Peter Blixt

Hybrid diode-laser fiber-amplifier source of high-energy ultrashort pulses

We demonstrate what we believe is the first compact laser system for generating ultrashort microjoule-energy optical pulses. Linearly chirped pulses from monolithic tunable Bragg-reflection laser diodes were amplified in a diode-pumped two-stage erbium-doped fiber amplifier and compressed with a grating-pair compressor. The laser diodes had their emission wavelengths at 1.538 and 1.562 microm. The highest pulse energies obtained were 2 microJ at the repetition frequencies of 1-10 kHz and were at the saturation energy level of the fiber amplifier. The shortest duration of compressed pulses is 1.8 ps.

Generation of femtosecond optical pulses with nanojoule energy from a diode laser and fiber based system

Linearly chirped, subnanosecond optical pulses, emitted at an arbitrary repetition rate by a fast‐tuned monolithic diode laser, were compressed down to 600 fs by group‐velocity dispersion in a standard optical fiber. Subsequent amplification and nonlinear compression in an erbium‐doped fiber amplifier produced pulses with the energy of up to 2 nJ and the duration down to 230 fs.

Simulations and experiments of mode-locking of semiconductor lasers: pulse evolution, frequency detuning, and bias dependence

Simulations of a mode-locked diode laser based on a travelling-wave rate-equation model have been compared with experiments. The pulse measurement technique involved a conventional intensity autocorrelator together with an internally generated second-harmonic emission measurement set-up. The latter is ideal for systematic relative measurements. For the first time, pulse evolution as a function of the number of round-trips was measured. Short optical pulses were obtained after approximately 40 round-trips. The experimental and simulated detuning range was about 1 MHz and the d.c. bias dependence was investigated.

Design of fiber gratings for total dispersion compensation.

An optical fiber grating has theoretically been designed that would be capable of compressing a dispersionbroadened pulse of 100 ps down to the transform limit of 20 ps, with a total reflectance of ~75%. A numerical recipe is presented for the design of a fiber grating, whose spectral response closely follows an arbitrarily chosen profile, both for the reflectance and the phase factor. The resulting grating consists of a number of subgratings, all of which have the same grating period but a different spatial phase and coupling coefficient.

Subnanosecond switching of bistable tandem lasers by subpicojoule optical triggering

We report on the switching‐on characteristics of a bistable two‐section laser diode triggered by subnanosecond optical input pulses. Minimum switching energy as a function of current bias level was measured for different input pulse wavelengths. Subnanosecond and subpicojoule switching was obtained. Estimating the input coupling to be 10%, the lowest bistable switching energy recorded was 23 fJ. The fastest recorded rise time was less than 100 ps.

Polarization‐independent optical switching of an inhomogeneously pumped laser diode

The polarization dependence of the optical input energy required to switch an inhomogeneously pumped bistable laser diode is studied at various input signal wavelengths. Polarization‐independent switching is achieved for input pulse wavelengths 30–40 nm shorter than the lasing wavelength of the bistable laser diode, whereas input pulse wavelengths close to the lasing wavelength result in a strong polarization dependence. A simple theory explains the observed behavior.

Bistability In Semiconductor Etalons And Lasers

Advances in the area of bistable semiconductor etalons and inhomogeneously pumped laser diodes are reviewed. Results concerning a novel method to fabricate thin AlGaAs etalons that can be thermally stable for 0.5 seconds is presented. The method is based on results from a rigorous numerical model for the temperature rise. Furthermore, results from optical triggering of multisection InGaAsP lasers at 500 MHz repetition rate with less than 1 fJ optical switching energy are reported.