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:
May. 12, 1992
Filed:
Dec. 12, 1990
Jan Opschoor, Eindhoven, NL;
Hubertus P Ambrosius, Eindhoven, NL;
U.S. Philips Corp., New York, NY (US);
Abstract
Semiconductor diode lasers of the so-called NAM (Non-Absorbing Mirror) type are used due to the high emanating power as writing (and reading) lasers in optical recording systems. The known lasers of this type include both in the active region (13') and in the mirror region (17, 19) a cladding layer (1), which fills a groove and is provided on an absorbing layer (9) (17, 19). The fundamental lateral mode is favored in both regions (13'), (17, 19) by absorption of part of the radiation produced. Due to the absorption in the mirror region (17, 19) mirror degradation occurs, which limits the maximum power and the life of the laser. A new semiconductor diode laser includes in the mirror region (17, 19) a first cladding layer (1'), a radiation-guiding layer (2') and a third cladding layer (6). In the radiation-guiding layer (2'), a radiation guide (15) is formed by an arrangement (12) in the radiation-guiding layer (2'), by which a step is formed in the effective refractive index. Further, the layers (1', 2', 6), which are located in the amplification profile of the radiation guide (15), have a larger band gap than the active layer (3). Due to the particular structure employed, no absorption of radiation occurs in the mirror region (17, 19). As a result, the occurrence of mirror degradation is limited so that lasers are obtained having a high power available and a long life.