Hai Feng Liu - Academia.edu (original) (raw)

Papers by Hai Feng Liu

We demonstrate an all-optical scheme for coding high frequency mode-locked semiconductor laser pu... more We demonstrate an all-optical scheme for coding high frequency mode-locked semiconductor laser pulse trains. The scheme is experimentally demonstrated by optically modulating a high frequency pulse train at 38 GHz generated by a subharmonic synchronous mode-locked semiconductor laser with binary information contained in multiple low bit rate optical data signals (3.8 Gb/s). Synchronization between the two signals is achieved through optical injection into the mode-locked laser while high speed modulation is achieved via a nonlinear optical loop mirror made of dispersion shifted fiber. The coding scheme has advantages over existing passive multiplexing schemes in generating high data rate optical signals due to its regeneration and wavelength conversion functionality.

In this paper we propose a novel technique for the generation of wideband dual-mode pulses from a... more In this paper we propose a novel technique for the generation of wideband dual-mode pulses from a single subharmonically synchronous mode-locked laser diode (LD). The obtained pulse source exhibits high extinction ratio (>15 dB) and low timing jitter (<0.5 ps) over all the channels from 1550 to 1564 nm. The proposed scheme is cost-effective and a promising candidate as a pulse source for generation of carrier suppressed return-to-zero (CSRZ) modulation format in dense wavelength division multiplexed (DWDM) systems and optical generation of millimeter-wave frequency signals in multiple channel fiber wireless systems.

Japanese Journal of Applied Physics, 1996

Spectrally narrowed pulses from a gain-switched 690 nm GaInP/AlGaInP Fabry-Perot laser are succes... more Spectrally narrowed pulses from a gain-switched 690 nm GaInP/AlGaInP Fabry-Perot laser are successfully obtained by the self-seeding technique. A commercially available laser diode emits 48 ps pulses with a spectral width of 0.10 nm or less. This scheme will provide a compact and efficient light source for generation of ultraviolet light by nonlinear optical methods such as second-harmonic generation.

Japanese Journal of Applied Physics, 1996

We report the successful generation of optical pulses (∼ 65 fs) from a 1.55 µm gain-switched dist... more We report the successful generation of optical pulses (∼ 65 fs) from a 1.55 µm gain-switched distributed feedback semiconductor laser with fiber optic compression techniques by a novel dispersion arrangement. These pulses are the shortest ever generated starting from a semiconductor laser diode and are promising for practical applications in ultrafast photonic systems.

IEEE Photonics Technology Letters, 1996

ABSTRACT Negligibly small amplitude modulation and sufficiently low timing jitter are achieved si... more ABSTRACT Negligibly small amplitude modulation and sufficiently low timing jitter are achieved simultaneously in a passively mode-locked monolithic semiconductor laser stabilized by applying an electrical signal at the second subharmonic of the pulse repetition frequency. Nearly transform-limited 33 GHz pulse trains with 0.56 ps timing jitter and -23 dBc amplitude modulation are obtained with 23 dBm driving signals at 16.5 GHz. Detailed investigations are carried out on the dependence of the amplitude modulation and timing jitter on RF driving power for the second- and third-order subharmonic cases. The excellent amplitude modulation property of the second subharmonic case with the specific laser used in this work is ascribed to the frequency response characteristics of the device.

IEEE Photonics Technology Letters, 2002

IEEE Journal of Selected Topics in Quantum Electronics, 1997

Optical pulse trains at millimeter-wave frequencies are generated by subharmonic synchronous mode... more Optical pulse trains at millimeter-wave frequencies are generated by subharmonic synchronous mode-locking of a monolithic distributed Bragg reflector semiconductor laser, by which an initially passively mode-locked semiconductor laser is stabilized by injecting optical pulses at subharmonic frequencies of its resonant frequency. The stabilized pulse trains are characterized in terms of phase noise, timing jitter, locking range and modulation depth under

IEEE Journal of Selected Topics in Quantum Electronics, 1996

Performance of a subharmonically hybrid mode-locked (SH-ML) monolithic semiconductor laser is inv... more Performance of a subharmonically hybrid mode-locked (SH-ML) monolithic semiconductor laser is investigated. A 33-GHz passively mode-locked distributed Bragg reflector semiconductor laser is stabilized by the injection of an electrical signal with a subharmonic frequency of the laser cavity resonance. Systematic measurements on the phase noise, timing jitter, amplitude modulation, and locking bandwidth are performed for the second- and third-order SH-ML

