40 GHz actively modelocked polarisation maintaining erbium fibrering laser

The first polarisation-maintaining actively modelocked erbium fibre ring laser (ML-EFRL) operating at a base rate of 40 GHz is presented. The laser generates highly stable and virtually transform-limited 1.2-1.9 ps pulses tunable over 40 nm with a timing jitter of <0.1 ps. These represent the shortest pulses and lowest timing jitter generated by a 40 GHz ML-EFRL     

Picosecond (<2.5 ps) wavelength-tunable ( approximately 20 nm) semiconductor laser pulses with repetition rates up to 12 GHz

A novel technique is used to produce picosecond wavelength-tunable optical pulses from gain-switched Fabry-Perot semiconductor lasers using fibre compression. Experiments are carried out with high power, large modulation-bandwidth lasers at 1.3 mu m. Pulses of 2.5 ps durations with repetition rates up to 12 GHz are obtained. Still shorter pulses ( approximately 1 ps) with higher repetition rates (18 GHz) are shown to be feasible.<>     

Transform-limited 5.6 ps optical pulse generation at 12 GHz repetition rate from gain-switched distributed feedback laser diode by employing pulse compression technique

12 GHz chirped optical pulses from a gain-switched 1.3 ?m distributed feedback laser diode are compressed to transform-limited 5.6 ps pulses by travelling through a dispersion shifted single-mode fibre with 46 ps/nm normal dispersion. A time-bandwidth product of 0.69 and a high on/off ratio of 20 dB are obtained for optimally compressed pulses.     

2.5 GHz and 5 GHz harmonic mode-locking of a diode-pumped bulkerbium-ytterbium glass laser at 1.5 microns

Third-order harmonic mode locking of a diode-laser pumped bulk Er:Yb:glass laser by frequency modulation with a lithium niobate modulator is reported. Stable pulses at a repetition rate of 2.5 and 5 GHz with a pulse duration down to 9.6 ps are obtained. The average output power is 3 mW, the pulse peak power is 120 mW at 2.5 GHz repetition rate, and the pulses are approximately 1.4 times transform limited. The pulse duration can be increased up to 30 ps by decreasing the mode-locker drive power     

Picosecond pulse generation with high extinction ratio employing electroabsorption modulator, fibre compressor, and self-phase-modulation-based pulse reshaper

A wavelength-tunable 3.5 ps pulse generator, which employs an electroabsorption modulator (EAM), a fibre pulse compressor, and a self-phase-modulation (SPM)-based pulse reshaper, is developed. An EAM directly generates 21 ps pulses at a repetition rate of 10 GHz, which are compressed to 6 ps by a fibre pulse compressor. An SPM-based pulse reshaper then eliminates the large pedestal of the compressed pulses. Thus, 3.5 ps pulses with extinction ratio larger than 27 dB and timing jitter as small as 150 fs are obtained.     

Sub-nanosecond coherent pulse generation at millimetre-wave frequencies

Described is a simple method to produce sub-nanosecond phase coherent pulses with rise times and fall times of at least 80 ps at power levels in excess of 200 mW at 94 GHz. The duration and timing of these pulses are controlled by fast input logic, and pulses as short as 110 ps have been achieved. The technique is easily extended to both higher and lower frequencies, and produces pulses with an infinite extinction ratio suitable for amplification to higher power levels     

Passively modelocked 832 nm vertical-external-cavity surface-emitting semiconductor laser producing 15.3 ps pulses at 1.9 GHz repetition rate

A passively modelocked 832 nm vertical-external-cavity surfaceemitting laser, producing pulses of a duration of 15.3 ps at a repetition rate of 1.9 GHz, has been demonstrated. A fast surface-recombination semiconductor saturable absorber mirror, with a bi-temporal absorption recovery characteristic, consisting of fast and slow time constants of 1.5 and 200 ps, respectively, was used to form the pulses.     

Generation of 6.3 ps optical pulses at a 10 GHz repetition rateusing a packaged electroabsorption modulator and dispersion compensatingfibre

Sinusoidal modulation of an MQW InGaAsP/InGaAsP EA modulator at a 10 GHz repetition rate was used to generate optical pulses of width as low as 7 ps. Pulses were linearly compressed using 400 m of dispersion compensating fibre and approximately transform limited pulses of 6.3 ps width were measured     

10 GHz再生锁模光纤激光器获得光纤超连续谱的研究

报道了利用10GHz再生锁模光纤环形激光器（RML-FRL）获得波长在1528～1563nm连续可调、脉宽为4．6～5．8ps的短脉冲输出作为高稳定的光纤超连续（SC）谱泵浦源。对RML-FRL输出的脉冲直接放大泵浦4．5km色散位移光纤（DSF）,得到20dB带宽46．08nm的SC谱输出,经阵列波导光栅（AWG）谱切片后,得到间隔100GHz、中心波长符合ITUT标准的30信道输出,脉宽在6．5～7．8ps,示波器显示任意信道的抖动均值小于1．4ps。     

