摘要:
The invention is a double chirped mirror and a method of constructing a double chirped mirror for a frequency range of electromagnetic radiation, comprising specifying a design including a plurality of layers, the plurality of layers being transparent to the electromagnetic radiation and having refractive indices which vary between layers in the plurality of layers, and wherein for a first set of layers the optical thickness of alternate layers in the set of layers varies monotonically and the total optical thickness of a layer and the two adjacent half layers in the set of layers varies monotonically. The design is optimized by adjusting the optical thickness of layers in the plurality of layers.
摘要:
The invention is a double chirped mirror and a method of constructing a double chirped mirror for a frequency range of electromagnetic radiation, comprising specifying a design including a plurality of layers, the plurality of layers being transparent to the electromagnetic radiation and having refractive indices which vary between layers in the plurality of layers, and wherein for a first set of layers the optical thickness of alternate layers in the set of layers varies monotonically and the total optical thickness of a layer and the two adjacent half layers in the set of layers varies monotonically. The design is optimized by adjusting the optical thickness of layers in the plurality of layers.
摘要:
The dielectric and/or semiconductor device influences the dispersion of electromagnetic radiation within a given spectral range. It comprises a substrate being essentially transparent to said electromagnetic radiation. The substrate has a first surface for incoupling said electromagnetic radiation into said substrate, and a second surface. The device further comprises a reflective multilayer structure on said second surface, said multilayer structure providing a controlled dispersion characteristic upon reflection of said electromagnetic radiation, e.g., a chirped mirror. The device is arranged in such a way that there is essentially no interference of electromagnetic radiation propagating in the direction of said multilayer structure and electromagnetic radiation reflected by said multilayer structure. An antireflection coating may be provided on the first surface of the substrate. With this device, oscillations in the group delay dispersion can almost completely be avoided.
摘要:
A laser light source comprises a semiconductor laser adapted for pulsed operation, a partially transmitting wavelength selective light reflector. The semiconductor laser comprises a front facet and a back facet. The front facet and the back facet define an internal laser cavity. The internal laser cavity comprises a laser active medium. The partially transmitting wavelength selective light reflector has a peak reflectivity within a gain bandwidth of said laser active medium. The wavelength selective light reflector and the back facet define an external laser cavity. A roundtrip time of light in the external laser cavity is about 20 nanoseconds or less. A full width half maximum bandwidth of the wavelength selective light reflector is adapted to accommodate at least 12 longitudinal modes of the internal laser cavity and at least 250 longitudinal modes of the external laser cavity.
摘要:
Semiconductor laser diodes, particularly broad area single emitter (BASE) laser diodes of high light output powers are commonly used in opto-electronics. Light output power and stability of such laser diodes are of crucial interest and any degradation during normal use is a significant disadvantage. The present invention concerns an improved design of such laser diodes, the improvement in particular significantly minimizing or avoiding (front) end section degradation at very high light output powers by controlling the current flow in the laser diode in a defined way. This is achieved by controlling the carrier injection, i.e. the injection current, into the laser diode in a novel way by creating single current injection points along the laser diode's longitudinal extension, e.g. along the waveguide. Further, the supply current/voltage of each single or group of current injection point(s) may be separately regulated, further enhancing controllability of the carrier injection.
摘要:
Semiconductor laser diodes, particularly broad area single emitter (BASE) laser diodes of high light output power, are commonly used in opto-electronics. Light output power and stability of such laser diodes are of crucial interest and any degradation during normal use is a significant disadvantage. The present invention concerns an improved design of such laser diodes, the improvement in particular significantly minimizing or avoiding degradation of such laser diodes at very high light output powers by controlling the current flow in the laser diode in a defined way. The minimization or avoidance of (front) end section degradation of such laser diodes significantly increases long-term stability compared to prior art designs. This is achieved by controlling the carrier injection into the laser diode in the vicinity of its facets in such a way that abrupt injection current peaks are avoided. To this, a current-blocking isolation layer (14) is shaped at its edge or border in such a way that it shows an uneven or partly discontinuous mechanical structure leading to a decreasing effective isolation towards the edge of said isolation layer, thus providing an essentially non-abrupt or even approximately continuous transition between isolated and non-isolated areas.
摘要:
Semiconductor laser diodes, particularly broad area single emitter (BASE) laser diodes of high light output powers are commonly used in opto-electronics. Light output power and stability of such laser diodes are of crucial interest and any degradation during normal use is a significant disadvantage. The present invention concerns an improved design of such laser diodes, the improvement in particular significantly minimizing or avoiding (front) end section degradation at very high light output powers by controlling the current flow in the laser diode in a defined way. This is achieved by controlling the carrier injection, i.e. the injection current, into the laser diode in a novel way by creating single current injection points along the laser diode's longitudinal extension, e.g. along the waveguide. Further, the supply current/voltage of each single or group of current injection point(s) may be separately regulated, further enhancing controllability of the carrier injection.
摘要:
A laser light source comprises a semiconductor laser adapted for pulsed operation, a partially transmitting wavelength selective light reflector. The semiconductor laser comprises a front facet and a back facet. The front facet and the back facet define an internal laser cavity. The internal laser cavity comprises a laser active medium. The partially transmitting wavelength selective light reflector has a peak reflectivity within a gain bandwidth of said laser active medium. The wavelength selective light reflector and the back facet define an external laser cavity. A roundtrip time of light in the external laser cavity is about 20 nanoseconds or less. A full width half maximum bandwidth of the wavelength selective light reflector is adapted to accommodate at least 12 longitudinal modes of the internal laser cavity and at least 250 longitudinal modes of the external laser cavity.
摘要:
The invention relates to the stabilization of high power semiconductor laser diode sources as they are extensively used in the field of optical communication. Such lasers are mostly employed as so-called pump laser sources for fiber amplifiers, e.g. erbium-doped fiber amplifiers, and are designed to provide a narrow-bandwidth optical radiation with a stable power output in a given frequency band. To improve the wavelength locking range of such laser sources when operating without an active temperature stabilizing element, an external reflector providing very high relative feedback is used. The reflectivity bandwidth of the external reflector is broadened for improving the stability of the laser source. In commonly employed optical fibers for conducting the laser beam, the external reflector is formed by one or a plurality of appropriately designed fiber Bragg gratings.
摘要:
Semiconductor laser diodes, particularly broad area single emitter (BASE) laser diodes of high light output power, are commonly used in opto-electronics. Light output power and stability of such laser diodes are of crucial interest and any degradation during normal use is a significant disadvantage. The present invention concerns an improved design of such laser diodes, the improvement in particular significantly minimizing or avoiding degradation of such laser diodes at very high light output powers by controlling the current flow in the laser diode in a defined way. The minimization or avoidance of (front) end section degradation of such laser diodes significantly increases long-term stability compared to prior art designs. This is achieved by controlling the carrier injection into the laser diode in the vicinity of its facets in such a way that abrupt injection current peaks are avoided. To this, a current-blocking isolation layer (14) is shaped at its edge or border in such a way that it shows an uneven or partly discontinuous mechanical structure leading to a decreasing effective isolation towards the edge of said isolation layer, thus providing an essentially non-abrupt or even approximately continuous transition between isolated and non-isolated areas.