W. Susaki

Bio: W. Susaki is an academic researcher from Mitsubishi Electric. The author has contributed to research in topics: Laser & Laser diode. The author has an hindex of 12, co-authored 42 publications receiving 453 citations.

Low threshold InGaAsP/InP buried crescent laser with double current confinement structure

Abstract: An InGaAsP/InP laser diode emitting at 1.3 μm with a crescent shaped active region is described. The active region is completely embedded in InP by a two-step LPE technique, and a double current confinement scheme is incorporated with two reverse biased p-n junctions at both sides of the active layer. A threshold current as low as 20 mA has been achieved in CW operation at room temperature. Fundamental transverse mode operation with linear light output-current characteristics and single longitudinal mode oscillation have been obtained.

New structures of GaAlAs lateral-injection laser for low-threshold and single-mode operation

Abstract: Two new structures of lateral-injection transverse junction stripe (TJS) lasers, in which the stripe geometry is formed by the double heterojunctions, have been developed. These lasers, the homojunction type and the single-heterojunction type, have a self-reverse-biased p-n junction for concentrating current into the narrow active region. The temperature dependence of the threshold current has been very much improved in one of the new structures, the homojunction type, and is fair compared with those of good conventional broad-contact lasers. The threshold current does not increase rapidly up to 350 K in the homojunction lasers. These lasers exhibit improved characteristics of low threshold, the single longitudinal mode oscillation as well as the single fundamental transverse-mode oscillation, and "kink-free" behavior in the current depedence of the light-output power.

A very narrow-beam AlGaAs laser with a thin tapered-thickness active layer (T 3 laser)

Abstract: A very narrow-beam and high-power laser which has a thin tapered-thickness active layer is developed. The property of LPE on a ridged substrate is utilized to obtain the thin tapered-thickness active layer. In the T3laser, the active layer is thinner near the mirror than in the inner region. The main feature of the T3laser is the independent control of the beam divergence perpendicular to the junction ( \theta_{\perp} ) and the threshold current ( Ith ). That is, the narrow beam is obtained with little increase of Ith . Thus \theta_{\perp} as narrow as 10° has been obtained with Ith about 60 mA. The large near-field spot size of the laser is also suitable for high-power operation. The maximum output power of 120 mW in the fundamental transverse mode has been realized for a laser emitting at 780 nm. Stable 30 mW operation at 50°C has been confirmed over 7000 h.

Single-mode junction-up TJS lasers with estimated lifetime of 10 6 hours

Abstract: Accelerated life test for single-mode junction-up TJS lasers have been carried out at ambient temperatures of 50, 60, 70, 80, and 90°C. The laser chips are passivated with Si 3 N 4 films and die bonded on Si submounts. Estimated mean time to failure is 106h at 25°C.

InGaAsP/InP buried crescent laser diode emitting at 1.3 µm wavelength

Abstract: The fabrication procedure, designing of an active region and a p-n-p-n current blocking structure, characteristics and the aging results of an InGaAsP/InP buried crescent (BC) laser diode are described. The BC laser diodes exhibit high laser performances, such as a low-threshold current, a fundamental transverse mode oscillation with linear light output-current characteristics. CW operation at as high as 100°C is achieved with a junction up configuration as a result of the improvement in the current blocking structure. A stable CW operation at 80°C has been realized with a constant optical output power of 5 mW.

A review on fabrication technologies for the monolithic integration of tapers with III-V semiconductor devices

Abstract: The past few years a lot of effort has been put in the development and fabrication of III-V semiconductor waveguiding devices with monolithic integrated mode size converters (tapers). By integrating a taper with a waveguide device, the coupling losses and the packaging cost of OEICs in future fiber-optical networks can be much reduced. This paper gives an overview of different taper designs, the possible fabrication technologies and performances of tapered devices.

InGaAsP double-channel- planar-buried-heterostructure laser diode (DC-PBH LD) with effective current confinement

Abstract: A new high-performance 1.3-μm InGaAsP semiconductor laser is described, in which effective current confinement into the active region has been realized. A p-n-p-n current blocking structure is made by liquid-phase epitaxy (LPE) on both sides of the active-stripe mesa which is defined by a pair of channels in the double-heterostructure wafer. The double-channel-planar-buried-heterostructure laser diodes (DC-PBH LD's) exhibit high-laser performances, such as a high differential quantum efficiency of 78-percent maximum, which results in high electrical to optical power conversion efficiency 43 percent, and high light output power of over 50 mW, as a result of the improvement in the current blocking structure. The threshold current temperature sensitivity is found experimentally to be reduced remarkably by increasing the doping concentration in the p-cladding layer. Characteristic temperature as high as 100 K has been obtained. CW operation is possible up to 130°C.

Modular microchannel cooled heatsinks for high average power laser diode arrays

Abstract: Detailed performance results for an efficient and low thermal impedance laser diode array heatsink are presented. High duty factor or CW operation of fully filled laser diode arrays is made possible at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using an anisotropic chemical etching process. A modular rack-and-stack architecture is adopted for the heatsink design, allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline lasers. >

The diode laser in atomic physics

Abstract: Over the past fiie years the use of diode lasers in physics research has expanded rapidly. In part, this has occurred because the diode laser is a highly monochromatic and tunable light source that, when compared to other laser systems, is quite inexpensive and easy to operate. These characteristics make the diode laser ideal for multi-laser experiments, or small scale/high quality research projects in general. In this article a brief introduction to the AlGaAs single-mode diode laser's characteristics and operation is presented, along with an overview of this laser's contributions to atomic physics research to date. It is hoped that this review will facilitate the further use of diode lasers in all aspects of physics, and in particular will aid the small scale researcher in attaining a more active place in mainstream physics.

Liquid phase epitaxy

Abstract: This paper presents a comprehensive review of the method of liquid phase epitaxy (LPE) of semiconductors. In Sect. 1 the physical principles including diffusion-limited growth and solid-liquid phase diagrams are treated in detail. In Sect. 2 technological aspects and various kind of growth systems including industrial versions are described. Section 3 summarizes the relevant properties of LPE grown layers. Section 4 contains the application of LPE to the material system InP/InGaAs/InGaAsP as a model system. In Sect. 5 the advantages and weaknesses of LPE with respect to device applications in comparison with competing methods are discussed, and finally we attempt to predict the future direction of LPE.