Showing papers on "Ring laser published in 2009"
TL;DR: Numerical simulations based on the coupled complex Ginzburg-Landau equations have well reproduced the results of the experimental observation of a novel type of vector dark soliton in a fiber ring laser.
Abstract: We observe a novel type of vector dark soliton in a fiber ring laser. The vector dark soliton consists of stable localized structures separating the two orthogonal linear polarization eigenstates of the laser emission and is visible only when the total laser emission is measured. Moreover, polarization domain splitting and moving polarization domain walls (PDWs) were also experimentally observed.
125 citations
TL;DR: A tunable and switchable multiwavelength erbium-doped fiber ring laser based on what the authors believe to be a new type of tunable comb filter is proposed and demonstrated and the dual-function operation of the channel-spacing tunability and the wavelength switching can be readily achieved.
Abstract: A tunable and switchable multiwavelength erbium-doped fiber ring laser based on what we believe to be a new type of tunable comb filter is proposed and demonstrated. By adjusting the polarization controllers, the dual-function operation of the channel-spacing tunability and the wavelength switching (interleaving) can be readily achieved. Up to 29 stable lasing lines with 0.4 nm spacing and 14 lasing wavelengths with 0.8 nm spacing in 3 dB bandwidth were obtained at room temperature. In addition, the lasing output, including the number of the lasing lines, the lasing evenness, and the lasing locations, can also be flexibly adjusted through the wavelength-dependent polarization rotation mechanism.
124 citations
TL;DR: The GEOsensor as discussed by the authors is a rotational seismological sensor with a scale factor on the order of about 1 m 2 or larger, which is the smallest scale factor achievable with a monolithic ring laser.
Abstract: Since the discovery of the wave nature of light, optical interferometry has assumed an important place in high precision metrology. This is mostly due to the inherent high sensor resolution for operational wavelengths in the vicinity of several hundred nanometers. In this context, interferometers in the Michelson configuration are most prominently used in gravitational wave antennas, such as the large projects VIRGO, LIGO, TAMA, and GEO600. In the Sagnac configuration they are used for high resolution rotation monitoring such as the precise observation of Earth rotation. Modern large-scale ring lasers reach a sensitivity for the measurement of rotation of 1 prad/sec (with approximately 1 hr of averaging). Because of the comparatively short wavelengths employed, optical interferometers are extremely sensitive to small mechanical perturbations of the entire apparatus. These can be caused by deformations, thermal or mechanical stress, and instabilities in the alignment of the optical components at the level of about λ /100. Ring lasers suitable for geophysical applications require a sensor resolution in the range of 10 -8 rad/sec and below. This demands a scale factor of the instrument that is only achievable with mechanical dimensions of the interferometer on the order of about 1 m 2 or larger. At the same time the necessary mechanical rigidity of the entire instrument has to be on the order of 5 nm. Currently, this has only been achieved with monolithic ring lasers made from blocks of Zerodur and installed in a temperature stabilized underground environment. However if long-term sensor stability is not required, compromises can be made and, in particular for studies of regional seismic events, it becomes feasible to build a heterolithic rotation sensor in a simpler and much cheaper way. Here, we report the design and first results from the GEOsensor, which has been specifically constructed for studies in rotational seismology. The sensor is operated at the Pinon Flat Seismological Observatory in Southern California.
83 citations
TL;DR: The direct generation of 55 fs pulses from an all-fiber Erbium-doped ring laser oscillator using the nonlinear polarization rotation mode-locking shows to resist optical wave breaking with a smooth spectrum without any side lobe and cw-breakthrough.
Abstract: We demonstrate the direct generation of 55 fs pulses from an all-fiber Erbium-doped ring laser oscillator using the nonlinear polarization rotation mode-locking. The average output power is 56.4 mW but limited by available pump power of 330 mW. The linear chirped pulse duration is 55 fs after recompression using standard single-mode fiber. The pulses show to resist optical wave breaking with a smooth spectrum without any side lobe and cw-breakthrough. This all-fiber laser exhibits relatively high transfer efficiency of 17% and the single pulse energy reaches 1.5 nJ.
