Mode-locking and Q-switching in multi-wavelength fiber ring laser using low frequency phase modulation

Abstract

We describe experimental investigation of pulsed output from a multi-wavelength fiber ring laser incorporating low frequency phase modulation with large modulation amplitude. The Erbium-doped fiber (EDF) ring laser generated more than 8 wavelength channels with the help of a phase modulator operating at 26.2 kHz and a periodic intra-cavity filter. For most cases, the laser output is pulsed in the form of mode-locking at 5.62 MHz and/or Q-switching at harmonic and sub-harmonic of the phase modulation frequency. Chaotic pulse output is also observed. The behavior of the output pulses are described as functions of pump power and phase modulation amplitude. The relative intensity noise (RIN) value of a single wavelength channel is measured to be under -100 dB/Hz (-140 dB/Hz beyond 1.5 GHz).

Q-switching and mode locking pulse generation from an all-fiber ring laser by intermodal acousto-optic bandpass modulation

“…Notwithstanding, a major shortcoming is the limited control over the output pulses parameters and a fixed repetition rate. In contrast, active schemes possess the advantages of tight control over intracavity parameters, enabling improvements on the output pulse characteristics [6,7,13,19]. However, their major drawback is the relatively long pulse generation associated with the limited optical bandwidth of the active device.…”

“…In this respect, a different type of pulsed regime, called Q-switched mode locking (QML), has been proposed and demonstrated to combine the inherent advantages of mode locking and Q switching techniques in order to produce a burst of high-intensity mode-locked optical pulses within a long Q-switching envelope [6][7][8][9][10]. Pulse operation in the QML regime is obtained either with passive or active techniques [6][7][8][9][10][11][12][13], or a hybrid combination of them [14][15][16]. Passive configurations are regarded as being the simplest schemes, without including an external signal source and the capacity of generating short or ultrashort internal sub-pulses [8][9][10][11][12]17,18].…”

Tunable and switchable six-wavelength erbium-doped fiber ring laser

“…In recent years, fiber Fabry-Perot (FP) comb filter has been used in all the kinds of fiber lasers. An FP comb filter accompanying a nonlinear HiBi-FLM [10] or a phase modulator [11] has been used to obtain the multiwavelength operation in the EDFLs. A fiber FP tunable filter along with an acoustooptic frequency shifter and a gain flattening filter has been used to obtain the multiwavelength emission in the EDFLs [12].…”