Low-Threshold Conjugated Polymer Distributed Feedback Lasers on InP Substrate

We demonstrate a low threshold polymer solid state thin-film distributed feedback （DFB） laser on an InP substrate with the DFB structure. The used gain medium is conjugated polymer poly[2-methoxy-5-（2-ethylhexyloxy）-l, 4- phenylenevinylene] （MEH-PPV） doped polystyrene （PS） and formed by drop-coating method. The second order Bragg scattering region on the InP substrate gave rise to strong feedback, thus a lasing emission at 638.9nm with a line width of 1.2nm is realized when pumped by a 532nm frequency-doubled Nd：YAG pulsed laser. The devices show a laser threshold as low as 7n J/pulse.     

Electrically Pumped Room-Temperature Pulsed InGaAsP-Si Hybrid Lasers Based on Metal Bonding

A pulsed InGaAsP-Si hybrid laser is fabricated using metal bonding. A novel structure in which the optical coupling and metal bonding areas are transversely separated is employed to integrate the silicon waveguide with an InGaAsP multi-quantum well distributed feedback structure. When electrically pumped at room temperature, the laser operates with a threshold current density of 2.9 kA/cm^2 and a slope efficiency of 0.02 W/A. The 1542nm laser output exits mainly from the Si waveguide.     

Threshold gain analysis of second order distributed feedback lasers based on [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene]

We present a theoretical study of the threshold analysis of second order surface emitting distributed feedback lasers based on the polymer [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). A coupled mode formalism that includes radiation modes is used to describe the propagation of the waves in the periodically corrugated region. A detailed calculation of the threshold gain of the laser that includes the effects of the radiation modes is described.     

Two-dimensional DFB laser fabricated on dye-doped hybrid zirconia film by soft lithography

A two-dimensional(2D) distributed feedback(DFB) structure is fabricated on dye-doped sol-gel derived hybrid zirconia films by soft lithography.The Q-switched Nd:YAG laser(λ = 532 nm) is used to pump these structures.The lasing emissions of the gain medium doped with Rhodamine 6G(Rh6G) in two perpendicular directions are shown,and the threshold pump energy is measured.     

DFDL产生超短脉冲的机制分析

本文综述介绍了用DFDL产生ps量级超短脉冲的方法,着重讨论了用DFDL产生超短脉冲的机制理论分析。分析表明:用DFDL产生超短脉冲可以通过建立适当的速率方程,恰当设置参数求解来预言其总体行为。通过理论和实验结果的比较,可以认为DFDL产生超短脉冲的机制是自Q调制。     

Integratable and High Speed Complex-Coupled MQW-DFB Lasers Fabricated on Semi-Insulating Substrates

A novel integratable and high speed InGaAsP multi-quantum well （MQW） complex-coupled distributed feedback （DFB） laser is successfully fabricated on a semi-insulating substrate. The fabricated ridge DFB laser exhibits a threshold current of 26 mA, a slope efficiency of 0. 14 W·A^-1 and a side mode suppression ratio of 40 dB together with a 3 dB bandwidth of more than 8 GHz. The device is suitable for 10 Gbit/s optical fiber communication.     

喇曼自由电子激光振荡器

本文报道喇曼自由电子激光振荡器的研究结果。脉冲加速器电子束能量０．４ＭｅＶ，束流８００Ａ。采用满足布喇格条件的分布反馈谐振腔，取代传统的激光器反射镜。理论上进行了分析和设计，采用正弦形波结构选择振荡模式。喇曼自由电子激光振荡器实验表明，输出光谱显著变窄。频率分布半高宽度，超辐射下范围为７．５ｍｍ～９．２ｍｍ，分布腔下范围为８．６ｍｍ～８．９ｍｍ。     

1.3μm分布反馈二极管激光器组件

开发了一种用于光纤公用天线电视（ＣＡＴＶ）的分布反馈激光二极管组成，组件包括１．３μｍＩｎＧａＡｓ／ＩｎＰ双沟－平面掩埋双异质结（ＤＣ－ＰＢＨ）分布反馈激光二极管和光隔离器，封装在蝴蝶型管壳内，组件的出纤线性功率为２．５ｍＷ，并具有极低的失真。     

Single Mode Er-Doped π-Phase-Shifted Distributed Feedback Fibre Grating Laser

A novel method incorporating the shielded method and the post-processing method has been proposed to fabricate the π-phase-shifted fibre grating. Then an Er-doped π-phase-shifted distributed feedback fibre grating laser has been fabricated using the grating. The laser threshold is 20mW. When pumped with 90mW light at 980nm, the laser gives an output of 1.1mW. Its signal-to-noise ratio is better than 60dB. It is demonstrated that the laser is single mode operation by means of a Fabry--Perot scanning interferometer.     

Integrated self‐aligned conjugated polymer fiber laser devices

In this letter we present a fully integrated self‐aligned distributed feedback (DFB) fiber laser device, which was directly imprinted in the conjugated polymer poly[2‐methoxy‐5 (2‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) on the top of optical fibers by using the soft lithographic technique of “liquid imprinting”. For this process master gratings (360 and 380 nm) for the feedback structure were fabricated via e‐beam lithography, transferred to an elastomeric stamp and used to imprint the grating into the highly luminescent conjugated polymer. Such second order gratings were photo‐pumped with a frequency doubled Nd:YAG laser, the laser emission (around 640 nm, depending on the used grating) was directly coupled into the waveguide and detected via a CCD spectrometer at the end of the fiber. The threshold of the laser devices was found to be in the range of 4.3 mJ/cm² and exhibited a line width of approximately 2 nm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Water-vapor isotope ratio measurements in air with a quantum-cascade laser spectrometer

A spectrometer was used in the laboratory to study water-vapor isotope ratio measurements in air: H2 18O/H2 16O and HDO/H2 16O near 6.7 microm. The spectral region ranging from 1483 to 1487 cm(-1), which is suitable for the in situ laser sensing of major water-vapor isotopologues in the middle atmosphere from airborne or balloonborne platforms, was investigated by use of a continuous-wave distributed feedback quantum-cascade laser. The concentrations obtained were compared with the concentrations obtained with a hygrometer. The sigma(18O) values were found to be in excellent agreement with the standard value for two individual lines. The sigma(D) value was slightly higher than the standard value.     

