High power and high brightness laser diode structures at 980nm using an Al-free active region.

High bit rate, WDM, networks are reliant on Er or Er/Yb doped fibre amplifiers. Reliable, high power laser diodes at 980nm and 1480nm are key devices for pumping these amplifiers. We have developed several 980nm laser diode structures at 980nm, using an Aluminium free active region and standard AR/HR coatings on the facets. Our lasers show low optical losses, low threshold current density and a high external differential efficiency. We demonstrate a mini-bar of small angle index guided tapered laser diodes (emissive width of 3mm) with an optical output power of 20W at 33A under CW operation (25degreesC). The far field of the slow axis has a Gaussian single lobed shape, with a FWHM of 3.5degrees at maximum power, which is two time less than obtained with multimode broad area lasers. With such a device, we expect to couple 10W into a 100mum diameter fibre. We also demonstrate a large aperture gain-guided tapered laser with an output power of 2.4W and a calculated M-1/c2(2) = 3, the M-1/c2(2) factor being calculated with the method based on measurements of the fields profiles widthes at 1/e(2).