Showing papers by "Barry Miller published in 1992"
TL;DR: In this paper, a broadly tunable grating assisted vertical coupler was used as an intracavity filter to demonstrate a novel monolithic multiple-quantum-well InGaAsP/InP laser.
Abstract: We have integrated a broadly tunable grating‐assisted vertical coupler as an intracavity filter to demonstrate a novel monolithic multiple‐quantum‐well InGaAsP/InP laser. The narrow, bandpass intracavity filter results in an extended cavity laser with a measured electrical tuning range of 57 nm with single‐frequency operation over most of that range.
144 citations
TL;DR: In this article, the carrier capture times in multiple quantum well semiconductor amplifiers of different structures were studied under high plasma density conditions, and the intermediate time constant was attributed to carrier diffusion in the cladding layers.
Abstract: The carrier capture times in multiple quantum well semiconductor amplifiers of different structures are studied under high plasma density conditions. Fast (<1 ps), slow (≳150 ps), and intermediate time constants (2–7 ps) are identified in InGaAs quantum well structures. The intermediate time constant is attributed to carrier diffusion in the cladding layers and identified as the carrier capture time. Short capture times can be achieved by proper design of the device structure.
75 citations
TL;DR: A 5.5mm-long monolithic extended-cavity laser with an integrated Bragg-reflector in the InGaAsP system for active mode-locking at low repetition rates at a wavelength of 1.55 mu m has been fabricated.
Abstract: A 5.5-mm-long monolithic extended-cavity laser with an integrated Bragg-reflector in the InGaAsP system for active mode-locking at low repetition rates at a wavelength of 1.55 mu m has been fabricated. The device, which is designed to be used as a pulse source in long-distance soliton systems and optical time-division multiplexed systems, generates 20-ps-wide transform-limited pulses with a time-bandwidth product of 0.34 at a repetition rate of 8.1 GHz. >
74 citations
TL;DR: In this paper, the first demonstration of broadly electrically tunable (215 A), narrowband (∼20 A full width at half maximum), wavelength selective, grating assisted coupling between vertically stacked buried rib InGaAsP/InP channel waveguides was presented.
Abstract: We report the first demonstration of broadly electrically tunable (215 A), narrow‐band (∼20 A full width at half maximum), wavelength selective, grating‐assisted coupling between vertically stacked buried rib InGaAsP/InP channel waveguides. This current injection tuned device is suitable for integration in a variety of photonic devices and integrated circuits including broadly tunable extended cavity lasers, amplifier/filter, and demultiplexer/detector circuits.
66 citations
TL;DR: In this paper, the authors reported lasing at temperatures as high as 144°C in long-wavelength InGaAsP vertical cavity lasers, which employed a novel cavity design using GaAs/AlAs quarterwavelength stacks for one mirror.
Abstract: We report lasing at temperatures as high as 144 °C in long‐wavelength InGaAsP vertical cavity lasers. The devices are optically pumped and employ a novel cavity design using GaAs/AlAs quarter‐wavelength stacks for one mirror. The characteristic temperature T0 of the device increases from 42 K at room temperature to 81 K at temperatures above 80 °C as the gain peak moves into resonance with the longer wavelength cavity mode.
66 citations
13 Apr 1992
TL;DR: By integrating a grating-assisted vertical coupler as a tunable intracavity filter in a novel active/passive monolithic laser, this paper achieved a measured tuning range of 57nm.
Abstract: Broadly tunable semiconductor lasers are important sources for a number of applications, especially wavelength division multiplexed networks and switching systems. Presently, the most developed monolithic tunable lasers, the distributed feedback (DFB) or distributed Bragg reflector (DBR), are limited to an ~10nm electrical tuning range. By integrating a grating-assisted vertical coupler as a tunable intracavity filter in a novel active/passive monolithic laser, we have achieved a measured tuning range of 57nm.
49 citations
TL;DR: The first monolithically integrated laser/interferometric modulator was reported in this paper, with a total chip length of 2.5 mm including a 970 μm-long strained InGaAs/InGaAsP quantum well gain section.
Abstract: The first monolithically integrated laser/interferometric modulator is reported. The total chip length of 2.5 mm includes a 970 μm-long strained InGaAs/InGaAsP quantum well gain section, a 230 μm-long wavelength tuning section containing a distributed Bragg reflector grating, and an 800 μm-long active length Mach-Zehnder modulator based on electrorefractive InGaAsP/InP quantum wells. 4 V pushpull drive voltage produces 12.5 dB modulation depth with −9 dBm optical power coupled into a cleaved fibre.