Ultrashort pulse generation by distributed feedback dye lasers. I

The N₂-laser pumped distributed feedback dye laser is a new type of picosecond light source. A rate equation model describing the ultrashort pulse formation is presented. The temporal behavior of the distributed feedback dye laser predicted by the model has been compared with experimental results obtained with a streak camera system. The observed good agreement allows application of the theoretical model for the engineering of an inexpensive picosecond laser     

Experimental Investigation of Chaos Synchronization in DFB Diode Lasers with Unsymmetrical Scheme

We experimentally generate high dimension chaotic waveforms with smooth spectrum using a distributed feedback （DFB） semiconductor laser with unidirectional fibre ring long-cavity feedback, and implement the stable chaos synchronization when the chaotic light is injected into a solitary DFB laser diode. The synchronization quality is investigated by time-domain and frequency-domain analysis separately, The frequency-domain analysis indicates that the synchronization has higher quality in the high frequency band. The influences of the injection strength and the frequency detuning on the synchronization are measured. Our experimental results show that the robust synchronization can be maintained with the optical frequency detuning from -11GHz to 40 GHz.     

Relative line intensity measurement in absorption spectra using a tunable diode laser at 1.6 μm: application to the determination of 13CO2/12CO2 isotope ratio

The measurement of relative intensities in CO₂ combination bands spectrum is performed using wavelength modulation spectroscopy (WMS) and a DFB (distributed feedback) diode laser operating at 1.6 μm. The diode laser is stabilized with an external Fabry–Pérot interferometer and absorption spectroscopy is performed in a multipass gas cell. A spectrum containing spectral lines of both ¹³CO₂ and ¹²CO₂ isotopic species is recorded. The variation of laser power during frequency scanning and the line shape are taken into account to accurately extract line intensities from experimental data. The isotopic concentration ratio is deduced from the intensity ratio. Both ratios are measured with an accuracy of about 0.5% in pure CO₂. Received: 9 June 2000 / Published online: 8 November 2000     

10 ps High Power Laser System at 248 nm

A simple 10 ps KrF laser system consisting of quenched dye laser oscillator pumped by a XeCl laser, a distributed feedback dye laser (DFDL), a three-stage dye amplifier and a two-stage KrF amplifier are described. The output of the laser system is 140 mJ with 10 ps pulse width by using polarization-multiplexing amplification. A focused output laser intensity of about 4×1015 W/cm2 is obtained. The saturation fluence for KrF laser is obtained with this laser.     

10 ps High Power Laser System at 248 nm

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分布反馈光纤激光器的研制

利用相位掩膜板,直接在掺饵光纤上紫外写入π／２相位光栅,研制出１０ｃｍ长相移分布反馈（ＤＦＢ）光纤激光器,并对其调制特性进行了研究。     

All optical Flip-Flop based on a nonlinear DFB semiconductor laser: Theoretical study

A new design of an all optical Flip-Flop is proposed. It consists of a nonlinear distributed feedback (DFB) laser. The wave guiding layer of the DFB laser consists of linear grating section followed by a nonlinear one, and both sections are separated by a phase shift section. In the OFF-state, the real part of the refractive index in the wave guiding layer forms a Bragg grating. In the ON-state, it forms a Bragg grating with a phase shift section. Optical gain is achieved by current injection in the semiconductor active layer. Nonlinearity in the nonlinear layers of the semiconductor grating was achieved by direct absorption at the edge of the absorption band (Urbach tail). Numerical simulation shows that the device switches in a nanosecond time scale.     

Distributed-feedback laser actions in zirconia-ORMOSIL waveguides based on energy transfer between co-doped laser dyes

Laser dyes such as pyrromethene 567 (PM567), perylene red (P-red) and coumarin 540A (C540A) were doped into zirconia-organically modified silicate (ORMOSIL) materials prepared by low temperature sol-gel technique. Narrow line-width distributed feedback (DFB) laser actions were induced in the PM567 and/or P-red doped sol-gel planar waveguide. Tuning of the output wavelength was achieved by varying the period of the gain modulation generated by a nanosecond Nd:YAG laser at 532 nm. Compared with those of PM567 and P-red solely doped thin films, tuning range of C540A, PM567 and P-red co-doped sol-gel planar waveguide was greatly extended, from 564.5 nm to 635.1 nm.     

Frequency stabilization of laser diodes using 1.51-1.55 μm absorption lines of 12C2H2 and 13C2H2

Frequency stabilization of an 1.5 μm distributed feedback laser diode (DFB-LB) is demonstrated using a vibrational-rotational absorption of acetylene ¹²C₂H₂ and ¹³C₂H₂ molecules (VRAM). Frequency stability within 2 MHz peak-to-peak fluctuation can be achieved in the wavelength region of 1.51-1.55 μm. Frequency-stabilized distributed feedback (DFB) laser compact modules have been constructed. When the fiber-pigtail-type acoustic optical modulator was used for small laser frequency scanning, frequency stability within 3 MHz peak-to-peak fluctuation was achieved without any broadening of laser spectral linewidth. In addition, temperature and pressure dependencies of the acetylene absorption lines are characterized.