Wave-mixing analysis for THz-signals generation in dc-biased semiconductor optical devices at room temperature

Wave-mixing at 370-GHz in a SOA and FP semiconductor laser is investigated by using a FROG-system. A comparison of the optical time-fluctuations measured at their output stresses the importance of a resonant cavity in THz-signals generation from semiconductor optical devices

Semiconductor optical amplifier-based heterodyning detection for resolving optical terahertz beat-tone signals from passively mode-locked semiconductor lasers

An all-optical heterodyne approach based on a room-temperature controlled semiconductor optical amplifier (SOA) for measuring the frequency and linewidth of the terahertz beat-tone signal from a passively mode-locked laser is proposed. Under the injection of two external cavity lasers, the SOA acts as a local oscillator at their detuning frequency and also as an optical frequency mixer whose inputs are the self-modulated spectrum of the device under test and the two laser beams. Frequency and linewidth of the intermediate frequency signal and therefore, the beat-tone signal are resolved by using a photodiode and an electrical spectrum analyze

Analysis of optical THz-signals from mode-locked semiconductor laser by using a semiconductor optical amplifier-based detection scheme

An all-optical approach based on nonlinear interactions inside a semiconductor optical amplifier for measuring the THz beat-tone of a passively mode-locked laser is proposed. This novel approach can be applied to beat-tones in the range from GHz to few TH

Short pulse generation with 40 GHz passively-mode locked Q-dashed Fabry-Perot laser

Generation of sub-picosecond pulses by a dc-biased passively mode-locked Fabry-Pérot laser is demonstrated. By using a tunable band-pass filter, it is observed that the width of the generated pulses decreases in direct proportion to the optical modes emitted by the laser. Furthermore, performing a passive compression by a piece of single mode fiber, we demonstrate the generation of 720 fs pulses by this type of mode-locked Fabry-Pérot laser

Sub-picosecond pulse generation by 40-GHz passively mode-locked quantum-dash 1-mm-long Fabry-Perot laser diode

Optical pulses at a repetition rate of 39.8 GHz have been observed in a dc-biased passively mode-locked quantum-dash Fabry-Perot ´ laser diode. The pulses generated by this diode are studied in the temporal and spectral domains using a second harmonic generation frequency-resolved optical gating system. By using a tunable band-pass filter, it is observed that the pulse width decreases as the number of lasing modes selected by the filter increases. Furthermore, by controlling the phase difference of the modes using a 450m-long single mode fibre, a passive compression of the pulses is obtained. A minimum pulse width of 720 fs has been measured with this type of mode-locked Fabry-Perot laser

720-fs pulse generation with 40 GHz passively-mode locked quantum-dash Fabry-Pérot laser

Generation of 720-fs pulses by passively mode-locked Fabry-Pérot lasers is demonstrated. Pulse width is analyzed in terms of the longitudinal modes passing through a variable band-pass filter placed at the laser outpu

Multi data-rate synchronization of 40 GHz mode-locked quantum-dash lasers diodes

Beat-tones at 40-GHz from a QDash-ML laser under 10 to 160 Gb/s optical injection are analyzed. A FWHM linewidth less than 8 Hz is obtained regardless of the rate of injected data strea

Analysis of a narrowband terahertz signal generated by a unitravelling carrier photodiode coupled with a dual-mode semiconductor Fabry–Pérot laser

A narrowband terahertz signal generated by a unitravelling carrier photodiode (UTC-PD) interfaced with a dual-mode Fabry–Pérot laser diode is demonstrated. A beat tone corresponding to the free spectral range is generated on the UTC-PD, and radiated by a transverse-electromagnetic-horn antenna. A terahertz signal at a frequency of 372 GHz, featuring a linewidth of 17 MHz is recorded by a subharmonic mixer coupled to an electrical spectrum analyzer. All components involved in this experiment operate at room temperature. The linewidth and the frequency of the emitted terahertz wave are analyzed, along with their dependency on dc-bias conditions applied to laser diode

Linewidth study of 40-GHz passively mode-locked multimode semiconductor lasers

In this work, an experimental study of the impact of the number of longitudinal modes on the linewidth of -40 GHz signals generated by various passively mode-locked multimode semiconductor lasers is addressed. Devices under test (DUT) are multi-quantum wells InAlGaAs FP laser, bulk DBR laser and quantum-dash FP laser. It is important to stress that we analyze the total number of modes oscillating into the laser cavity, without implementing an external optical processing. In our experiment, the output of each DUT is coupled into a single mode fiber (SMF) and measured both electrically and optically. Our experimental results show that, independently from the nature of the cavity and the active media, the FWHM-linewidth of the -40 GHz signal generated by these lasers is reduced as the number of longitudinal modes selected by the laser cavity is increased