46 citations
TL;DR: In this article, a distributed Bragg reflector (DBR) laser tuned by resistive heating is presented, which has a tuning range greater than 10 nm with only a 33% reduction in output power and a 10% increase in linewidth.
Abstract: A distributed Bragg reflector (DBR) laser tuned by resistive heating is presented. It has a tuning range greater than 10 nm with only a 33% reduction in output power and a 10% increase in linewidth. Its behavior is easily modeled, agreeing well with simple theory. >
44 citations
TL;DR: In this article, a monolithic semiconductor ring laser with a diameter of 3.0 mm was fabricated, which exhibits a threshold current of 157 mA, operates in a single longitudinal mode with a linewidth of 900 kHz at a wavelength of 1.54 mu m.
Abstract: The authors have fabricated a monolithic semiconductor ring laser with a diameter of 3.0 mm. A straight tangent waveguide provides two output ports through evanescent coupling. The laser, which exhibits a threshold current of 157 mA, operates in a single longitudinal mode with a linewidth of 900 kHz at a wavelength of 1.54 mu m. The device has been actively mode-locked at the fundamental resonance frequency of 9.0 GHz, yielding 27-ps pulses with a time-bandwidth product of 0.47. Differences in the characteristics of the pulses emitted from the two output ports indicate counterpropagating pulse trains, which because of the mode-locking scheme must collide in the modulated gain section. >
44 citations
Patent•
10 Dec 1992TL;DR: In this paper, a graphite path is formed along the surface of a diamond plate by means of a laser or ion-implantation induced conductivity, and the path advantageously can be a surface of the sidewall of a via hole (fig. 2: 200) drilled by the laser through the plate or a path running along a side surface of an opposed major surfaces of the plate.
Abstract: A graphite path (FIG. 2: 10) is formed along the surface of a diamond plate (100), preferably a CVD diamond plate, by means of a laser or ion-implantation induced conductivity. The path advantageously can be the surface of a sidewall of a via hole (FIG. 2: 200) drilled by the laser through the plate or a path running along a side surface of the plate from top (FIG. 4: 101) to bottom (102) opposed major surfaces of the plate. The graphite path is metallized, as by electroplating or electroless plating. In this way, for example, an electrically conducting metallic connection (FIG. 2: 11; FIG. 4: 403) can be made between a metallized backplane (FIG. 2: 103, 104; FIG. 4: 402) located on the bottom surface of the plate and a metallic layer (FIG. 2: 105, 106; FIG. 4: 401) located on the top surface of the plate.
29 citations
TL;DR: A reproducible technique of lateral bandgap control can be used in quantum-well photonic integrated circuits to produce regions of low-loss waveguide, e.g., for interconnects or large passive cavities as mentioned in this paper.
Abstract: We demonstrate that phosphorous ion implantation in InGaAs/InP quantum wells can be used to produce large (from 1550 to 1200 nm) blueshifts of the band edge. This reproducible technique of lateral band‐gap control can be used in quantum‐well photonic integrated circuits to produce regions of low‐loss waveguide, e.g., for interconnects or large passive cavities. Phosphorous implants with subsequent p‐type InP regrowth produces blueshifted quantum‐well diodes with good reverse‐bias characteristics and low‐loss p‐i(multiple quantum well)‐n waveguides.
02 Feb 1992
TL;DR: In this paper, a novel monolithic extended cavity laser with an integrated grating-assisted vertical coupler as a tunable intracavity filter is presented, with a measured tuning range of 57nm and a tuning response that depends monotonically on the filter tuning current.
Abstract: Widely tunable semiconductor lasers are critical components for future wavelength division multiplexed networks and switching systems. Indeed, the total capacity of such systems is presently limited by the laser tuning range. The electrical tuning range of DFB and DBR lasers is limited to less than ~15nm. This limitation results from the fact that the fractional tuning range, Δλ/λ, of the fine-pitch Bragg grating wavelength-selective reflector is simply proportional to the normalized effective index change, ΔN/N. However, we have recently demonstrated that the grating-assisted vertical coupler provides an attractive bandpass filter that can be electrically tuned over a range substantially greater than a grating reflector for the same induced refractive index change [1,2]. Indeed, very recently a tunable twin guide laser that includes a vertical coupler structure between two nearly-synchronous guides exhibited evidence of extended, but irregular tuning [3]. Here we report a novel monolithic extended cavity laser with an integrated grating-assisted vertical coupler as a tunable intracavity filter. This laser has measured tuning range of 57nm and a tuning response that depends monotonically on the filter tuning current.
TL;DR: In this paper, a 1.5-mu m multiquantum well amplifier divided into three sections with short contacts at the input and output facets is described, and a simple derivation shows that the amplifier optical gain is proportional to the ratio of voltage changes at the facet contacts induced by the optical signal.