77 citations
TL;DR: Ring laser gyroscopes exploit the Sagnac effect and measure rotations absolute, and therefore provide an independent method to monitor Earth rotation as mentioned in this paper. But they do not require an external reference frame and therefore do not provide a high resolution for the measurement of the variations in the Earth rotation rate.
Abstract: Ring Laser gyroscopes exploit the Sagnac effect and measure rotations absolute. They do not require an external reference frame and therefore provide an independent method to monitor Earth rotation. Large-scale versions of these gyroscopes promise to eventually provide a similar high resolution for the measurement of the variations in the Earth rotation rate as the established methods based on VLBI and GNSS. This would open the door to a continuous monitoring of LOD (Length of Day) and polar motion, which is not yet available today. Another advantage is the access to the sub-daily frequency regime of Earth rotation. The ring laser “G” (Grossring), located at the Geodetic Observatory Wettzell (Germany) is the most advanced realization of such a large gyroscope. This paper outlines the current sensor design and properties.
75 citations
TL;DR: In this paper, a sideband controllable erbium-doped fiber ring laser passively mode-locked by using the nonlinear polarization rotation technique is reported, and the 3 dB bandwidth of 19.68 nm and the pulse duration of 132 fs were obtained.
Abstract: A sideband controllable erbium-doped fiber ring laser passively mode-locked by using the nonlinear polarization rotation technique is reported. In our fiber laser, spectral sideband generation or suppression can be easily achieved by properly rotating the polarization controllers. When the sideband suppression achieved, the 3 dB bandwidth of 19.68 nm and the pulse duration of 132 fs were obtained. It is evident that the limitation of pulse duration resulting from the sideband was eliminated in our experiment. Based on the experimental results, we believed that the sideband control in the fiber laser is a result of the dispersive waves filtered by the passive polarizer in the laser cavity.
70 citations
TL;DR: In this paper, an all-fiber, all-normal dispersion ytterbium ring laser was used to produce stable mode-locking of 10 ps pulses that can be externally compressed to as short as 200 fs.
Abstract: Experimental results on an all-fiber, all-normal dispersion ytterbium ring laser are reported. It produces stable mode-locking of ~ 10 ps pulses that can be externally compressed to as short as ~ 200 fs.
62 citations
TL;DR: The design has been numerically and experimentally demonstrated using Er(3+)-doped fiber at the emission wavelength of 1550 nm and a set of location-dependent rate equations is established for Q-switching modeling.
Abstract: We propose a simple design of a saturable absorber Q-switched all-fiber ring laser. By locating a saturable absorber fiber in the intensity-enhanced section of a ring resonator, the laser is passively Q-switched. A set of location-dependent rate equations is established for Q-switching modeling. The design has been numerically and experimentally demonstrated using Er3+ -doped fiber at the emission wavelength of 1550 nm. A single-mode Q-switched pulse with pulse energy of 0.37 μJ and pulse duration of 218 ns was achieved with 980-nm pump power near 7 mW.
55 citations
TL;DR: An ultralarge ring He-Ne ring laser gyroscope, UG-2, with area 834m2 and dimensions 39.7×21m2, has been built underground at Cashmere Cavern, Christchurch, New Zealand (latitude −43.575°) as discussed by the authors.
Abstract: An ultralarge ring He–Ne ring laser gyroscope, UG-2, with area 834 m2 and dimensions 39.7×21 m2, has been built underground at Cashmere Cavern, Christchurch, New Zealand (latitude −43.575°). Earth rotation is sufficient to unlock it, giving a Sagnac frequency of 2.18 kHz. Supermirrors are used with transmission ∼0.18 parts per million (ppm) and optical loss unexpectedly high at ∼200 ppm per reflection. The cavity Q is 1.5×1012. Residual Sagnac frequency error caused by backscatter coupling is measured as 1000 s, mechanical movement of the mirror assemblies, which act to change the geometrical dimensions and tilt. At all averaging times the residual rotational noise is well above the li...
