Gain-switched Fabry-Perot Laser Diode Research Articles

基于自注入式法布里—珀罗激光二极管与倾斜多模光纤光栅的多波长可调谐短脉冲激光器

We experimentally demonstrate the simultaneous generation of tunable multi-wavelength picosecond laser pulses using a self-seeding configuration that consists of a gain-switched Fabry-Perot laser diode (FPLD) with an external cavity formed by a tilted multimode fiber Bragg grating. Dual- and triple-wavelength pulses are obtained and tuned in a flexible manner by changing the temperature of the FPLD. The side mode suppression ratio larger than 25 dB is achieved at different dual- and triple-wavelengths and the typical pulsewidth of the output pulses is ~70 ps. In the experiment, the wavelength separation can be narrowed to 0.57 nm.

32 GHz microwave photonic pulse train generation using 1.6 GHz electronics and optical repetition rate multiplication

A 32 GHz microwave photonic pulse train is generated from a semiconductor fibre ring laser (SFRL) by injecting 1.6 GHz gain-switched Fabry-Perot laser diode (GS-FPLD) output. To achieve a stable modelocking of SFRL at 32 GHz by efficient cross-gain modulation of a semiconductor optical amplifier, individual lasing modes of the injecting 1.6 GHz GS-FPLD output are separated by 31.3 picoseconds by passing a dispersive fibre.

Detailed Comparison of Injection-Seeded and Self-Seeded Performance of a 1060-nm Gain-Switched Fabry–PÉrot Laser Diode

We investigate and compare the performance of a gain-switched picosecond Fabry-Perot laser diode operated at 1.06 mum under both injection- and self-seeded conditions. Our experiments show that comparable performance can be obtained for both modes of operation, with the self-seeding arrangement offering overall benefits in terms of reduced system complexity and cost, providing the associated quantization of available pulse repetition rate can be tolerated.

Pulse-Width Jitter Measurement for Laser Diode Pulses

Theoretical analysis and experimental measurement of pulse-width jitterof diode laser pulses are presented. The expression of pulse powerspectra with all amplitude jitter, timing jitter and pulse-width jitteris deduced. The power spectra with and without pulse-width jitter arenumerically simulated. The simulation results indicate that thepulse-width jitter will contribute considerably noise to the pulse powerspectrum while the product of pulse width and angular frequency islarger than 1. The experimental measurement of pulse-width jitter ofa gain-switched Fabry–Perot laser diode with 2.4 GHz repetition rate isalso reported. In comparison of the noise power spectra of the first,fourth and seventh harmonics of the pulse repetition rate, 2.3 pspulse-width jitter is obtained.

Measuring optical fiber length by use of a short-pulse optical fiber ring laser in a self-injection seeding scheme

A method for measuring the length of an optical fiber by use of an optical fiber ring laser pulse source is proposed and demonstrated. The key element of the optical fiber ring laser is a gain-switched Fabry-Perot laser diode operated in a self-injection seeding scheme. This method is especially suitable for measuring a medium or long fiber, and a resolution of 0.1 m is experimentally achieved. The measurement is implemented by accurately determining the pulse frequency that can maximize the output power of the fiber ring laser. The measurement results depend only on the refractive index of the fiber corresponding to this single wavelength, instead of the group index of the fiber, which represents a great advantage over both optical time-domain reflectometry and optical low-coherence reflectometry methods.

Generation of low jitter and discrete tunable dual-wavelength optical pulses at arbitrary repetition rates

A novel and simple method to generate low timing jitter and discrete tunable dual-wavelength optical pulses at arbitrary repetition rates is demonstrated in this paper. Two multiple quantum wells distributed feedback laser diodes, were used as the external seeding sources to inject the external photons into a gain-switched Fabry-Perot laser diode. The output wavelengths can be tuned discretely to coincide with any two lasing modes in the gain spectra range of the Fabry-Perot Laser diode, and the output side mode suppression ratio was better than 25 dB. Moreover, the timing jitter of optical pulses was reduced from 1.89 ps to 0.83 ps. It was empirically found that the lowest timing jitter operation occurred when the injected light wavelength is 0.2–0.3 nm shorter than the locked mode of the Fabry-Perot laser diode. To our knowledge, this is the first report of using two DFB laser diodes as a seeding source to reduce pulses jitter and select lasing dual-wavelength simultaneously.

Design of a new optical impulse radio system for ultra-wideband wireless communications

This study presents a novel optical impulse radio (IR) system for generating Gaussian monocycle pulses for ultrawideband (UWB) radio-over-fiber communications. The proposed system consists of a gain-switched Fabry-Perot laser diode, tunable filter, Er/sup 3+/-doped fiber amplifier and a microwave differentiator. This new optical technique can tolerate pulse dispersion and avoid the generation of intersymbol interference (ISI) due to its easily adjustable optical pulse width, and can perform better radio communication in terms of generating the UWB signal. Simulated results indicate that the generated Gaussian pulse signal can provide a bandwidth of several gigahertz for the high-bit-rate transmissions. Moreover, experimental and analytical results demonstrate that the proposed system can generate high-quality Gaussian pulse trains for applying future high-bit-rate UWB wireless communications.

