Abstract: A high power laser source comprises at least a bar of laser diodes with a first coefficient of thermal expansion (CTEbar), a submount onto which said laser bar is affixed with a second coefficient of thermal expansion (CTEsub), and a cooler onto which said submount is affixed with a third coefficient of thermal expansion (CTEcool). The submount/cooling assembly exhibits an effective fourth coefficient of expansion (CTEeff). According to the invention, mechanical stress exerted to the laser bar improves reliability and optical performance. To effect this, CTEeff must differ from CTEbar, CTEeff?CTEbar. Preferably, CTEeff should differ by a predetermined amount from CTEbar. The difference is achieved in two ways: either by selecting CTEsub>CTEbar and CTEsub?CTEcool, or by selecting CTEsub<CTEbar and CTEsub<CTEcool. Thereby, all coefficients must be selected such that CTEeff differs from CTEbar: CTEeff?CTEbar, preferably by a percentage of 5% or by a predetermined amount of +/?3-4×10?7K?1.

Abstract: The present invention provides a switch assembly for use with a single-port OPM to realize a multi-port OPM having improved reliability. In one embodiment, an N×1 optical switch assembly, wherein N is an integer greater than one, is provided. The optical switch assembly includes N optical input ports, N micro-electro-mechanical system (MEMS) variable optical attenuators (VOAs), where each MEMS VOA is optically coupled to a respective optical input port and is operable between an on position and an off position, and an N×1 optical combiner optically coupled to the N MEMS VOAs. Each MEMS VOA is configured to transmit an optical signal from a respective one of the optical input ports to the N×1 optical combiner in the on position and to not transmit the optical signal in the off position.

Abstract: The present invention concerns tunable distributed Bragg reflector (DBR) semiconductor lasers, in particular a DBR laser with a branched optical waveguide 5 within which a plurality of differently shaped lasing cavities may be formed, and a method of operation of such a laser. The laser may comprise a phase control section (418), gain section (420, 422), a sampled grating DBR (412) giving a comb-line spectrum and two tunable, chirped DBRs (414, 416) for broadband frequency training and a coupling section (410).

Abstract: Semiconductor laser diodes, particularly high power AlGaAs-based ridge-waveguide laser diodes, are often used in opto-electronics as so-called pump lasers for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement in particular significantly minimizing or avoiding (front) end section degradation of such a laser diode and significantly increasing long-term stability. This is achieved by separating the waveguide ridge into an active main ridge section (4) and at least one separate section (12) located at an end of the laser diode, which may be passive. The separation is provided by a trench or gap (10) in the waveguide ridge.

Abstract: An apodised Bragg grating comprises a base grating section formed by a base order 5 periodic pattern of marks and spaces. The Bragg grating further comprises one or more apodised grating sections that are formed by a periodic pattern of marks and spaces, each defined by the base order pattern from which at least some of the marks are missing. The determination of which marks are missing may be performed by combining the base order pattern with a higher order modulation envelope function.

Abstract: An optoelectric subassembly including a receptacle assembly with an optoelectric device mounted therein to define a light axis. The receptacle assembly includes an optical fiber mounting structure defining an opening with an end of an optical fiber received therein. The mounting structure and opening are designed to position the received optical fiber with an end facet substantially perpendicular to the light axis. A first lens is mounted in the receptacle assembly adjacent the optoelectronic device in the light axis and a ball lens is mounted in the receptacle assembly and positioned in the light axis. The ball lens is mounted so as to be in abutting engagement with the facet of an optical fiber inserted into the opening. By forming the ball lens with a diameter equal to the diameter of a mounting ferrule on the end of the fiber and also equal to the diameter of the ferrule receiving opening, the ball lens is self-aligning.

Abstract: Semiconductor laser diodes, particularly high power ridge waveguide laser diodes, are often used in opto-electronics as so-called pump laser diodes for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement concerns a method of suppressing the undesired first and higher order modes of the laser which consume energy and do not contribute to the optical output of the laser, thus reducing it's efficiency. This novel effect is provided by a structure comprising CIG—for Complex Index Guiding—elements on top of the laser diode, said CIG being established by fabricating CIG elements consisting of one or a plurality of layers and containing at least one layer which provides the optical absorption of undesired modes of the lasing wavelength.

Abstract: Disclosed is a fiber amplifier system including a gain fiber having a single-mode core containing dopant ions capable of producing stimulated emission of light at wavelength ?s when pumped with light of wavelength ?p. Absorbing ion filtering means is operatively associated with the gain fiber to alter the gain curve. If the absorbing ions are the same as the gain ions of the gain fiber, the system further includes means for preventing pump light from exciting the gain ions of the filtering means. The excitation prevention means may take the form of means for attenuating pump light. If the absorbing ions are different from the dopant ions of the gain fiber, such absorbing ions can be subjected to light at wavelength ?p, but they will remain unexcited. Such absorbing ions can be used to co-dope the gain fiber, or they can be incorporated into the core of a fiber that is in series with the gain fiber.