Bend-resistant Large Mode Area Research Articles

Design and analysis of a multi-layer core, hole-assisted bend-resistant large mode area fiber for 2 μm operation

A novel bend-resistant large mode area fiber with multi-layer core and hole assistance is proposed for 2 μm operation. Taking advantage of the modulation of a three-layer core, the single-mode operation performance at a tight bending radius is improved. The introduction of air holes can further help to reduce bending loss. Numerical results show that robust single-mode operation with a large mode area exceeding 2050 μm2 can be achieved under a tight bending radius of 10 cm. The loss ratio can reach 3.6 × 103. Moreover, the excellent bend-resistance performance can be maintained in a broad waveband from 1.6 μm to 2.1 μm.

Design of a large-mode-area pixeled leakage channel fiber with an ultrahigh loss ratio for 2 µm operation.

A novel bend-resistant large mode area fiber with pixeled structure and leakage channel is proposed for application with a tight bend radius at the 2 µm wavelength region. Two layers of discontinuous fluorine-doped silica rods, which are called pixels, are introduced in the cladding. By removing four pixels, the loss of high-order modes is enhanced significantly due to the leakage channel. Bend properties of the fiber are investigated thoroughly by numerical simulations. As a result, a robust single-mode operation is obtained with an ultrahigh loss ratio (the minimum loss of high-order modes to the loss of fundamental mode) exceeding 3×105 when the fiber is bent with a tight radius as 10 cm. The effective mode area can reach 1764µm2. In addition, the fiber can keep high performance within a broad waveband from 1.75 to 2.15 µm. Large mode area and robust single-mode operation with a tight bend radius make this fiber beneficial to the development of 2 µm miniaturized fiber lasers.

A bending-resistant large mode area pixelated trench assisted segmented cladding fiber

In this paper, a novel bend-resistant large mode area fiber with pixelated trench-assisted segmented cladding is proposed and investigated. This structure has large mode area and excellent higher order modes (HOMs) suppression. Numerical results show, when the bending radius is 20 cm and the operating wavelength is 1.06μm, the effective mode area of the fiber can reach 914μm2 and the loss ratio between lowest-HOMs and fundamental mode is larger than 100. In addition, the proposed optical fiber is insensitive to the bending direction. This fiber has great potential in high power fiber lasers and amplifiers.

Bend-Resistant Large Mode Area Fiber With an Azimuthally Segmented Trench in the Cladding

A bend-resistant large mode area fiber with an azimuthally segmented trench in the cladding is proposed and investigated in this paper. The loss ratio of the proposed fiber between the lowest higher order modes (HOMs) and fundamental mode can reach 1000, which is much larger than 130 of multi-trench fiber (MTF). Meanwhile, the mode area of the proposed fiber achieves 790 μm2 at core radius of 23 μm, which is the same large as MTF. Moreover, the effective mode area of our design can achieve 920 μm2 at core radius of 26 μm with effective single-mode operation at the bending radius of 20 cm. The fiber performance is stable with bending orientation at the range of [0°, 360°]. The proposed fiber ensures better HOMs suppression than the MTF. The new fiber design shows great potential in high-power fiber lasers.

Bend resistant large mode area fiber with step-index core and single trench

Abstract A novel bend resistant large mode area fiber with step-index core and single trench in the cladding is proposed. Numerical results demonstrate that the largest effective mode area reaches up to 2460 μm2 at the wavelength of 2 μm when the bend radius is only 10 cm. To achieve the better performance of single mode, the loss ratio of the lowest loss of higher order mode to the highest loss of fundamental mode can reach up to 886 with a fundamental mode bend loss lower than 0.0083 dB/m through optimizing structure parameters. The circular symmetry of fiber structure makes it insensitive to the bending direction. Furthermore, this fiber structure can be also used to develop bend resistant large mode area fiber with high performance at the wavelengths of 1.06 μm and 1.55 μm. Due to large mode area, good single mode properties, small bend radius and insensitivity to bend direction, this fiber has the potential application for compact high power fiber lasers.

A bend-resistant low bending loss and large mode area two-layer core single-mode fiber with gradient refractive index ring and multi-trench

Abstract We propose a bend-resistant large mode area single-mode fiber with low bending loss. The fiber consists of three parts, including a two-layer core, a gradient refractive index ring and multi-trench. Performance of the proposed fiber is investigated by using a finite element method at 1550 nm wavelength. Large mode area of 2622 μm2 at a bend radius of 20 cm can be achieved with the function of the two-layer core and the gradient refractive index ring. The gradient refractive index ring acts as a resonant ring, which also contributes to bend-resistant performance. Bending loss can be reduced to about 0.092 dB/m due to the multi-trench in the cladding, which is also beneficial to improve transmission efficiency. Moreover, the fiber can ensure single-mode operation by exploiting high suppression of the higher order modes. The bending direction has no effect on the performance of the fiber because of the symmetric design.

Bend-resistant large mode area fiber with novel segmented cladding

A novel structure of segment cladding fiber (SCF) with characteristics of bend-resistance and large-mode-area (LMA) is proposed. In this new structure, the high refractive index (RI) core is periodically surrounded by high RI fan-segmented claddings. Numerical investigations show that effective single-mode operation of the proposed fiber with mode field area of 700μm2 can be achieved when the bending radius is 15cm. Besides, this fiber is insensitive to the bending orientation at the ranging of [−180°, 180°]. The proposed design shows great potential in high power fiber lasers and amplifiers with compact structure.

Bend Resistant Large Mode Area Fiber With Multi-Trench in the Core

A bend resistant large mode area fiber with multitrench in the core is proposed. Four layers of trenches with high refractive index are introduced to modulate the mode field distribution. Low refractive index trenches in traditional designs are replaced with pure silica trenches to reduce the difficulty of manufacture. Meanwhile, the core region with a refractive index higher than pure silica cladding conforms to the practical requirement for active fibers. Numerical investigations show that single mode operation with a mode field area of 1100 μm2 is achieved at a bend radius of 15 cm. This design shows the potential of mode field scaling for multitrench fibers and makes a contribution to compact high power fiber lasers.