M. Xia

InGaAs Quantum-Dot Mode-Locked Laser Diodes

This paper presents a selection of recent advances on two-section passively mode-locked InGaAs-based quantum-dot laser diodes. Pulse generation is demonstrated for repetition rates ranging from 310 MHz to 240 GHz, and with pulse durations ranging from the picosecond to the sub-400 fs regime. Mode-locking trends in these devices are discussed, and device performance improvements in terms of pulse duration, output power, and noise properties are presented. Design rules for reducing the pulse duration, increasing the output power, and improving noise performance are outlined. Implementation of tapered waveguide structures yields significant performance improvements, allowing the simultaneous achievement of ultrashort, Fourier-limited pulse generation with low amplitude noise, low timing jitter, and narrow RF linewidths.

External-Cavity Mode-Locked Quantum-Dot Laser Diodes for Low Repetition Rate, Sub-Picosecond Pulse Generation

This paper presents an investigation of the mode-locking performance of a two-section external-cavity mode-locked InGaAs quantum-dot laser diode, focusing on repetition rate, pulse duration and pulse energy. The lowest repetition rate to-date of any passively mode-locked semiconductor laser diode is demonstrated (310 MHz) and a restriction on the pulse energy (at 0.4 pJ) for the shortest pulse durations is identified. Fundamental mode-locking from 310 MHz to 1.1 GHz was investigated, and harmonic mode-locking was achieved up to a repetition rate of 4.4 GHz. Fourier transform limited subpicosecond pulse generation was realized through implementation of an intra-cavity glass etalon, and pulse durations from 930 fs to 8.3 ps were demonstrated for a repetition rate of 1 GHz. For all investigations, mode-locking with the shortest pulse durations yielded constant pulse energies of ~0.4 pJ, revealing an independence of the pulse energy on all the mode-locking parameters investigated (cavity configuration, driving conditions, pulse duration, repetition rate, and output power).

Temperature Independent Optical Amplification in Uncooled Quantum Dot Optical Amplifiers

1.3 μm QD SOAs are shown to provide 19 dB optical gain at temperatures up to 70 °C, allowing <; 0.1 dB system penalty at 10 Gb/s. The gain is constant to within ± 3.5 dB from 20°C-70°C for 10 nm spectral bandwidth.

External-cavity mode-locked quantum-dot lasers for low repetition rate, sub-picosecond pulse generation

External-cavity mode-locking of a quantum-dot laser is demonstrated with record-low repetition-rates of 310 MHz, and harmonic repetition-rates up to 4 GHz. Fourier-limited 930 fs pulse generation is achieved. The pulse-energy of ~0.45 pJ is independent of operating conditions.

Superradiant emission from a tapered quantum-dot semiconductor diode emitter

Superradiant emission pulses from a quantum-dot tapered device are generated on demand at repetition rates of up to 5 MHz. The pulses have durations as short as 320 fs at a wavelength of 1270 nm.

Femtosecond superradiant emission in AlGaInAs quantum-well semiconductor laser structures.

Ultrashort superradiant pulse generation from a 1580 nm AlGaInAs multiple quantum-well (MQW) semiconductor structure has been experimentally demonstrated for the first time. Superradiance is confirmed by analyzing the evolution of the optical temporal waveforms and spectra. Superradiant trends and regimes are studied as a function of driving condition. An optical pulse train is obtained at 1580 nm wavelength, with pulse durations as short as 390 fs and pulse peak powers of 7.2 W.

Ultra-short optical pulse generation by InGaAs quantum-dot diode emitters

A selection of recent advances on ultra-short optical pulse generation by InGaAs-based quantum-dot devices is reviewed. Generation is demonstrated for a wide range of repetition rates, with pulse durations as short as 400fs, using mode-locking and superradiant emission.