Switchable dual-wavelength erbium-doped fibre laser utilizing two-channel fibre Bragg grating fabricated by femtosecond laser

Abstract

Abstract:We propose and demonstrate a switchable dual-wavelength erbium-doped fibre ring laser. Competition between the lasing wavelengths in erbium-doped fibre laser at room temperature is suppressed by incorporating a two-channel fibre Bragg grating (TC-FBG), which consists of two highly localized sub-gratings fabricated by femtosecond laser in single mode fibre. Wavelengths and polarization states of the lasing lines are selected by the TC-FBG. Laser output can be switched between single-and dual-wavelength operations by simply adjusting the polarization controller. Stable dual-wavelength output is verified at room temperature with a power fluctuation less than 0.27 dB, and wavelength fluctuation less than 0.004 nm.

Ultrashort Bessel beam photoinscription of Bragg grating waveguides and their application as temperature sensors

“…The red curve presents the simulation result by using Eqs. (6) and 12, which is well fitted with experimental results. We note, however, that this model, though physically intuitive, treats the evolution in a simple manner, as phase transitions and mechanical expansion are not treated self-consistently in Eqs.…”

“…Since δn eff has a negative value in our work, the effective refractive index of BGWs will increase with the increase of grating offset, according to Eq. (6). This can reasonably explain the red-shift of resonant peak as shown in Fig.…”

“…If we define the coupling strength at grating offset of 0 μm as k 0 , the grating coupling strength has an expression of k t k 0 exp−8x 2 0 ∕a 2 , according to Eqs. (6) and (12). This means that the coupling strength decreases with the increase of grating offset.…”

“…The point-by-point (PbP) laser writing method using ultrashort laser pulses [1] is a recently emerged direct fabrication technique for fiber Bragg gratings (FBGs) that has attracted significant attention and has been applied for various optical systems such as optical networks, sensors, and fiber lasers [2][3][4][5][6][7][8]. The tightly focused laser pulse, with intrinsic high laser intensity, allows creation of localized refractive index modifications (positive or negative) from structural and morphology changes inside the fiber component via nonlinear photoionization mechanisms [9,10].…”

Wavelength-switchable L-band fiber laser assisted by random reflectors

“…In addition to the above, these fiber-optic microstructures also have interesting applications in areas such as fiber-optic lasers [8], fiber Bragg gratings (FBGs) [9], long period fiber gratings (LPGs) [10], tilted fiber Bragg gratings [11], interferometers [12--14], couplers [15] or birefringence adjustable elements [1], [16]. In further, changes in the birefringence of a fiber can be caused by its twist [17].…”