IEEE Journal of Quantum Electronics, 1991

Pulses of 1.26 ps, the shortest directly triggered single-mode pulses ever reported, are generate... more Pulses of 1.26 ps, the shortest directly triggered single-mode pulses ever reported, are generated from a 1.3 pm distributed feedback laser diode using higher order soliton-effect compression. This is realized by compressing a gainswitched 17.5 ps pulse with a conventional fiber-optic compressor, i.e., a fiber with normal dispersion, and further, with a soliton-effect compressor where a two-stage traveling-wave semiconductor laser amplifier is used to increase the peak power of the compressed pulse from the first-stage compressor into the soliton regime required by the second-stage compressor.

IEEE Journal of Quantum Electronics, 2000

A regeneratively mode-locked fiber ring laser (RML-FRL) and an active harmonically mode-locked fi... more A regeneratively mode-locked fiber ring laser (RML-FRL) and an active harmonically mode-locked fiber ring laser (ML-FRL) have been characterized for both amplitude and phase noise by investigating the detected RF spectra of the optical pulse trains. Quantification of noise in the optical pulses reveals that the stability of the RML-FRL in terms of noise performance is superior to its ML-FRL counterpart. The optical pulse noise was measured over a frequency band of 100 Hz to 100 kHz and it was found that the pulse amplitude noise reduced from 0.6% in the ML-FRL to 0.3% in the RML-FRL. The total rms noise in the detected optical pulses from the RML-FRL improved by more than 30% compared to that measured for the ML-FRL, with a phase noise improvement of 15 dB at 100 kHz offset frequency from the carrier. An rms timing jitter of 0.38 ps was estimated in the optical pulse train from the ML-FRL, which reduced to 0.26 ps in the RML-FRL. In addition, complete elimination of the relaxation oscillations noise spikes in the detected RF spectrum of the optical pulses from the RML-FRL has been observed.

We demonstrate an all-optical scheme for coding high frequency mode-locked semiconductor laser pu... more We demonstrate an all-optical scheme for coding high frequency mode-locked semiconductor laser pulse trains. The scheme is experimentally demonstrated by optically modulating a high frequency pulse train at 38 GHz generated by a subharmonic synchronous mode-locked semiconductor laser with binary information contained in multiple low bit rate optical data signals (3.8 Gb/s). Synchronization between the two signals is achieved through optical injection into the mode-locked laser while high speed modulation is achieved via a nonlinear optical loop mirror made of dispersion shifted fiber. The coding scheme has advantages over existing passive multiplexing schemes in generating high data rate optical signals due to its regeneration and wavelength conversion functionality.

In this paper we propose a novel technique for the generation of wideband dual-mode pulses from a... more In this paper we propose a novel technique for the generation of wideband dual-mode pulses from a single subharmonically synchronous mode-locked laser diode (LD). The obtained pulse source exhibits high extinction ratio (>15 dB) and low timing jitter (<0.5 ps) over all the channels from 1550 to 1564 nm. The proposed scheme is cost-effective and a promising candidate as a pulse source for generation of carrier suppressed return-to-zero (CSRZ) modulation format in dense wavelength division multiplexed (DWDM) systems and optical generation of millimeter-wave frequency signals in multiple channel fiber wireless systems.

Japanese Journal of Applied Physics, 1996

Spectrally narrowed pulses from a gain-switched 690 nm GaInP/AlGaInP Fabry-Perot laser are succes... more Spectrally narrowed pulses from a gain-switched 690 nm GaInP/AlGaInP Fabry-Perot laser are successfully obtained by the self-seeding technique. A commercially available laser diode emits 48 ps pulses with a spectral width of 0.10 nm or less. This scheme will provide a compact and efficient light source for generation of ultraviolet light by nonlinear optical methods such as second-harmonic generation.

