Single-mode optical fiber couplers made of fluoride glass.

We demonstrate the first single-mode optical fiber couplers made with ZBLAN optical fiber. Couplers are fabricated using a controlled tapering procedure enabling high reproducibility while limiting glass crystallization. A coupling ratio of up to 41%/59% in cross/through ports with an excess loss of 2.

3 kW forward-pumped fiber laser via pump recycler.

We report a single-end forward-pumped fiber laser with a record high output power of 3 kW. The laser is assembled exclusively from commercially widespread components such as the Yb-doped fiber with core/cladding diameter of 20/400 µm, pump laser diodes at an emission wavelength of 915 nm, and a signal and pump fiber combiner that serves as the pump recycler. The record high power arises from the combination of the 915 nm pumping and pump recycler with an effective reflectivity of 78%, increasing simultaneously the thresholds for stimulated Raman scattering and transverse mode instability (TMI).

Effective all-fiber pump recycler for kilowatt fiber lasers.

We report an effective pump recycler for industrial kilowatt fiber lasers. The pump recycler is a (6+1)×1 tapered fiber bundle, with signal ports of Ge-doped fiber (GDF) with core/cladding diameters of 20/400 µm and pump fiber ports (PFPs) with core/cladding diameters of 135/155 µm. By splicing PFPs in pairs, 77.

Nonlinear chalcogenide optical fiber couplers.

We demonstrate chalcogenide optical fiber couplers with a power-dependent coupling coefficient. The couplers are designed and fabricated using an AsSe fiber and characterized at a wavelength of 1938 nm, leading to a critical power of 126 W, the lowest ever reported for any optical fiber coupler. These nonlinear couplers enable all-optical switching and will be useful for passive mode-locking over a wide wavelength range from the telecommunication band to the mid-infrared.

Fiber optical parametric oscillator made of soft glass.

Fiber optical parametric oscillators (FOPOs) are compact optical sources of coherent and broadly tunable light compatible with operation in unconventional spectral bands. Highly nonlinear silica fibers have enabled the development of FOPOs in the telecommunication wavelength band, but the strong material absorption of silica glass at wavelengths >2 µm limits its applicability in the mid-infrared (MIR) spectral range. In this work, we overcome this issue and report a FOPO designed entirely out of soft glass fiber.

Thulium-doped fiber laser mode-locked by nonlinear polarization rotation in a chalcogenide tapered fiber.

We demonstrate a thulium-doped fiber laser that is mode-locked thanks to nonlinear polarization rotation (NPR) in a chalcogenide tapered fiber. The high nonlinearity of the tapered fiber leads to a combined reduction in mode-locking threshold power and cavity length compared to any all-silica NPR based mode-locked lasers. In the continuous wave mode-locking regime, the laser generates stable, tunable solitons pulses.

Mid-infrared soliton self-frequency shift in chalcogenide glass.

Emerging applications in the mid-infrared (MIR) stimulate the growth and development of novel optical light sources. Soliton self-frequency shift (SSFS) in soft glass fiber currently shows great potential as an efficient approach toward the generation of broadly tunable femtosecond pulses in the MIR. In this work, we demonstrate a highly efficient tunable soliton source based on SSFS in chalcogenide glass.

High extinction ratio elliptical core Panda-type polarization-maintaining fiber coil.

The polarization-maintaining performance of the traditional Panda-type polarization-maintaining fiber (PMF) coil is significantly affected by winding stress and temperature. Here, we present an elliptical core Panda-type PMF coil based on a fiber that employs both geometric and stress birefringence. The extinction ratio of the elliptical core PMF coil was found to be 20.

Raman suppression within the gain fiber of high-power fiber lasers.

We report the effective suppression of Raman emission in a monolithic ytterbium-doped fiber laser by the insertion of a chirped and tilted fiber Bragg grating (CTFBG) directly within the gain fiber of the laser. In comparison with a non-compensated filtered laser cavity for which the Raman threshold occurs at an output power of 1.54 kW, the insertion of a CTFBG within the gain medium leads to an increase in the Raman threshold by 260 W.

All-fiber nonlinear optical wavelength conversion system from the C-band to the mid-infrared.

We demonstrate an all-fiber wavelength conversion system from the C-band to the wavelength range of 2.30-2.64 µm of the mid-infrared (MIR).

All-chalcogenide single-mode optical fiber couplers.

We demonstrate the fabrication of all chalcogenide single-mode optical fiber couplers including broadband couplers, wavelength division multiplexers, and polarization beamsplitters. The functionality of each coupler is engineered with a careful design of geometry. As a result, broadband couplers can be set to any arbitrary coupling ratio.

In situ fabrication of far-detuned optical fiber wavelength converters.

