Showing papers by "Kenichi Iga published in 1990"
TL;DR: In this paper, the electron wave reflectivities of the AlGaInP-based multi-quantum barrier (MQB) with changing of several parameters such as well and barrier thickness and pair number were examined.
Abstract: We have examined the electron wave reflectivities of the AlGaInP-based multi-quantum barrier (MQB) with changing of several parameters such as well and barrier thickness and pair number. We have optimized the MQB structure by clarifying several choices of the MQB parameters. Even in the 630-nm-range AlGaInP lasers, we can obtain effective potential barrier height 2 times greater than the classical potential barrier height U0 in the MQB composed of relatively nallow superlattices. The increased potential barrier height is about 114 meV and this suggests the possibility of higher-temperature CW operation of 630-nm-range AlGaInP lasers.
35 citations
TL;DR: Minimum levels of laser facet reflectivities have been obtained as a function of the array fill factor for practical devices with low threshold current densities.
Abstract: Using a self-imaged diffraction coupled model in a Talbot cavity for vertical cavity surface emitting laser arrays, the effect of self-imaged reflections on the lasing threshold of a finite 2-D array was investigated. Array size and the ratio defined by the element diameter/element spacing were found to affect the effective reflectivity as seen from the laser cavities and, ultimately, the device threshold. A general curve showing the dependence of the 2-D coupling coefficient on the array fill factor and array size has been found. Minimum levels of laser facet reflectivities have been obtained as a function of the array fill factor for practical devices with low threshold current densities.
29 citations
TL;DR: Beryllium-doped Ga047In053As was grown on InP to examine its doping characteristics by chemical beam epitaxy, and a net hole concentration as high as 2 × 1020 cm-3 was obtained with mirror-like surface morphology, while maintaining a constant growth temperature of 540 °C and a growth rate of 32 μm/h.
15 citations
TL;DR: It was found that a planar microlens has a relatively good distortion property and low MTF sensitivity for oblique imaging, even if an image height goes to as high as 60% of the lens radius.
Abstract: An image multiplexer (IMX) composed of a planar microlens array is proposed for an input device of an optical parallel processing system. Imaging properties were evaluated experimentally and numerically to find a design rule and the limitations of use of the IMX. As a result, it was found that a planar microlens has a relatively good distortion property and low MTF sensitivity for oblique imaging, even if an image height goes to as high as 60% of the lens radius. Furthermore, a compensation method for image shift nonlinearity is proposed. The effective lens number in an array is estimated.
12 citations
TL;DR: In this paper, an optical beam scanner with the possibility of high-speed steering has been fabricated and its operation was confirmed and the obtained deflection angle was 0.67 degrees under 9.5 V reverse bias.
Abstract: An optical beam scanner which has the possibility of high-speed steering has been fabricated and its steering operation was confirmed. The obtained deflection angle was 0.67 degrees under 9.5 V reverse bias.
11 citations
Journal Article•
01 Sep 1990-Transactions of the Institute of Electronics and Communication Engineers of Japan. Section E
10 citations
TL;DR: There are four types of SE laser; vertical cavity, 45° mirror, grating coupled, and folded cavity as mentioned in this paper, and the performance of these SE lasers are described and compared, and some characteristics of vertical cavity SE laser are summarized.
Abstract: This paper reviews the present status of research on surface emitting (SE) semiconductor lasers. There are four types of SE laser; vertical cavity, 45° mirror, grating coupled, and folded cavity. Lasing performances of these lasers are described and compared. Some characteristics of vertical cavity SE lasers are also summarized.
7 citations
TL;DR: In this paper, the enhancement of electron wave confinement of GaAs/AlGaAs multi-quantum barrier (MQB) using photoluminescence (PL) measurement was confirmed.
Abstract: We have confirmed the enhancement of electron wave confinement of GaAs/AlGaAs multi-quantum barrier (MQB) using photoluminescence (PL) measurement. We observed less saturated PL excitation dependence and less sensitive temperature dependence. This could be due to the quantum enhancement in the potential barrier of the MQB structure, and shows a superior carrier confinement of MQB over a classical bulk barrier.
7 citations
TL;DR: In this paper, a 1.45 µm-wavelength GaInAsP was grown by chemical beam epitaxy with a solid Be source and the hole concentration was linearly related to the Be effusion cell temperature.
Abstract: Highly Be-doped (>1019 cm-3) 1.45 µm-wavelength GaInAsP was grown by chemical beam epitaxy with a solid Be source. The hole concentration for both GaInAsP and InP was linearly related to the Be effusion cell temperature. In spite of high doping levels, neither obvious lattice mismatch nor surface degradation was observed. A stripe contact laser was also successfully fabricated using the results obtained.
6 citations
TL;DR: In this paper, Beryllium-doped GaInAs layers were grown on InP by chemical beam epitaxy and were electrically characterized, achieving hole concentrations as high as 2×1020 cm-3 at a growth temperature of 540°C without degrading the surface morphology.
Abstract: Beryllium-doped GaInAs layers were grown on InP by chemical beam epitaxy and were electrically characterized. A hole concentration of as high as 2×1020 cm-3 at a growth temperature of 540°C was obtained without degrading the surface morphology. Highly doped growth was possible without changing any growth parameter. Hole concentrations were also investigated at different growth temperatures for a given Be cell temperature. Hole concentrations were found to increase with decreasing growth temperatures. Furthermore, we did not observe lattice mismatch (Δa/a<3×10-4) for any of the doped samples grown under the same growth condition as for undoped samples.
4 citations
TL;DR: In this paper, the relative intensity noise (RIN) of a vertical cavity surface emitting (SE) laser diode was measured for the first time and it was shown that the RIN was - 135 dB/Hz at the injection current 11×Ith.
