摘要:
Process for the production of a monolithic integrated optical device incorporating a semiconductor laser and an optical waveguide, as well as to a device obtained by this process.The substrate is given a profile having at least one step. On said substrate is deposited by a single epitaxy operation performed in the vapour phase and in a successive manner a first confinement layer, a guidance layer made from a material transparent for the radiation emitted by the laser, a second confinement layer, an active layer, a third confinement layer and a contact layer. The transparent material has a refractive index higher than the indices of the confinement layers surrounding the same. Thickness values are given to the different layers such that the active layer of the lower stack faces the transparent layer of the upper stack.Application to optical telecommunications.
摘要:
Process for manufacturing a semiconductor laser having a buried ribbon. After making a double heterostructure (2, 3, 4, 5) on a substrate (1), there is implanted in the contact layer (5) a p-type doping material, which has the effect of rendering it amorphous. The unit, except for a ribbon, is etched which leaves a mesa. A resumption of epitaxy makes it possible to bury the channel. This resumption does not lead to a crystalline growth on the upper surface of the contact layer, although the annealing that takes place during the resumption of epitaxy gives good ohmic contacts at the level of the implanted layer.
摘要:
The invention relates to polarization mode dispersion; writing index variations in a grating written in an optical fiber generates polarization mode dispersion. The invention proposes to compensate this polarization mode dispersion by mechanical curvature of the fiber. The invention provides a simple method of compensating polarization mode dispersion effectively and improving the performance of a grating written in a fiber; it applies in particular to Bragg gratings.
摘要:
Dispersion-shifted monomode optical fibers have an effective mode surface area greater than 65 &mgr;m2 by optimization of the geometrical characteristics that characterize the fibers.
摘要:
An optical amplifier of the type including an inlet for a light signal to be amplified and an outlet for an amplified light signal that has been amplified by means of an amplifying waveguide that is controlled by regulation light coming from a pumping diode; the amplifier comprising: an optical circulator having an inlet port receiving the light signal to be amplified, an outlet port delivering the amplified light signal, and two intermediate ports, the first of the intermediate ports being connected to the amplifying waveguide; and regulation means having an inlet connected to the second of the intermediate ports and an outlet connected to the pumping diode, whereby the amplifying waveguide has equalized gain for all of the carrier waves constituting the amplified light signal.
摘要:
A band-pass filter written into an optical waveguide includes at least one Bragg grating creating coupling between two propagation modes. In one version the pitch of the grating is equal to the length of beating of these two modes, to create codirectional coupling for the LP01 and LP0i modes. In another version the grating couples the LP01 mode to any contradirectional radiation mode. The filter includes, at one point at least of the grating, an area in which one half-period of the grating is omitted to create a phase-shift of .pi. between the two coupled modes.
摘要:
Dispersion-shifted monomode optical fibers have an effective mode surface area greater than 65 .mu.m.sup.2 by optimization of the geometrical characteristics that characterize the fibers. The fibers have substantially zero chromatic dispersion in the vicinity of 1.55 .mu.m, and they include an optical core having a central portion, a first layer having an index lower than the index of the central portion, and a second layer having an index higher than the index of the first layer and higher than the index of the optical cladding.
摘要:
An in-fiber mode converter comprises fiber portions (10) constituting an input microlens, a fiber portion (20) constituting a phase shifting region adapted to convert a propagation mode of an optical signal into another propagation mode, and fiber portions (30) constituting an output microlens. The fiber portions are spliced, the converter is compact and losses are minimized relative to mode conversion in free space.
摘要:
It is shown that by modifying the photosensitivity profile it is possible to provide better adjustment of the characteristic curve of a filter, and in particular to eliminate a reflection peak that is present within the working band. The photosensitivity profile is inverted to a considerable extent. In practice, the core of the fiber has only 20% of photosensitive doping material compared with the quantity of photosensitive doping material present in the cladding of the fiber.
摘要:
To adjust the spectral band of an attenuating optical fiber, a section of the optical fiber is formed that has a sloping Bragg grating. To smooth the spectral band of the attenuation, it is shown that the filter section must be short. Independently of selectivity, the smoothing makes it possible to avoid distorting the filtered signal. The length of the filter section is preferably 0.7 mm.