Marlin W. Focht

Optical injection induced polarization bistability in vertical-cavity surface-emitting lasers

We report the observation of bistable polarization switching in a vertical‐cavity surface‐emitting laser under optical injection. The wavelength dependence of the switching is measured. It is found that this polarization switching is achieved through injection locking where both the wavelength and the polarization of the vertical‐cavity laser are locked to the injected optical signal.

Transverse mode control of vertical-cavity top-surface-emitting lasers

Transverse mode characteristics and control for vertical-cavity top-surface-emitting lasers (VCSELs) are discussed. A spatial filtering concept for the control of VCSEL transverse modes that allows over 1.5-mW single TEM/sub 00/ transverse mode emission to be routinely achieved from continuous-wave electrically excited VCSELs is introduced. Without spatial filtering, L-I and V-I kinks are observed.<<ETX>>

High‐power coherently coupled 8×8 vertical cavity surface emitting laser array

We demonstrate record high pulsed output power exceeding 530 mW from an electrically pumped phase‐coupled 8×8 vertical cavity surface emitting laser array (SELA) at room temperature. Three array types are compared: an 8×8 pixellated SELA(PSELA), an 8×8 grid contact SELA(CSELA), and a 78 μm×78 μm single broad area SEL(BSEL) emitter. The CSELA operating in a phase‐coupled supermode exhibits the lowest threshold current (100 mA) and voltage (1.6 V), highest damage threshold and a smooth L‐I characteristic with differential quantum efficiency ηd≳27%, the BSEL has the largest output power≳580 mW and a large ηd≳48%, the PSELA exhibited a large voltage with the largest ηd≳80%.

Progress in planarized vertical-cavity surface-emitting laser devices and arrays

We report batch-processed, totally planar, vertical-cavity top surface emitting GaAs/AlGaAs laser devices and arrays. Different size devices are studied experimentally. We measure continuous-wave threshold currents down to 1.7 mA and output powers > 3.7 mW at room temperature. We also discuss interesting characteristics such as differential quantum efficiencies exceeding unity and multi-transverse mode behavior. An array having 64 X 1 individually-accessed elements is characterized and shown to have uniform room-temperature continuous-wave operating characteristics in threshold current approximately equals 2.1 +/- 0.1 mA, wavelength approximately equals 849.4 +/- 0.8 nm, and output power approximately equals 0.5 +/- 0.1 mW.

Operation of a fully integrated GaAs-Al/sub x/Ga/sub 1-x/As FET-SEED: a basic optically addressed integrated circuit

The authors experimentally demonstrate the operation of a fully integrated optoelectronic circuit with optical input and output consisting of a p-i-n photodetector and load resistor, a depletion-mode GaAs-Al/sub x/Ga/sub 1-x/As heterostructure field-effect transistor (HFET) and self-biased HFET load, together with an output GaAs-Al/sub x/Ga/sub 1-x/As multiple quantum-well optical modulator. All elements have been monolithically integrated within a 50- mu m*50- mu m area. A low optical power input causes a modulation of a higher-power output, demonstrating optical signal amplification.<<ETX>>

Low‐voltage, high‐saturation, optically bistable self‐electro‐optic effect devices using extremely shallow quantum wells

Symmetric self‐electro‐optic effect devices (S‐SEEDs) using extremely shallow GaAs/Al0.04Ga0.96As multiple quantum wells are demonstrated. By exploiting mainly exciton ionization, rather than the usual quantum‐confined Stark shift, room‐temperature optical bistability is obtained with no applied bias. The extremely shallow symmetric‐SEED (symmetric E‐SEED) exhibits contrast ratios (CRs)≂3.5, with biasses<5 V, demonstrating system applicability and compatability with electronics. Large system tolerances Δλ≂6 nm and maximum bistability loop width ≂70% are also obtained. Moreover, due to fast carrier escape times, the symmetric E‐SEED exhibits useful CRs≳2 even at continuous‐wave intensities ≳70 μW/μm2.

High resistivity in InP by helium bombardment

Helium implants over a fluence range from 1011 to 1016 ions/cm2, reproducibly form high resistivity regions in both p‐ and n‐type InP. Average resistivities of greater than 109 Ω cm for p‐type InP and of 103 Ω cm for n‐type InP are reported. Results are presented of a Monte Carlo simulation of helium bombardment into the compound target InP that yields the mean projected range and the range straggling.

Progress and properties of high-power coherent vertical-cavity surface-emitting laser arrays

We discuss the potential of using coherently-coupled vertical cavity surface emitting laser arrays as high-intensity light sources. In particular, the design and performance of a novel two-dimensional phase-coupled grid Contact vertical cavity Surface Emitting Laser Array (C- SELA) is reported. We discuss the optical properties of the C-SELA; in addition to the usual out-of-phase array mode, we demonstrate in-phase SELA coupling. We introduce a simple physical model to describe our experimental results. Over 1.2 Watt optical power emission is obtained at room temperature from an electrically-excited 10 X 10 C-SELA. This laser array exhibited a low threshold current density of only 600 Amps/cm2 and over 60% single-ended differential quantum efficiency.

4/spl times/4 arrays of FET-SEED embedded control 2/spl times/1 optoelectronic switching nodes with electrical fan-out

We describe a 4 by 4 array of embedded control two input, one output optoelectronic switching nodes based on the field effect transistor self electro-optic effect device (FET-SEED) technology. The arrays have electrical fan-out to remove the loss associated with optical fan-out in the system application. Extensive testing was done on several arrays at 156 Mb/s per channel with optical switching energies below 100 fJ, with the output driver limiting the maximum data rate to 400 Mb/s. Power dissipation, noise margin, crosstalk, sensitivity to stray light, and uniformity of both threshold and output waveforms are also discussed.<<ETX>>

Bistability in coupled cavity semiconductor lasers

Experimental results on bistable operation of coupled cavity semiconductor lasers are presented. The light level at the upper and lower states can be controlled by varying the injection current. A model calculation of the coupled cavity laser system shows that the bistability is due to nonlinearities associated with above threshold gain saturation. Our results show that a coupled cavity laser can exhibit bistability at all temperatures and, in addition, the size of the ‘‘hysteresis loop’’ can be easily controlled by varying the injection current. These results are significant for a practical bistable optical device.