A single-mode erbium laser with switchable single- and dual-wavelength operation

Abstract

In the paper, we study a single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser with a switchable single-and dual-wavelength output in C-band scale simultaneously. When a 1×4 wavelength-division-multiplexing (WDM) multiplexer is placed inside the ring cavity, four tunable single wavelengths and five sets of dual-wavelength with several mode-spacing can be accomplished, respectively. To achieve the selective and stable output characteristic, the suitable adjustment of cavity and birefringent losses are operated. Additionally, the laser characteristics of output wavelength, detected power, and optical signal to noise ratio (OSNR) have also been discussed.

A Selectable Single-Mode Erbium Fiber Laser With Mach-Zehnder Interferometer and Rayleigh Injection Scheme

“…However, the EDF ring lasers with stable single-longitudinal-mode (SLM) operation will be hard to accomplish principally because of the long fiber cavity and the dense multi-longitudinal-mode (MLM) oscillation induced by the homogenous broadening effect of EDF [6], [7]. To ensure and reach the SLM action in the EDF ring fiber laser with advantageous output performance, numerous methods have been operated in the fiber ring cavity, such as using the Mach-Zehnder interferometer (MZI) scheme [8], saturable absorber (SA) based filter [9], [10], Rayleigh backscattering (RB) injection [11], compound fiber ring configuration [12], [13], and narrower optical filter [14], [15]. Chien-Hung Yeh, Li-Hung Liu, Han-Shin Ko, and Yi-Ting Lai are with the Department of Photonics, Feng Chia University, Taichung 407802, Taiwan (e-mail: yeh1974@gmail.com; jk1992581@gmail.com; xzbc699@gmail.com; laietn@gmail.com).…”

Use of Simple Octa-Ring Configuration for Tunable Erbium Laser With Single-Mode Output

“…However, the strong homogeneous line broadening of EDF gain could produce wavelength competition and longer fiber cavity of fiber laser would cause the unstable multi-longitudinal-mode (MLM) oscillation [9]. To achieve stable and wide SLM wavelength output, some related methods have been demonstrated, such as using the compound-fiber-ring structure [10], [11], Mach-Zehnder interferometer (MZI) method [12], [13], Sagnac interferometer (SI) loop [4], [14], saturable absorber (SA) based filter [15], [16], optical injection [17] and ultranarrow bandpass filter [18], [19]. Besides, to obtain a wider wavelengthselection range of EDF laser scheme, the parallel erbiumdoped fiber amplifier (EDFA), hybrid optical amplifiers and…”