DBR Fiber Laser Research Articles

Femtosecond laser plane-by-plane inscription of ultra-short DBR fiber lasers for sensing applications

We propose and demonstrate the inscription of ultra-short distributed Bragg reflector fiber lasers (DBR-FLs) in Er/Yb co-doped fiber (EYDF) using a femtosecond laser plane-by-plane (Pl-b-Pl) method. By integrating the spherical aberration (SA) with a laser 2D scanning process, a planar refractive index modification (RIM) region can be induced in the fiber core. Thanks to the Pl-b-Pl inscription, a high-quality fiber Bragg grating (FBG) in an EYDF is produced, exhibiting a grating strength exceeding 40 dB and an insertion loss of 0.1 dB. Subsequently, an ultra-short DBR-FL with an entire length of 7.3 mm is fabricated by the Pl-b-Pl inscription. The Pl-b-Pl ultra-short DBR-FL exhibits an improved slope efficiency of 0.7% compared with the DBR-FLs fabricated using another two direct-writing techniques, namely line-by-line (LbL) and point-by-point (PbP) methods. Furthermore, this ultra-short DBR-FL generates single-frequency and single-polarization radiation with a narrow linewidth (9.4 kHz) and a low relative intensity noise (-105.8 dB/Hz). Moreover, a wavelength-division-multiplexed array consisting of eight ultra-short DBR-FLs with distinct lasing wavelengths is successfully created. The Pl-b-Pl ultra-short DBR-FLs with excellent output performances offer significant potential for high-sensitivity sensing applications requiring high spatial resolution.

Femtosecond Laser Direct Writing of Polarization-Controllable DBR Fiber Lasers for Harsh Environmental Vibration/Acoustic Sensing

Femtosecond Laser Direct Writing of Polarization-Controllable DBR Fiber Lasers for Harsh Environmental Vibration/Acoustic Sensing

Fabrication of Integrated Single Frequency DBR Fiber Laser Directly on YDF by Femtosecond Laser

Fabrication of Integrated Single Frequency DBR Fiber Laser Directly on YDF by Femtosecond Laser

Demodulation of DBR Fiber Laser Sensors With Speckle Patterns

Demodulation of DBR Fiber Laser Sensors With Speckle Patterns

All-Fiber Laser-Self-Mixing Interferometer With Adjustable Injection Intensity for Remote Sensing of 40 km

In this article, we propose an all-fiber self-mixing velocimeter based on a DBR fiber laser with adjustable injection intensity for the first time, and theoretically and experimentally explore the behavior of fiber lasers in detecting non-cooperative target under different injection intensities. When the ultra-strong injection level is attained, the linewidth of the DBR fiber laser will be narrowed to about 10 kHz, thus extending the coherence distance of laser tremendously. Simultaneously, the intensity noise can be also significantly suppressed. The non-cooperative target velocity measurement with 40 km single-channel transmission distance has been successfully achieved. This velocimeter is shown to be of great significance in the field of remote sensing with simple and compact configuration, and adjustable dynamical monitoring range.

基于超稳腔PDH稳频的280 mHz线宽DBR光纤激光器

基于超稳腔PDH稳频的280 mHz线宽DBR光纤激光器

具有32 GHz频差的掺Yb3+双频DBR光纤激光器

具有32 GHz频差的掺Yb3+双频DBR光纤激光器

基于开槽型DBR光纤激光器拍频的折射率探测

基于开槽型DBR光纤激光器拍频的折射率探测

Study of lateral-drilled DBR fiber laser and its responsivity to external refractive index.

We report a lateral-drilled DBR fiber laser which contains a defective parabola-like opening inside the cavity fabricated by the CO2-laser exposure and study the laser responsivity to external refractive index (RI). Surrounding materials can readily reach the vicinity of the fiber core via the opening and interact with the laser mode. Research shows that the laser emission power mainly relies on changes of external RI while the lasing wavelength on temperature. The effects of structural parameters, pump power, and external refractive index on the RI responsivity of the device are demonstrated. The lasing threshold condition is also concerned. This work provides an opportunity for controlling emission characteristics of the DBR fiber laser through modification of external RI value, of which the results are valuable for the potential applications in optical sensing, tunable lasing, and etc.

Stabilization of microwave signal generated by a dual-polarization DBR fiber laser via optical feedback.

Microwave signals can be generated by beating the two orthogonal polarization modes from a dual-frequency fiber grating laser. In this paper, we present that the phase noise of the microwave signal can be significantly reduced via optical feedback by cascading an external cavity. This is achieved as a result of the bandwidth narrowing of each polarization laser mode when introducing phase-matched feedbacks into the laser cavity. By optimizing the external cavity length and the feedback ratio, the noise level over low frequencies has been reduced by up to 30 dB, from -42 to -72 dBc/Hz at 1 kHz, and from -72 to -102 dBc/Hz at 10 kHz. Meanwhile the relaxation resonant peaks can be eliminated. Compared with the existing techniques, the present method can offer a cost-effective, low-noise microwave signal, without the requirement for complex electrical feedback system.

