Tapered-EDF-Based Mach–Zehnder Interferometer for Dual-Wavelength Fiber Laser

Abstract

An all-fiber comb filter using a tapered-erbium-doped fiber in a Mach-Zehnder interferometer structure is presented. The free spectral range, extinction ratio, bandwidth, and interference pattern of the comb filter can be shaped by controlling the taper waist length and the length of up and down taper transition regions. By varying the taper waist length from 5 to 25 mm, the free spectral range changes from 14.7 to 1.0 nm, and the linewidth varies from 3.3 to 0.3 nm, respectively. We demonstrate a tunable dualwavelength laser by using the tapered-erbium-doped fiber as a gain medium as well as a wavelength-selective element. The laser can be tuned at a resolution of 0.2 nm with a side-mode suppression ratio of up to 46.88 dB and a linewidth of 0.09 nm.

All-polarization maintaining single-longitudinal-mode fiber laser with ultra-high OSNR, sub-KHz linewidth and extremely high stability

“…However, it is difficult to obtain SLM EDF ring laser with outstanding performance due to the unavoidable multi-longitudinal mode (MLM) oscillation or mode hopping, which is mainly caused by the homogeneous broadening of the EDF and the long cavity length of the EDFL [11]. To achieve stable SLM lasing for EDF ring lasers, researchers have utilized substantial techniques and optical components in the cavity, such as the multiple-ring compound resonator [7][8][12][13], the unpumped EDF-based saturable absorber (SA) filter [14], the Mazh-zehnder interferometer [15], the ultra-narrow pass-band filter [16], the phase shifted fiber Bragg grating (FBG) [17], the micro-ring resonator filter [18] and the micro-sphere filter [19].…”

S-band single-longitudinal-mode fiber laser with ultra-narrow linewidth, ultra-high OSNR and high stability

“…Among them, SLM erbium-doped fiber (EDF) ring lasers with narrow linewidth, high optical signal to noise ratio (OSNR), easy operability, high stability and low relative intensity noise (RIN) have been recognized as the preferred light sources for fields such as optical communication, optical metrology, atomic spectroscopy and high-resolution spectroscopy [7][8][9][10], to enable better accuracy and higher stability. To deepen the study, many proposals with substantial techniques and optical components have been put forward to solve the problem of obtaining a stable SLM EDF ring laser, such as the compound-cavity structure [5][6], the unpumped EDF-based saturable absorber (SA) filter [11], the optical injection method [12], the Mazh-zehnder interferometer [13], the self-and external-injection technologies in the EDF [14][15], the ultra-narrow pass-band filter [16] and the phase shifted fiber Bragg grating (FBG) [17]. By contrast, we can find very few studies on the S-band EDFLs [18][19][20], let alone those on the S-band ring cavity lasers [18][19].…”

Stable Single-Longitudinal-Mode Fiber Laser With Ultra-Narrow Linewidth Based on Convex-Shaped Fiber Ring and Sagnac Loop

“…The associate editor coordinating the review of this manuscript and approving it for publication was Zinan Wang . stable SLM behavior is difficult to achieve mainly due to the long lasing cavity and the unstable multi-longitudinal-mode (MLM) oscillation caused by the homogenous broadening of the EDF. To obtain a stable SLM EDF ring fiber laser with superior performance, many approaches have been applied in the laser cavity, such as using the expensive ultra-narrow passband optical filter [9], employing the complicated optical injection method [10], applying the Mach-Zehnder interferometer (MZI) structure [11], utilizing unpumped EDF-based saturable absorber (SA) [12], applying Rayleigh backscattering in tapered fiber [13], employing phase-shifted FBG filter [8], using FBG Fabry-Pérot filter [14] and designing the compound-ring structure [15]- [17].…”