Optical frequency conversion device with asymmetric κ-DBRstructure

An optical-frequency conversion device is fabricated, using monolithically integrated distributed Bragg reflector (DBR) mirrors with different coupling coefficients at the outer sides of the active and the saturable absorber regions. The input-end DBR mirror has a higher coupling coefficient than that of the output-end DBR mirror. The converted light is reflected by the input-end DBR mirror and is emitted only from the output end of the device. This device successfully performs optical frequency conversion when the input TM-polarized light has a wavelength within the wavelength range for which the reflection of the input-end DBR mirror is fairly high for TE-polarized light. The ratio of the converted-light output power for TE-polarized light from the input end to that from the output end is less than -30 dB     

Analysis of wavelength conversion using a multisection DBR laserwith a saturable absorber

The static performance of a wavelength converter obtained by a multisection distributed Bragg reflector (DBR) laser with a saturable absorber between two gain sections is analyzed. For this device an optical input signal at one given wavelength is converted into an output signal at the lasing wavelength. The performances are evaluated in terms of conversion efficiency, suppression ratio, and minimum input power needed for wavelength conversion. It is shown that a proper choice of the injected signal wavelength with respect to the lasing wavelength enhances the conversion efficiency and the suppression ratio and reduces the switching power. The performance can be enhanced also by increasing the electrical current applied to the first gain section provided that the second gain section is biased above the transparency level. The authors have shown that reduction of the front facet reflectivity results in a dramatic increase for the conversion efficiency. The sensitivity to the electrical bias condition and to the resonant condition of the injected signal with respect to the cavity has also been investigated     

High-speed signal wavelength conversion using aunidirectional-output wavelength conversion device withasymmetric-κ DBR structure

The wavelength conversion device whose frequency response is evaluated analytically and experimentally in this work has a saturable absorber region, which acts as an optical gate, within the active region. The 3-dB bandwidth of this device was measured to be 800 MHz and found to be limited by the frequency response of the saturable absorber region. To speed up this device, the electrodes of the saturable absorber and the gain regions were connected electrically so that the device would act as a unidirectional-output distributed Bragg reflector (DBR) laser. When the active region (saturable absorber and the gain regions) of this DBR laser were biased above threshold condition, the 3-dB bandwidth was more than 10 GHz, and clear eye patterns were observed when the input TM-polarized light intensity was modulated by a 10-Gbit/s pseudo-random NRZ signal. These results show that high-speed wavelength conversion can be achieved when the device is operated as a laser diode     

基于LOA的XGM全光波长转换消光比特性的研究

建立了线性光放大器(LOA)的交叉增益调制(XGM)波长转换理论模型.着重讨论了抽运光与探测光的波长和功率、LOA中分布式布拉格反射镜(DBR)的反射率和注入电流等参量对输出消光比特性的影响.结果表明,输出消光比随着抽运光(探测光)波长的增加而增加(减小);适当的减小探测光功率和选择合适的注入电流可以获得较大的消光比;波长向下转换时的消光比明显优于向上转换时的消光比;同样,提高LOA中DBR的反射率,也可以获得较高的消光比.     

Frequency stabilization of tunable DBR laser using multiwavelengthlight injection locking technique

This paper proposes a frequency stabilization scheme for tunable three-section DBR laser diodes (3S-DBR LD) that use multiwavelength light injection locking. The oscillating wavelength of the SS-DBR LD is discretely switched between cavity modes when the injection current into DBR section is changed, and locked to one wavelength of the multiwavelength light injected from the DBR section facet under the injection locking condition. The light injection properties of the capture range and the relationships of relaxation oscillation versus input power and detuning are investigated experimentally. Injection locking on the multistate wavelength of a tunable DBR LD is performed using a two wavelength multiplexed light. As a result, we demonstrate 1 GHz capture range and more than 26 dB rejection ratio for the multiplexed injected light     

Wavelength conversion for frequency-modulated light using opticalmodulation to oscillation frequency of a DFB laser diode

A technique for wavelength conversion for frequency-modulated (FM) light is described. It utilizes the light-injection-induced frequency shift of a distributed-feedback (DFB) laser diode and the frequency-modulated-to-intensity-modulated (FM-IM) conversion function of the Mach-Zehnder (M-Z) optical filter. Input FM light is converted into IM light by the M-Z filter. The IM light is injected into the DFB-LD oscillating at another wavelength, modulating its oscillation frequency. The output from the DFB-LD has an FM signal identical to the input FM light. Thus, wavelength conversion for FM light is achieved. The characteristics of the frequency shift induced by this optical injection were experimentally studied using a λ/4 phase-shift DFB-LD. A wavelength conversion experiment was performed. In the experimental demonstration, FM light at 1.534 μm was converted into FM light at 1.550 μm     

