We demonstrate a Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing...We demonstrate a Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing. In the initial phase of our study, we focus on optimizing the lasing wavelength to be centered at 1550 nm. This optimization is achieved by conducting experiments with 27 mode-locked lasers, each incorporating optical amplifiers featuring distinct multiple-quantum-well photoluminescence values. Subsequently we present a comprehensive study investigating the behavior of the mode-locking regime when the electrical driving parameters are varied. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the precise control of the optical spectrum across a wide range of wavelengths spanning from 1530 to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23-nm-wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.展开更多
The use of fundamental modelocking to generate short terahertz(THz)pulses and THz frequency combs from semiconductor lasers has become a routine affair,using quantum cascade lasers(QCLs)as a gain medium.However,unlike...The use of fundamental modelocking to generate short terahertz(THz)pulses and THz frequency combs from semiconductor lasers has become a routine affair,using quantum cascade lasers(QCLs)as a gain medium.However,unlike classic laser diodes,no demonstrations of harmonic modelocking,active or passive,have been shown in THz QCLs,where multiple pulses per round trip are generated when the laser is modulated at the harmonics of the cavity’s fundamental round-trip frequency.Here,using time-resolved THz techniques,we show for the first time harmonic injection and mode-locking in which THz QCLs are modulated at the harmonics of the round-trip frequency.We demonstrate the generation of the harmonic electrical beatnote within a QCL,its injection locking to an active modulation and its direct translation to harmonic pulse generation using the unique ultrafast nature of our approach.Finally,we show indications of self-starting harmonic emission,i.e.,without external modulation,where the QCL operates exclusively on a harmonic(up to its 15th harmonic)of the round-trip frequency.This behaviour is supported by time-resolved simulations of induced gain and loss in the system and shows the importance of the electronic,as well as photonic,nature of QCLs.These results open up the prospect of passive harmonic modelocking and THz pulse generation,as well as the generation of low-noise microwave generation in the hundreds of GHz region.展开更多
文摘We demonstrate a Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing. In the initial phase of our study, we focus on optimizing the lasing wavelength to be centered at 1550 nm. This optimization is achieved by conducting experiments with 27 mode-locked lasers, each incorporating optical amplifiers featuring distinct multiple-quantum-well photoluminescence values. Subsequently we present a comprehensive study investigating the behavior of the mode-locking regime when the electrical driving parameters are varied. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the precise control of the optical spectrum across a wide range of wavelengths spanning from 1530 to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23-nm-wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.
基金funding from the European Union FET-Open grant ULTRAQCL 665158the German Research Foundation(DFG)within the Heisenberg program(JI 115/4-2).
文摘The use of fundamental modelocking to generate short terahertz(THz)pulses and THz frequency combs from semiconductor lasers has become a routine affair,using quantum cascade lasers(QCLs)as a gain medium.However,unlike classic laser diodes,no demonstrations of harmonic modelocking,active or passive,have been shown in THz QCLs,where multiple pulses per round trip are generated when the laser is modulated at the harmonics of the cavity’s fundamental round-trip frequency.Here,using time-resolved THz techniques,we show for the first time harmonic injection and mode-locking in which THz QCLs are modulated at the harmonics of the round-trip frequency.We demonstrate the generation of the harmonic electrical beatnote within a QCL,its injection locking to an active modulation and its direct translation to harmonic pulse generation using the unique ultrafast nature of our approach.Finally,we show indications of self-starting harmonic emission,i.e.,without external modulation,where the QCL operates exclusively on a harmonic(up to its 15th harmonic)of the round-trip frequency.This behaviour is supported by time-resolved simulations of induced gain and loss in the system and shows the importance of the electronic,as well as photonic,nature of QCLs.These results open up the prospect of passive harmonic modelocking and THz pulse generation,as well as the generation of low-noise microwave generation in the hundreds of GHz region.
