Analysis of monolithic integrated master oscillator poweramplifiers

An analysis of a novel, monolithic integrated master oscillator power amplifier (M-MOPA) is presented. The M-MOPA consists of a DBR master oscillator which injects power into a linear chain of amplifiers and detuned second-order grating output couplers. The analysis self-consistently includes amplified spontaneous emission buildup and residual reflections throughout the amplifier stages. It predicts that output powers in excess of 1 W can be expected from a single-lateral-mode waveguide multistage amplifier less than 1 cm in length, injected with less than 15 mW of input power. In addition to the signal gain of >25 dB, the signal-to-noise ratio at 1-W output exceeds 15 dB. Because of the small reflections associated with the grating output couplers, and gain saturation by the injected signal, the amplifier self-oscillation threshold is suppressed to current densities above 15 kA/cm²     

1047 nm laser diode master oscillator Nd:YLF power amplifier laser system

A master oscillator power amplifier (MOPA) laser transmitter system at 1047 nm wavelength using a semiconductor laser diode and a diode pumped solid state (Nd:YLF) laser (DPSSL) amplifier is described. A small signal gain of 23 dB, a near diffraction limited beam, l Gbit/s modulation rates and >0.6 W average power are achieved. This MOPA laser has the advantage of amplifying the modulation signal from the laser diode master oscillator (MO) with no signal degradation.<>     

高功率声光调Q主振荡功率放大器

为了实现在高重复频率调Q的同时,又有好的光束质量。实验设计了激光二极管抽运的高重复频率、高功率的主功率放大（MOPA）结构激光器,激光器采用声-光调Q,主振荡功率放大+二级放大的结构。优化了主功率放大（MOPA）激光器的结构和相关参数,完成了关于高功率高重频主功率放大（MOPA）结构激光器的实验研究,并且通过合理排列光学元件在谐振腔中的位置来实现光束质量的提高,利用聚焦镜和狭缝来实现激光模式的匹配。在重复频率为50 kHz时,实现了最高功率为51.3 W,输出脉宽为18.62 ns,光束质量为MX2=1.882、MY2=1.971的激光输出,光-光转换效率为23.75%。在增益导引的作用下,主振荡功率放大（MOPA）激光器的输出光光束质量得到了有效的提高。     

1.6 W hybrid master oscillator power amplifier withα-DFB-laser as master oscillator at 1057 nm

A hybrid master oscillator power amplifier is realised on a small area less than 100 mm² combining an α-DFB-laser as master oscillator and a broad area laser as power amplifier. A quasi-cw output power of P=1.6 W at the wavelength) λ=1057 nm is achieved with a beam quality factor M² less than 2 and a spectral width less than 6 pm     

Dynamic instabilities in master oscillator power amplifiersemiconductor lasers

We investigate theoretically the master oscillator power amplifier using a semiconductor laser model that is fully time and space (laterally and longitudinally) resolved. We numerically examine the stability of the device and identify the nature of the different instabilities. These can arise from undamped relaxation oscillations, beating between the longitudinal modes of any of the cavities that comprise the device, or lateral filamentation     

Mode-locked operation of a master oscillator power amplifier

We report the first mode-locked operation of a tapered amplifier MOPA to generate short optical pulses with record high average powers and pulse energies. The MOPA is constructed using a discrete semiconductor oscillator and amplifier operating at 940 mm wavelength. Pulses of 4.2 ps duration are generated with average powers of 296 mW and peak powers of 28.1 W. The energy of these pulses was 118 pJ, corresponding to energies more than an order magnitude greater than the gain saturation energy in the mode-locked laser itself, and also corresponds to energies internal in the amplifier in excess of the gain saturation energy. Although the amplifier saturation energy limits the pulse energy obtainable in a mode-locked laser, the MOPA configuration demonstrates that generation of pulses with energies in excess of the amplifier saturation energy is feasible in a post-amplification stage     

All-fiber phase-modulated master oscillator power amplifier forcoherent communication

An all-fiber phase-modulated master oscillator power amplifier for free-space coherent communication is presented. A distributed-feedback fiber laser at 1.06 μm is used as master oscillator. A novel phase modulator based on a ZnO-coated single-mode fiber modulates the single frequency communication signal. The modulated signal is then amplified in a double-clad doped fiber power amplifier. Up to 1 W cw single-frequency output power, phase modulated at 196 MHz, has been obtained     

A periodic planar Gunn diode power combining oscillator

Several planar periodic power combining oscillators containing two to six Gunn diodes operating in the X-band region are discussed. The maximum power combining efficiency, 126.7% was obtained from the three-diode oscillator. The frequency dependence of all the power combiners on the bias voltage variation seemed to be independent of the number of diodes. Injection locking was maintained over a large variation of the bias voltage     

980-nm master oscillator power amplifiers with nonabsorbing mirrors

High-power master oscillator power amplifiers with nonabsorbing mirrors have been fabricated. These devices exhibit 1.0 and 1.5 W of single-frequency diffraction-limited continuous-wave optical powers at relatively low-amplifier currents of 1.75 and 2.6 A, respectively. These devices operate with a single longitudinal mode with a 40-dB sidemode suppression ratio over the entire amplifier current range without any longitudinal mode hops as a result of the very low optical feedback from the PA facet. Coupling of over 500 mW into a single-mode fiber is also achieved     