The Y-laser: a multifunctional device for optical communicationsystems and switching networks

This paper gives a comprehensive review of the recent progress obtained with various operation modes of a Y-shaped all active waveguide device with three optical input/output ports, the so called Y-laser. Used as a monolithic semiconductor light source, single-mode emission with an extremely large cw tuning range of more than 50 nm is accessed. Single current step tuning spans up to 8-nm range. Several-GHz bandwidth AM and FM response is achieved. Operation as a wavelength processing device is demonstrated with data-stream transformation from short wavelength fiber windows (around 780 nm or 1310 nm) to the long wavelength window (1550 nm), as well as with ultra wide range wavelength conversion within the 1550-nm region, across +/-20 nm (blue and red shift). Optical high-speed space switching/gating functions are verified up to 1 Gb/s, and packet switching of 5-Gb/s data streams is demonstrated. Further features as a pulse reshaping device, as an electrically triggerable wavelength bistable device and as a mode locked pulse generator are addressed. Possible applications of this multifunctional device in future optical communication systems and switching networks are discussed     

Repeated wavelength conversion of 10 Gbit/s signal usingwavelength-tunable semiconductor lasers

Repeated wavelength conversion of 10 Gbit/s pseudorandom non-return-to-zero signals is demonstrated using superstructure grating distributed Bragg reflector lasers operating in the 1.55-μm wavelength region. Error-free and very low-power-penalty wavelength conversion can be achieved in both first and second wavelength conversion for a fixed converted wavelength over a broad wavelength range from 1.486 to 1.573 μm (about 90-nm wide). The power penalty of the transmitted signal light through the first wavelength conversion device increases when the converted wavelength is switched from 1.544 to 1.573 μm periodically at a repetition frequency of 40 MHz. The increase in power penalty, however, is less than 6 dB even when the bit error rate is 10^-12     

Wavelength conversion for FM light using light injection induced frequency shift in DFB-LD

A novel wavelength conversion is described. Wavelength conversion of frequency-modulated (FM) light is achieved by combining the lasing frequency shift induced by external light in a DFB-LD and the FM-IM conversion function of a Mach-Zehnder optical filter. In the experiment, 1534 nm FM light is converted to 1550 nm light.<>     

基于光纤光栅外腔半导体激光器增益饱和效应的全光波长转换实验研究

对基于光纤光栅外腔半导体激光器增益饱和效应的全光波长转换器的静态与动态特性进行了实验研究。为消除反馈光与转换信号输出光对光源的不利影响及提高光输入、输出信号耦合效率 ,提出了采用环形器进行信号耦合的光学结构。实验结果表明 ,转换器件具有高于 30nm的波长转换间隔 ,并可实现波长上、下转换。进行了15 5Mbit/s伪随机码调制信号的动态波长转换实验。     

Monolithic integration of widely tunable sampled grating DBR laser with tilted semiconductor optical amplifier

High output powers and wide range tuning have been achieved in a sampled grating distributed Bragg reflector laser with an integrated semiconductor optical amplifier. Tilted amplifier and anti-reflection facet coating are used to suppress reflection. We have demonstrated sampled grating DBR laser with a tuning range over 38 nm, good wavelength coverage and peak output powers of more than 9 mW for all wavelengths.     

Wavelength conversion based on nonlinear polarization rotation in gain transparent SOA

We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier(GT-SOA) which brings in the assistant light to improve the property of the converted light.From the SOA carrier density equations,the 1310 nm-to-1550 nm wavelength conversion scheme is analyzed by the Jones matrix.The phase shift between TE and TM modes and the converted light are simulated at bit rate of 30 Gbit/s.We also analyze the influence of the input signal power,the injected current and the assistant light power on the extinction ratio of the converted light.     

单片集成倾斜SOA的宽可调谐取样光栅分布布拉格反射激光器

高功率和宽调谐范围的单片集成倾斜SOA的宽可调谐取样光栅分布布拉格反射激光器被成功制备。倾斜的SOA结构和端面增透膜有效的降低了端面的反射率。器件调谐范围大于38nm,波长覆盖较好,调谐范围内波长输出功率均大于9mW。     

宽反射角DBR红光发光二极管

对用于提高AlGaInP红光发光二极管出光效率的传统DBR进行了分析,用MOCVD生长了包含对垂直入射光反射的DBR和对斜入射光反射的DBR复合在一起的红光LED,在20 mA注入电流下,LED的峰值波长为630 nm,轴向光强达到137 mcd,输出光功率为2.32 mW.与常规的LED相比,光强和输出光功率有很大的提高.     