Japanese Journal of Applied Physics, 1996

We report the successful generation of optical pulses (∼ 65 fs) from a 1.55 µm gain-switched dist... more We report the successful generation of optical pulses (∼ 65 fs) from a 1.55 µm gain-switched distributed feedback semiconductor laser with fiber optic compression techniques by a novel dispersion arrangement. These pulses are the shortest ever generated starting from a semiconductor laser diode and are promising for practical applications in ultrafast photonic systems.

IEEE Photonics Technology Letters, 1996

ABSTRACT Negligibly small amplitude modulation and sufficiently low timing jitter are achieved si... more ABSTRACT Negligibly small amplitude modulation and sufficiently low timing jitter are achieved simultaneously in a passively mode-locked monolithic semiconductor laser stabilized by applying an electrical signal at the second subharmonic of the pulse repetition frequency. Nearly transform-limited 33 GHz pulse trains with 0.56 ps timing jitter and -23 dBc amplitude modulation are obtained with 23 dBm driving signals at 16.5 GHz. Detailed investigations are carried out on the dependence of the amplitude modulation and timing jitter on RF driving power for the second- and third-order subharmonic cases. The excellent amplitude modulation property of the second subharmonic case with the specific laser used in this work is ascribed to the frequency response characteristics of the device.

IEEE Photonics Technology Letters, 2002

IEEE Journal of Selected Topics in Quantum Electronics, 1997

Optical pulse trains at millimeter-wave frequencies are generated by subharmonic synchronous mode... more Optical pulse trains at millimeter-wave frequencies are generated by subharmonic synchronous mode-locking of a monolithic distributed Bragg reflector semiconductor laser, by which an initially passively mode-locked semiconductor laser is stabilized by injecting optical pulses at subharmonic frequencies of its resonant frequency. The stabilized pulse trains are characterized in terms of phase noise, timing jitter, locking range and modulation depth under

IEEE Journal of Selected Topics in Quantum Electronics, 1996

Performance of a subharmonically hybrid mode-locked (SH-ML) monolithic semiconductor laser is inv... more Performance of a subharmonically hybrid mode-locked (SH-ML) monolithic semiconductor laser is investigated. A 33-GHz passively mode-locked distributed Bragg reflector semiconductor laser is stabilized by the injection of an electrical signal with a subharmonic frequency of the laser cavity resonance. Systematic measurements on the phase noise, timing jitter, amplitude modulation, and locking bandwidth are performed for the second- and third-order SH-ML

IEEE Journal of Quantum Electronics, 1991

Pulses of 1.26 ps, the shortest directly triggered single-mode pulses ever reported, are generate... more Pulses of 1.26 ps, the shortest directly triggered single-mode pulses ever reported, are generated from a 1.3 pm distributed feedback laser diode using higher order soliton-effect compression. This is realized by compressing a gainswitched 17.5 ps pulse with a conventional fiber-optic compressor, i.e., a fiber with normal dispersion, and further, with a soliton-effect compressor where a two-stage traveling-wave semiconductor laser amplifier is used to increase the peak power of the compressed pulse from the first-stage compressor into the soliton regime required by the second-stage compressor.

IEEE Journal of Quantum Electronics, 2000

A regeneratively mode-locked fiber ring laser (RML-FRL) and an active harmonically mode-locked fi... more A regeneratively mode-locked fiber ring laser (RML-FRL) and an active harmonically mode-locked fiber ring laser (ML-FRL) have been characterized for both amplitude and phase noise by investigating the detected RF spectra of the optical pulse trains. Quantification of noise in the optical pulses reveals that the stability of the RML-FRL in terms of noise performance is superior to its ML-FRL counterpart. The optical pulse noise was measured over a frequency band of 100 Hz to 100 kHz and it was found that the pulse amplitude noise reduced from 0.6% in the ML-FRL to 0.3% in the RML-FRL. The total rms noise in the detected optical pulses from the RML-FRL improved by more than 30% compared to that measured for the ML-FRL, with a phase noise improvement of 15 dB at 100 kHz offset frequency from the carrier. An rms timing jitter of 0.38 ps was estimated in the optical pulse train from the ML-FRL, which reduced to 0.26 ps in the RML-FRL. In addition, complete elimination of the relaxation oscillations noise spikes in the detected RF spectrum of the optical pulses from the RML-FRL has been observed.