摘要:
A tunable optical cavity constructed from a fixed mirror and a movable mirror. The fixed mirror is attached to a substrate having a first electrically conducting surface. A support member having the moveable mirror supported thereon and having a second electrically conducting surface, is suspended above the substrate. A circuit applies an electrical potential between the first and second electrically conducting surfaces thereby adjusting the distance between the fixed and movable mirrors. The fixed mirror and the moveable mirror are positioned such that the mirrors form the opposite ends of the optical cavity. The distance between the fixed mirror and the moveable mirror is a function of the applied electrical potential. The fixed mirror is mounted in a well in the substrate such that distance between the support member and the substrate is less than half the distance between the mirrors.
摘要:
A tunable optical cavity constructed from a fixed mirror and a movable mirror. The fixed mirror is attached to a substrate having a first electrically conducting surface. A support member having the moveable mirror supported thereon and having a second electrically conducting surface, is suspended above the substrate. A circuit applies an electrical potential between the first and second electrically conducting surfaces thereby adjusting the distance between the fixed and movable mirrors. The fixed mirror and the moveable mirror are positioned such that the mirrors form the opposite ends of the optical cavity. The distance between the fixed mirror and the moveable mirror is a function of the applied electrical potential. The support member has physical dimensions that are chosen such that the amplitude of thermally induced vibrations in the support member are less than 0.01 percent of the wavelength of the resonating light. The support member is preferably a thin film membrane having the moveable mirror attached thereto and having openings communicating between the top and bottom surfaces of the membrane. The openings are located so as to reduce the vibration amplitude of the moveable mirror at any mechanical resonances of the membrane. The openings occupy less than 90% of the surface area of the membrane.
摘要:
A tunable optical resonator whose resonance frequency is determined by a light signal introduced into the resonator. The resonator includes an optical cavity having a first mirror and a second mirror. The first mirror and second mirror are supported relative to one another such that the distance between the first and second mirrors may be altered by applying a force to said second mirror thereby altering the resonance frequency of said cavity. The resonator includes a light input port for receiving a tuning light signal, and a light signal generator for generating the tuning light source. The tuning light signal is introduced into the optical cavity such that the tuning light signal is reflected between the first and second mirrors. In the absence of the tuning light signal, the resonator has a resonance characterized by a resonance response curve centered at &lgr;0. The tuning light signal has a wavelength &lgr;1 within said resonance response curve and sufficient power to cause said resonance response curve to shift such that the resonance response curve is now centered at &lgr;2, where &lgr;2>&lgr;1. In one embodiment of the invention, a circuit for monitoring the light leaving the resonator is utilized to control the wavelength and/or amplitude of the tuning light signal such that the light leaving the resonator has a predetermined wavelength.
摘要:
A tunable optical cavity constructed from a fixed mirror and a movable mirror is disclosed. A circuit applies an electrical potential between first and second electrically conducting surfaces thereby adjusting the distance between the fixed and movable mirrors. The fixed mirror and the moveable mirror are positioned such that the mirrors form the opposite ends of the optical cavity. The distance between the fixed mirror and the moveable mirror is a function of the applied electrical potential. The thermally induced vibrations are reduced by utilizing an electrical feedback circuit that measures the distance between the mirrors. The feedback circuit dynamically changes the potential between the substrate and the support member so as to reduce fluctuations in the cavity resonance frequency.
摘要:
An optical heterodyne detection system includes a tunable optical pre-selector that is adjusted to track the frequency of a swept local oscillator signal. The tunable optical pre-selector is adjusted in response to a measure of the frequency of the swept local oscillator signal and in response to a measure of a portion of the swept local oscillator signal after the portion of the swept local oscillator signal has optically interacted with the optical pre-selector. In an embodiment, at least some portion of the swept local oscillator signal is modulated before it interacts with the optical pre-selector. In an embodiment, the portion of the swept local oscillator signal that interacts with the pre-selector is detected and used in a feedback control circuit to generate a control signal which causes the error between the center frequency of the pre-selector and the frequency of the swept local oscillator signal to be small.
摘要:
A tunable optical resonator constructed from a fixed mirror and a moveable mirror. The fixed mirror is attached to a substrate having a first electrically conducting surface. A support member having the moveable mirror supported thereon and a second electrically conducting surface is suspended above the substrate such that the moveable mirror is separated from the fixed mirror. A light output port transmits a light signal of a wavelength determined by the distance between the fixed and moveable mirrors. An optical circuit measures the power level of the light signal and generates an electrical signal that depends on the measured power level. A frequency adjustment circuit, responsive to the electrical signal and a tuning voltage, applies an electrical potential between the first and second electrically conducting surfaces. The electrical potential causes the distance to remain at a distance determined by the tuning voltage independent of the power level for power levels less than a predetermined power level. The resonator can be used to construct a laser by incorporating an active layer for amplifying light trapped in the cavity. The resonator can also be used a tunable optical filter by including an input port for receiving a light signal that is to be filtered. In one embodiment of the invention, a feedback circuit consisting of an optical coupler, photodiode, amplifier, and signal adder is used to generate the potential between the first and second electrically conducting surfaces.
摘要:
An improved semiconductor optical amplifier with shortened gain-recovery time is disclosed. In the inventive device a carrier-storage region is placed adjacent to the gain region of the amplifier. Passage of carriers from the storage region to the gain region rapidly replenishes the carrier population within the gain region, thereby permitting rapid recovery of the amplifier gain.
摘要:
A semiconductor laser comprises a plurality of laser sections (10, 11, 12) defined in a body and isolated electrically from one another. The active region (14) of each section are optically coupled together and electrical connections (9) connect the sections in series and provide connections to an external drive current source. In a practical embodiment the laser is constructed in planar form in a body (16) of semi-insulating material and wells (23a, 23b, 23c) are etched into the body and are provided with metallization (24) which forms the electrical connections. The active region (14) extends continuously through the body with separate p-type anodes thereabove and separate n-type cathodes beneath the active region and extending on either side thereof.
摘要:
High-power, single transverse mode laser operation is achieved in an extended-cavity structure by combining a semiconductor gain medium having a large optical cavity together with a length of single mode optical fiber between first and second reflector surfaces. The first reflector surface is formed on an end facet of the semiconductor gain medium; the second reflector surface is formed on an end of the optical fiber. Output power is efficiently coupled from the fiber end of the extended-cavity laser to a standard transmission medium.
摘要:
A self-tuning mode locked semi-conductor laser automatically adjusts itself to produce short (less than 200 ps and preferably less than 50 ps) stable optical pulses. Tuning is achieved by means of a feedback loop which includes a spectrum analyzer (18) which receives a small amount of the optical output of the laser and monitors the spectral wavelength, spectral width or spectral shape of the output. A controller (19) is connected to said analyzer and produces a control signal based on said spectral information. The control signal causes adjustment of one or more parameters influencing operation of said laser, such as frequency or power of an RF drive signal, level of dc bias, cavity length, for example, in order to produce said short stable pulses.