We demonstrate an in situ approach for the fabrication of all-fiber wavelength converters with a wavelength offset that is both far-detuned and precisely engineered. Such wavelength converters are fabricated using the parametric gain of ASe microwires and finely tuned from successive adjustments of microwire diameter along with real-time monitoring. Wavelength conversion is achieved from a pump at a wavelength of 1.

Free-running mode-locked laser based dual-comb spectroscopy.

We present a real-time dual-comb spectrometer operated from a bidirectional mode-locked fiber laser in the wavelength range of 1.9 μm. Two pulsed signals emitted from a common cavity ensure mutual coherence and common mode noise rejection.

Pulse characterization by cross-phase modulation in chalcogenide glass.

We report, to the best of our knowledge, the first all-fiber frequency-resolved optical gating (FROG) device based on cross-phase modulation in chalcogenide glass. The amplitude and phase of pulses as short as 390 fs at femtojoule energy levels are accurately characterized without direction-of-time ambiguity in the retrieved pulse. A measurement sensitivity of 18  mW is achieved from the strong nonlinearity of a 10 cm long chalcogenide microwire.

Bidirectional mode-locked thulium-doped fiber laser.

We report a bidirectional mode-locked thulium-doped fiber laser. Mode-locking is enabled by the combination of semiconductor saturable absorption and nonlinear polarization rotation. Two stable mode-locked picosecond pulse trains in opposite directions are generated with a fundamental repetition rate of ∼16.

All-fiber frequency-resolved optical gating pulse characterization from chalcogenide glass.

We report, to the best of our knowledge, the first all-fiber frequency-resolved optical gating device from nonlinear processing in chalcogenide glass. The strong four-wave mixing efficiency of an 11 cm long chalcogenide microwire enables a high sensitivity characterization of pulses in the 2 μm wavelength band. The amplitude and phase of chirped and unchirped picosecond pulses are accurately characterized with a high sensitivity of 0.

Fourier transform spectroscopy by repetition rate sweeping of a single electro-optic frequency comb.

We demonstrate the operation of a Fourier transform spectrometer that operates by sweeping the pulse repetition frequency of an electro-optic frequency comb. Incorporating a length-imbalanced interferometer, this single-comb system is analogous to a conventional dual-comb system, but with a greatly simplified design. The functionality of the spectrometer is demonstrated via the high-resolution spectrum measurement of an HCN reference gas cell.

Optical frequency comb generation with ultra-narrow spectral lines.

We demonstrate an optical comb source that generates 550 ultra-narrow spectral lines with a spectral linewidth of 1.5-3 kHz, spanning over the C-band. The source originates from a single-mode Brillouin laser processed with phase modulation, pulse compression, and four-wave mixing.

Mid-infrared wavelength conversion from AsSe microwires.

We demonstrate all-fiber far-detuned and widely tunable mid-infrared wavelength conversion using AsSe microwires. In a first experiment, an idler is generated and tuned from 2.351 to >2.

Passively synchronized Q-switched and mode-locked dual-band Tm:ZBLAN fiber lasers using a common graphene saturable absorber.

Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm:ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.

Chalcogenide-based optical parametric oscillator at 2 μm.

We report the first chalcogenide-based optical parametric oscillator (OPO) relying on pure parametric gain. The all-fiber OPO operates in the wavelength range of 2 μm and is tunable over 290 nm from the combined Stokes and anti-Stokes contributions. The gain medium is a 10 cm long chalcogenide microwire made from a high modal confinement AsSe core with cyclo olefin polymer cladding, leading to optimized chromatic dispersion, high nonlinearity, and broadband transparency.

Chalcogenide optical microwires cladded with fluorine-based CYTOP.

We demonstrate optical transmission results of highly nonlinear AsSe optical microwires cladded with fluorine-based CYTOP, and compare them with microwires cladded with typical hydrogen-based polymers. In the linear optics regime, the CYTOP-cladded microwire transmits light in the spectral range from 1.3 µm up to >2.

Low-threshold lasing at 1975 nm in thulium-doped tellurite glass microspheres.

Thulium-doped (Tm-doped) tellurite glass microspheres are used as laser media. Emission lines at wavelengths near 1975 nm are observed. The onset of laser emission is achieved with 8.

Broadband supercontinuum generation in all-normal dispersion chalcogenide microwires.

We report the first chalcogenide microwire designed with all-normal dispersion to generate supercontinuum by optical wave breaking, a low-noise nonlinear process. The chalcogenide (As2S3) microwire is coated with PMMA and tapered to a diameter of 0.58 μm to achieve the all-normal dispersion regime.

All-optical wavelength conversion based on time-domain holography: erratum.

Eq. (5.1) in our recently published manuscript is incorrect.