Abstract: A laser module can include one or more lasers, an optical I/O interface, an optical receive interface, an optical transmit interface, a first optical device, and a second optical device. The first optical device is disposed between the optical I/O interface and the optical transmit interface, and the second optical device is disposed between the optical I/O interface and the optical receive interface.

Abstract: A process evaluates an aging property of a distributed Bragg reflector (DBR) laser. The process includes illuminating a Bragg grating of the distributed Bragg reflector (DBR) laser with light while the DBR laser is both supplied a tuning current and not lasing. The process also includes performing an action to the DBR laser responsive to a wavelength of a Bragg peak in a portion of the light reflected by the Bragg grating and a value of the tuning current supplied during the illuminating.

Abstract: The invention is a semiconductor optical device and a method of manufacture. The device includes a first waveguide having an edge, and a second waveguide adjacent to at least a portion of the first waveguide including the edge so that light is coupled from the first to the second waveguide. The second waveguide has a modal index which is essentially constant at least at the edge of the first waveguide. The method includes forming at least the second waveguide by Selective Area Growth (SAG) using oxide pads of a particular geometry to achieve the essentially constant modal index. In one embodiment, the device is an expanded beam laser with an expander portion which is less than 300 microns.

Abstract: The invention is a semiconductor device, and a method of fabrication, where a waveguide layer in which light is propagated and an integral photodetector are formed in the device. A light absorbing layer of the photodetector includes a portion of the waveguide layer which is modified to absorb a portion of the light while transmitting the remainder of the light. Additional components, such as a laser, optical amplifier and modulator can be included with the photodetector.

Abstract: A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an “optical isolator.” The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s).

Abstract: An optical transmitter for generating any one of N carrier signals for use in an M-channel WDM system (M≧N), each channel operating at a different carrier wavelength &lgr;s (s=1, 2 . . . M), includes an optical source for generating the carrier signals at any one of multiplicity of N wavelengths &lgr;i (i=1, 2 . . . N), where (1≦N≦M). A first controller selects a particular one of the wavelengths &lgr;i at which the source operates. An optical modulator receives the carrier signal corresponding to the selected wavelength &lgr;i and impresses information on the received signal. The modulator has a characteristic electronic bandgap and a wavelength &lgr;g corresponding thereto. At a given temperature, &lgr;g is offset from each &lgr;i by an amount &Dgr;&lgr;i. For each wavelength &lgr;i there is a predetermined value of &Dgr;&lgr;i which delivers preferred (e.g., optimum) transmission performance.

Abstract: A method of fabricating an expanded beam optical waveguide device (e.g., a laser), comprises the steps of (a) forming a first semiconductor waveguide region having first and second sections of different thickness and an intermediate vertical taper section of varying thickness coupling the first and second sections to one another, the first waveguide region being effective to expand the size of the beam as it propagates from the first section to the second section, (b) forming a second semiconductor region (e.g., a laser active region) on the first waveguide region, (c) etching the second region so as to form an essentially vertical first surface of length A-B which extends obliquely across the propagation axis of the device, (d) forming a third semiconductor region (e.g.

Abstract: In accordance with the present invention, a wavelength selectable laser source comprises a tunable pump source, an array of waveguide lasers for emitting light at respectively different wavelengths and a router for directing light from the pump source to an appropriate waveguide laser. A second router can be used to direct all laser outputs to a common output waveguide. The result is a wavelength selectable, stable signal source. In preferred embodiments the routers are dense wavelength-division multiplexers (DWDMs) and the waveguide lasers are rare-earth doped fiber lasers. Alternative embodiments provide a variety of ways of routing the pumping source.

Abstract: Methods and apparatus for stabilizing or otherwise controlling wavelength in tunable semiconductor lasers and other optical sources. A tunable semiconductor laser includes a gain section and at least one tuning section. Spontaneous emission (SE) from the tuning section is detected and used in a feedback control loop to control the amount of current applied to the tuning section. The SE may be detected using an integrated detector on the semiconductor laser chip, an external detector arranged adjacent the chip to detect SE emitted from a side of the tuning section, or an external detector arranged to detect SE coupled from an optical fiber or other signal line connected to an optical signal output of the laser. The feedback control loop may operate to maintain the detected SE at a constant level, such that the current applied to the tuning section is adjusted to compensate for the effects of aging and the laser output wavelength is thereby stabilized.

Abstract: An automatic access code dialer stores a user entered telephone number and compares the first three digits of the stored telephone number to a list of three digit numbers that specify telephone exchanges that may be contacted using an alternative shorthaul long distance service provider. If the stored digits match one of the numbers on the list, the user entered telephone number and an access code for a alternative service provider are passed to the telephone network. If the stored digits do not match one of the numbers on the list, the user entered telephone number is passed to the telephone network.