Erbium Fiber Ring Laser Research Articles

A Study of the generation of laser soliton from spontaneous emission by ring cavity with carbon nanotube

We demonstrate a behavior of laser pulse grows through fiber laser inside and output cavity with a soliton fiber laser based on the multi-wall carbon nanotube saturable absorber (SA), we investigate the effects of a saturable absorber parameter on the mode-locking of a realistic Erbium fiber ring laser. Generalized nonlinear Schrodinger equation including the nonlinear effects as gain dispersion, second anomalous group velocity dispersion (GVD), self phase modulation (SPM), and two photon absorption used to describe pulse evolution. An analytical method has been used to understand and to quantify the role of the SA parameter on the propagation dynamics of pulse laser. We compute the chirp, power, width and phase of the soliton for range of SA parameters and we studied stability against nonlinear effects at different SA parameter ranges.

Feasibility Study of a Fiber Ring Laser Working on the SLM Regime in a BOTDA Sensor

A feasibility study of the employment of a fiber laser working as the laser source of a Brillouin distributed sensor is presented in this paper. The erbium fiber ring laser structure designed works on the single longitudinal mode regime. The main parameters of the ring cavity are analyzed in terms of the laser requirements and the performance of a Brillouin optical time domain analysis sensor using the fiber laser as light source.

Comparative assessment of erbium fiber ring lasers and reflective SOA linear lasers for fiber Bragg grating dynamic strain sensing.

Fiber Bragg grating (FBG) dynamic strain sensors using both an erbium-based fiber ring laser configuration and a reflective semiconductor optical amplifier (RSOA)-based linear laser configuration are investigated theoretically and experimentally. Fiber laser models are first presented to analyze the output characteristics of both fiber laser configurations when the FBG sensor is subjected to dynamic strains at high frequencies. Due to differences in the transition times of erbium and the semiconductor (InP/InGaAsP), erbium-doped fiber amplifier (EDFA)- and RSOA-based fiber lasers exhibit different responses and regimes of stability when the FBG is subjected to dynamic strains. The responses of both systems are experimentally verified using an adaptive photorefractive two-wave mixing (TWM) spectral demodulation technique. The experimental results show that the RSOA-FBG fiber linear cavity laser is stable and can stably respond to dynamic strains at high frequencies. An example application using a multiplexed TWM interferometer to demodulate multiple FBG sensors is also discussed.

Transient response of a passively mode-locked Er-doped fiber ring laser

In this study, we report on the transient response of a passively mode-locked erbium fiber ring laser as studied by switching the optical pumping of the erbium doped fiber on and off. We confirm that the laser can maintain its mode-locking state even while the pump is modulated, and describe the laser behavior and its typical transient response upon abrupt changes in the intensity of the optical pump.

Stable Multiwavelength Erbium Fiber Ring Laser With Optical Feedback for Remote Sensing

In this paper, we demonstrate a stable fiber sensing system for remote temperature measurements, where the sensing element is an array of four fiber Bragg gratings and sensor interrogation is achieved with a multiwavelength erbium fiber ring laser. By introducing a feedback fiber loop in a fiber ring cavity, four laser emission lines were obtained simultaneously in single-longitudinal mode operation (SLM). The power instability obtained was lower than 0.5 dB with an optical signal-to-noise ratio higher than 50 dB for all the emitted wavelengths. The application of this system for remote temperature measurements has been demonstrated even though the SLM regime cannot be preserved.

A switchable single- and dual-wavelength erbium fiber ring laser in single-longitudinal-mode operation

A simple stable single-longitudinal-mode (SLM) single- and dual-wavelength erbium-doped fiber ring laser using an arrayed waveguide grating as the wavelength filter is proposed and demonstrated. SLM operation is guaranteed by a saturable-absorber-based auto-tracking filter. A 40/60 optical coupler is used to form two imbalanced loss cavities in the fiber laser initially, and single- and dual-wavelength operation can be changed by properly modifying the variable optical attenuator. The side mode suppression ratios of the laser outputs are higher than 60 dB. Through switching the two fiber optical switches, the dual-wavelength spacing is tuned from the narrowest 0.82 nm to the widest 12.05 nm, which offers potential uses in the generation of terahertz (THz) radiation.

