The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 25, 2017
Filed:
May. 12, 2014
Phovel.co.ltd., Yuseong-gu, Daejeon, KR;
Jeong-Soo Kim, Gongju-si, KR;
PHOVEL.CO.LTD., Yuseong-Gu, Daejeon, KR;
Abstract
The present invention relates to an external cavity type laser provided with a wavemeter capable of precisely measuring a wavelength of a laser beam based on a transmission wavelength band of a wavelength selective filter inserted into a cavity regardless of a driving current of a laser diode chip. The external cavity type laser apparatus includes: a laser diode chipemitting a laser beam; a beam feedback partial reflection mirrorreflecting a portion of the beam emitted from the laser diode chipto feed the beam back to the laser diode chip; a collimating lensinstalled on a path of a beam between the laser diode chipand the beam feedback partial reflection mirrorto collimate the beam emitted from the laser diode chip; a 45-degree partial reflection mirrorconverting a laser beam moving in parallel with a package bottom surface into a laser beam moving perpendicularly to the package bottom surface; a wavelength selective filtertransmitting a beam having a selected specific wavelength therethrough; a beam strength monitoring photodiodedisposed on a path of a beam moving from the collimating lensto the 45-degree partial reflection mirrorand transmitting through the 45-degree partial reflection mirror; and a wavelength monitoring photodiodedisposed on a path of a beam moving from the wavelength selective filterto the 45-degree partial reflection mirrorand transmitting through the 45-degree partial reflection mirror. A magnitude of a photocurrent flowing to the wavelength monitoring photodiodeis changed depending on a strength of a beam output oscillated in the laser diode chipand a reflectivity at the wavelength selective filter, and a photocurrent flowing to the beam strength monitoring photodiodeis determined by the strength of the beam output outputted from the laser diode chip. Therefore, a value obtained by dividing the photocurrent flowing to the wavelength monitoring photodiodeby the photocurrent flowing to the beam strength monitoring photodiodedepends on only the reflectivity at the wavelength selective filter. Therefore, the value obtained by dividing the photocurrent flowing to the wavelength monitoring photodiodeby the photocurrent flowing to the beam strength monitoring photodiodeprovides information on the wavelength of the laser beam based on the transmission band wavelength of the wavelength selective filter, and the wavelength of the laser beam may be figured out by measuring the value, and may be very precisely determined to be a predetermined wavelength.