High output power GaInAsP/InP superluminescent diode at 1.3 μm

The authors have developed a 1.3 μm superluminescent diode using a revolutionary structure. A light diffusion surface is placed diagonally on the active layer within the device to suppress the lasing action. Superluminescent diode characteristics were achieved in the range 0-50°C, and the coupled power into a single-mode fibre reached 1 mW     

1.3 μm fluoride fibre laser

Laser action has been achieved in the 1.33-1.34 μm range using an Nd³⁺-doped fluorozirconate glass multimode fibre. These operating wavelengths are the closest to the important telecommunications channel at 1.3 μm of any reported for a glass laser     

1.3 mu m semiconductor laser power amplifier

The performance of a 3.4-Gb/s system using a low-power 1.318- mu m distributed-feedback (DFB) laser transmitter and a traveling-wave semiconductor laser power amplifier is studied. The -14.5-dBm, input from a directly modulated DFB laser is boosted to +10.3 dBm, of which +4.8 dBm is coupled into the transmission fiber. The penalty, caused by amplifier noise and pattern effects due to gain saturation, is less than 0.5 dB.<>     

Very large bandwidth strained MQW DFB laser at 1.3 μm

A 3-dB bandwidth of 20 GHz has been demonstrated for a compressively strained multiquantum well InGaAsP-InP DPB laser operating at 1.3 μm. The laser displayed superior static performance including very low threshold current (~8 mA), high external quantum efficiency (0.44 mW/mA), high CW output power (>60 mW) and high temperature operation     

High reliability low-threshold InGaAsP ridge waveguide lasersemitting at 1.3 μm

The fabrication, performance, and reliability of InP/InGaAsP ridge waveguide lasers emitting at 1.3 μm is described. The structure requires only one stage of planar wafer growth and simple fabrication steps and is therefore an inherently low-cost product. Threshold currents are typically 25-30 mA, and the external quantum efficiency is 20-25% per facet. Output power in the fundamental mode is maintained to above 10 mW, while total power in excess of 100-mW CW at 20° has been obtained. The life test data have been fitted to a power-law drift model to predict long-term behavior and is consistent with total lifetimes in excess of 25 years. The device is eminently suited for applications in high-reliability high-capacity fiber-optic communications systems     

Vertical-cavity amplifying modulator at 1.3 μm

The modulation/switching properties of a vertical-cavity semiconductor optical amplifier operating at 1.3 μm wavelength are investigated. The device was optically pumped and operated in reflection mode. A 150-mV (100 mA) modulation of the drive to the pump source produced a 7-dB modulation of the pump power, which produced a 35-dB modulation in the output signal. The maximum extinction ratio was 35 dB, and limited by device heating. Frequency response measurements revealed a modulation bandwidth of 1.8 GHz when the amplifier was saturated. This enabled 2.5-Gb/s modulation of a -10 dBm input signal with 5.5-dB fiber-to-fiber gain     

High speed III-V electrooptic waveguide modulators at λ-1.3μm

Traveling wave GaAs electrooptic waveguide modulators at a wavelength of 1.3 μm with bandwidth in excess of 20 GHz have been developed and characterized. The design and characteristics of both p-i-n modulators in microstrip configuration and Schottky barrier on n ^--GaAs/semi-insulating (SI) GaAs in the coplanar strip configuration modulators are discussed. It is shown that microwave loss and slowing on n⁺ GaAs substrates will limit the bandwidth of the microstrip modulator to less than 10 GHz for a device 8 mm in length. Modulators with bandwidths in excess of 10 GHz are fabricated on SI GaAs substrates     

1.3 μm beam-expander integrated laser grown by single-step MOVPE

A new structure for a 1.3 μm-wave length beam-expander integrated ridge-waveguide laser is demonstrated that does not require a regrowth step. A narrow beam divergence of 5.4° (lateral) and 18.9° (vertical) enables a laser diode to be coupled to a cleaved singlemode fibre with an efficiency as high as 33% with a 1 dB alignment tolerance of ±2.4 μm laterally and +1.5 μm vertically     

Tensile-strained GaInAsP-InP quantum-well lasers emitting at 1.3μm

Tensile-strained GaInAsP-InP quantum-well (QW) lasers emitting at 1.3 μm are investigated. Low-pressure metalorganic chemical vapor deposition (LP-MOCVD) is used for crystal growth. High-resolution X-ray diffraction shows good agreement with theoretical simulation, photoluminescence spectra have good energy separation between light-hole and heavy-hole bands due to biaxial tension. The lowest threshold current density for infinite cavity length J_th/N_w ^∞ of 100 A/cm² is obtained for the device with -1.15% strain and N_w=3. The amount of strain which gives the lowest J_th/N_w^∞ experimentally clarified is around -1.2%. Threshold current of a buried-heterostructure (BH) laser is reduced to be as low as 1.0 mA. Enhanced differential gain of 7.1×10^-16 cm² is also confirmed by measurements of relative intensity noise. Much improved threshold characteristic with the feasibility of submilliamp threshold current can be achievable by optimizing the BH structure. The tensile-strained QW laser emitting at 1.3 μm with very low power consumption is attractive for the light source of fiber in the loop system and optical interconnection applications     

A linearized optical directional-coupler modulator at 1.3 μm

We investigate electrooptic directional-coupler modulators operating at the wavelength of 1.3 μm, to have high linearity in their response function. The inverse Fourier transform technique was used to synthesize the spatially varying coupling function from a specified response function. The resulting coupling function was then used to determine the shape of the modulator structure. Modulators to have the response function of the form of a triangular (“linear”) function have been designed, fabricated, and tested. The third-order intermodulation-limited spurious-free dynamic range, at -130-dBm normalized noise floor, of 96.2 dB/Hz^2/3 was obtained     

