Widely tunable linear-cavity multiwavelength fiber laser with distributed Brillouin scattering.

We demonstrate a multiple wavelength Brillouin/erbium fiber laser in a linear cavity configuration. The laser cavity is made up of a fiber loop mirror on one end of the resonator and a virtual mirror generated from the distributed stimulated Brillouin scattering effect on the other end. Due to the weak reflectivity provided by the virtual mirror, self-lasing cavity modes are completely suppressed from the laser cavity. At Brillouin pump and 1480-nm pump powers of 2 and 130 mW, respectively, 11 channels of the demonstrated laser with an average total power of 7.13 dBm can freely be tuned over a span of 37-nm wavelength from 1530 to 1567 nm

All-optical wavelength conversion based on degenerate four-wave mixing in Raman ring laser.

We demonstrate an all-optical wavelength converter using a ring cavity that produces conversion efficiency of more than unity within a certain bandwidth. The highly nonlinear fiber is used as the parametric amplifying medium and it is pumped by four independent pump lasers at 1427, 1443, 1461, and 1493 nm. The parametric pump is formed internally from the ring cavity through the effect of stimulated Raman scattering. The interaction between signal and parametric pump becomes intensified as they propagate along the fiber from input to the output ports. This un-depleted pump power condition enhances the process of degenerate four-wave mixing in the proposed structure. The maximum conversion efficiency is obtained at 9.5 dB and the bandwidth of positive conversion efficiency is about 20.6 nm

Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber.

A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm

OSNR enhancement utilizing large effective area fiber in a multiwavelength Brillouin-Raman fiber laser.

We propose a simple Brillouin-Raman multichannel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels

Tunable multiwavelength Brillouin-Erbium fiber laser with intra-cavity pre-amplified Brillouin pump

We have demonstrated a new configuration of Brillouin-Erbium fiber laser, in which the Brillouin pump is pre-amplified within the laser cavity before entering the single-mode fiber. By using this simple scheme, a lower external Brillouin pump power is required to create the Brillouin gain and suppresses the laser cavity modes. The proposed laser structure exhibits a wide tuning range of 13 nm from 1597 nm to 1610 nm with 1480 nm pump power of 100 mW. The number of channels obtained within this wavelength range is 14 channels with 0.089 nm spacing

Analytical analysis of second-order stokes wave in brillouin ring fiber laser

This paper details a theoretical modeling of Brillouin ring fiber laser which incorporates the interaction between multiple Brillouin Stokes signals. The ring cavity was pumped at several Brillouin pump (BP) powers and the output was measured through an optical coupler with various coupling ratios. The first-order Brillouin Stokes signal was saturated with the presence of the second-order Stokes signal in the cavity as a result of energy transfer between them. The outcome of the study found that the optimum point for the first-order Stokes wave performance is at laser power reduction of 10. Resultantly, at the optimum output coupling ratio of 90, the BFL was able to produce 19.2 mW output power at BP power and Brillouin threshold power of 60 and 21.3 mW respectively. The findings also exhibited the feasibility of the theoretical models application to ring-type Brillouin fiber laser of various design parameters. (C) 2011 Optical Society of Americ

Broadly tunable multi-wavelength Brillouin-erbium fiber laser in a Fabry-Perot cavity

The paper demonstrates the utilization of a tunable band-pass filter in producing tunable multi-wavelength Brillouin-erbium fiber lasers within a Fabry-Perot cavity. ne optimization of the Brillouin pump wavelength position within the bandwidth of the self-lasing cavity modes is important to achieve the maximum stable output channels. The same number of 14 output channels with constant channel spacing of 10.5 GHz were able to be generated within 32 nm range. Besides the tunability, this design also has the advantage of consistent power requirement of both the 980 nm laser diode and the Brillouin pump in generating the 14 channels through die broad tuning range

Optimisation of remotely-pumped EDFA location for unrepeatered transmission systems

In this paper, a new technique of determining the location of a remotely-pumped Erbium doped fibre amplifier (R-EDFA) in unrepeatered transmission system is presented. The location of the R-EDFA is varied over the transmission span with its optimised pump power. The unrepeatered transmission link is optimised when the R-EDFA is located closer to the receiver end

Optimisation of remotely-pumped Er3+-doped fibre amplifier location in repeaterless transmission systems

In this paper, a new technique of designing repeaterless transmission links using a remotely-pumped erbium-doped fibre amplifier (R-EDFA) is discussed. The transmission losses before and after the R-EDFA are varied using variable optical attenuators and the bit error rate test is executed to monitor the performance of the repeaterless transmission systems. The optimised location of R-EDFA for the longest transmission distance can be experimentally determined by determining the threshold of bit error rate. The proposed technique is also verified in practical repeaterless transmission systems using real transmission fibres. (c) 2006 Elsevier B.V. All rights reserved

Efficient technique for intracavity loss optimization in a dual-wavelength erbium-doped fiber laser

An efficient technique to improve the quality of a tunable dual-wavelength fiber laser is reported. The power of both channels can be equalized with efficient intracavity loss optimization. The maximum power difference between the two wavelengths is less than +/- 0.37 dB and the output power is approximately flat within C-band