1.3-μm continuous-wave lasing operation in GaInNAs quantum-welllasers

A 1.3-μm continuous wave lasing operation is demonstrated, for the first time, in a GaInNAs quantum-well laser at room temperature. This lasing performance is achieved by increasing the nitrogen content (up to 1%) in GaInNAs quantum layer. It is thus confirmed that this type of laser is suitable for use as a light source for optical fiber communications     

GaInNAs-GaAs long-wavelength vertical-cavity surface-emitting laserdiodes

Vertical-cavity surface-emitting laser diodes with GaInNAs-GaAs quantum-well (QW) active layers are demonstrated for the first time. GaInNAs permits the realization of a long-wavelength vertical-cavity laser grown directly on a GaAs substrate. Room-temperature (RT) pulsed operation is achieved, with an active wavelength near 1.18 μm, threshold current density of 3.1 kA/cm², slope efficiency of ~0.04 W/A, and output power above 5 mW for 45-μm-diameter devices. Laser oscillation is observed for temperatures at high as 95°C     

Highly reliable operation of strain-compensated 0.98 μmInGaAs/lnGaP/GaAs lasers with InGaAsP strained barriers for EDFAs

Highly reliable operation of 0.98 μm strain-compensated InGaAs/ InGaAsP lasers is demonstrated for the first time with an estimated lifetime of 170 kh at 25°C. Moreover, we reveal that the degradation rates at 90°C and 80 mW output power are four times smaller than those of identical lasers with GaAs barriers     

Low threshold, room temperature pulsed operation of 1.5 μmvertical-cavity surface-emitting lasers with an optimized multi-quantumwell active layer

Room temperature, pulsed operation of 1.5 μm vertical-cavity surface-emitting laser is demonstrated by the optimization of an InGaAs/InGaAsP multi-quantum well active layer, especially the number of quantum wells and the barrier thickness considering matched gain effect. Low threshold currents of 17 mA in 5×7 μm²-devices and 25 mA in 7×10 μm²-devices were achieved     

High-extinction-ratio MQW electroabsorption-modulator integratedDFB laser fabricated by in-plane bandgap energy control technique

The local bandgap energy of an InGaAs/InGaAsP multiple quantum well (MQW) structure was precisely adjusted by in-plane Eg control in one-step selective area metalorganic chemical vapor deposition (MOCVD) growth. The technique was then applied to an MQW electroabsorption-modulator integrated distributed feedback (DFB) laser. Experimental results showed superior device characteristics, such as a high extinction ratio of 25 dB and low threshold current of 15 mA     

Reduced turn-on delay time in 1.3 μm InGaAsP/lnP n-typemodulation-doped strained multiquantum well lasers

Reductions in carrier lifetime, threshold current, and thus turn-on delay time, due to n-type modulation doping, have been experimentally demonstrated in 1.3 μm InGaAsP strained multiquantum well lasers for the first time     

Ultralow chirp and high-speed 1.55 μm multiquantum wellλ/4-shifted DFB lasers

An ultra-low-chirp, high-speed, 1.55-μm, multi-quantum-well (MQW), λ/4-shifted, InGaAsP distributed-feedback (DFB) laser is demonstrated. A record chirp width of 0.4-0.5 nm (20-dB down full width) is achieved at 10-Gb/s direct modulation. This low-chirp single-longitudinal-mode operation is attained by an increase in the quantum size effect in the MQW active layer     

Intrinsic modulation bandwidth in ultra-high-speed 1.3 and 1.55 mu m GaInAsP DFB lasers

By using an ultra-low capacitance structure, the wavelength dependence, 1.3 or 1.55 mu m, of the intrinsic modulation bandwidth relating to the relaxation oscillation frequency and the nonlinear damping in GaInAsP DFB lasers is investigated.<>     

10 Gbit/s, 100 km nonrepeatered fibre transmission experiment using a high-sensitivity semiconductor optical preamplifier

10 Gbit/s, 100 km nonrepeated fibre transmission has been demonstrated using a high-sensitivity receiver with two-stage cascade-connected semiconductor optical amplifiers and a pin PD front end. The sensitivity and its improvement were -23.5 dBm and 12.2 dB respectively, resulting in the allowable span-loss of 24.5 dB.<>     

Alternate-mark-inversion optical continuous phase FSK heterodynetransmission using delay-line demodulation

Alternate-mark-inversion (AMI) optical continuous phase (CP) frequency-shift keying (FSK) heterodyne transmission using delay-line demodulation which has a higher receiver sensitivity compared to the transmission using single-filter demodulation has been achieved. Since the proposed delay-line demodulation method directly converts the received AMI-CPFSK signal into the nonreturn to zero (NRZ) baseband signal without the use of an AMI decoder, a heterodyne receiver with the same configuration as the conventional CPFSK transmission system is realized, even though AMI line coding is applied to the system. Transmission experiments at 622 Mb/s have been demonstrated for both pseudorandom 2⁷-1 and 2²³-1-b patterns at the same receiver sensitivity of -41.1 dBm (the PD input power)