Multiwavelength Fiber Laser Research Articles

Stable power multi-wavelength fibre laser based on four-wave mixing in a short length ofhighly non-linear fibre

A multi-wavelength fibre laser utilizing the four-wave mixing (FWM) effect in a 100 m longhighly non-linear fibre (HNLF) is proposed and demonstrated. The multi-wavelength fibrelaser is configured in a ring cavity and only needs a low power erbium doped fibre amplifier(EDFA) as the gain medium to generate 11 lines in the range of 1582–1600 nm with asignal-to-noise ratio (SNR) of 43 dB. The proposed system is very stable, with only minorfluctuations of 0.1 dB in the output power of the generated multi-wavelengths observed for atest period of more than an hour. The multi-wavelength fibre laser has manypotential applications in optical communications and optical sensing systems.

Thermally Tunable Multiwavelength Raman Fiber Laser Based on a Novel In-line Interferometer

A thermally tunable multiwavelength Raman fiber laser based on a simple in-line interferometer is investigated. A novel in-line interferometer is realized by using a single long-period fiber grating incorporating a core misalignment method. Cladding modes from the guided core mode are excited in the splicing point between two optical fibers when two core regions are misaligned. By removing an external buffer coating layer in the fiber, the cladding modes can be propagated and recoupled to the core mode at a long-period fiber grating. Since the long-period fiber grating couples the core mode to the cladding modes, the interaction between the core mode and the cladding modes induces an interference pattern, which realizes a multichannel filter. Since the transmission characteristics of the long-period fiber grating are effectively controlled by changing the applied temperature, a thermally tunable multichannel filter based on the proposed in-line interferometer can be obtained. When the proposed multichannel filter is inserted within the ring cavity of a Raman fiber laser, a multiwavelength Raman fiber laser is realized. A high extinction ratio of more than 40 dB is achieved. The output power is stable, and the power fluctuation is measured to be less than 0.7 dB, and the proposed multiwavelength Raman laser has a high thermal tunablity of -0.48 nm/◦C.

Design of multiwavelength DFB fiber laser with equivalent phase shifts

A dual-wavelength distributed feedback fiber laser with two equivalent phase shifts is proposed and demonstrated experimentally. By studying varied parameters of the fiber laser, which show different impacts on the lasers' characteristic, a dual-wavelength laser of 31 pm spacing is designed and fabricated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1453–1456, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25969

Switchable multiwavelength erbium-doped fiber laser employing wavelength-dependent loss

A novel switchable multiwavelength erbium-doped fiber laser (EDFL) is proposed and demonstrated based on two comb filters. One comb filter is used to define the wavelength spacing, the other filter with a very narrow wavelength spacing is used to induce wavelength-dependent loss (WDL) effect to suppress the mode competition caused by homogeneous gain broadening of the erbium-doped fiber (EDF). As a result, triple-wavelength lasing operation with wavelength spacing of 0.8 nm has been achieved. Wavelength switching operation of the laser was also obtained by adjustment of a polarization controller (PC) in the cavity. The measured power fluctuation of each wavelength is less than 0.4 dB.

A pump power controlled multiwavelength fiber laser with adjustable output channels at fixed wavelength

We report an experimental demonstration of multiwavelength erbium-doped fiber laser with adjustable wavelength number exploiting a power-symmetric nonlinear optical loop mirror (NOLM). As the pump power increases from 53 mW to 410 mW, one–seven lasing line(s) at fixed wavelength around 1571 nm are obtained. A theoretical model describing the NOLM and the EDF is established to investigate the effect of the pump power on the lasing characteristics. Numerical results confirm the experiment measurements and indicate that it is the intensity-dependent loss of lasing beams generated in the NOLM that leads to such phenomena.

Tunable multi-wavelength fiber laser based on a polarization-maintaining erbium-doped fiber and a polarization controller

A stable and tunable multi-wavelength fiber laser with a polarization-maintaining erbium-doped fiber (PM-EDF) and a polarization controller (PC) is proposed and demonstrated. A homemade PM-EDF incorporated in the ring cavity is used as the gain medium. Simultaneous multi-wavelength oscillation is achieved at room temperature. The theory of the PM-EDF and PC to suppress the wavelength competition is described in detail. The 3 dB bandwidth is less than 0.01 nm. The power fluctuation and wavelength shift are measured to be less than 0.5 dB and 0.05 nm over 32 min. The wavelength tuning between single-, double-, triple-, and four-wavelength is realized.

Tunable multi-wavelength SOA based linear cavity dual-output port fiber laser using Lyot-Sagnac loop mirror

We propose and demonstrate a simple dual port tunable from the C- to the L-band multi-wavelength fiber laser based on a SOA designed for C-band operation and fiber loop mirrors. The laser incorporates a polarization maintaining fiber in one of the fiber loop mirrors and delivers multi-wavelength operation at 9 laser lines with a wavelength separation of ~2.8 nm at room temperature. We show that the number of lasing wavelengths increases with the increase of the bias current of the SOA. Wavelength tunability from the C to L-band is achieved by exploiting the gain compression of a SOA. Stable multi-wavelength operation is achieved at room temperature without temperature compensation techniques, with measured power and the wavelength stability within < ±0.5 dB and ±0.1 nm, respectively.

A linear cavity multiwavelength fiber laser with adjustable lasing line number for fixed spectral regions

We report an experimental demonstration of muliwavelength erbium-doped fiber laser with adjustable wavelength number based on a power-symmetric nonlinear optical loop mirror (NOLM) in a linear cavity. The intensity-dependent loss (IDL) induced by the NOLM is used to suppress the mode competition and realize the stable multiwavelength oscillation. The controlling of the wavelength number is achieved by adjusting the strength of IDL, which is dependent on the pump power. As the pump power increases from 40 to 408 mW, 1–7 lasing line(s) at fixed wavelength around 1601 nm are obtained. The output power stability is also investigated. The most power fluctuation of single wavelength is less than 0.9 dB, when the wavelength number is increased from 1–7.