54 citations
TL;DR: The intensity-dependent loss induced by nonlinear polarization rotation in a power-symmetric nonlinear optical loop mirror (NOLM) suppresses the mode competition of an Erbium-doped fiber and ensures stable multiwavelength operation at room temperature.
Abstract: A new multiwavelength Erbium-doped fiber laser is proposed and demonstrated. The intensity-dependent loss induced by nonlinear polarization rotation in a power-symmetric nonlinear optical loop mirror (NOLM) suppresses the mode competition of an Erbium-doped fiber and ensures stable multiwavelength operation at room temperature. The polarization state and its evolution conditions for stable multiwavelength operation in the ring laser cavity are discussed. The number and spectra region of output wavelength can be controlled by adjusting the work states of NOLM.
48 citations
TL;DR: In this article, a fiber ring laser with single-polarization output using an intracavity 45°-tilted fiber grating (45°-TFG) has been proposed and demonstrated.
Abstract: We have proposed and demonstrated a fiber ring laser with single-polarization output using an intracavity 45°-tilted fiber grating (45°-TFG). The properties of the 45°-TFG have been investigated both theoretically and experimentally. The fiber ring laser incorporating the 45°-TFG has been systematically characterized, showing a significant improvement in the polarization extinction ratio (PER) and achieving a PER of >30 dB. The slope efficiencies of the ring laser with and without the 45°-TFG have been measured. This laser shows a very stable polarized output with a PER variation of less than 2 dB for 5 hours at laboratory conditions. In addition, we also demonstrated the tunability of the laser.
TL;DR: In this paper, a switchable erbium-doped fiber-ring laser providing dual-wavelength outputs with orthogonal polarizations when operating at room temperature is proposed.
Abstract: A switchable erbium-doped fiber-ring laser providing dual-wavelength outputs with orthogonal polarizations when operating at room temperature is proposed. One polarization-maintaining fiber Bragg grating (PMFBG) in a Sagnac loop interferometer is used as the wavelength-selective filter. Due to the enhancement of the polarization hole burning (PHB) by the PMFBG, the laser can be designed to operate in stable dual-wavelength or wavelength-switching modes with a wavelength spacing of 0.336 nm at room temperature by adjusting a polarization controller (PC). The optical signal-to-noise ratio (OSNR) is over 42 dB. The amplitude variation over 90 min is less than 0.6 dB for both wavelengths.
TL;DR: In this article, the periodic power variation of the pulse-train in a passively mode-locked soliton fiber ring laser was investigated and it was shown that the non-uniformity is caused by the interaction between the nonuniform polarization states of the soliton pulses and the passive polarizer in the cavity.
Abstract: This paper reports the periodic power variation of the pulse-train in a passively mode-locked soliton fiber ring laser. It can obtain either the uniform or nonuniform pulse-train output by simply rotating the polarization controllers. The experimental results show that the pulse-train nonuniformity is caused by the interaction between the nonuniform polarization states of the soliton pulses and the passive polarizer in the cavity.
TL;DR: In this paper, an experimental comparison of stability between two different fiber laser topologies is carried out, and the experimental results confirm that the novel topology based on fiber optic circulators arranged in a hybrid serial-parallel configuration offers better stability and a higher optical signal-to-noise ratio (OSNR) than the simpler one based on a parallel configuration.
Abstract: An experimental comparison of stability between two different fiber laser topologies is carried out. The lasers are based on ring resonators that include highly doped Er-fibers. Both topologies use fiber Bragg grating reflectors in order to select the emission wavelengths. The experimental results confirms that the novel topology based on fiber optic circulators arranged in a hybrid serial-parallel configuration offers better stability and a higher optical signal-to-noise ratio (OSNR) than the simpler one based on a parallel configuration.
TL;DR: In this paper, a simple switchable and tunable dual-wavelength passively mode-locked erbium-doped fiber ring laser based on nonlinear polarization rotation (NPR) effect is proposed and experimentally demonstrated.
TL;DR: In this paper, a fiber Bragg grating (FBG) sensor system with a two-level ring architecture is proposed to enhance the survivability and capacity of a FBG for a multipoint sensor system.