Experimental investigation on a Q-switched, mode-locked fiber laser based on the combination of active mode locking and passive Q switching

We performed an experimental investigation on a Q-switched, mode-locked laser based on the combination of passive Q switching and active mode locking. This study was carried out using an erbium fiber ring laser incorporating an active mode locker employing a fast Si-based variable optical attenuator and a passive Q switch based on a carbon nanotube saturable absorber. It was found that stable Q-switched, mode-locked pulses can be readily generated when using a particular cavity modulation index and pump power. It was also found that our scheme can easily alter the operating regime among the Q switching, Q-switched mode locking, and mode locking by simply controlling the cavity modulation index and/or the pump power. For this particular laser configuration, the cavity modulation index and pump power operating conditions have been experimentally analyzed for three laser operating regimes.

Numerical Study on the Saturable Absorber Parameter Selection in an Erbium Fiber Ring Oscillator

Based on a non-distributed numerical model including fiber birefringence and orthogonal mode coupling, we investigate the effects of saturable absorber (SA) parameters on the mode-locking of a realistic Erbium fiber ring laser. We compute the pulse evolution in the oscillator where the pulse properties are also affected by the intracavity polarization controller (PC). Simultaneous effect of the SA and PC parameters on the properties of the generated vector solitons are studied, and their stability against intracavity polarization perturbation at different SA parameter ranges is discussed.

Wavelength-tunable erbium fiber ring laser in single-frequency operation utilizing Fabry–Perot laser with Sagnac cavity

We propose and demonstrate experimentally a stabilized and wavelength-selective erbium-doped fiber ring laser in single-longitudinal-mode operation with Fabry–Perot laser diode (FP-LD) and using a tunable bandpass filter (TBF) inside and outside a Sagnac ring cavity. The side-mode suppression ratios of 21dB and 36.5dB and the output power of –3.6dBm and –8.7dBm in the wavelengths of 1524.45–1562.35nm and 1531.07–1562.35nm with the tuning step of 1.4nm can be achieved when the TBF outside and inside Sagnac loop, respectively. The output wavelength variation of zero and the output power fluctuation of <0.1dB are also obtained. Moreover, the transmission efficiency of the ring laser has also been performed experimentally under a 1.25, 2.5 and 10Gb/s external modulation, respectively.

Investigation of the Dynamic Response of Erbium Fiber Lasers With Potential Application for Sensors

We derive a theoretical description of the transient response for erbium fiber ring lasers, which includes the effects of amplified spontaneous emission and the large number of longitudinal modes that are present in large cavities. Based on these modified rate equations, the full transient period is simulated and compared with experimental measurements performed at 1560 nm, showing reasonable agreement with theory. Approximate analytical relations are also derived for the key characteristics of the laser response, including steady-state and transient parameters such as build-up time, frequency, and the decay constant of relaxation oscillations. The results are useful in the measurement of fiber laser parameters and in the design of novel fiber laser sensors, such as intracavity laser absorption sensors based on spectral narrowing during the transient period of power build-up in a laser cavity.

Triple-wavelength erbium fiber ring laser based on compound-ring scheme

.A triple-wavelength erbium-doped compound ring fiber laser using the fiber-based triple-ring filter (TRF) is proposed and experimentally investigated. Using the fiber-based TRF laser scheme, the proposed laser can lase three wavelengths simultaneously. The fiber laser retrieve the optical side-mode suppression ratios (SMSRs) of 40.2, 40.4 and 41.6 dB and the output powers of -9, -8.8 and -7.6 dBm at the wavelengths 1555.89, 1556.77 and 1557.66 nm, respectively. The mode spacing of the triple-wavelength fiber laser is nearly 0.9 nm. Moreover, the output power stability of the ring laser has also been measured and analyzed.

Stable single-mode operation of a narrow-linewidth, linearly polarized, erbium-fiber ring laser using a saturable absorber

This paper describes the design and operation of a stable narrow-linewidth linearly polarized fiber ring laser using a polarization-maintaining (PM) erbium-doped fiber as a saturable absorber. The effect of the PM fiber on suppressing mode hopping is experimentally demonstrated and optimum conditions for single-mode operation are identified. Laser output power is /spl sim/ 4.7 mW at 1535 nm for a pump power of 94 mW, the polarization extinction ratio is 24.8 dB, the SNR is larger than 45 dB, the relative intensity noise is below -104 dB/Hz at frequencies above 150 kHz, and the linewidth is less than 1.5 kHz. Potential applications of the fiber laser for interferometric or spectroscopic fiber sensors are briefly discussed.

