We demonstrated a simple technique to obtain stable room temperature multiwavelength lasing in an erbium-doped fiber laser by the inhomogeneous loss mechanism. Successful reduction of the cross-gain saturation in erbium-doped fiber was achieved by incorporating a section of highly nonlinear fiber (HNLF) and a Fabry-Perot filter (FPF) in the laser cavity. More than 70 wavelengths simultaneous lasing were observed with the same frequency space of 25GHz. The laser had a total output power of ~3.2dBm, a bandwidth of 0.012nm (~1.5GHz) and a signal-to-spontaneous-noise ratio of ~44dB. Furthermore, the total output power can be increased to more than 190mW by moving the output port right after the EDFA.

Multiwavelength erbium-doped fiber laser based on inhomogeneous loss mechanism by use of a highly nonlinear fiber and a Fabry-Perot filter.

https://www.eie.polyu.edu.hk/~wai/journal/oc_06b.pdf

Multiwavelength erbium-doped fiber laser employing a nonlinear optical loop mirror

A multi-wavelength Erbium-doped fiber (EDF) laser based on four-wave-mixing is proposed and experimentally demonstrated. The 5 km single mode fiber in the cavity enhances the four-wave-mixing to suppress the homogenous broadening of the erbium-doped fiber and get the stable multi-wavelength comb. The lasing stability is investigated. When the pump power is 300 mW, the fiber laser has 5-lasing lines and the maximum fluctuation of the output power is about 3.18 dB. At the same time, a laser with 110 m high nonlinear fiber (HNFL) is demonstrated. When the pump power is 300 mW, it has 7-lasing lines (above -30 dBm) and the maximum fluctuation is 0.18dB.

Multi-wavelength Erbium-doped fiber laser based on four-wave-mixing effect in single mode fiber and high nonlinear fiber

We propose and experimentally demonstrate a switchable multiwavelength erbium doped fiber laser based on a highly nonlinear dispersion shifted fiber and multiple fiber Bragg gratings. A nonlinear optical loop mirror based on a highly nonlinear dispersion shifted fiber is implemented in the ring laser cavity to stabilize the multiwavelength output at room temperature. Multiple fiber Bragg gratings with the wavelength spacing of 0.8 nm are connected with an arrayed waveguide grating to establish a multichannel filter. The high quality of the multiwavelength output with a high extinction ratio of ~60 dB and high output flatness of ~0.5 dB is realized. The nonlinear polarization rotation based on the nonlinear optical loop mirror can provide the switching performance of the proposed multiwavelength fiber laser. The lasing wavelength can be switched individually by controlling the polarization controller and the cavity loss.

Switchable multiwavelength erbium doped fiber laser based on a nonlinear optical loop mirror incorporating multiple fiber Bragg gratings

A multiwavelength erbium-doped fiber (EDF) laser based on a nonlinear amplifying loop mirror (NALM) is proposed and experimentally demonstrated. The NALM provides intensity-dependent transmissivity to equalize different-wavelength powers and the transmission can be uniquely optimized by controlling the cavity loss associated with a section of un-pumped EDF, which also enhances the output signal-to-noise ratio (SNR). Through adjusting the polarization controllers (PCs), under only 70 mW pump power, up to 62-wavelength output with channel spacing of 0.45 nm has been achieved. Also, the lasing tunability and stability are verified.

http://www.physics.sjtu.edu.cn/laserlab/sites/www.physics.sjtu.edu.cn.laserlab/files/2012-Multiwavelength%20erbium-doped%20fiber%20laser%20based%20on%20a%20nonlinear%20amplifying%20loop%20mirror%20assisted%20by%20un-pumped%20EDF.pdf

Multiwavelength erbium-doped fiber laser based on a nonlinear amplifying loop mirror assisted by un-pumped EDF

A stable and broad bandwidth multiwavelength fiber ring laser suitable for use in dense wavelength-division-multiplexing systems is demonstrated. A highly nonlinear photonic crystal fiber is inserted in the ring cavity to stabilize the power fluctuation and broaden the output spectrum. A thin-film Fabry-Pe/spl acute/rot etalon filter is used to get stable wavelength lasing. A Sagnac filter is employed to achieve uniform power distribution at each wavelength at the laser output. A laser with a power fluctuation about 0.1 dB in each wavelength within 20 min and with wavelength shift of less than 0.016 nm within 10 min is achieved. A stable 24-wavelength lasing operation with wavelength spacing of 0.8 nm within the 3-dB spectral range of 1573-1594 nm and signal-to-noise ratio better than 48 dB is observed experimentally.

/pdf/stable-and-broad-bandwidth-multiwavelength-fiber-ring-laser-22aopj04jd.pdf

Stable and broad bandwidth multiwavelength fiber ring laser incorporating a highly nonlinear photonic crystal fiber

We demonstrate both width and wavelength-tunable optical pulse train generation based on four-wave mixing in highly nonlinear photonic crystal fiber. By tuning the delay time between two pulse trains, the pulsewidth of the generated pulse train is continuously tuned. By tuning the wavelength of one of the pulse trains, the wavelength of the generated pulse train is also continuously tuned. In our experiment, the pulsewidth of a 5-GHz repetition rate pulse train is tuned from 88 to 19 ps and the pulsewidth of a 10-GHz pulse train is tuned from 39 to 19 ps. The 3-dB wavelength tuning range is about 70 nm.

/pdf/width-and-wavelength-tunable-optical-pulse-train-generation-jn1nwd12dq.pdf

M.S. Demokan

Papers

Stable and broad bandwidth multiwavelength fiber ring laser incorporating a highly nonlinear photonic crystal fiber

Width and wavelength-tunable optical pulse train generation based on four-wave mixing in highly nonlinear photonic crystal fiber