Gelin Zhang

Soliton rains in a graphene-oxide passively mode-locked ytterbium-doped fiber laser with all-normal dispersion

We experimentally investigated soliton rains in an ytterbium-doped fiber (YDF) laser with a net normal dispersion cavity using a graphene-oxide (GO) saturable absorber (SA). The 195 m-long-cavity, the fiber birefringence filter and the inserted 2.5 nm narrow bandwidth filter play important roles in the formation of the soliton rains. The soliton rain states can be changed by the effective gain bandwidth of the laser. The experimental results can be conducive to an understanding of dissipative soliton features and mode-locking dynamics in all-normal dispersion fiber lasers with GOSAs. To the best of our knowledge, this is the first demonstration of soliton rains in a GOSA passively mode-locked YDF laser with a net normal dispersion cavity.

An L-band graphene-oxide mode-locked fiber laser delivering bright and dark pulses

In this work we have demonstrated the generation of L-band bright and dark pulses from a graphene-oxide (GO) mode-locked erbium-doped fiber laser. The polymer-hosted graphene-oxide saturable absorber (SA) was fabricated by a vertical evaporation method, which permitted a flexible choice of GO concentration and SA thickness. Stable fundamental solitons with a width of ~770 fs and repetition rate of ~21.79 MHz could be directly generated from the laser cavity. The corresponding spectrum was centered at ~1596.0 nm with a 3 dB bandwidth of ~4.454 nm. Triple solitons and fundamentally repetitive dark pulses could also be achieved. By changing the laser cavity design, we also achieved the generation of dark pulses, which had one to three times the repetition rate. The multiple soliton and dark pulse generation were experimentally observed for the first time in such a GO mode-locked fiber laser system, to the best of our knowledge. Our experimental results indicate that the GOSA can be successfully utilized to realize different mode-locked states in the L-band.

Double Cladding Seven-Core Photonic Crystal Fibers With Different GVD Properties and Fundamental Supermode Output

We fabricated three kinds of double cladding nonlinear seven-core photonic crystal fibers (PCFs) with different group velocity dispersion (GVD) properties and fundamental supermode output. Pumped by a 150 ps polarization maintaining a ytterbium-doped fiber laser based on the gain-switched technique, octave-spanning supercontinua were generated within the wavelengths from 450 to at least 2000 nm in these fibers with a high spatial quality.

High order harmonic mode-locking in an all-normal-dispersion Yb-doped fiber laser with a graphene oxide saturable absorber

A high order passive harmonic mode-locking (HML) Yb-doped all-normal-dispersion fiber laser based on a graphene oxide saturable absorber has been experimentally demonstrated. For two different pump powers and different polarization states of the laser cavity, lower order and higher order HML have been achieved. The highest 30th-order harmonic (31.86 MHz) was achieved with subnanosecond pulse duration; this is transitional from a bunched multipulse state.

Bright and Dark Square Pulses Generated From a Graphene-Oxide Mode-Locked Ytterbium-Doped Fiber Laser

The observation of the bright pulses and dark square pulses in a graphene-oxide saturable absorber (GOSA) passively mode-locked ytterbium-doped fiber laser has been investigated experimentally. Bright pulses are achieved at a pump power of ~ 200 mW. However, the dark-square-pulse generation starts at a much higher pump power of ~ 450 mW. At the maximum pump power of 600 mW, the dark-square-pulse bunches and harmonic mode locking (HML) can be also obtained by tuning the polarization controller (PC) to different orientations. It is the first demonstration of the bunches and HML of dark square pulses in a GOSA passively mode-locked ytterbium-doped fiber laser with large normal dispersion cavity.

Passively harmonic mode locking in ytterbium-doped fiber laser with graphene oxide saturable absorber

Abstract. We have demonstrated the dissipative solitons generated in an ytterbium-doped fiber laser cavity using graphene oxide as the saturable absorber. The lasing light, centered at 1077.2 nm, has a 3 dB spectral bandwidth of ∼1.12  nm. Under different launched pump powers and appropriate polarization orientations, harmonic mode-locked of second- and third-order pulse trains have been achieved; the corresponding 3-dB bandwidth and pulse duration have been detected.

Two different output states from an all-normal dispersion yetterbium-doped fiber laser using graphene-oxide as a saturable absorber

We have experimentally obtained two different applied output states from an all-normal dispersion yetterbium-doped fiber laser using graphene-oxide as a saturable absorber without additional components (like tunable filter, dispersion compensation), including the wavelength-switched mode-locking operation, and the dissipative soliton resonance (DSR) operation with high energy square pulses. These two experimental phenomena indicate that the graphene-oxide saturable absorber can be successfully used to realize different mode-locking states in a fiber laser by system-parameter management. The yetterbium-doped fiber laser in all-normal dispersion with flexible outputs can meet different application needs.