Abstract:
A stable, high-speed-operation, high-performance, high-reliability single-wavelength semiconductor laser device; which comprises, between an upper clad layer and a lower clad layer, an active area, a front light reflection area located in front of the active area, a rear light reflection area located behind the active area, and a phase control area located close to the active area, the front light reflection area and the rear light reflection area respectively being provided with alternating diffraction lattice units and non-diffraction units; and which oscillates at a wavelength corresponding to a value of current running through the diffraction lattice units, wherein current block layers for preventing the flow of current into the non-diffraction units are formed on the non-diffraction units of at least one of the front light reflection area and the rear light reflection area.
Abstract:
A wavelength converter assembly includes a substrate. An epitaxial structure is formed on the substrate with areas of different optical properties. A laser and a photodetector are formed in the epitaxial structure. The photodetector generates a first electrical signal in response to an optical signal. A conditioning circuit is coupled to the laser and the photodetector. The conditioning circuit receives the first electrical signal and provides a second electrical signal to the laser to modulate its optical output.
Abstract:
A method of converting an optical wavelength includes providing a wavelength converter assembly with a photodetector and a laser with a common epitaxial structure. The epitaxial structure has areas of differing bandgap. An optical input having a first wavelength at the wavelength converter assembly is absorbed. A first electrical signal is generated from the photodetector in response to the optical input. The first electrical signal is conditioned to produce a conditioned first electrical signal. A second electrical signal is generated from the conditioned first electrical signal. A laser output is generated from a gain medium of the laser at a second wavelength in response to the second electrical signal.
Abstract:
A laser assembly includes an epitaxial structure formed on a substrate. A separately controllable tunable laser resonator and external optical amplifier are formed in the epitaxial structure. At least a portion of the laser and amplifier share a common waveguide, which may have non-uniform optical or geometrical properties along the waveguide centerline or across a normal to the centerline.
Abstract:
A method of wavelength locking and mode monitoring a tuneable laser (15) that includes two or more tuneable sections in which injected current can be varied, said sections including at least one reflector section and one phase section, wherein the laser (15) has been characterised with respect to suitable laser operation points that have been determined as different current combinations through the different laser sections, and wherein said laser operates in a predetermined, selected operation point. The invention is characterised by detecting the light emitted by the laser with respect to its wavelength with the aid of a wavelength selective filter; controlling the laser in an iterative process in which alternated currents through the reflector section (17) of said laser and, when applicable, its coupler section (19), and the current through the phase section (18) of said laser are adjusted; adjusting the currents through the reflector section and the coupler section so as to obtain a minimum with respect to the ratio between power rearwards (I3) and power forwards (I2); and adjusting the current through the phase section (18) of the laser so as to hold the wavelength constant, said wavelength being measured against a wavelength reference (32).
Abstract:
An optical filter is formed from at least two gratings (102, 103) located in a waveguide region (104) of a semiconductor optical device (101). Each grating has a multiple peak optical passband. The gratings are spaced apart in the waveguide region and form an optical cavity having a comb-filter characteristic. The gratings may be located in the active region of an optical gain element and in a preferred example are superstructure gratings (SSGs). A number of filters may be joined together in series.
Abstract:
A semiconductor laser device is disclosed that includes a laser resonator situated to produce a laser beam, with the laser resonator including an angled distributed Bragg reflector (a-DBR) region including first and second ends defining an a-DBR region length corresponding to a Bragg resonance condition with the first end being uncleaved and including a first mode hop region having a first end optically coupled to the a-DBR region first end and extending a first mode hop region length associated with the a-DBR region length to a second end so as to provide a variable longitudinal mode selection for the laser beam.
Abstract:
Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.
Abstract:
A combined Gain-SOA chip is provided for forming an external cavity laser that is provided with a monolithically integrated power amplifier The Gain-SOA chip comprises a gain section (3), an SOA section (5), and an optical grating (7) arranged between the gain section and the SOA section. A laser cavity may be formed by the optical grating in combination with an external mirror (2) placed adjacent to the gain section. The grating may be formed as DFB or as DBR grating, wherein the grating may be at least partly uncovered an open to the surrounding.
Abstract:
A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising a laser chip having epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a passive section, wherein at least one of the reflectors is a distributed Bragg reflector section comprising a grating and configured to have a tunable reflection spectrum, wherein the laser is provided with a common earth electrode that is configured to be electrically grounded in use, wherein control electrodes are provided on the optical waveguide in at least the optical gain section and the at least one distributed Bragg reflector section, wherein the passive section is provided with a passive section electrode that electrically contacts the opposite side of the optical waveguide from the substrate, the passive section is configured not to be drivable by an electrical control signal, and no grating is present within the passive section, and wherein the passive section is a grounded passive section in which the passive section electrode is configured to be electrically grounded in use and electrically contacts the passive section, and wherein the passive section electrode and the common earth electrode electrically contact opposite sides of the optical waveguide.