Simple system for optical short-pulse generation in both active mode-locking and self-seeding schemes

A simple system that simultaneously supports active mode-locking and self-seeding schemes for wavelength-tunable optical short-pulse generation is proposed. The system consists of a gain-switched Fabry-Perot laser diode, an erbium-doped fiber amplifier, a tunable optical filter, and two circulators. The mode-locked optical pulses exhibit good stability, a high side-mode suppression ratio of more than 31 dB over a wide wavelength tuning range of 42 nm, and a pulse width of around 35 ps at a repetition frequency of approximately 2.8 GHz.

Interrogation of fiber Bragg grating displacement/bending sensors using dual-wavelength pulses generated from a self-seeded Fabry-Perot laser diode

We demonstrate a simple technique for the interrogation of fiber Bragg grating (FBG) displacement/bending sensors using a self-seeded Fabry-Perot laser diode (FP-LD). The sensing element consists of two almost identical FBGs mounted on the surface of a cantilever beam, which results in a reflection spectrum containing two close peaks with a separation depending on the amount of bending of the beam. The sensing element is made to select a particular mode of a gain-switched FP-LD, so that stable short pulses at the two wavelengths defined by the reflection peaks of the FBGs are generated simultaneously when the modulating frequency of the FP-LD is set properly. The wavelength separation of the dual-wavelength pulses is converted into a time difference by transmitting the pulses through a dispersive fiber, so that the wavelength measurement is replaced by the less expensive time measurement. To multiplex similar sensors that are sufficiently far apart spectrally, it is only necessary to change the modulating frequency of the FP-LD. This technique provides an intensity-referencing-free demodulation scheme, an easy way to interrogate a series of sensors, and an effective means to compensate for drifts due to temperature changes.

Generation of picosecond pulses at five close wavelengths by use of a self-seeded Fabry–Perot laser diode and a spectrum-split fiber Bragg grating

We have demonstrated simultaneous generation of stable picosecond laser pulses at five close wavelengths at a pulse repetition rate of approximately 2 GHz by using a self-seeding configuration that consisted of a gain-switched Fabry-Perot laser diode (FPLD) with an external cavity formed by a tunable spectrum-split fiber Bragg grating (FBG). The FBG selected only one of the modes of the FPLD and, at the same time, filtered the selected FPLD mode such that the reflection from the FBG, tapped with a directional coupler, provided an output of dual-wavelength pulses and the transmission through the FBG provided an output of three-wavelength pulses. We could change the intensities and the wavelength separations of the pulses by adjusting the modulating radio frequency and the temperature of the FPLD and the separation of the FBG reflection peaks. In our experiments the highest side-mode suppression ratios of the pulses obtained were 44.5 dB for the dual-wavelength output and 25.0 dB for the three-wavelength output. Also, the laser was demonstrated to minimize pulse intensity imbalance and produce equally separated wavelengths (with a wavelength separation of 0.2 nm). This simple laser offers considerable flexibility for various applications.

Low jitter femtosecond semiconductor laser system with arbitrary repetition rate

A modified photon injection setup to generate low jitter singlemode laser pulses from a gain-switched Fabry-Perot laser diode at arbitrary repetition rates is presented. The output pulses show sub-picosecond timing jitter and, upon nonlinear compression in comb-like dispersion profiled fibre, pulse widths (FWHM) below 500 fs.

Generation of wavelength-tunable optical short pulses with a highly improved side-mode-suppression ratio over a large wavelength-tuning range

We have developed a self-seeding system to generate wavelength-tunable optical short pulses with a highly improved side-mode-suppression ratio (SMSR) over a large wavelength-tuning range. The external cavity of the gain-switched Fabry–Perot laser diode consists of two fiber Bragg gratings (FBGs) connected in series, an erbium-doped fiber amplifier (EDFA), an optical coupler, and two circulators. The two gratings exhibit distinct peak wavelengths and each can be tuned across nearly the 20-nm range. The system is simple and efficient and the side-mode-suppression ratio achieved is about 40 dB over a 24-nm wavelength-tuning range. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 395–399, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20998

Optical-Pulse-Injection-Induced 40 GHz Photonic Frequency Multiplication in Erbium-Doped Fiber Laser

The generation of a 40 GHz regeneratively amplified and frequency-multiplied optical pulse train from an erbium-doped fiber ring laser is demonstrated. This is achieved by seeding a 1 GHz gain-switched Fabry–Perot laser diode and detuning its repetition frequency to coincide with the harmonic resonant cavity mode. The peak power of frequency-multiplied erbium-doped fiber lasers (EDFL) pulses increases from 80 mW to 230 mW as the modulation level of the Fabry–Perot laser diode (FPLD) increases from 18 dBm to 30 dBm. The pulsewidth and peak power are 10 ps and 5 mW at a repetition rate of 40 GHz. The EDFL longitudinal mode frequency fluctuation is within ±2.5 kHz during 2 h. The frequency-multiplied EDFL pulses exhibit relatively low phase noises of -95 dBc/Hz and -120 dBc/Hz at offset frequencies of 10 kHz and 1 MHz, respectively. The associated timing jitter of the EDFL pulses exponentially increases from 0.6 ps to beyond 5.8 ps as the frequency multiplication order increases from 1 to 40.

