We review the family of optoelectronic devices whose performance is enhanced by placing the active device structure inside a Fabry‐Perot resonantmicrocavity. Such resonantcavity enhanced (RCE) devices benefit from the wavelength selectivity and the large increase of the resonant optical field introduced by the cavity. The increased optical field allows RCE photodetector structures to be thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. Off‐resonance wavelengths are rejected by the cavity making RCE photodetectors promising for low crosstalk wavelength division multiplexing(WDM) applications. RCE optical modulators require fewer quantum wells so are capable of reduced voltage operation. The spontaneous emission spectrum of RCE light emitting diodes(LED) is drastically altered, improving the spectral purity and directivity. RCE devices are also highly suitable for integrated detectors and emitters with applications as in optical logic and in communication networks. This review attempts an encyclopedic overview of RCE photonicdevices and systems. Considerable attention is devoted to the theoretical formulation and calculation of important RCE device parameters. Materials criteria are outlined and the suitability of common heteroepitaxial systems for RCE devices is examined. Arguments for the improved bandwidth in RCE detectors are presented intuitively, and results from advanced numerical simulations confirming the simple model are provided. An overview of experimental results on discrete RCE photodiodes, phototransistors, modulators, and LEDs is given. Work aimed at integrated RCE devices,optical logic and WDM systems is also covered. We conclude by speculating what remains to be accomplished to implement a practical RCE WDM system.

Resonant cavity enhanced photonic devices

Technologies now exist for implementing dense surface-normal optical interconnections for silicon CMOS VLSI using hybrid integration techniques. The critical factors in determining the performance of the resulting photonic chip are the yield on the transceiver device arrays, the sensitivity and power dissipation of the receiver and transmitter circuits, and the total optical power budget available. The use of GaAs-AlGaAs multiple-quantum-well p-i-n diodes for on-chip detection and modulation is one effective means of implementing the optoelectronic transceivers. We discuss a potential roadmap for the scaling of this hybrid optoelectronic VLSI technology as CMOS linewidths shrink and the characteristics of the hybrid optoelectronic transceiver technology improve. An important general conclusion is that, unlike electrical interconnects, such dense optical interconnections directly to an electronic circuit will likely be able to scale in capacity to match the improved performance of future CMOS technology.

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Scaling optoelectronic-VLSI circuits into the 21st century: a technology roadmap

The symmetric self-electrooptic-effect device (S-SEED), a structure consisting of two p-i-n diodes electrically connected in series and acting as an optically bistable set-reset latch, is discussed. Applications and extensions of this device are also discussed. The devices do not require the critical biasing that is common to most optically bistable devices and thus is more useful for system applications. They have been optically cascaded in a photonic ring counter and have been used to perform different NOR, OR, NAND, and AND logic functions. Using the same device, a differential modulator that generates a set of complementary output beams with a single voltage control lead and a differential detector that gives an output voltage dependent on the ratio of the two optical input powers have been demonstrated. >

Symmetric self-electrooptic effect device : optical set-reset latch, defferential logic gate and differential modulator/detector

Using passively mode-locked femtosecond (fs) fiber laser and polarization maintaining fibers, the compact system of wavelength-tunable femtosecond (fs) fundamental soliton pulse generation is realized. The monocolored soliton pulse, not multicolored ones, with the ideal sech/sup 2/ shape is generated, and its wavelength can be linearly shifted by varying merely the fiber-input power in the wide wavelength region of 1.56-1.78 /spl mu/m for a 75-m fiber. The soliton pulses of less than 200 fs are generated with the high conversion efficiency of 75%-85%. This system can be widely used as a portable and practical wavelength-tunable fs optical pulse sources.

Compact system of wavelength-tunable femtosecond soliton pulse generation using optical fibers

Modelocked fiber laser resonators may be coupled with optical amplifiers. An isolator optionally may separate the resonator from the amplifier. A reflective optical element on one end of the resonator having a relatively low reflectivity may be employed to couple light from the resonator to the amplifier. Enhanced pulse-width control may be provided with concatenated sections of both polarization-maintaining and non-polarization-maintaining fibers. Apodized fiber Bragg gratings and integrated fiber polarizers may also be included in the laser cavity to assist in linearly polarizing the output of the cavity. Very short pulses with a large optical bandwidth may be obtained by matching the dispersion value of the grating to the inverse of the dispersion of the intra-cavity fiber. Frequency comb sources may be constructed from such modelocked fiber oscillators. Low dispersion and an in-line interferometer that provides feedback may assist in controlling the frequency components output from the comb source.

Pulsed laser sources

We report the demonstration of a high-contrast (> 100:1), low-voltage multiple quantum well reflection modulator. The performance is achieved by using resonantly-enhanced electroabsorption in GaAs quantum wells embedded in the spacer region of an asymmetric Fabry-Perot cavity, which is at the same time a pin diode. Optimum contrast is observed at ≃860nm with only 9 V bias and ≈3.5dB insertion loss.

Low-voltage multiple quantum well reflection modulator with on:off ratio >100:1

Using a semiconductor saturable absorber, an erbium‐doped fiber laser has been passively mode locked to yield pulses of 840 fs with pulse energies of 0.85 nJ. Stable mode locking at the fundamental roundtrip frequency and also at the second and third harmonic has been achieved.

All-solid-state subpicosecond passively mode locked erbium-doped fiber laser

Using the electro-absorptive properties of ≈ 150 A quantum wells in an asymmetric Fabry–Perot modulator (AFPM), a normally-off reflection modulator with very low drive voltage was demonstrated. With this device contrasts of more than 6 dB at normal incidence in reflection have been achieved, with a voltage swing of only 3.5 V and ≤3 dB insertion loss.

Very low voltage, normally-off asymmetric Fabry-Perot reflection modulator

We report the first pin multiple quantum well reflection modulator grown on Si with a quarter-wave stack dielectric mirror. The structures demonstrated were grown by MBE, with a 75 period MQW, and achieved a relative change in reflectivity of 31% with 8 V applied bias at 865 nm. The absolute change in reflectivity was 17%.

GaAs/AlGaAs multiple quantum well optical modulator using multilayer reflector stack grown on Si substrate

We compare the characteristics of three electroabsorption modulators fabricated using GaAs/AlGaAs multiple quantum well structures with well widths 47, 87, and 145 A. We find that the narrow well structure provides the largest change in transmission. The 87 A well structure provides the largest contrast ratio, while the wide well sample offers the lowest operating voltage.

A. Rivers

Papers

Low-voltage multiple quantum well reflection modulator with on:off ratio >100:1

All-solid-state subpicosecond passively mode locked erbium-doped fiber laser

Very low voltage, normally-off asymmetric Fabry-Perot reflection modulator

GaAs/AlGaAs multiple quantum well optical modulator using multilayer reflector stack grown on Si substrate

Effects of well width on the characteristics of GaAs/AlGaAs multiple quantum well electroabsorption modulators