller (PC) [6,8,9,11,14] or a variable optical attenuator (VOA) [13,15] in the cavity, it is highly desirable that, in the meantime, the laser wavelength and wavelength spacing could be tunable for practical applications. Many efforts have been devoted to the tunable and switchable multiwavelength fiber lasers.…”

Room-Temperature Power-Stabilized Narrow-Linewidth Tunable Erbium-Doped Fiber Ring Laser Based on Cascaded Mach-Zehnder Interferometers With Different Free Spectral Range for Strain Sensing

“…W ITH the advent of various rare-earth-ion doped silica optical fibers and high power single-mode diode lasers, fiber lasers with many excellent optical characteristics such as high quantum efficiency, high gain bandwidth, high SMSR, high polarization extinction ratio, high output power, high pulse energy, low threshold pump power, wide tuning range and ultra-narrow linewidth have been developed extensively for applications in the field of communications, sensing, imaging, and micro-or nano-machining [1]- [3]. Further, practical applications of tunable erbium-doped fiber lasers (EDFL) include laser ranging, optical coherence tomography, wavelength division multiplexing and biosensing [4]- [7]. The wavelength tuning can usually be achieved using volume/fiber Bragg gratings (FBG) [8], [9], fiber filters, interferometers [10], [11] or indeed through many other methods [12]- [14].…”