Impact of mode partition noise in free-running gain-switched Fabry-Perot laser for 2-dimensional OCDMA

Free-running gain-switched Fabry-Perot laser diode is an appropriate incoherent broadband optical source for incoherent 2-dimensional optical code division multiple access. However, the mode partition noise (MPN) in the laser seriously degrades performance. We derived a bit error rate (BER) expression in the presence of MPN using the power spectra of the laser. The theory agreed with the experimental results. There was a power penalty and BER floor due to the MPN in the laser. Therefore, this scheme should be operated with a sufficiently large number of modes. At least 9 modes should be used for error-free transmission at 1 Gbit/s for the laser we investigated in this work.

Simple self-seeding scheme for generation of wavelength-tunable optical short pulses

A simple and efficient system for generating wavelength-tunable optical short pulses from a self-seeded, gain-switched Fabry–Perot laser diode is presented. The laser’s external cavity consists only of a tunable optical filter. The side-mode suppression ratio is better than 30 dB over a relatively wide wavelength-tuning range of 26 nm. In addition, a constant repetition frequency of 534.65 MHz can be maintained during wavelength tuning.

Optical control of period doubling in a gain-switched Fabry–Perot laser diode and its application in all-optical clock division

Optical injection is shown to be an effective means to suppress or to enhance period doubling of a gain-switched laser diode. The role that the injection plays depends on whether the laser resonance frequency is larger or smaller than half the modulation frequency. Reversible control of period doubling has been demonstrated experimentally using a modulated injection source. An injection power as low as 0.03 mW has been used to control the output pulse repetition frequency of the slave laser. The response time is measured to be shorter than 100 ps. The phenomenon has been applied successfully for use in all-optical clock frequency division. Replacing the electrical modulation with an input clock signal at 19.6 GHz, a frequency-halved output clock with a remarkable low-level phase noise (−87.7 dBc/Hz at 10 kHz offset frequency) has been obtained. The change in the phase noise level is observed to be smaller than 1 dB over a frequency detuning range of 400 MHz.

Electrically wavelength‐tunable optical short‐pulse generation in a self‐seeding scheme with intensity controllable feedback

AbstractA simple and robust system is presented to generate electrically wavelength‐tunable optical short pulses from a gain‐switched Fabry–Perot laser diode. The laser external cavity consists of a tunable filter and an erbium‐doped fiber amplifier, which provides wavelength selectivity and intensity controllable feedback. As a result, a side mode suppression ratio SMSR of better than 30 dB over the wavelength tuning range of 17.5 nm can be obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 98–99, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10982

Generation of electrically wavelength-tunable optical short pulses using a Fabry-Perot laser diode in an external-injection seeding scheme with improved sidemode suppression ratio

Electrically wavelength-tunable optical short pulses are generated from a gain-switched Fabry-Perot (F-P) laser diode with another F-P laser diode used as the external-injection-seeding light source. The injection wavelength is selected by a tunable filter and intensified by the use of an erbium-doped fiber amplifier before being directed to the gain-switched F-P laser diode. The sidemode suppression ratio achieved is better than 25 dB over the wavelength-tuning range of 9 nm. The system is simple and of low cost.

Simple approach for wavelength tunable picosecond pulse generation by an external injection seeding scheme

A simple scheme to generate wavelength tunable picosecond pulses by the external injection seeding of a gain-switched Fabry-Perot laser diode (FP-LD) is demonstrated. The key parts of the system consist of a FP-LD, a fiber Bragg grating (FBG), and a 3-dB coupler. The peak wavelength can be tuned from one longitudinal lasing mode to another by changing the Bragg wavelength of the FBG. The wavelength tuning range achieved is about 10 nm and the overall side mode suppression ratio (SMSR) is better than 15 dB.

A novel chromatic dispersion measurement method in frequency domain using a multi-wavelength optical pulse train generated by Fabry–Perot laser diode

We propose and demonstrate a simple and robust measurement method for the chromatic dispersion of single mode fibers. Multi-wavelength picosecond optical pulse train from a gain-switched Fabry–Perot laser diode in conjunction with the highly dispersive fiber is used for multi-wavelength light source. The frequency of the separated pulse train may suffer a frequency change in dispersive optical fiber, which can be measured very accurately by an electrical spectrum analyzer. This method was applied to measure the chromatic dispersion of the standard single mode fiber for various lengths. The measured chromatic dispersion of a standard single mode fiber was 17.60 ps/nm/km at 1561 nm with an experimental standard deviation of 0.20 ps/nm/km and time resolution was less than 0.18 ps. The measurement setup is compact and economical compared to conventional methods. This technique can be applied in both long and short lengths (∼50 m) of fibers with very high accuracy.