Ville Vilokkinen

Effects of Lateral Diffusion on the Temperature Sensitivity of the Threshold Current for 1.3-

We present an experimental and theoretical investigation of the temperature dependence of the threshold current for double quantum well GaInNAs-GaAs lasers in the temperature range 10 degC-110 degC. Pulsed measurements of the threshold current have been performed on broad and narrow ridge wave guide (RWG) lasers. The narrow RWG lasers exhibit high characteristic temperatures (T0) of 200 K up to a critical temperature (Tc), above which T0 is reduced by approximately a factor of 2. The T0-values for broad RWG lasers are significantly lower than those for the narrow RWG lasers, with characteristic temperatures on the order of 100 (60) K below (above) Tc. Numerical simulations, using a model that accounts for lateral diffusion effects, show good agreement with experimental data and reveal that a weakly temperature dependent lateral diffusion current dominates the threshold current for narrow RWG lasers.

\mu{\hbox {m}}

State-of-the-art modulation bandwidths are presented for multiquantum well resonant cavity light emitting diodes (RCLEDs) emitting at 650 nm. 84-/spl mu/m size epoxy coated RCLEDs have a 1.4-mW (CW) output power and a small signal modulation bandwidth of 200 MHz at 40 mA bias. 150-/spl mu/m diameter devices yield 3.25-mW and 150-MHz bandwidth at 70-mA bias. An open eye-diagram at 622 Mb/s achieved for the 84-/spl mu/m device makes it very attractive for SONET OC-12 data communication links.

Double Quantum-Well GaInNAs–GaAs Lasers

Performance characteristics of resonant cavity light-emitting diodes operating at the wavelength of 650 nm have been studied. It has been shown that a variation in device temperature significantly modifies the far-field pattern and thus the fibre coupling efficiency, due to a cavity detuning effect. Temperature dependences of output power and emission wavelength are also studied. Modulation bandwidth of >120 MHz and light power of 2 mW (cw) have been achieved for 84 µm devices driven at a 40 mA current. Accelerated ageing tests for 36 000 device hours indicate no degradation in output power.

Light-emitting diode emitting at 650 nm with 200-MHz small-signal modulation bandwidth

This paper presents the performance characteristics and reliability data of AlGaInP-based VISIBLE laser diodes emitting at the wavelengths from 630 to 670 nm. The lasers are grown by toxic gas free solid source molecular beam epitaxy.

Temperature behaviour of resonant cavity light-emitting diodes at 650 nm

Abstract Resonant cavity light-emitting diodes (RCLEDs) operating at λ≅660 nm and λ≅880 nm have been fabricated and studied. The RCLED layer structures consisted of 1−λ thick cavities sandwiched between AlGaAs distributed Bragg reflectors. The cavities were detuned to improve temperature stability and light extraction. The temperature induced red-shifts in the peak emission wavelength were found to be 0.14 and 0.22 nm °C−1 for the 660- and 880-nm devices, respectively.

High-power 600-nm-range lasers grown by solid-source molecular beam epitaxy

Abstract Monolithic top emitting resonant cavity light-emitting diodes (RC-LEDs) operating at 660 and 880 nm have been prepared using solid-source molecular beam epitaxy (SSMBE) growth. Transfer matrix based modelling together with a self-consistent model have been used to optimise the devices’ performances. Intermediate-composition barrier-reduction layers were introduced in the distributed Bragg reflector (DBR) mirrors for improving the I – V characteristics and the cavity and mirrors were detuned aiming at maximum extraction efficiency. The fabricated devices showed line widths below 15 nm, CW light power output of 8 and 22.5 mW, and wall-plug efficiencies of 3% and 14.1% in the 660 nm and 880 nm ranges, respectively, while the simulations indicate significant performance improvement possibilities.

Resonant cavity light-emitting diodes at 660 and 880 nm

Monolithic resonant cavity light-emitting diodes exhibiting an external quantum efficiency (/spl eta//sub ex/) up to 6.5% for 84-/spl mu/m size devices at a wavelength at 655 nm have been demonstrated. Larger diodes, 150-300 /spl mu/m in diameter, have the maximum /spl eta//sub ex/ between 5.5% and 4.9% and launch power output up to 8 mW.

Modeling and optimization of resonant cavity light-emitting diodes grown by solid source molecular beam epitaxy

We present results from measurements of the subthreshold lateral spontaneous emission profile in 1.3-mu m wavelength ridge waveguide InGaNAs quantum-well lasers using a scanning near-field optical microscopy technique. The measurements reveal the presence of significant lateral carrier diffusion which has a profound effect on the temperature dependence of the threshold current. This effect is frequently omitted when the characteristic temperature of the threshold current is considered.

Resonant-cavity light-emitting diodes operating at 655 nm with a high external quantum efficiency and light power

Monolithic top-emitting resonant cavity light-emitting diodes (RCLEDs) have been fabricated by solid-source MBE. The RCLEDs in the 650-nm range, with modulation bandwidths exceeding 180 MHz, are possible low-cost transmitter candidates for systems using plastic optical fibers (POFs), such as IEEE-1394 at 100 Mb/s and 200 Mb/s and ATM at 155 Mb/s. Modulation bandwidth of greater than 120 MHz and light power of 2 mW (cw) have been achieved for (phi )84-micrometer devices driven at a 40 mA current. Accelerated aging tests for 27,500 device-hours indicate no degradation in output power. A variation in device temperature significantly modifies the far-field pattern and thus the fiber coupling efficiency, due to a cavity detuning effect. The effects of detuning and the temperature and bias dependencies of the devices are investigated. The 880-nm RCLEDs have a maximum output power of 25 mW. Applications include open-air optical communication systems, collision avoidance and measurement systems.

Direct Observation of Lateral Carrier Diffusion in Ridge Waveguide InGaNAs Lasers

InP-based two-section distributed Bragg reflector lasers employing surface defined lateral gratings, which are compatible with low-cost nanoimprint technology, were fabricated. A newly developed inductively coupled plasma reactive ion etching process was utilized for obtaining large aspect ratios and good device performance. The lasers operate in a single mode up to 50°C under continuous-wave conditions. A modulation bandwidth of about 10 GHz was obtained for 0.9-mm-long devices.