A 1.3-/spl mu/m wavelength laser with an integrated output power monitor using a directional coupler optical power tap

A 1.3-/spl mu/m Fabry-Perot laser with a directional coupler power tap inside the laser cavity, used for diverting optical power to an integrated waveguide monitoring photodetector is demonstrated. The monitoring detector provides photocurrent which is linear with the front facet output power, with responsivity as high as 0.37 mA/mW, depending on the length of the directional coupler coupling region.     

Fabrication and characteristics of GaP-AlGaP tapered waveguide semiconductor Raman amplifiers

We have fabricated GaP-AlGaP tapered waveguide semiconductor Raman amplifiers, and analyzed the effect of tapering in pulse-pumped high-gain operation. The finesse measurement and 80-ps pulse pumped Raman amplification experiment were performed. Although the tapering has caused additional optical loss, the highest gain of 23 dB has been obtained for a tapered waveguide with input facet of 6.0 /spl mu/m/sup 2/ and back facet of 2.9 /spl mu/m/sup 2/ at averaged input power of 170 mW (peak power 26 W). It is shown that the optical loss of the pump light is more severe than the linear optical loss of the signal light when the gain is higher than 20 dB.     

Multiple-quantum-well GaInAs/GaInAsP tapered broad-area amplifierswith monolithically integrated waveguide lens for high-powerapplications

A 1.48-μm tapered broad-area semiconductor laser amplifier with a monolithically integrated waveguide lens as demonstrated. The gain saturation characteristics of the tapered amplifier were examined. A maximum output power of 300 mW and a 3-dB saturation power of 200 mW under quasi-CW conditions were obtained from the amplifier without the waveguide lens. Output power of 200 mW was obtained with a broad emission spectrum of ~30 nm when the device was used as a superluminescent diode. The amplified output was focused to a single lobe by the monolithically integrated aspheric waveguide lens, which may be useful for efficient coupling of the output into a single-mode fiber     

Highly reliable 200 mW AlGaAs laser diode with fundamental transverse mode

A highly reliable 200 mW AlGaAs laser diode with a fundamental transverse mode has been developed, by optimising its structure with a 0.8 mu m thick p-cladding layer, a 1200 mu m long cavity length, and a front facet coating with a low reflectivity of 2%. The maximum output power was 500 mW, and stable fundamental transverse mode operation was obtained up to 350 mW. Stable operation under 200 mW and 50 degrees C was confirmed for more than 1200 h. Optical feedback noise was below 3*10/sup -14/ Hz/sup -1/.<>     

Operational Properties of Ridge Waveguide Lasers with Laterally Tapered Waveguides for Monolithic Integration

We report on a ridge waveguide laser diode with laterally tapered waveguides fabricated in a single growing step using a double patterning method. In this structure, nearly constant output power is obtained with the change of the lower tapered waveguide width, and the facet power ratio of 1.4 to 1.5 is observed over the current range. The asymmetric facet power property is also investigated.     

Short-cavity distributed Bragg reflector laser with an integrated tapered output waveguide

A distributed Bragg reflector strained-layer multiple-quantum-well laser at 1.5- mu m wavelength with an integrated tapered waveguide beam expander is discussed. The far-field FWHMs in the lateral and vertical directions are 10 and 15 degrees , respectively. A quantum efficiency of 17% out the tapered facet was measured with a corresponding threshold current of 28 mA. The alignment tolerances for coupling into a cleaved single-mode fiber are 9.5 and 7.5 mu m FWHM in the lateral and vertical directions, respectively. A 3-dB improvement for single-mode fiber coupling using a SELFOC lens was obtained.<>     

16 W continuous-wave output power from 100 /spl mu/m-aperture laser with quantum well asymmetric heterostructure

16 W continuous-wave room temperature front facet output optical power and 74% wallplug efficiency were attained in 100 /spl mu/m-aperture 1.06 /spl mu/m-emitting laser diodes with 2-3 mm cavity length. The lasers are based on AlGaAs/GaAs/InGaAs quantum well asymmetric heterostructures with 1.7 /spl mu/m-thick waveguide having 0.34 cm/sup -1/ internal optical loss.     