Abstract: This investigation proposes a fiber Bragg grating (FBG) sensor system with a two-level ring architecture. The survivability and capacity of a FBG for a multipoint sensor system are enhanced by adding remote nodes and optical switches in the two-level ring architecture. Additionally, to enhance the signal-to-noise ratio (SNR) of the sensor system, a fiber ring laser approach is utilized to construct the proposed two-level ring architecture. The fiber ring laser adopted herein yields the high SNR of the sensor system. The proposed system can increase the reliability of FBG sensor systems for multipoint smart structures.
TL;DR: A monolithic double diffusion-bonded monolithic Tm:YAG nonplanar ring laser pumped by a fiber-coupled laser diode is demonstrated.
Abstract: We demonstrate a monolithic double diffusion-bonded monolithic Tm:YAG nonplanar ring laser pumped by a fiber-coupled laser diode. Up to 867 mW single-frequency output at 2.01 μm was obtained from the Tm:YAG system at room temperature, with a slope efficiency and an optical-optical efficiency of 31.6% and 19.2%. The power stability of the single frequency laser was 0.32% within 30 min.
TL;DR: In this article, a high fundamental repetition rate erbium-doped fiber ring laser operated in strong normal dispersion regime passively mode-locked by the nonlinear polarization rotation technique is demonstrated.
Abstract: We demonstrate a high fundamental repetition rate erbium-doped fiber ring laser operated in strong normal dispersion regime passively mode-locked by the nonlinear polarization rotation technique. A novel scheme of using a polarization beam splitter as both the pump input coupler and the fiber laser output coupler is employed to increase the repetition rate of the fiber laser. Gain-guided solitons with a fundamental repetition rate of 234 MHz and 1.11 ps pulsewidth are achieved from the ring laser cavity.
TL;DR: This paper demonstrates an optical node that simultaneously carries out multicast optical switching and all-optical label swapping and is the first demonstration of bit-level data processing using the all- optical logic capabilities of a semiconductor ring laser.
Abstract: This paper demonstrates an optical node that simultaneously carries out multicast optical switching and all-optical label swapping. While the optical payload is being forwarded by a fast optical switch matrix, the optical label is processed by a semiconductor ring laser (SRL) bistable. Old address bits in the label are erased by optically blocking the switching of the ring laser and new address bits are inserted by modulating the output from SRL directly. This label swapping scheme is the first demonstration of bit-level data processing using the all-optical logic capabilities of a semiconductor ring laser.
TL;DR: In this article, a simple and cost-effective erbium-doped fiber (EDF) ring laser using a Fabry-Perot etalon inside a linear cavity and employing the accurate fiber cavity length to satisfy the least common multiple number for generating multiwavelength in C-band at room temperature.
TL;DR: In this article, the authors demonstrate experimental generation of multi-bound solitons of up to sextuple in an active FM mode-locked fiber ring laser operating under power saturation in the locking state.
TL;DR: In this article, the design optimization of a dual wavelength erbium-doped fiber ring laser was investigated. But the effects of pump wavelength, active fiber length, and coupling ratio on threshold pump power, output power, and side mode suppression ratio (SMSR) of the laser were investigated.
Abstract: This paper reports the design optimization of a novel tunable dual wavelength erbium doped fiber ring laser. The effects of pump wavelength, active fiber length, and coupling ratio on threshold pump power, output power, and side mode suppression ratio (SMSR) of the lasers are investigated. Pumping at wavelength of 1480 nm provides high output and lower threshold power of 2.8 mW. The optimum erbium-doped fiber (EDF) length requires for a given pump power varies as a function of pump wavelengths. The pump wavelength and EDF length have no effect on the laser stability.
TL;DR: In this article, the authors derived analytical expressions for the computation of synthetic seismograms for ring laser based on normal mode summation and found that horizontal ring laser are predominantly sensitive to torsional motion.