Abstract: A 1.5- mu m multiquantum well amplifier divided into three sections with short contacts at the input and output facets is described. A simple derivation shows that the amplifier optical gain is proportional to the ratio of voltage changes at the facet contacts induced by the optical signal. Measurements of optical gain and contact voltage as a function of amplifier bias current are in good agreement with the theory. >
02 Feb 1992
TL;DR: In this article, the first interferometric waveguide intensity modulator with optical gain was reported, where a monolithically integrated compressively strained InGaAs quantum well amplifier provided a net 4.2 dB fiber-to-fiber gain at 120 mA forward bias.
Abstract: We report the first interferometric waveguide intensity modulator with optical gain. A monolithically integrated compressively strained InGaAs quantum well amplifier provides a net 4.2 dB fiber‐to‐fiber gain at 120 mA forward bias. Reversed‐biased InGaAsP quantum wells provide enhanced electrorefraction for the modulator in which we demonstrate a 3 dB electrical modulation bandwidth of 2.25 GHz. The voltage‐length product for 180° phase shift is a record Vπ × L = 1.9 V mm. The total device length is under 2 mm.
TL;DR: In this article, an InP-based 1×16 optical switch is demonstrated, where sixteen output ports are spaced 250 μm apart, and the total device length is 5.9 mm.
Abstract: An InP based 1×16 optical switch is demonstrated. The sixteen output ports are spaced 250 μm apart, and the total device length is 5.9 mm. Optical amplifiers are used to gate the optical signals and to provide optical gain. The total loss of the device, excluding coupling, is less than 2.5 dB and loss free operation was observed at low input powers. The output extinction ratios are lower than 18 dB and the uniformity spread of the sixteen channels is as low as 6.7 dB.
TL;DR: In this article, the authors used standard lithographic techniques to fabricate naked quantum wells from spatially and compositionally modulated III-V superlattices in which alternate layers of the structures are sacrificed by selective etching.
Abstract: Standard lithographic techniques have been utilized to fabricate quantum wells which are confined on both sides by vacuum. These ‘‘naked’’ quantum wells are fabricated from spatially and compositionally modulated III‐V superlattices in which alternate layers of the structures are sacrificed by selective etching. These structures are patterned such that the quantum wells are suspended between support posts.
TL;DR: In this paper, the design, fabrication and properties of the first interferometric intensity modulators with monolithically integrated optical gain are presented, which make use of two sets of InP-based quantum well heterostructures that are contained in a single base wafer.
Abstract: Details on the design, fabrication and properties of the first interferometric intensity modulators with monolithically integrated optical gain are presented. These guided-wave devices make use of two sets of InP-based quantum well heterostructures that are contained in a single base wafer and individually designed for enhanced electrorefraction and amplification at 1.55 mu m. The unique quantum well electrooptic properties as well as the fabrication techniques and waveguide design issues that determine final device performance are discussed. >
TL;DR: In this paper, the diffusion coefficients of both fullerenes in ODCB/0.5M tetra n-butyl ammonium bromide were measured by two RDE techniques, Levich limiting current behavior and the frequency response of sinusoidal hydrodynamic modulation (SHM).
Abstract: The reductions of and fullerenes in o‐dichlorobenzene (ODCB) electrolytes under controlled potential and convection at rotating disk and ring‐disk electrodes (RDE and RRDE) illuminate several aspects of the electron transfer processes. The stability of the successive one‐electron transfer products (up to and ions) is demonstrated through the RRDE. The diffusion coefficients of both fullerenes in ODCB/0.5M tetra n‐butyl ammonium bromide were measured by two RDE techniques, Levich limiting current behavior and the frequency response of sinusoidal hydrodynamic modulation (SHM). The former gave values of at 25°C for and , respectively, and the latter results were theoretically consistent with the Schmidt number of 17,400 so calculated, confirming the number of electrons transferred without the aid of Faraday's law. Voltammograms of the SHM current at the RDE show kinetic effects at the foot of each successive wave.
TL;DR: In this paper, the authors used InGaAsP as an alternative to AlGaAs in the cladding layers and achieved a slope efficiency of 0.67 mW/mA and output power of 60 mW at 160 mA.
Abstract: MOVPE-grown InGaAs/GaAs strained-layered lasers emitting at 0.98 mu m have been fabricated using InGaAsP as an alternative to AlGaAs in the cladding layers. Semi-insulating blocked planar buried heterostructure lasers 2.5 mu m wide have thresholds as low as 8 mA for 350 mu m long devices. With the addition of reflective coatings, slope efficiencies of 0.67 mW/mA and output powers of 60 mW at 160 mA have been obtained. >
TL;DR: In this article, a 1.0 cm long, two contact, monolithic extended-cavity laser has been fabricated and actively mode-locked at a repetition rate of 4.4 GHz to produce 9.0 ps optical pulses.