Abstract: The relative intensity noise (RIN) of a vertical cavity surface emitting (SE) laser diode was measured for the first time We found that the relative intensity noise was - 135 dB/Hz at the injection current 11×Ith which is comparable to that of a low noise edge emitting laser
TL;DR: In this article, GaInAs/InP wafers with a thick active layer (0.5-2.0 µm) were grown by chemical beam epitaxy (CBE).
Abstract: GaInAs/InP wafers with a thick active layer (0.5-2.0 µm) were grown by chemical beam epitaxy (CBE). Stripe-contact lasers were fabricated to evaluate these wafers. The lowest normalized threshold current density obtained was 7.9 kA/cm2µm for devices with a 2.0 µm thick active layer. This value is almost acceptable for application to surface emitting lasers.
TL;DR: In this article, the design and fabrication of a vertical cavity surfaceemitting (SE) laser using GaAlAs/A1As distributed Bragg reflectors (DBR) is presented.
Abstract: This paper presents the design considerationand fabrication of a vertical cavity surfaceemitting (SE) laser using GaAlAs/ A1As distributed Bragg reflectors (DBR). From theoretical calculation, a peak reflectivity of 99% can be expected even when we consider a reasonable loss .The deterioration of reflectivity due to thickness errors was examined. An MOCVD-grown DBRexhibited are flectivity of 97% at the wavelength of O.88 μm . The thre shold current of a 30 μmdiameter device with a simple mesa cap structure was 200 mA under the room-temperature pulsedcondition. The threshold of 40 mA was obtained by a 10 μm diameter device with a claddingetchedcurrent confinement structure.
TL;DR: In this article, a high P2-yield cracking cell was developed for chemical beam epitaxy, where the use of tantalum baffles in a PBN-made cell significantly increased the P2 yield when comparing it to a cell using PBN baffles.
Abstract: A high P2-yield cracking cell was newly developed for chemical beam epitaxy. Dramatic improvements in crystal quality were obtained in comparison to a lesser-yield cell. The use of tantalum baffles in a PBN-made cell significantly increased the P2 yield when comparing it to a cell using PBN baffles. The growth mechanism of InP differed from cells with different P2 yields. For the same PH3 and TMI flow rates, higher growth rates and narrower photoluminescence linewidths were obtained with a higher P2 yield cell. Silicon and beryllium doping incorporation mechanisms were also found to be different with these cells.
01 Jul 1990
TL;DR: Two-Dimensional (2D) arrayed configuration for active microoptics wifi be introduced and present status of planar microlens surface emitting lasers some functional devices and applied microoptic systems are discussed.
Abstract: Two-Dimensional (2D) arrayed configuration for active microoptics wifi be introduced. Present status of planar microlens surface emitting lasers some functional devices and applied microoptic systems are discussed.
Proceedings Article•
21 May 1990
Patent•
20 Feb 1990
TL;DR: In this paper, the authors proposed a simple manufacturing process by completing the polymerization of the whole transparent substrate after diffusing a 2nd monomer which polymerizes with a 1st monomer selectively into a transparent substrate formed by half-polymerizing the first monomer.
Abstract: PURPOSE:To enable mass-production by a simple manufacturing process by completing the polymerization of the whole transparent substrate after diffusing a 2nd monomer which polymerizes with a 1st monomer selectively into a transparent substrate formed by half-polymerizing the 1st monomer. CONSTITUTION:The transparent substrate 11 is formed by half-polymerizing the 1st monomer and a mask 12 which has a circular window or hole 12a is formed in the center of the transparent substrate 11. Then the 2nd monomer is diffused and moved by copolymerizing with the 1st monomer through the hole 12a to polymerize the whole of the substrate 11, thus forming a distributed index lens part 13. Consequently, the lens body which has plural distributed index lens parts 13 is mass-produced by the simple manufacturing process at low cost in a short time.
23 Apr 1990
TL;DR: In this article, high growth rates have been obtained for Ga/sub 0.47/In/sub sub 0.53/As and InP using chemical beam epitaxy and good thickness controllability was demonstrated by growing multi-quantum-wells at growth rates of 5.15 and 2.5 mu m/h.
Abstract: High growth rates have been obtained for Ga/sub 0.47/In/sub 0.53/As and InP using chemical beam epitaxy. The GaInAs growth rate was controlled over the range from 1.2 to 6 mu m/h, the latter being the highest growth rate obtained without sacrificing the optical and electrical properties of the crystal. Good thickness controllability was demonstrated by growing multi-quantum-wells at growth rates of 5.15 and 2.5 mu m/h. An emission wavelength shift from 1.56 mu m to 1.1 mu m was observed in room temperature photoluminescence measurements. Based on X-ray spectra satellite peaks, well widths associated with these wavelength ranged from 80 AA to 10 AA. The results agree with theoretical calculations and show good thickness controllability and wavelength tunability at high growth rates. >
TL;DR: To obtain a low damage etching condition and to eliminate the damage to InP induced by reactive ion beam etching (RIBE), the authors compared photoluminescence intensities of etched samples.
Abstract: To obtain a low damage etching condition and to eliminate the damage to InP induced by reactive ion beam etching (RIBE), we compared photoluminescence intensities of etched samples. We also compared electroluminescence of a buried heterostructure laser fabricated using RIBE with stripe lasers. The obtained suitable condition is as follows: the substrate temperature is 150~175°C; the ion extraction voltage is 300 V; and gas pressure is 1.2×10-3 Torr.
Proceedings Article•
01 Dec 199004 Nov 1990