摘要:
Semi-integrated external cavity diode laser (ECDL) designs including integrated structures comprising a gain section, modulator section, and optional phase control section. Each integrated structure includes a waveguide that passes through each of the sections, with the waveguide further including an in-waveguide mirror. The in-waveguide mirror defines one end of an “effective” laser cavity, with the other end defined by a reflective element disposed generally opposite a rear facet of the integrated structure, forming an external cavity therebetween. The in-waveguide mirror is formed by using a focused ion beam (FIB) cut through the waveguide, or by etching one or more trenches through the waveguide and backfilling the trenches using a re-grown crystal or amorphous material deposition process. A tunable filter is disposed in the external cavity to effectuate tuning of the laser. The modulation section of the integrated structure enables high-speed modulation of an optical signal at a selected communication channel without requiring an external modulator.
摘要:
Semi-integrated external cavity diode laser (ECDL) designs including integrated structures comprising a gain section, phase control section, and optional modulator section. Each integrated structure includes a waveguide that passes through each of the sections. A mirror is defined in the structure to define one end of a laser cavity. A reflective element is disposed generally opposite a rear facet of the gain section, forming an external cavity therebetween. A tunable filter is disposed in the external cavity to effectuate tuning of the laser. During operation, a modulated drive signal is provided to the phase control section. This modulates an optical path length of the laser cavity, which produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop. Upon passing through the modulator section, an optical signal is modulated with data.
摘要:
A wavelength meter, an associated method, and system are generally described. In one example, an apparatus includes a photodiode to receive an optical signal and to generate a photocurrent upon receiving the optical signal, the photodiode having an absorption edge that is substantially aligned with a band of wavelengths, wherein the absorption edge shifts toward longer wavelengths when a reverse bias is applied to the photodiode, and control electronics coupled with the photodiode to apply at least a first reverse bias and a second reverse bias to the photodiode, wherein a ratio of a first measurement of the photocurrent at the first reverse bias and a second measurement of the photocurrent at the second reverse bias provides information about the wavelength of the optical signal.
摘要:
A wavelength meter, an associated method, and system are generally described. In one example, an apparatus includes a photodiode to receive an optical signal and to generate a photocurrent upon receiving the optical signal, the photodiode having an absorption edge that is substantially aligned with a band of wavelengths, wherein the absorption edge shifts toward longer wavelengths when a reverse bias is applied to the photodiode, and control electronics coupled with the photodiode to apply at least a first reverse bias and a second reverse bias to the photodiode, wherein a ratio of a first measurement of the photocurrent at the first reverse bias and a second measurement of the photocurrent at the second reverse bias provides information about the wavelength of the optical signal.
摘要:
Mode behavior of single longitudinal mode semiconductor lasers are modeled and employed for configuring external cavity lasers, including external cavity diode lasers (ECDLs). In particular, equations employed for modeling active and passive mode pulling effects are derived, and the equations are combined to formulate an equation corresponding to an optimal operating condition under which longitudinal lasing mode stability is enhanced. Under the optimal condition, the laser will operate in a lasing mode with the lowest threshold losses that is also stable. Based on the equation, a full-width-half maximum (FWHM) value for in intracavity filter can be selected to enable the laser to operate under or approach the optimal operating condition.
摘要:
A method and system for providing an energy assisted magnetic recording (EAMR) head are described. The EAMR head includes a laser, a slider, and an EAMR transducer. The laser has a main emitter and at least one alignment emitter. The slider includes at least one alignment waveguide, at least one output device, and an air-bearing surface (ABS). The alignment waveguide(s) are aligned with the alignment emitter(s). The EAMR transducer is coupled with the slider and includes a waveguide aligned with main emitter. The waveguide is for directing energy from the main emitter toward the ABS.
摘要:
A structure for measuring energy absorption by a surface plasmon receptor or NFT on a waveguide comprises a first waveguide, a first input grating for coupling light comprising a first wavelength into the first waveguide, a first output grating for coupling light out of the first waveguide, a first plurality of surface plasmon receptors in cooperation with the first waveguide to receive light energy and located between the first input grating and the first output grating. The structure may further comprise a second waveguide, a second input grating for coupling light into the second waveguide, a second output grating for coupling light out of the second waveguide, a second plurality of surface plasmon receptors between the second input grating and the second output grating and in cooperation with the second waveguide to receive light energy, wherein the second plurality may be less than or greater than the first plurality.
摘要:
Alignment of a laser apparatus is achieved by actively aligning components of the laser apparatus and then passively deriving an optical axis from that alignment. This passive derivation can be achieved by identifying features of an actively aligned optical element, deriving positional data for those features, and developing an optical axis from that positional data. The derivation of positional data may be performed over a particular coordinate system of an image taken of the feature, e.g., obtained by a vision system. The positional data and optical axis may be extrapolated out to a reference coordinate system for use in passively aligning other optical elements.
摘要:
Systems and methods for controlling light phase difference in interferometric waveguides at near field transducers by selectively heating the light source are provided. One such system for controlling light phase at the NFT of an interferometric waveguide includes a laser, a heater configured to heat the laser, a splitter configured to receive light from the laser and to split the light into a first waveguide arm and a second waveguide arm, the first waveguide arm and the second waveguide arm converging at a junction about opposite the splitter, and the NFT proximate the junction and configured to receive the light, where the first waveguide arm is longer than the second waveguide arm by a preselected distance, and where the heater is configured to generate and maintain a preselected phase difference in the light arriving at the NFT via the first waveguide arm and the second waveguide arm.
摘要:
A method and system for providing an energy assisted magnetic recording (EAMR) head are described. The EAMR head includes a laser, a slider, and an EAMR transducer. The laser has a main emitter and at least one alignment emitter. The slider includes at least one alignment waveguide, at least one output device, and an air-bearing surface (ABS). The alignment waveguide(s) are aligned with the alignment emitter(s). The EAMR transducer is coupled with the slider and includes a waveguide aligned with main emitter. The waveguide is for directing energy from the main emitter toward the ABS.