Abstract: Variations in the ring laser signal of the rotating Earth are caused by local rotations and by north–south tilts. Analytic expressions for the computation of synthetic seismograms for ring lasers based on normal mode summation are derived. We find that horizontal ring lasers are predominantly sensitive to torsional motion. Synthetic Sagnac signals are computed for recent earthquakes and for spherical Earth models in order to establish the general characteristics and amplitude of the expected ring laser signals. In the normal mode band north–south tilts typically amount to less than 10% of the total signal for a horizontal ring laser. The fact that no free oscillation spectra have so far been reported from ring lasers is consistent with amplitudes of our synthetic Sagnac signals and current noise levels of these sensors.
TL;DR: In this article, an all-optical AND gate with simultaneous wavelength conversion was demonstrated using cavity-enhanced four-wave-mixing (CE-FWM) combined with optical injection locking phenomena in monolithicically integrated semiconductor ring lasers (SRLs).
Abstract: Novel all-optical implementations for logic AND and XOR gates are experimentally demonstrated at 2.5 Gbit/s based on cavity-enhanced four-wave-mixing (CE-FWM) combined with optical injection locking phenomena in monolithically integrated semiconductor ring lasers (SRLs). An all-optical AND gate with simultaneous wavelength conversion has been achieved using CE-FWM. An XOR function is demonstrated using two parallel SRLs, each performing one part of the XOR Boolean equation A ⊕ B=AB+AB. Error-free operation with extinction ratio higher than 10 dB confirms the suitability of SRLs for all-optical logic applications.
TL;DR: In this article, a phase modulator composed of a piece of fiber wrapped around a cylindrical piezoelectric transducer is used to suppress the mode competition and the combined action between optical fiber and polarization-dependent isolator provides the wavelengthdependent loss induced by wavelength-dependent polarization rotation mechanism to flatten the output spectrum, tune the locations and improve the number of the lasing lines.
Abstract: A stable room-temperature multi-wavelength erbium-doped fiber ring laser has been proposed and investigated experimentally. A phase modulator composed of a piece of fiber wrapped around a cylindrical piezoelectric transducer is used to suppress the mode competition. And the combined action between optical fiber and polarization-dependent isolator provides the wavelength-dependent loss induced by wavelength-dependent polarization rotation mechanism to flatten the output spectrum, tune the locations and improve the number of the lasing lines. Stable multi-wavelength lasing with wavelengths up to 23 and the wavelength spacing of 0.4 nm is demonstrated. Moreover, the pulse train output was also observed.
TL;DR: It is shown that the level of angular random-walk noise in the presence of mechanical dithering depends only on the quality of the cavity mirrors, as is the case with typical helium-neon ring laser gyros.
Abstract: Nonlinear couplings induced by crystal diffusion and spatial inhomogeneities of the gain have been suppressed over a broad range of angular velocities in a solid-state ring laser gyro by vibrating the gain crystal at 168 kHz and 0.4 microm along the laser cavity axis. This device behaves in the same way as a typical helium-neon ring laser gyro, with a zone of frequency lock-in (or dead band) resulting from the backscattering of light on the cavity mirrors. Furthermore, it is shown that the level of angular random-walk noise in the presence of mechanical dithering depends only on the quality of the cavity mirrors, as is the case with typical helium-neon ring laser gyros.
Patent•
15 Jul 2009
TL;DR: In this article, a polarization relevant output multi-wavelength and passive mode-locking optical fiber laser which belongs to laser and light communication field is presented, where a ring laser cavity includes Er-doped fiber that is taken as gain medium; a 980nm/1550nm wavelength-division multiplexer is used to couple pumping laser of 980nm into the Er doped fiber; a polarizationrelevant isolator with tail optical fiber on two ends guaranties the laser work in one way, meanwhile plays the role of a polarizer; two polarization controllers respectively on two side
Abstract: The present invention discloses a polarization relevant output multi-wavelength and passive mode-locking optical fiber laser which belongs to laser and light communication field. A ring laser cavity includes Er-doped fiber that is taken as gain medium; a 980nm/1550nm wavelength-division multiplexer is used to couple pumping laser of 980nm into the Er-doped fiber; a polarization relevant isolator with tail optical fiber on two ends guaranties the laser work in one way, meanwhile plays the role of a polarizer; two polarization controllers respectively on two side of the polarization relevant isolator are used to control polarization state, a 10dB coupler with 10% of the terminal port used to output optical signal and 90% of the optical signal stays in the cavity for cycle. A segment of long single mode fiber is inserted in the laser cavity and used to increase nonlinear effect inside the laser cavity; a piece of polarization maintaining optical fiber and a polarization relevant isolator constitute a birefraction optical fiber periodicity filter; the optical fiber laser is provided with two different output modes, namely mode locking pulse output and multi- wavelength continuous wave output, and can adjust polarization and switch between the two output modes.
