S. Pradhan

Dynamic characteristics of high-speed In0.4Ga0.6As/GaAs self-organized quantum dot lasers at room temperature

We have measured the room-temperature modulation characteristics of self-organized In0.4Ga0.6As/GaAs quantum dot lasers in which electrons are injected into the dot lasing states by tunneling. A small-signal modulation bandwidth of f−3 dB=22 GHz is measured. Values of differential gain at 288 K of dg/dn≅8.85×10−14 cm2 and gain compression factor e=7.2×10−16 cm3 are derived from the modulation data. Extremely low values of linewidth enhancement factor α∼1 and chirp <0.6 A were also measured in the devices.

Electrically injected photonic crystal edge-emitting quantum-dot light source

An electrically injected photonic crystal (PC) edge-emitting light source with horizontally coupled waveguide, based on a GaAs heterostructure with self-organized InGaAs quantum dots emitting near 1 /spl mu/m, is demonstrated. The emission spectra and near-field images indicate that the spontaneous emission from the low-Q resonant PC cavity is coupled to an adjacent PC missing defect waveguide and guided over the 70-/spl mu/m waveguide length.

Low-power phototransceiver arrays with vertically integrated resonant-cavity LEDs and heterostructure phototransistors

Low-power phototransceivers and phototransceiver arrays, with vertically integrated high-gain heterojunction phototransistors (HPTs) and resonant-cavity light-emitting diodes (RCLEDs), are demonstrated. A tunnel junction was used as a low resistance interconnect between the two devices. The input and output wavelengths are 0.63-0.85 and 0.98 /spl mu/m, respectively. The phototransceiver exhibits an optical gain of 13 dB and power dissipation of 400 /spl mu/W for an input power of 5 /spl mu/W. The phototransceiver arrays demonstrate good uniformity, low optical crosstalk, and imaging capabilities.

Electrically injected photonic crystal edge emitting quantum dot light source

This study addresses the need for integrable, electrically injected microcavity light sources for compact photonic integrated circuits and presents a novel electrically injected 2D PC-based quantum dot edge emitting light source with coupled PC waveguide that avoids carrier recombination in PC air-holes and allows for easy integration with PC planar waveguides. It is envisaged that ultimately, with a single dot in the PC microcavity, the coupled device will be an ideal vehicle for the study of cavity quantum-electrodynamics (CQED) phenomena.

Modulation characteristics of high-speed tunnel injection In/sub 0.4/Ga/sub 0.6/As quantum dot lasers

Summary form only given. We have recently demonstrated higher small-signal modulation bandwidth (15 GHz) at room temperature in single mode InGaAs/GaAs quantum dot lasers in which electrons are injected to the lasing ground state of the dots by tunneling. We report here the room-temperature small- and large-signal modulation characteristics of tunnel injection quantum dot lasers. The devices are characterized by high quantum efficiency, very large modulation bandwidth and very small chirp and /spl alpha/-factor. The tunnel injection quantum dot laser heterostructures were grown by molecular beam epitaxy.

Modulation characteristics of In/sub 0.4/Ga/sub 0.6/As/GaAs quantum dot gain-coupled distributed feedback lasers

This paper presents the high-speed modulation characteristics of In/sub 0.4/Ga/sub 0.60/As/GaAs self-organized quantum dot gain-coupled DFB lasers. The maximum measured 3 dB bandwidth, at 300 K, is 5 GHz and high frequency chirp in the devices is undetectable.

Two dimensional photonic crystal active and passive devices

The properties of electrically injected photonic crystal surface and edge emitting light sources and passive waveguides for microfluidic discrimination and their applications are presented.