Method for manufacturing laser diode chip, optical transmitting/receiving module and method for aligning positions thereof

The present invention relates an optical element used in the field of optical communication and a method for aligning an optical fiber to connect an external optical communication system to the optical element. The present invention relates to an optical transmitting module which consists of a silicon substrate, an optical fiber fixed to the substrate and a laser diode chip, with the first fixing groove for supporting and fixing the optical fiber, with the second fixing groove for supporting and fixing the laser diode chip and with a mediating groove for positioning the optical fiber and the laser diode chip at a definite distance, said mediating groove being formed between the first and the second groove, all those grooves being formed on the top side of said substrate, wherein the first and the second fixing groove are each formed in their predetermined depths on the top side of the substrate so that the central axis of the optical fiber exactly agrees with the center of optical beams from the laser diode chip, the optical fiber and the laser diode chip being received in the first and the second groove, with the result that the relation of mutual positions for the optical fiber and the laser diode chip is precisely determined merely by seating the optical fiber and the laser diode chip in the first and the second groove. Further, the present invention also relates to a method for manufacturing a laser diode chip which comprises the steps of: vapor-depositing a nitride thin film(Si3N4) on the surface of a wafer on which the n type InP, p type InP, n type InP, p type InP and InGaAs layers are successively laminated with the completion of the tertiary MOCVD growth, and etching the InGaAs layer by using the mixed solution of sulfuric acid, hydrogen peroxide and distilled water after opening an etching window by means of photolithography to form V-mesa and V-grooves; etching an InP layer as a current cut-off layer by using a solution based on a hydrochloric acid; vapor-depositing a nitride thin film(SiNx) by using a PECVD process; opening the electrode forming window to form electrodes by means of a photolithography and forming P type electrodes on the surface of the wafer; forming a N type electrode on the back surface of the wafer after polishing the bottom surface.