Abstract: A 1.0 cm long, two contact, monolithic extended-cavity laser has been fabricated and actively mode-locked at a repetition rate of 4.4 GHz to produce 9.0 ps optical pulses. Doubling of the optical pulse repetition rate of 8.8 GHz without changing the sinusoidal drive frequency is achieved by synchronously modulating two separate active regions.
TL;DR: In this article, the integrated operation of an amplifier-based optical switch with distributed Bragg reflector lasers fabricated using photonic integrated circuit technology was demonstrated, where the multiple-quantum-well amplifiers allowed light from the DBR laser to be spatially switched to one of two output ports with low switching current on the amplifiers.
Abstract: The integrated operation of an amplifier-based optical switch with distributed Bragg reflector lasers fabricated using photonic integrated circuit technology was demonstrated. The multiple-quantum-well amplifiers allow light from the DBR laser to be spatially switched to one of two output ports with low switching current on the amplifiers. The switching region is only 450 mu m long by 250 mu m wide, and the total device length is 1200 mu m. When 70 mA is applied to the laser and 50 mA is applied to one of the amplifier pairs, the output power of the device at each output port is 0.8 mW, with an extinction ratio of approximately 12 dB. >
TL;DR: In this article, a photonic integrated transmitter for RZ transmission provides 50 ps optical pulses on-off modulated at a bit rate of 3Gbit/s with a back-to-back transmission experiment and compared to NRZ transmission using the same photonic circuit with the laser operated CW.
Abstract: A photonic integrated transmitter for RZ transmission provides 50 ps optical pulses on-off modulated at a bit rate of 3Gbit/s. BER performance is measured in a back-to-back transmission experiment and compared to NRZ transmission using the same photonic circuit with the laser operated CW. A 2.8 dB improvement in receiver sensitivity is obtained for the RZ case.
TL;DR: In this article, an etchless implant technique was used to produce buried InGaAsP/InP quantum well waveguides by means of phosphorus ion implantation and thermal annealing during regrowth.
Abstract: Formation of buried InGaAsP/InP quantum well waveguides by means of phosphorus ion implantation and thermal annealing during regrowth is demonstrated. Absorption spectra of implanted and unimplanted regions are used to estimate the induced index difference, which is of the order of 1% at 1.55 μm. Calculated mode intensities are in good agreement with the observed near field intensity patterns. With this etchless implant technique, we achieve a significant reduction in propagation loss for singlemode pin waveguides relative to etched semi-insulating planar buried heterostructure waveguides fabricated from the same quantum well structure. In addition to reduced scattering loss, buried quantum well waveguides produced by ion implantation are more manufacturable because fewer and less-critical processing steps are involved.
24 Jun 1992
TL;DR: In this paper, an InP-based 1×16 optical switch is demonstrated, where the output ports are spaced 250 microns apart, and the total device length is 5.9 mm.
Abstract: An InP based 1×16 optical switch is demonstrated. The output ports are spaced 250 microns apart, and the total device length is 5.9 mm. Optical amplifiers are used to both gate the optical signals and to provide optical gain. The total net loss of the device, excluding coupling, is 0-2.5 dB with extinction ratios in excess of 18 dB. The uniformity spread of the 16 channels is better than 6.7 dB.
02 Feb 1992
Proceedings Article•
10 May 1992
01 Jan 1992
TL;DR: In this article, an active mode-locking of a broadly tunable monolithic semiconductor laser based on a grating assisted vertical coupler filter resulted in 10 - 12 ps pulses at a repetition rate of 15.8 GHz.
Abstract: Active mode-locking of a broadly tunable monolithic semiconductor laser based on a grating assisted vertical coupler filter resulted in 10 - 12 ps pulses at a repetition rate of 15.8 GHz. Mode-locking was achieved at discrete wavelengths from 1544.5 nm to 1564.7 nm.
Patent•
AT&T1
TL;DR: In this paper, it has been found that selective metallization in integrated circuits is expeditiously achieved through a copper plating procedure, where palladium silicide is used as a catalytic surface.
Abstract: It has been found that selective metallization in integrated circuits is expeditiously achieved through a copper plating procedure. In this process, palladium silicide is used as a catalytic surface and an electroless plating bath is employed to introduce copper plating only in regions where the silicide is present. Use of this procedure yields superior filling of vias and windows with excellent conductivity.