Experimental study on seed light source coherence dependence of continuous-wave supercontinuum performance

We experimentally compare output performance between laser beam (erbium fiber ring laser) and amplified spontaneous emission (ASE) beam (erbium fiber ASE) driven supercontinuums (SCs) in terms of seed beam temporal coherence. We control the degree of temporal coherence of the seed beams by using an optical filter to change their spectral linewidth. The random phase ASE driven SC is found to have better performance than the phase-correlated laser driven SC in terms of spectral smoothness and output power. Significantly high relative-intensity-noise in the output SCs is observed for both cases, i.e. the laser driven SC and the ASE driven SC irrespective of the seed beam temporal coherence due to the nonlinear amplification of quantum fluctuations both in the input pump beam and in the Raman scattering process.

Four-wave mixing assisted self-stable 4×10 GHz actively mode-locked Erbium fiber ring laser

We proposed and developed a self-stable multiwavelength (4 cbannels) 10-GHz actively mode-locked Erbium-doped fiber ring laser with 0.8 nm wavelength spacing. A 1-km highly nonlinear fiber is incorporated in the laser cavity to eliminate the strong gain competitions in the homogeneously broadened EDF by multiple parametric four-wave mixing processes. The fiber nonlinearity is also helpful to provide phase locking and stabilize the output pulse. Stable laser pulses at 1556.55, 1557.36, 1558.17, and 1558.98 nm are successfully obtained simultaneously with supermode noise suppression ratio greater than 50 dB. The corresponding time-bandwidth products of four channels are 0.39 ~ 0.41.

Pulse stabilisation in harmonically FM modelocked erbium fibre ring laser with DFBLD

A new pulse stabilisation scheme for a harmonically frequency modulated (FM) modelocked erbium fibre ring laser using a distributed feedback laser diode (DFBLD) is presented. More than 65 dB supermode noise suppression in the RF spectrum was obtained with the proposed method. Effective reduction of supermode noise can be accomplished as the DFBLD in the fibre laser acts not only as a fast-gain saturated medium but also as an optical bandpass filter for suppressing supermode noise in a harmonically modelocked laser system.

Wavelength‐tunable actively mode‐locked fiber‐ring laser using an F‐P LD as a modulator and a tunable comb filter

AbstractA wavelength‐tunable actively mode‐locked erbium fiber ring laser is demonstrated using an F–P semiconductor as a modulator and a tunable comb filler. Continuous wavelength tuning is enlarged to 6 nm by successively choosing different cavity modes of the F–P LD and tuning the temperature of the LD. The ∼2‐GHz frequency pulse is generated with a side‐mode suppression ratio over 30 dB in the entire tuning range. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 318–320, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10753

Self-stabilized passive, harmonically mode-locked stretched-pulse erbium fiber ring laser

We have studied a passive, harmonically mode-locked stretched-pulse erbium fiber ring laser with net positive dispersion that is self-stabilized by gain depletion and electrostriction. Periodic pulses with supermode suppression of >75 dB and picosecond jitter are achieved. The pulses are compressible to 125 fs by external chirp compensation. The repetition rate is 220 MHz, and the average power is as high as 80 mW.

40 GHz actively modelocked polarisation-maintainingerbium fibre ring laser

The first polarisation-maintaining actively modelocked erbium fibre ring laser (ML-EFRL) operating at a base rate of 40 GHz is presented. The laser generates highly stable and virtually transform-limited 1.2–1.9 ps pulses tunable over 40 nm with a timing jitter of < 0.1 ps. These represent the shortest pulses and lowest timing jitter generated by a 40 GHz ML-EFRL.

Pulse chirp control in an actively modelocked fibrelaser using a dual-drive variable-chirp modulator

It has been experimentally demonstrated that the chirp imposed on the pulses from an actively modelocked erbium fibre ring laser can be controlled by using a dual-drive variable-chirp modulator as a modelocker.

Wavelength-tunable actively mode-locked erbium-doped fiber ring laser using a distributed feedback semiconductor laser as mode locker and tunable filter

A wavelength-tunable actively mode-locked erbium fiber ring laser was demonstrated using a distributed feedback semiconductor laser as an intensity mode locker and a tunable optical filter. Very stable optical pulse trains at gigabit repetition rates were generated using harmonica mode locking. The supermode noise was suppressed to 60 dB below the signal level and the root-mean-square timing jitter (0.45 kHz–1 MHz) was found to be about 1% of the pulse duration. A continuous wavelength tuning range of 1.8 nm was achieved by changing the semiconductor laser temperature from 11.4 to 30 °C.