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.<>     

2.0 W CW, diffraction-limited operation of a monolithicallyintegrated master oscillator power amplifier

The authors fabricated a monolithically integrated master oscillator power amplifier, M-MOPA, with a flared power amplifier region which radiates in a single diffraction limited lobe to an output power in excess of 2 W CW. The radiation pattern is stable with increasing drive current. The spectral output of the M-MOPA is a single longitudinal mode with a side-mode suppression ratio greater than 25 dB     

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。     

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     

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     

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     

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.<>     

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.     

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.<>     

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.     

Compact hybrid master oscillator power amplifier with 3.1-W CW output power at wavelengths around 1061 nm

A hybrid master oscillator power amplifier (MOPA) laser source has been realized by coupling a single-mode three-section distributed Bragg reflector (DBR) laser as master oscillator and a tapered power amplifier with a single lens only. A maximum continuous-wave optical output power of 3.1 W was achieved. The emission spectrum was completely determined by the DBR laser. Single longitudinal mode operation at a wavelength of /spl lambda/=1061 nm was maintained over the whole power range. Up to an output power of 1.8 W, the beam propagation factor M/sup 2/was less than 1.6.     

High power, diffraction-limited emission from monolithically integrated active grating master oscillator power amplifier (lasers)

A novel monolithically integrated master oscillator power amplifier with a distributed amplifier/grating output coupler is demonstrated which emits 370 mW in a single-frequency diffraction-limited beam without any form of active phase control. The distributed amplifier/grating output coupler results in a guided mode power that saturates along the direction of propagation, providing a uniform carrier density to preserve the flatness of the radiated phase front.<>     

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.     

Coherent operation of monolithically integrated master oscillator amplifiers

Monolithically integrated master oscillator power amplifiers have been fabricated. The oscillator is a second order distributed Bragg reflector (DBR) laser. The epitaxial layer structure consists of a double quantum well active region bonded by Al/sub 0.3/Ga/sub 0.7/As confining layers and Al/sub 0.4/Ga/sub 0.6/As cladding layers. The resultant output is a single longitudinal mode in a nearly diffraction limited output to a power level of 485 mW.<>     

Frequency-doubled monolithic master oscillator power amplifierlaser diode

Single-pass frequency doubling of laser diodes extends the wavelength range of infrared laser diodes to blue-green wavelengths. We describe the first experiments of frequency doubling of a coherent, high-power, monolithic master oscillator power amplifier (M-MOPA) laser diode. The output from a l-W M-MOPA is frequency doubled in a single pass through an 8.2-mm-long KNbO₃ crystal. We obtained 3.7-mW diffraction-limited output power at a wavelength of 491 nm and modulation at 20 MHz was demonstrated     

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     

基于大模面积掺Yb光纤的100W种子光主振荡器功率放大技术

演示了一种基于大模面积掺Yb3+离子的全光纤放大器系统,该系统采用975 nm泵浦。系统是利用泵浦与Yb3+离子有源光纤相互作用产生信号源,光源为半导体激光放大的单频种子。通过优化系统,合理设计搭建光学器件,控制光束逆传输,减少非线性光学的干扰。100 W信号源作用于系统上,采用多级掺镱光放大的主振荡器功率放大器（MOPA）,最大输出3.2 kW连续激光。平均光-光转化效率为78.26%。光束质量Mx21.657,My21.735。输出稳定性小于2%。系统连续信号放大输出光具有广泛的应用范围。掺Yb3+离子的全光纤放大主要用于激光检测、工业测量技术研究等领域。     

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.     

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     

Spontaneous spatiotemporal instabilities in current modulatedmaster oscillator power amplifier lasers

We provide the first comprehensive theoretical evidence for nonlinear space-time dynamical behavior which seriously degrades the performance of a monolithically integrated master oscillator power amplifier laser under direct current modulation of the master oscillator. A host of instabilities, reflecting dynamical behavior of different sections of the device, are possible. These instabilities are due to the combination of weak feedback from the power amplifier section of the device causing leakage into the master oscillator section, from the buildup of unsaturated carriers along the narrow edges of the expanding flare and differential saturation of the passive regions under the distributed Bragg reflector grating sections