High-accuracy fiber optical microphone in a DBR fiber laser based on a nanothick silver diaphragm by self-mixing technique

A high-accuracy fiber optical microphone (FOM) is first applied by self-mixing technique in a DBR fiber laser based on a nanothick silver diaphragm. The nanothick silver diaphragm fabricated by the convenient and low cost electroless plating method is functioned as sensing diaphragm due to critically susceptible to the air vibration. Simultaneously, micro-vibration theory model of self-mixing interference fiber optical microphone is deduced based on quasi-analytical method. The dynamic property to frequencies and amplitudes are experimentally carried out to characterize the fabricated FOM and also the reproduced sound of news and music can clearly meet the ear of the people which shows the technique proposed in this paper guarantee steady, high signal-noise ratio operation and outstanding accuracy in the DBR fiber laser which is potential to medical and security applications such as real-time voice reproduction for throat and voiceprint verification.

Fiber-optic displacement sensor based on the DBR fiber laser

The fiber-optic displacement sensor based on the distributed Bragg reflector fiber laser is proposed, that is, the fiber laser cavity is attached to the measured object, when the measured object is stretched or contracted, and the length of the fiber laser cavity is also stretched or contracted accordingly. In view of the nonlinearity of the fiber-optic displacement sensor, the calibration based on piezoelectric ceramics is applied to improve the linearity of the displacement sensor. Experiment results show that the fiber-optic displacement sensor has a linear response with the nominal working distance of 90 μm.

Research on a novel composite structure Er^3+-doped DBR fiber laser with a π-phase shifted FBG

A simple composite cavity structure Er³⁺-doped fiber laser was proposed and demonstrated experimentally. The resonant cavity consists of a pair of uniform fiber Bragg gratings (FBGs) and a π-phase shifted FBG. By introducing the π-phase shifted FBG into the cavity as the selective wavelength component, it can increase the effective length of the laser cavity and suppress the multi-longitudinal modes simultaneously. The narrow linewidth of 900 Hz and low RIN of -95 dB/Hz were obtained. And the lasing wavelength was rather stable with the pump power changing. The SMRS was more than 67 dB. The results show that the proposed fiber laser has a good performance and considerable potential application for fiber sensor and optical communication.

Direct measurement of DBR fiber laser linewidth based on the sidebands’ interference

We present a method of directly measuring DBR fiber laser linewidth with the sidebands’ interference based on the phase modulations. The interference visibility depending on the modulation frequency difference between the two phase modulators is obtained, and the results are fitted with a Voigt function to extract the Lorentzian and Gaussian linewidths. The experimental result of a DBR fiber laser linewidth is 532 ± 14 Hz. The effects of a 25 km fiber on the Lorentzian and Gaussian broadening have been demonstrated experimentally.

短腔单频DBR光纤激光器中弛豫振荡噪声抑制的研究

短腔单频DBR光纤激光器中弛豫振荡噪声抑制的研究

Self-mixing effect in Yb3+ doped DBR fiber laser with different linewidth enhancement factor

We present a self-mixing interference model approach to stimulate the self-mixing interference in YDBR fiber laser with optical self-mixing interference operating in the weak feedback regime. The self-mixing interference model includes Yb3+ doped fibers pumped at 920nm, with distributed Bragg reflector mirrors at both fiber ends and external reflector. Using the quasi-analytical YDBR fiber laser model and self-mixing three-mirror cavity model, the output power expression is deduced and the Peak-to-Peak values and asymmetry values of self-mixing waveform at different linewidth enhancement factor have been studied in detail.

Research of Laser Mechanism of High Power Double-Cladding DBR Fiber Laser

A mathematical model of double-cladding DBR Er3+-Yb3+ codoped fiber laser is established based on rate-equation theory, taking into account the energy transfer between Er3+ and Yb3+. The population of upper level of Er3+ & Yb3+and the output power and laser gain are analyzed and their factors influenced by pump power, fiber length, scatter loss and mirror reflectivity. The results calculated can directly be used in design and applications of fiber laser.

Dual-wavelength DBR fiber laser

Stable continuous-wave lasing of two longitudinal modes of a distributed Bragg reflector fiber laser is reported. Intensity noise and coupling between the modes was characterized for both 0.8- and 0.2-nm mode separations

Chirped and phase-sampled fiber Bragg grating for tunable DBR fiber laser

Chirped and phase-sampled fiber Bragg gratings are fabricated and used as reflectors in tunable DBR fiber laser for the first time. By controlling the phase of each sampling section, sampled Bragg gratings (SBG) with different channel spacing can be obtained using only a single chirped phase mask. A 30nm-wide tunable Erbium-doped fiber (EDF) laser is designed and experimentally demonstrated by utilizing the vernier effect of two such SBGs with channel spacing of 3.2nm and 3.6nm, respectively. The lasers' output power of different channels is almost identical (difference less than 1dB) within the tunable range.

Single-frequency MOPA Er/sup 3+/ DBR fiber laser for WDM digital telecommunication systems

The realization, the characteristics and the bit-error-rate (BER) performance of a single frequency, linear polarization Er/sup 3+/-doped distributed Bragg reflector fiber laser are reported. The device, pumped at 980 nm, gives a maximum output power of 13 mW with an overall slope efficiency /spl eta/=24%, a continuous-wave intensity ripple around 1% and a linewidth of 2.2 kHz. The BER test, performed without any polarization control system in a complete 475-km-long 2.5-Gb/s wavelength-division-multiplexed transmission line, shows only a 0.5-dB penalty is introduced.