Repeated wavelength conversion of 10 Gb/s signals and convertedsignal gating using wavelength-tunable semiconductor lasers

Repeated wavelength conversion of 10 Gb/s pseudorandom nonreturn-to-zero signals is demonstrated using semiconductor lasers that can be tuned wavelength over a broad range. Error-free tunable wavelength conversion with a very low power penalty can be achieved in both first and second wavelength conversion over a broad wavelength range from 1.486-1.573 μm. The converted signal can be switched rapidly within this wavelength region. High-speed converted signal gating controlled by adjusting the bias current to the device active region is also demonstrated     

A tunable wavelength-conversion laser

A wavelength-conversion laser was fabricated using monolithic integration of a bistable laser diode and a wavelength-tunable distributed Bragg reflector (DBR) laser. This device converts an input light signal with a certain wavelength to output light with a tunable wavelength over 3.5 nm. Input power required for switching is investigated, and its resonant dependence on input wavelength is revealed. Input polarization is also discussed, and suppression of crosstalk is demonstrated. This device's turn-off switching response is greatly influenced by the light power of the input signal as well as bias current, and the first 1 Gb/s operation is achieved in optimum conditions for fast turn-off and stable turn-on     

Semiconductor optical amplifier for wavelength conversion in subcarrier multiplexed systems

The fabrication and performance of a InGaAsP-InP semiconductor optical amplifier for wavelength conversion in subcarrier multiplexed system is described. The amplifier is of the buried facet design and has polarization and reflectivity gain ripple of less than 1 dB. Using subcarrier multiplexing, multiple 50-Mb/s data streams at a wavelength of 1.553 /spl mu/m are infected into the amplifier. The gain nonlinearity of the amplifier transfers the data to a different wavelength of light simultaneously injected into the amplifier. Error free retrieval of subcarrier multiplexed data has been demonstrated for the wavelength converted output. The small signal bandwidth of the wavelength conversion process is 5 GHz. Calculation suggests that higher bandwidth is feasible at higher input powers at the expense of lower modulation transfer during wavelength conversion.     

Y-Branch Surface-Etched Distributed Bragg Reflector Lasers at 850 nm for Optical Heterodyning

This letter presents a monolithically integrated dual-wavelength source at 850 nm suitable for use in optical heterodyning. The device consists of two surface-etched distributed Bragg reflector (DBR) lasers, a Y-branch coupler, and a curved waveguide outcoupler. The Y-branch coupler and curved outcoupler are fabricated with the same epitaxial material as the DBR lasers, enabling operation as a semiconductor optical amplifier. The spectral characteristics and frequency stability of the two wavelength lasers are reported.     

Wavelength Conversion Based on Copolarized Pumps Generated by Optical Carrier Suppression

Polarization-insensitive wavelength conversion based on four-wave mixing for 112-Gb/s polarization- multiplexed return-to-zero quadrature phase-shift keying signals (PolMux-RZ-QPSK) with digital coherent detection is experimentally demonstrated. The dual-pumps always have the same polarization direction and fixed frequency spacing because they are generated by the optical carrier suppression technique. The conversion efficiency at different pumping powers and signal wavelengths has also been investigated. A tuning range of a signal wavelength of wider than 18 nm is realized with the same conversion efficiency in this proposed architecture. There is no obvious optical signal-to-noise ratio penalty for the converted 112-Gb/s PolMux-RZ-QPSK signals.      

低频移拉曼模式多阶级联的1.7 μm激光器

基于固体介质的拉曼频率变换是产生新波段激光的有效技术方案。利用1572 nm KTP光参量振荡器腔内泵浦KGW晶体,实现了1616 nm （2阶）、1638 nm （3阶）、1662 nm （4阶）、1686 nm （5阶）、1711 nm （6阶）拉曼激光输出,其中1711 nm占据主导地位。激光器最大总平均输出功率为1.13 W,最小脉冲宽度为20 ns。该多阶级联拉曼变频对应的单阶平均拉曼频移为86 cm?1,与文献报道的KGW晶体低频拉曼模式相吻合。采用1572 nm KTP光参量振荡器作为拉曼激光器的腔内泵浦源有两个优势,一方面可以有效拓展拉曼变频的输出波长,另一方面可以基于光参量振荡器的脉冲窄化特性为后续多阶拉曼转换提供高强度的泵浦光。通过引入多阶级联拉曼变频的方案,为有效利用固体介质非常规低频移拉曼模式提供了新思路。