Synchronous mode-locking in passively mode-locked semiconductor laser diodes using optical short pulses repeated at subharmonics of the cavity round-trip frequency

Synchronous mode-locking was achieved in passively mode-locked semiconductor lasers using optical pulses with repetition rates at subharmonics of the cavity round-trip frequency. Stable and continuous mode-locked pulses at 8.5 GHz were generated when the repetition rate of the control optical pulses was 4.25 GHz (2nd subharmonic). The timing jitter of the mode-locked pulses was reduced to 1 ps. The relationship between repetition rates of the control pulses and the realization of stable and continuous mode-locking was examined.     

Multigigabit/s pulse source based on the switching of an optical beat signal in a nonlinear fibre loop mirror

A novel technique for the generation of a high repetition rate train of transform-limited pulses is demonstrated. A 32 GHz train of 4.2 ps pulses has been generated.<>     

Tunable GHz Repetitive ps Pulse InGaN Laser

Using sinusoidal waveform, an InGaN laser unit which incorporated a 50-Omega impedance-matching unit was used to generate <70-ps pulses with a repetition frequency ranging from 800MHz to 3.0 GHz. At 1.0 GHz, the pulses with a pulsewidth of 31ps and a peak power of >450 mW were obtained using +27dBm of RF power. Tuning characteristics of this gain-switching laser were studied     

11.2 GHz picosecond optical pulse generation in gain-switched short-cavity InGaAsP injection lasers by high-frequency direct modulation

We report the generation of high-speed optical pulses in gain-switched short-cavity InGaAsP injection lasers by high-frequency direct modulation. Short pulses (25 ps) with high on/off ratio were obtained at 11.2 GHz from a short-cavity double-channel planar buried-heterostructure (DCPBH) InGaAsP semiconductor laser biased at three times the threshold current. This is the first report of direct modulation above 10 GHz for InGaAsP lasers.     

High speed 2×4 array of differential quantum well modulators

The 3-dB bandwidth of the modulators was measured to greater than 3 GHz, and the time response was measured to 200 ps. By using short mode-locked pulses, the 3-dB bandwidth of the devices used as differential detectors was measured to be greater than 4 GHz and the risetime to be ~100 ps     

154 GHz polarisation-maintaining dispersion-managed activelymodelocked fibre ring laser

Optical pulses with a repetition rate of 154 GHz are generated directly from a polarisation-maintaining dispersion-managed fibre ring laser using fourth-order FM modelocking. External chirp compensation of the laser output yields transform-limited Gaussian pulses with 1.1 ps duration corresponding to a duty cycle of <0.2     

Wavelength and duration tunable subpicosecond source usingadiabatic Raman compression

A wavelength and pulse duration tunable source of subpicosecond pulses has been demonstrated at a repetition rate of 10 GHz using adiabatic Raman compression of 10 ps pulses from an external cavity laser and an electro-absorption modulator     

Short-pulse modulation of gallium-arsenide lasers with TRAPATT diodes

TRAPATT diodes producing current pulses with a halfwidth of 150 ps at a repetition rate around 1 GHz have been used to modulate successfully a double-heterostructure gallium-arsenide laser.     

High rate pulse generation from InGaAsP laser in selfoc lens external resonator

High rate modulation of an InGaAsP diode laser at rates of 5?10 GHz was demonstrated using a selfoc microlens external resonator. At a rate of 5.3 GHz modelocked pulses of 30 ps duration were obtained, whereas deeply modulated output was observed at 8.1 and 9.4 GHz rates.     

Picosecond optical pulse compression from gain-switched 1.3 ?m distributed-feedback laser diode through highly dispersive single-mode fibre

The first demonstration to compress the linearly chirped optical pulses from a gain-switched distributed-feedback laser diode (DFB-LD) is described at 1.3 ?m wavelength. By travelling through a highly dispersive single-mode fibre with 48 ps/nm normal dispersion, a 26 ps (FWHM) pulse having red-shift frequency chirping of 85 GHz (FWHM) is compressed to 8.3 ps with the time-bandwidth product of 0.71.     

Passively modelocked 50 GHz Er:Yb:glass laser

A diode-pumped Er:Yb:glass miniature laser has been passively mode locked to generate 2.0 ps pulses at a 50 GHz repetition rate with up to 7.5 mW average power. By combining this laser with a dynamic gain equaliser, a flat optical spectrum has been generated with up to 10 discrete channels with a 50 GHz channel spacing locked to the 50 GHz ITU grid.