1.3 μm GaSb metal-semiconductor-metal photodetectors

Metal-semiconductor-metal photodetectors employing GaSb active regions and Al_0.5Ga_0.5Sb barrier-enhancing abrupt regions have been fabricated on InP substrates to assess the role of hole velocity and to compare with similar photodetectors made using Ga _0.47In_0.53As active region. Devices exhibit photoresponse in the 0.2-0.65 A/W range, dark currents of ≈10^-6 A at 300 K and ≈10^-10 A at 77K for 25×25 μm² area, and have a voltage-sensitive 3-dB bandwidth exceeding ≈1 GHz at 300 K and 10 GHz at 77 K. The enhanced barrier heights are estimated to be ≈0.30 eV. The fall time continues to be the significant component of time delay; its temperature dependence indicates that the hole velocities do improve significantly at lower temperatures. The 300 K behavior appears to be dominated by defect and impurity densities, and the effects of abrupt barriers. The larger than expected dark currents are believed to result from defects associated with lattice mismatch     

1.3μm行波式半导体激光放大器

利用多级尝试法对主动监控法进行优化,获得了两端面剩余模式反射率几何平均值小于3×10-4的行波式半导体激光放大器,并在1.3μm波段获得了20dB的信号增益。     

External-cavity semiconductor laser tunable from 1.3 to 1.54 μmfor optical communication

Using semiconductor optical amplifiers with properly designed nonidentical quantum wells made of InGaAsP-InP materials in the external-cavity configuration, the semiconductor laser is broadly tunable. The tuning range covers from 1.3 μm to 1.54 μm. Without additional filtering techniques, the laser beam emitted from the linear external cavity has the sidemode suppression ratio better than 30 dB. Also, the power ratio of the lasing mode to the total output power is 90%-99%, indicating the dominance of the lasing mode in the amplification process due to the broad gain spectrum     

Long-haul soliton transmission at 1.3 μm using distributed Ramanamplification

10 Gb/s single channel soliton transmission over more than 10000 km in a standard communication fiber with distributed Raman amplification has been demonstrated in a recirculating fiber loop setup. It has been found that the Gordon-Haus timing jitter becomes the main limiting factor, provided that the generation of dispersive waves due to polarization mode dispersion has been minimized by adjusting the polarization state of the signal     

Active mode-locking of 1.3 μm extended-cavity silicon chip Braggreflector laser

The authors report active mode-locking of an extended-cavity silicon chip Bragg reflector laser. Pulses of 27 ps duration at repetition rates up to 7 GHz, have been achieved with a controllable narrow optical spectrum     

Slab-coupled 1.3-μm semiconductor laser with single-spatiallarge-diameter mode

A high brightness semiconductor diode laser structure, which utilizes a slab-coupled optical waveguide region to achieve several potentially important advances in performance, is proposed and experimentally demonstrated using a simple rib waveguide in an InGaAsP-InP quantum-well structure operating at 1.3-μm wavelength. These lasers operate in a large low-aspect-ratio lowest-order spatial mode, which can be butt coupled to a single-mode fiber with high coupling efficiency     

Tunable absolute-frequency laser at 1.5 μm

Frequency stabilisation of a two-frequency diode-pumped Er,Yb:glass laser is demonstrated using Doppler-broadened or saturated-absorption lines of ¹³C₂H₂. Continuous tunability in the 1530-1550 nm range is obtained. Beat note measurements lead to a frequency accuracy better than 10 kHz for a 10s response time     

Novel design of AlGaInAs-InP lasers operating at 1.3 μm

A novel design of AlGaInAs-InP lasers operating at 1.3 μm is proposed. A distinctive attribute of the proposed design is that the AlInGaAs active region is surrounded by an AlInAs electron stopper layer on the p-side and an InP hole stopper layer on the n-side. The stopper layers do not impede the carrier injection into the active region and at the same time reduce the thermionic emission of carriers out of the active region. Utilization of stopper layers allows one to increase the value of internal quantum efficiency and to select the waveguide material corresponding to the optimum optical confinement factor value     

Dynamic behaviors of semiconductor lasers under strong sinusoidalcurrent modulation: modeling and experiments at 1.3 μm

The theoretical analysis is based on rate equations including gain-compression effects. General criteria are established to predict the existence of irregular behaviors. Experiments are performed on a single-mode buried-heterostructure InGaAsP laser at 1.3 μm. An original method is proposed to evaluate the parameters of the rate equations. Fully optical measurements are used. The nonlinear gain coefficient and the electrical response of the packaged laser are simultaneously determined from small-signal characteristics. Time-domain measurements show the three behaviors achieved with the laser, i.e., simple periodic, periodic with multiple spikes, and periodic doubling. Excellent agreement is found between experiments and calculations. Frequency-domain measurements are focused on distortions in periodic regimes. A quantitative limit of perturbation theories is given which corresponds to a second-order harmonic level exceeding -15 dB     

Spot-size converted 1.3 μm laser with butt-jointed selectivelygrown vertically tapered waveguide

A 1.3 μm laser has been developed with a butt-jointed selectively grown spot-sire converter (SSC). The SSC vertically tapered waveguide and strained multiquantum well (MQW) active region are independently optimised. The laser was buried with semi-insulating InP to reduce optical loss in the SSC. A threshold current of 7 mA and an output power of >20 mW were obtained. Minimum coupling loss to a flat-end fibre of 1.06 dB was achieved. Long-term stability was also confirmed