High-power 0.98 mu m GaInAs strained quantum well lasers for Er/sup 3+/-doped fibre amplifier

High-power GaInAs strained quantum well lasers with an emission wavelength of 0.98 mu m, suitable for Er/sup 3+/-doped fibre amplifier pumping, have been fabricated. A threshold current of 15 mA and a peak output power as high as 85 mW have been obtained for the ridge waveguide structure with AR/HR facet coating. Highly efficient pumping for the 1.536 mu m signals has been confirmed.<>     

GaSb-based tapered diode lasers at 1.93 /spl mu/m with 1.5-W nearly diffraction-limited power

High-power high-brightness 1.93-/spl mu/m wavelength (AlGaIn)(AsSb) tapered diode lasers with a narrow vertical waveguide design are reported for the first time. A nearly diffraction-limited continuous-wave output power of 1.5 W together with a remarkable low fast axis divergence of 43/spl deg/ full-width at half-maximum have been demonstrated. The maximum brightness amounts to 32 MW/cm/sup 2/sr.     

Dependence of output properties on ridge structures and asymmetricfacet reflectivity in 0.98-μm InGaAs-InGaAsP-InGaP SQW FP-LDs

The dependence of output performances on the waveguide structures and the facet reflectivity of 0.98-μm Al-free InGaAs-InGaAsP-InGaP ridge waveguide single-quantum-well Fabry-Perot laser diodes are investigated theoretically and experimentally. In our analysis, lateral and longitudinal spatial hole-burning, carrier-density-dependent optical loss in the well, and gain saturation are considered simultaneously. Permissible ranges of the ridge width, the InGaP cladding thickness, and the front facet reflectivity are presented in conjunction with the desired performance parameters such as maximum kink-free output power, beam divergence, and peak light density at the front facet     

Continuous-wave operation of GaInAsSb-GaSb type-II ridge waveguide lasers emitting at 2.8 /spl mu/m

We have realized compressively strained GaInAsSb-GaSb type-II double quantum-well lasers with an emission wavelength of 2.8 /spl mu/m. Using broad area devices, an internal absorption of 9.8 cm/sup -1/ and an internal quantum efficiency of 0.57 is determined. For the increase of the threshold current with temperature, a T/sub 0/ of 44 K is obtained. Narrow ridge waveguide lasers show continuous-wave laser operation at temperatures up to 45 /spl deg/C, with room-temperature (RT) threshold current of 37 mA. At RT, the maximum optical output power per facet of an uncoated 800/spl times/7 /spl mu/m/sup 2/ ridge waveguide laser exceeds 8 mW.     

Fabrication of Butt‐Coupled SGDBR Laser Integrated with Semiconductor Optical Amplifier Having a Lateral Tapered Waveguide

We have demonstrated a high‐power widely tunable sampled grating distributed Bragg reflector (SGDBR) laser integrated monolithically with a semiconductor optical amplifier (SOA) having a lateral tapered waveguide, which is the first to emit a fiber‐coupled output power of more than 10 dBm using a planar buried heterostructure (PBH). The output facet reflectivity of the integrated SOA using a lateral tapered waveguide and two‐layer AR coating of TiO₂ and SiO₂ was lower than 3 × 10^?4 over a wide bandwidth of 85 nm. The spectra of 40 channels spaced by 50 GHz within the tuning range of 33 nm were obtained by a precise control of SG and phase control currents. A side‐mode suppression ratio of more than 35 dB was obtained in the whole tuning range. Fiber‐coupled output power of more than 11 dBm and an output power variation of less than 1 dB were obtained for the whole tuning range.     

WDM-PON module using a planar lightwave circuit with a coated WDM filter

We have presented a new configuration of a planar lightwave circuit (PLC) module coated directly with a filter which divides 1310/1550-nm wavelength bands for a wavelength-division-multiplexing passive optical network module in order to improve the conventional insertion process of thin film filter into the narrow trench located at the Y-junction of a PLC platform. The broadly tapered output facet width of a V-shaped waveguide was designed to be 12 /spl mu/m to minimize the reflected loss. The receiver module integrated with a PIN-photodiode on a silicon optical bench was fabricated. Data transmission of 2.5-Gb/s was demonstrated with clear eye diagrams.     

