Abstract: A method to manufacture an optical device with enhanced high frequency performance is disclosed. The method includes steps of: (a) forming semiconductor layers on a semiconductor substrate, (b) etching the semiconductor layers by using a mask to form a plurality of diffraction gratings, where the mask provides a plurality of periodic patterns each corresponding to respective gratings and having a specific pitch different from others, (c) forming an active layer on the etched semiconductor layers, (d) measuring a maximum optical gain of the active layer, (e) selecting one of diffraction gratings based on the measured optical gain, and (f) forming a current confinement structure aligned with the selected diffraction grating.

Abstract: A method to manufacture an optical device with enhanced high frequency performance is disclosed. The method includes steps of: (a) forming semiconductor layers on a semiconductor substrate, (b) etching the semiconductor layers by using a mask to form a plurality of diffraction gratings, where the mask provides a plurality of periodic patterns each corresponding to respective gratings and having a specific pitch different from others, (c) forming an active layer on the etched semiconductor layers, (d) measuring a maximum optical gain of the active layer, (e) selecting one of diffraction gratings based on the measured optical gain, and (f) forming a current confinement structure aligned with the selected diffraction grating.

Abstract: Disclosed herein are a highly purified tocopheryl phosphate and/or a salt thereof (tocopheryl phosphates) wherein a P,P'-bistocopheryl hypophosphate and/or a salt thereof (P,P'-bistocopheryl diphoshates) is contained in a proportion of not higher than 3% by weight; a process for producing a highly purified tocopheryl phosphate and/or a salt thereof, which comprises the steps of reacting a tocopherol with an oxyphosphorus trihalide followed by treating with an acid or basic aqueous solution to thereby form tocopheryl phosphates (i) in which P,P'-bistocopheryl diphoshates (ii) formed as by-products are contained, hydrolyzing the P,P'-bistocopheryl diphoshates (ii) under acid condition, and, optionally, rendering the hydrolyzate neutral or basic under basic condition; and a method of analyzing tocopheryl phosphates, comprising analyzing a sample containing components (i) and (ii) with the use of a high-performance liquid chromatograph column packed with a gel of a polymethacrylate having, bonded thereto, long-ch

Abstract: Disclosed herein are a highly purified tocopheryl phosphate and/or a salt thereof (tocopheryl phosphates) wherein a P,P'-bistocopheryl hypophosphate and/or a salt thereof (P,P'-bistocopheryl diphoshates) is contained in a proportion of not higher than 3% by weight; a process for producing a highly purified tocopheryl phosphate and/or a salt thereof, which comprises the steps of reacting a tocopherol with an oxyphosphorus trihalide followed by treating with an acid or basic aqueous solution to thereby form tocopheryl phosphates (i) in which P,P'-bistocopheryl diphoshates (ii) formed as by-products are contained, hydrolyzing the P,P'-bistocopheryl diphoshates (ii) under acid condition, and, optionally, rendering the hydrolyzate neutral or basic under basic condition; and a method of analyzing tocopheryl phosphates, comprising analyzing a sample containing components (i) and (ii) with the use of a high-performance liquid chromatograph column packed with a gel of a polymethacrylate having, bonded thereto, long-ch

Abstract: A resistance welding device includes a base structure having vertically separated ceiling and floor members. The ceiling member includes a first pair of rail members to establish a y-axis and to thereby dependently support a first mounting structure. The first mounting structure in turn includes a second pair of rail members to establish an x-axis and to dependently support a pair of electrode guns therefrom. In such a manner, a matrix configuration of welding points can be welded so as to weld a pair of weldable members to one another.