TL;DR: In this article, the authors used a direct double pass and a novel isolator-assisted double-pass waveguide-based Mach-Zehnder interferometer (MZI) with the single-pass free spectral range (FSR) of 43 GHz, up to 115 and 104-channel simultaneous oscillations spaced at 21.5 GHz in the L-band and C-band, respectively, with a power non-uniformity of less than 3 dB and an extinction ratio of ∼30 dB.
Abstract: In this paper, using a direct double-pass and a novel isolator-assisted double-pass waveguide-based Mach-Zehnder interferometer (MZI), high-performance SOA-based multiwavelength fiber lasers (MFL) are proposed and demonstrated experimentally. The filtering characteristics of the proposed isolator-assisted double-pass MZI are analyzed and examined theoretically in comparison with those of the single-pass and direct double-pass MZI. Using a direct double-pass waveguide-based MZI with the single-pass free spectral range (FSR) of 43 GHz, up to 115- and 104-channel simultaneous oscillations spaced at 21.5 GHz in the L-band and C-band are obtained, respectively, with a power non-uniformity of less than 3 dB and an extinction ratio of ∼30 dB. To the best of our knowledge, it is the highest lasing-channel count that has been achieved from an SOA-based MFL. To enhance the extinction ratio while maintaining the FSR, the proposed isolator-assisted double-pass MZI is then utilized in the laser cavity, and a stable 55-wavelength simultaneous oscillation spaced at 43 GHz is accordingly achieved in C-band with an extinction ratio of higher than 50 dB. Compared with the lasing linewidth of 0.058 nm with the conventional single-pass MZI, narrower linewidths of 0.038 and 0.028 nm are obtained with the isolator-assisted and direct double-pass MZI configurations, respectively. The lasers are stable with a maximum power fluctuation per channel of less than 0.8 dB during an hour’s test.
TL;DR: In this article, a polymer ring laser was fabricated with 1,4-bis[2]-4-[N,N-di(p-totyl)amino]phenyl]vinyl]benzene (DADSB)-doped polyvinyl-pyrrolidone (PVP) thin films coated on an inner surface of a quartz microcapillary.
Abstract: Polymer ring laser was fabricated with 1,4-bis[2-[4-[N,N-di(p-totyl)amino]phenyl]vinyl]benzene (DADSB)-doped polyvinyl-pyrrolidone (PVP) thin films coated on an inner surface of a quartz microcapillary. Ring-waveguided multimode lasing was observed under pulsed optical pumping. With increasing excitation wavelengths, an additional emission peak based on stimulated resonant Raman scattering (SRRS) appeared with a Raman shift of the stretching vibration of DADSB. When the SRRS peak just overlapped with each ring laser modes, the emission intensity was periodically enhanced. Such a wavelength-selective Raman coupling can demonstrate a tunable single-mode microring laser.
TL;DR: In this article, a monolithically integrated tunable semiconductor ring laser consisting of a semiconductor optical amplifier and two ring resonators with tilted multimode interference couplers is presented.
Abstract: A monolithically integrated tunable semiconductor ring laser consisting of a semiconductor optical amplifier and two ring resonators with tilted multimode interference (MMI) couplers is presented. The characteristic response of the ring resonators is discussed for various cross coupling strengths by adjusting the angle of the tilted MMI couplers. The ring laser has a wavelength tuning range of 11 nm and a sidemode suppression ratio larger than 40 dB for a cross coupling strength of 0.09. The peak power of the laser is larger than -3 dBm for chip-to-fiber coupling.