Low noise GHz passive harmonic mode-locking of soliton fiber laser using evanescent wave interaction with carbon nanotubes

Abstract

Passive harmonic mode-locking in soliton fiber laser is presented with excellent noise characteristics by employing a single-walled carbon nanotubes saturable absorber designed to interact with evanescent wave of the laser field. The 34(th) harmonic mode-locking pulses at 943.16 MHz repetition rate were stably generated with 18 mW output power, >50 dB side-mode suppression and -140 dB/Hz relative intensity noise. Soliton energy control with polarization controller further increased the harmonic order to 61st, 1.692 GHz, but with compromised performance. Scaling to higher-order harmonic mode-locking is discussed for practical application in optical communication system.

Toward higher-order passive harmonic mode-locking of a soliton fiber laser

“…As an alternative, we recently demonstrated low-noise GHz (943. 16 MHz at 34th harmonics) passive H-ML with 195 mW of pump power using a CNT SA of the evanescent-wave interaction type [16]. For efficient utilization of the pump power to further increase the repetition rate, it is important to systematically investigate the key parameters affecting the maximum harmonic order of passive H-ML.…”

“…The experimental setup is shown in Fig. 1(a), similar to that of [16]. An EDF (small signal gain of 17 dB∕m at 1530 nm) with a length of 2.9 m and a CNT SA based on evanescent field interaction are used for laser operation.…”

Passively harmonic mode-locked erbium-doped fiber laser at a 580 MHz repetition rate based on carbon nanotubes film

“…Moreover, in order to improve the damage threshold and emit higher energy, a CNT SA of the evanescent-wave interaction type is proposed, which is formed by deposition on a D-shaped fiber [23] , a fiber taper [24] , or a microfiber [25] . Jun et al first obtained a 943 MHz pulse train at the 34th harmonics with excellent noise performance under 195 mW pump power [26] . Furthermore, through engineering the dispersion of the cavity, 4.9 GHz pulses, corresponding to the 128th HML was finally realized under 395 mW pump power with 40 dB super-mode suppression ratio (SMSR) [27] .…”

Stable dual-wavelength erbium-doped fiber laser using novel fabricated side-polished arc-shaped fiber with deposited ZnO nanoparticles

“…Furthermore, the use of the D-shaped fiber makes this approach very cost effective and easy to deploy [4] . Removing a portion of the cladding from the fiber provides various additional advantages, including low modelocking threshold and a high-power operation [5,6] . One of the possible applications of the D-shaped fiber is that it provides a platform in which various materials can be deposited, thus allowing for various optical phenomena as the evanescent field interacts with these materials.…”