Optitune Plc

Coronado Instruments, Inc.

Ieade Instruments Corp.

Coronado Technology Group, LLC

Optitune Public Limited Company

Yakov Sidorin

Geraldine Hogan, Legal Representative

David Lunt

Manuel B Serrano

Andrew G Lunt

Abdul H Damirji

Salah A Al-Chalabi

Ari H Kärkkåinnen

An optical characterization device has a guiding body and a diffractive structure integrated with it. The guiding body delivers radiation to the diffractive structure at a preselected angle and the diffractive structure diffracts at least a portion of radiation guided to it to give spatial resolution according to wavelength. A position sensitive detector detects the position of the spatially resolved radiation and thus the radiation can be characterized according to wavelength. Embodiments can be used to monitor and adjust the wavelength of a radiation source, using a feedback connection. By using the integrated approach, a very small structure can be realized and the structure can be relatively simply fabricated and assembled. The guiding body might be either capable of supporting multimode propagation of the radiation or might be a single mode waveguide. Where it is capable of supporting multimode propagation, an input to the guiding body acts to select a mode for propagation of the radiation.

Optical wavelength measuring device using guiding body and diffractive structure

A multi-layer thin-film narrow-band filter is fabricated by a process wherein each half of a symmetric stack is deposited under exact conditions, either successively or contemporaneously. The two halves of the filter structure are then combined and bonded together using a wet bonding process that remains reversible for a period of time sufficient for testing the filter and, if necessary, for separating the two halves to regain access to the spacer layer. Accordingly, the spacer layer may be adjusted to shift the peak wavelength, if necessary, to the precise design specifications for a particular application. After correction, the components of the symmetric filter are bonded again using the same wet process.

Fabrication of narrow-band thin-film optical filters

Two reflective surfaces disposed in a predetermined angular orientation inside the optical tube assembly of a telescope intercept the optical beam and deliver it from the objective to the eye-piece. By translating these surfaces simultaneously along the axis bisecting the angle between them, the separation between the focal points of the objective and the eye-piece is adjusted as required to re-focus the telescope in a continuous and reversible fashion without changing its overall dimensions.

Re-focusing mechanism for imaging system

A targeting unit is incorporated into the main body of a solar telescope. The targeting image is provided by an aperture facing the sun in the housing of the telescope through which sunlight is received and directed to a transmissive viewing screen placed in the housing on the same side of the telescope's eyepiece. All parts of the targeting system are fixed to the housing of the telescope and removed from accidental contact by personnel operating the telescope, thereby minimizing the chance for events that might cause misalignment. In addition, this configuration makes it possible to easily position both the viewing screen and the eyepiece on the same side of the telescope following any degree of folding of the objective beam.

Solar telescope with integrated alignment mechanism

A solar filter assembly combines a high-precision Fabry-Perot etalon with a variety of conditioning filters judiciously selected to effectively block completely all radiation except for the spectral line of interest. In addition, a tuning mechanism is provided to precisely control the peak frequency of the filter's output by varying the optical length of the etalon's cavity.

Solar tunable filter assembly

A temperature-stable and temperature-tunable composite etalon with an increased field of view is constructed by partially filling the cavity with a transmissive parallel-plate filler. The coefficient of thermal expansion and the index of refraction of the filler material are selected so as to produce the desired rate of change of the optical length of the cavity as a function of temperature. The filler plate is preferably chosen to be significantly thicker than the remaining air gap in the etalon cavity. As a result, the fact that the filler plate occupies a large part of the cavity space increases the acceptance angle of the etalon of the invention in comparison with corresponding conventional air-spaced etalons.

Etalon cavity with filler layer for thermal tuning

A compressive force is applied to a conventional air-spaced etalon filter to fine tune the thickness of the spacers to a precise and uniform optical length. The etalon is coupled to a housing device capable of adjusting the thickness of each spacer, thereby tuning the etalon to the desired filter wavelength. The resulting assembly is permanently set to the desired parameters for direct use in optical applications.

Etalon assembly tuned by applying counterbalanced compression forces

In a tunable optical source, a diffraction deviceis used to provide wavelength selective feedback to a laser diode. The diffraction deviceis at least partially fabricated in a material whose refractive index is controllable so as to control the diffraction performance of the device. This allows the diffraction deviceto be used in tuning the optical source, potentially without using moving parts. For instance, the refractive index can be controlled using a temperature change across material of the device. The diffraction devicecan be mounted in free space in an external cavity with respect to the laser diode. Novel forms of diffraction deviceare described. Tunable optical sources of this type can be used for instance in communications, particularly wavelength division multiplexing.

Tunable filter

In a tunable optical source, a zone plate deviceis used to provide frequency selective feedback to a laser diodeThe zone plate deviceis positioned to receive an output mode of the laser diodeand to return a frequency selected image of the mode spot to the laser diodeBy changing the refractive index of material of the zone plate deviceit is possible to change the frequency providing the image at the point of return to the laser diodeThis allows the zone plate deviceto be used in tuning the optical source, without using moving parts. In an embodiment, the zone plate deviceis at least partially fabricated in an electro-optic material such as SBN:75 and can therefore be tuned by using electrodes to apply an elecric field across it. The zone plate devicecan be coupled directly to the laser diodeor via a waveguide sectionwhich can be used to increase the output mode spot size from the laser diodefor delivery to the zone plate deviceThe zone plate devicecan alternatively be used as a standalone component for filtering optical radiation from other sources. Tunable optical sources can be used for instance in communications, particularly wavelength division multiplexing.

Tunable diffractive device

A tunable optical source comprises a laser diode and an external optical feedback device. The feedback device has a waveguiding portion fabricated at least in part out of a glass material having both organic and inorganic components. A control device is provided for controlling the refractive index of the glass material so as to change the wavelength of feedback to the laser diode. The glass material may for example have thermo-optic properties and the control device might then be a heating device for heating the glass material. The feedback device can have more than one portion, a second portion for example having controllable coupling characteristics for coupling optical radiation into or out of the feedback device. It also preferably has a portion for controlling optical path length in the feedback device.

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Tucson, AZ, United States of America

Yakov Sidorin