10 W近衍射极限输出的高效率窄线宽主控振荡放大半导体激光器

为研制近衍射极限的高功率半导体激光器,采用了片上光栅、窄脊型波导、锥形放大器一体集成的主控放大(Master Oscillator Power-Amplifier,MOPA)技术路线,以长度为8 mm、脊型宽度为3μm的波导为单模种子源,配合长度为7 mm、全角为3.3°的锥形放大器,实现了功率10.3 W、慢轴光束质量M²(1/e²)因子=1.06,3 d B线宽40 pm,工作电光效率50.5%的半导体激光输出,并采用片上电致加热光栅调谐技术,实现了中心波长在4 nm范围内连续可调。     

1047-nm master oscillator power amplifier free-space opticalcommunications laser transmitter

We report on the performance of a 1047-nm laser diode master oscillator (MO) diode pumped Nd:YLF power amplifier (PA) laser transmitter in a 50-Mbps quaternary pulse position modulation (Q-PPM) free-space optical direct detection communications experiment. The transmitter produced greater than 1 W of 1047-nm average optical power. At optical transmitter powers up to 0.2 W, we achieved nearly the same communications performance (~210 photons/b at 10^-6 bit-error rate) using the 1047-nm MOPA transmitter as with the 50 mW laser diode alone. We relied on an external-cavity grating feedback scheme for the 1047-nm laser diode MO to achieve this communications performance     

High average power, high repetition rate, picosecond pulsed fiber master oscillator power amplifier source seeded by a gain-switched laser diode at 1060 nm

We demonstrate a pulsed ytterbium-doped fiber master-oscillator power amplifier source at 1060 nm producing over 300 W of average power in 20-ps pulses at 1-GHz repetition rate. The pulses generated by a gain-switched diode were compressed by a chirped fiber Bragg grating and amplified without any distortion with excellent spectral quality. This fiber master oscillator power amplifier system offers versatility and potential for further power scaling.     

1 W, coherent, monolithically integrated master oscillator power amplifier

Monolithically integrated master oscillator power amplifiers (M-MOPA) have been fabricated consisting of a single mode distributed Bragg reflector oscillator coupled to a chain of nine single mode amplifiers and detuned second order grating output couplers. The M-MOPA emits in excess of 1 W in a coherent, single longitudinal mode, beam.<>     

Coherent operation of 2-D monolithically integrated master oscillator power amplifier

Two dimensional monolithically integrated master oscillator power amplifiers (M-MOPAs) have been fabricated that emit in a single longitudinal mode to an output power of greater than 4.5 W. The spectral output is a single longitudinal mode throughout the operating range and is identical to the output of the master oscillator. The far field radiation pattern transverse to the direction of propagation is characteristic of inphase diffraction limited operation at low output powers.<>     

7.4 W continuous-wave output power of master oscillator power amplifier system at 1083 nm

A 1083 nm hybrid master oscillator power amplifier system consisting of a DBR laser and a tapered amplifier has been realised. A maximum output power of 7.4 W in single-longitudinal mode operation with a narrow spectral linewidth and a sidemode suppression ratio better than 40 dB is presented.     

Ultra-high-power quasi-CW monolithic laser diode arrays with high power conversion efficiency

An optical power output of 134 W from one facet and power conversion efficiencies as high as 49% have been obtained from monolithic AlGaAs laser arrays with 1 cm emitting widths for 150^s pulse widths (quasi-CW operation). The arrays have etched grooves to prevent transverse lasing and amplified spontaneous emission.     

Pr/sup 3+/-doped fluoride fiber amplifier module pumped by a fiber coupled master oscillator/power amplifier laser diode

We constructed the first Pr/sup 3+/-doped fluoride fiber amplifier (PDFA) module pumped by a fiber-coupled master oscillator/power amplifier laser diode (MOPA-LD) operating at 1.017 /spl mu/m. The maximum signal gain and noise figure were 30.5 and 5.5 dB, respectively. An output power of 18 dBm was achieved at an input signal power of 0 dBm. Furthermore, we showed that the use of MOPA-LD pumping, rather than conventional Nd-YLF laser pumping, makes it possible to halve the length of the Pr/sup 3+/-doped fluoride required in the amplifier module and also allows a broader spectral bandwidth to be achieved.     

Stable monolithic GaAs FET oscillator

A monolithic X-band GaAs FET oscillator has been developed. Passive circuit components are lumped capacitors and inductors on semi-insulating GaAs; the chip size is 1.2 × 1.4 mm2. Stabilised with a Ba2Ti9O20 dielectric resonator, the oscillator delivers more than 30 mW output power at 10.8 GHz with a maximum chip efficiency of 20%. The frequency drift is better than 1 × 10?6/K from ?20°C to 80°C.     

2.2-W continuous-wave diffraction-limited monolithically integrated master oscillator power amplifier at 854 nm

A monolithically integrated master oscillator power amplifier (M-MOPA) with a flared power amplifier region operating at 854 nm has been fabricated that radiates in a single diffraction-limited lobe to an output power of 2.2-W continuous wave (CW). Additionally, the far field is extinguished by 26 dB with the master oscillator turned off enabling applications requiring digital modulation.