腔面反射率对超辐射发光二极管输出特性的影响

本文用耦合速率方程,从理论上分析研究了超辐射发光二极管(SLD)的功率输出特性。主要讨论了腔面反射率对其功率输出特性的影响。研究结果表明,半导体激光器(LD)存在一最佳输出功率腔面反射率,随腔面反射率的降低,SLD的功率曲线斜率减小,输出功率降低,光谱调制深度减小。增大后腔面反射率可以提高SLD的输出功率,减小其工作电流。由于腔面反射率的降低,前后传输的光子在有源区内的分布的对称性发生了变化,表现为非均匀性,后向传输波大于前向传输波。最后,把理论计算结果同我们研制的1.3μm徐层结构超辐射发光二极管的实验结果作了比较,得到了较好符合。     

Low-threshold distributed reflector laser consisting of wide and narrow wirelike active regions

We demonstrate a low-threshold distributed reflector laser, consisting of a distributed feedback section with wirelike active regions and a passive distributed Bragg reflector section with narrower ones, by utilizing the lateral quantum confinement effect. A threshold current under the room-temperature continuous-wave condition as low as 3.2 mA, which corresponds to a threshold current density of 290 A/cm/sup 2/, was obtained with the stripe width of 4.3 /spl mu/m and the active region length of 260 /spl mu/m. The differential quantum efficiency of 19% from the front facet, a high output ratio of 11 from the front facet to the rear facet, and a submode suppression ratio of 47 dB at a bias current 3.75 times the threshold were also achieved.     

High-power output over 200 mW of 1.3 µm GaInAsP VIPS lasers

Maximum CW output power was investigated in GaInAsP 1.3μm V-grooved inner stripe on P-substrate (VIPS) lasers considering both cavity length and facet reflectivity. Long-cavity lasers show a strong dependence of maximum output power on front reflectivity. A CW light output over 200 mW was obtained at room temperature using a 700 μm long cavity laser with 5 and 98 percent reflectivity of the front and rear facets, respectively. The fundamental transverse mode operation was confirmed up to 170 mW. A coupled power over 110 mW into a single-mode fiber was achieved with a coupling efficiency of 58 percent. We have verified the high reliability under high power levels, as high as 75 percent of the maximum CW output powers at room temperature.     

High-Performance 1.55-$mu$ m Superluminescent Diode With Butt-Coupled Spot-Size Converter

We report the design and fabrication of a novel 1.55-m spot-size converter superluminescent diode (SLD) for optical access networks. The active section of SLD was fabricated by using a planar buried heterostructure to adopt the double-waveguide-core structure for low-threshold and high-output power operation at a low injection current. A ridge-based passive waveguide was employed for an efficient coupling to a planar lightwave circuit. The threshold current was as low as 14 mA, and the maximum output power was as high as 28 mW with ripple less than 3 dB at an injection current of 200 mA.     

A simple laterally tapered waveguide for low-loss coupling tosingle-mode fibers

Low-loss coupling between semiconductor photonic devices and single-mode fibers is achieved using a simple InP/InGaAsP tapered waveguide. The proposed simple structure has a small and nearly square guiding core at its output facet. In this structure, the output field has a non-Gaussian profile, but low-pass filter coupling can be achieved by optimizing the design of the guiding core sizes. The waveguide is composed of a laterally tapered InGaAsP guiding layer and an InP cladding region on an InP substrate, facilitating integration of the waveguide with active devices using conventional processes. The waveguide is shown to have a total insertion loss of 2.6 dB, including a coupling loss of 0.9 dB and large ±2.5-μm misalignment tolerance in lateral and vertical directions with single-mode filters     

电极分离的980nm锥形激光器的研制

对脊形波导区和锥形区电极分离的980nm锥形激光器(简称电极分离的980nm锥形激光器)改变脊形波导区所加电流,测试激光器的P-I特性和光束质量因子,与脊形波导区和锥形区共用电极的980nm锥形激光器(简称电极共用的980nm锥形激光器)的测量参数进行对比.发现电极分离的980nm锥形激光器的P-I特性曲线比较光滑,没有明显的扭折.随着脊形波导区的电流逐渐超过150mA以后,器件的最大输出功率逐渐达到4.28W,与电极共用的980nm锥形激光器相同并趋于饱和,光束质量因子从3.79降到2.45(输出功率为1W).     

Wavelength stabilized single-mode lasers by coupled micro-square resonators

Wavelength stabilized single-mode lasers were realized by on-chip coupling of a ridge waveguide laser with two micro-ring resonators. The micro-ring resonators were fabricated by deeply etching to achieve high lateral optical confinement and to allow small ring diameters in the range between 20-60 /spl mu/m. A square-like ring geometry with 45/spl deg/ facets was used to improve design control and side-wall quality. By using micro rings with two different diameters of 50 and 60 /spl mu/m, a free spectral range of about 18 nm could be obtained which allow a stable single-mode operation with a side-mode suppression ratio of more than 40 dB and a continuous-wave output power of 30 mW per facet at room temperature.