Wide range optofluidically tunable multimode interference fiber laser

Abstract

An optofluidically tunable fiber laser based on multimode interference (MMI) effects with a wide tuning range is proposed and demonstrated. The tunable mechanism is based on an MMI fiber filter fabricated using a special fiber known as no-core fiber, which is a multimode fiber (MMF) without cladding. Therefore, when the MMI filter is covered by liquid the optical properties of the no-core fiber are modified, which allow us to tune the peak wavelength response of the MMI filter. Rather than applying the liquid on the entire no-core fiber, we change the liquid level along the no-core fiber, which provides a highly linear tuning response. In addition, by selecting the adequate refractive index of the liquid we can also choose the tuning range. We demonstrate the versatility of the optofluidically tunable MMI filter by wavelength tuning two different gain media, erbium doped fiber and a semiconductor optical amplifier, achieving tuning ranges of 55 and 90 nm respectively. In both cases, we achieve side-mode suppression ratios (SMSR) better than 50 dBm with output power variations of less than 0.76 dBm over the whole tuning range.

Discrete liquid level fiber sensor

“…The low insertion loss contributes to low overall loss for the total reflected power and hence maximizes the dynamic range of the sensor. The main advantage of this sensor scheme is that it could provide customization of liquid level measurement range up to hundred meters with simple configuration instead of the complicated point measurement scheme employed by MMI [9,[16][17][18], U-shaped [16,19,20,21] and POF [17,22,23,24] based sensors. Since our sensor is based on intensity measurement, it is suggested to have one of the multiple outputs acting as the reference signal using the ratio metric scheme.…”

Wavelength Tuning of Multimode Interference Fiber Lasers: A Review

“…[ 18,19 ] A few years later, based on a similar liquid‐level approach, the same team demonstrated a laser tuning over an extended range by using a booster optical amplifier (BOA) with wider bandwidth. [ 20 ] They achieved laser tuning over 90 nm, ranging from 1480 to 1570 nm, in CW operation with a single laser output. Fundamentally, this tells that one could, in principle, use broader sources and still be able to design the operation of the MMI to higher‐order self‐images, i.e., larger values of p in Equation (), to cover a large dynamic range.…”

“…Summary of the central wavelength and the tuning range of wavelength‐tuned MMI fiber lasers tracked over time. Squares (orange) markers indicate ytterbium MMI fiber lasers: a) Selvas et al [ 13 ] b) Anzueto et al [ 14 ] c) Mukhopadhyay et al [ 29 ] d) Chakravarty et al [ 30 ] Circles (green) markers indicate Erbium MMI fiber lasers: e) Castillo et al [ 15 ] f) Castillo et al [ 16 ] g) Walbaum et al [ 26 ] h,i) Ma et al, [ 21,22 ] j) Antonio et al, [ 20 ] k) Ahmad et al [ 28 ] l) Khattak et al [ 31 ] m) Li et al [ 34 ] n) Zhang et al [ 32 ] Triangles (purple) markers indicate Thulium MMI fiber lasers: o) Ma et al [ 23 ] p) Zhang et al [ 33 ] q) Li et al [ 27 ] r) Ibarra et al [ 24 ] s,t) Sakata et al [ 25 ] u) Li et al [ 35 ] v,w) Sakata et al [ 36 ] The diamond and down triangle indicate exceptional cases where special light sources were used for Erbium, x) Antonio et al, [ 20 ] and Thulium, y) Yan et al [ 37 ] , respectively (see text for details).…”

Tunable dual-wavelength Er3+-doped fibre laser based on a single multimode interference filter

“…The MMIF is fabricated by a segment of MMF, spliced between two standard SMFs (as shown in figure 1(a)). It works on the principle of the multimode interference effect [17][18][19][20], which can be briefly expressed as follows. When the light is coupled into the MMF from the input SMF1, the interference of the excited transverse modes will be generated in the MMF, where self-images of the input mode field will be generated when the accumulated phase shift of all the excited modes is a multiple of 2π.…”