Tunable Multiwavelength Fiber Ring Lasers Based on an Opto-VLSI Processor

We propose and experimentally demonstrate the principle of a tunable multiwavelength fiber ring laser based on the use of an opto-very-large-scale-integration (Opto-VLSI) processor in conjunction with an erbium-doped fiber amplifier and a semiconductor optical amplifier. Multiple wavelength channels within the gain range of the optical amplifiers can independently be generated, tuned and/or switched on/off, through applying appropriate phase holograms onto the Opto-VLSI processor. A tunable five-wavelength fiber ring laser of output power of around +6 dBm per channel and a sidemode suppression ratio (SMSR) greater than 30 dB is demonstrated. The tunable multiwavelength fiber lasers have excellent stability at room temperature.

Multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing

We demonstrate a multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing. The wider channel spacing is realized by circulating the odd-order Stokes signals in the Brillouin gain medium through a four-port circulator. The circulated odd-order Stokes signals are amplified by the Brillouin gain and thus produce even-order Stokes signals at the output. These signals are then amplified by erbium gain block to form a ring-cavity laser. Ten channels with 0.174 nm spacing that are generated at 0.5 mW Brillouin pump power and 150 mW pump power at 1480 nm can be tuned from 1556 nm to 1564 nm. The minimum optical signal-to-noise ratio of the generated output channels is 30 dB with maximum power fluctuations of ±0.5 dB.

Wavelength-spacing switchable multiwavelength fiber lasers based on nonlinear polarization rotation with cascaded birefringence fibers

A wavelength-spacing switchable multiwavelength erbium-doped fiber lasers incorporating a highly nonlinear fiber (HNLF) based on nonlinear polarization rotation (NPR) has been demonstrated. The intensity-dependent transmission effect originating from NPR ensures room-temperature multi-wavelength lasing, which is further self-stabilized by the four-wave mixing in the HNF. Moreover, the equivalent Lyot birefringence fiber filter with two cascaded birefringence fibers makes the wavelength spacing switchable depending on the effective length of the birefringence fiber. The experimentally obtained multiwavelength outputs agree well with the simulation filter transmission spectra.

Broadly tunable multiwavelength fiber laser with bismuth-oxide EDF using large effective area fiber

A multiwavelength laser comb using 2.49 m Bismuth-oxide erbium-doped fiber (Bi-EDF) with different lengths of large effective area fiber (LEAF) in a ring cavity configuration is realized. The Bi-EDF is used as the linear gain medium and LEAF is used as the non-linear gain medium for stimulated Brillouin scattering. Out of the four different lengths, the longest length of 25 km LEAF exhibits the widest tuning range of 44 nm (1576 to 1620 nm) in the L-band at 264 mW pump power and 5 mW Brillouin pump power. In addition, a total of 15 output channels are achieved with total average output power of −8 dBm from this laser structure. All Brillouin Stokes signals exhibit high peak power of above −20 dBm per signal and their optical signal-to-noise ratio of greater than 15 dB.

Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation

We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.

DETECTION OF GAS CONCENTRATION BY CORRELATION SPECTROSCOPY USING A MULTI-WAVELENGTH FIBER LASER

A correlation spectroscopy (COSPEC) based on a multi-wavelength fiber laser is first proposed for the detection of gas concentration. The lasing wavelengths are selected to match several characteristic absorption peaks of the gas under test, and the gas concentration is easily measured by correlating it with the reference gas. The present method is immune from the instability of the light source and the influence of other gases. The concentration measurement of C2H2 is demonstrated in the experiment in its near-infrared dominant absorption region. The technique has prospects for simultaneous detection of multiple gases, and the measurement of mixed gases of C2H2 and CO2 is also analyzed.

Stable multiwavelength erbium-doped fibre laser using intensity-dependent loss mechanism with short cavity length

A simple and stable multiwavelength fibre laser using an intensity-dependent-loss mechanism with a short cavity length is demonstrated. By employing a semiconductor saturable absorber mirror in the cavity to passively modelock the lasing wavelengths, the nonlinear polarisation rotation-induced intensity-dependent-loss is greatly enhanced, which can be used to suppress the mode competition. In the experiment, up to 10 wavelength stable lasing lines in a 3 dB bandwidth with 0.8 nm channel spacing were obtained and the maximum power fluctuation was 0.98 dB.

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

基于光子晶体光纤的多波长布里渊双通放大激光器

A simple technique for achieving a stable, room temperature and multi-wavelength lasing with narrow linewidth is demonstrated using Brillouin fiber laser (BFL) with a 100-m-long photonic crystal fiber (PCF) in conjunction with a dual-pass configuration. A broadband fiber Bragg grating (FBG) operating in the C-band region is incorporated at the end side of the setup to allow a dual-pass operation. The proposed BFL can operate at any wavelength depending on the Brillouin pump wavelength and the FBG's reflection region used. With a Brillouin pump (BP) of 15.7 dBm, approximately 7 Stokes and 4 anti-Stokes lines are obtained with a line spacing of 0.08 nm.

Multi-wavelength erbium-doped fiber laser using four-wave mixing effect in doped fiber

We demonstrate a multi-wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration. The EDF has a pump absorption rate of 24.6 dB/m at 979 nm and is bi-directionally pumped by 980-nm laser diodes. FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation. The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

Photonic crystal fiber-based multi-wavelength Brillouin fiber laser with dual-pass amplification configuration

Photonic crystal fiber-based multi-wavelength Brillouin fiber laser with dual-pass amplification configuration