Optical Saturation Power Research Articles

Effect of heterobarrier leakage on the performance of high-power 1.5 μm InGaAsP multiple-quantum-well lasers

Broad stripe 1.5 μm InGaAsP/InP multiple-quantum-well graded-index separate-confinement heterostructure lasers with different waveguide widths and doping profiles were designed, fabricated, and characterized. A record value of more than 16 W of pulsed optical power was obtained from lasers with a broadened waveguide design. Studies of the characteristics of lasers with different p-doping profiles as well as modeling data show that the heterobarrier electron leakage is responsible for the effect of the device optical power saturation with current.

Waveguide integrated photodiode for analog fiber-optics links

We present the design, fabrication, and characterization of a vertically coupled 1.3-/spl mu/m wavelength waveguide integrated InGaAs photodiode with distributed absorption. This design, by employing an index-matching layer and a thick waveguiding layer, can yield a significant improvement in the optical power saturation, responsivity, and speed in the same device. The 1-dB compression point of the photodiode response at 20 GHz occurs at 10.2-mA continuous-wave photocurrent. Moreover, the same device exhibits a 47-GHz 3-dB bandwidth with a 50-/spl Omega/ microwave probe, and a 0.4-A/W microwave responsivity at 20 GHz without antireflection coating at the input facet. Its two-tone output referenced third-order intercept point is +20.32 dBm at 1 GHz and +5.25 dBm at 18 GHz.

High saturation power 1.3-μm MQW electroabsorption waveguide modulators on GaAs substrates

An analog InGaAs-InAlAs multiple-quantum-well electroabsorption waveguide modulator operating at 1.32-/spl mu/m wavelength has been designed, fabricated, and characterized for the first time on a GaAs substrate. A typical 3-/spl mu/m-wide 115-/spl mu/m-long device exhibits a high optical saturation power in excess of 17 mW and a 3-dB electrical bandwidth of 20 GHz. An equivalent half-wave voltage V/sub /spl pi// of 2.8 V has also been achieved.

Performance of strained InGaAs/InAlAs multiple-quantum-well electroabsorption modulators

The performance of a strained InGaAs/InAlAs multiple-quantum-well (MQW) electroabsorption (EA) modulator was evaluated theoretically and experimentally, The theoretical analysis showed that adding tensile strain to the InGaAs wells widens the wells and reduces the driving voltage; it also showed that adding compressive strain to the InAlAs barriers reduces the band discontinuities and increases the optical saturation power. A fabricated InGaAs/InAlAs MQW modulator with tensile strain in the wells and compressive strain in the barriers had a large modulation bandwidth (f/sub 3 dB/>20 GHz) and a lower driving voltage (V/sub 15 dB/=1.2 V) compared to an unstrained InGaAs/InAlAs MQW modulator, so it had a higher modulation efficiency (17 GHz/V). This strained MQW modulator produced a 10 Gb/s optical signal with a clear eye opening and small chirping (/spl alpha//sub eff/=0.6). Moreover, it had shorter carrier escape times, so it has better optical saturation behavior. Introducing strain thus significantly improves the performance of the MQW-EA modulators.