J.D. Minelly

Efficient single-frequency fiber lasers with novel photosensitive Er/Yb optical fibers

Boron- and germanium-doped highly photosensitive cladding is used in a novel design to achieve photosensitive Er/Yb-doped fibers, permitting short, strong gratings (length approximately 1 cm, reflectivity >99%) to be written without hydrogenation. The high absorption at 980 nm in Er/Yb fibers permits efficient pump absorption over a short device length, which is ideal for achieving highly efficient single-frequency fiber lasers. Both single-frequency Bragg-grating reflector and distributed-feedback lasers with slope efficiencies of 25% with respect to launched pump power have been realized in such fibers.

Enhanced Q-switching in double clad fiber lasers

A novel cladding pumped Nd(3+) fiber laser operating in an enhanced Q-switched regime with a stable repetition rate is described. By exploiting fiber nonlinearities in the laser cavity, we demonstrated a peak power of 3.7 kW enhanced by an order of magnitude greater than that of conventional Q-switched fiber devices. Pulse durations as short as 2 ns have been achieved.

Femtosecond pulse amplification in cladding-pumped fibers

Femtosecond pulse amplification in a cladding-pumped fiber amplifier is demonstrated for the first time to our knowledge. Using a cladding-pumped erbium-doped fiber power amplifier and a passively mode-locked fiber seed oscillator in conjunction with an all-fiber chirped-pulse amplification system, we obtain 380-fs near-bandwidth-limited pulses with an average power of 260 mW. The pulse repetition rate is varied between 5 and 50 MHz, and pulse energies as high as 20 nJ are generated.

Environmentally stable picosecond ytterbium fiber laser with a broad tuning range

We demonstrate a widely tunable passively mode-locked fiber laser operating at a fundamental frequency of 80 MHz with an output power of 90 mW. The laser is capable of generating 5-ps pulses in the region 1010-1064 nm. A strong mode-locking mechanism promoted by frequency-shifted feedback allows us to operate in simultaneous Q-switched and mode-locked regimes and to obtain peak power in excess of 1.2 kW.

Cladding-pumped fiber laser\amplifier system generating 100 /spl mu/J energy picosecond pulses

In addition to enabling the construction of high-power femtosecond amplifiers, doubleclad fibers may also be applied toward the construction of high-performance fiber oscillat o r ~ . ~ An example of a cladding-pumped Er/% fiber laser capable of generating 100 fs pulses with repetition rates up to 50 MHz and average powers of 15 mW is shown in Fig. 1. Here simple broad-stripe diode lasers may be used as pump sources. The autocorrelation and corresponding pulse spectrum are shown in Fig. 2. Wavelengths around 1.55 pm are useful because of the availability of reliable pump sources, however other emission wavelengths compatible with cladding pumping have also been demonstrated, namely Nd and Yb-doped fiber lasers. Though their emission wavelengths are in the positive dispersion regime of silica glass, compact soliton type fiber lasers may still be constructed by adding chirped fiber Bragg gratings for dispersion compensation to the cavity.6 In fact passively modelocked soliton-type fiber lasers may in principle be demonstrated in the whole trans100

Broad-area diode-pumped 1 W femtosecond fiber system

Summary form only given. High-average-power 310-fs pulses were obtained with an all-fiber chirped pulse amplification (CPA) system. Both the oscillator and the power amplifier are based on Er/Yb-doped fiber for cladding-pumping with broad-area laser diodes. A single 10-cm-long fiber grating is employed in the CPA system as a compact femtosecond-pulse stretcher/compressor.

Superfluorescent Er/Yb single-mode fiber source with 1 W output power

We describe a superfluorescent Er/Yb single-mode fibre source capable of generating 1 Watt of output power with variable bandwidths between 0.5 nm and 4 nm

High-energy high-average-power femtosecond fiber system using a QPM-grating pulse compressor

We demonstrate a simple and compact chirped pulse amplification (CPA) circuit for boosting both the accessible powers and energies from a femtosecond fiber amplifier. The system is based on a novel pulse compressor, chirped period quasi-phase-matched (QPM) grating, implemented in electric-field poled lithium niobate. A QPM grating compressor is unique in that it combines second-harmonic generation (SHG) and pulse compression in one crystal.

Passive WDM channel equaliser using a twin-core erbium-doped fibre amplifier

A passive WDM channel equaliser using a twin-core EDFA is studied in detail. Gain saturation limits the range of input signal powers from ~−20dBm to ~0dBm. Channel equalisation rates as high as 0.35dB/dB are predicted.

Er3+/Yb3+ co-doped power amplifier pumped by a 1W diode array.

We report the first Er3+/Yb3+ co-doped fibre power amplifier pumped by a 962nm diode array via an inner-cladding waveguide. The device exhibits a small signal gain of 24dB and a saturated output power of +17dBm.