The Gemini North Adaptive Optics (GNAO) facility is the upcoming Adaptive Optics (AO) facility for Gemini North providing a state-of-the-art AO system for surveys and time domain science in the era of James Webb Space Telescope (JWST) and Rubin operations. GNAO will be optimized to feed the Gemini Infrared Multi Object Spectrograph (GIRMOS).
The GNAO project includes the development of a new laser guide star facility which will consist of four side launched laser beams supporting the two primary AO modes of GNAO: a wide-field mode providing an improved image quality over natural seeing for a 2-arcminute circular field-of-view using Ground Layer AO (GLAO) and a narrow-field mode providing near diffraction-limited performance over a 20 × 20 arcsecond square field-of-view using Laser Tomography AO (LTAO).
After a competitive phase A study among three teams for the conceptual design of the AO bench, one team has been selected to complete the design, build and commissioning it at the telescope. We will be presenting the overall GNAO facility design, including specifics related to the AO bench and its architectural design. We will provide updates on all subsystems of the facility.
Recently, dual mode lasers proved to be interesting sources for radio frequency generation at millimeter wave frequency and beyond, to be used in photonic RoF systems. As the optical modes can eventually be correlated, such sources associate the simplicity of heterodyning technique with the frequency stability. Still, most architectures require active frequency control loop to reach communication requirements to limit frequency drift, and reduce the phase noise of the generated carrier. In this communication, we propose the use of a free running dual mode laser integrated on glass for radio frequency generation. The device is fabricated on an ion-exchanged co-doped Erbium Ytterbium substrate to emit in the C-band. We demonstrate that this device is able to generate an ultra-narrow spectrum radio-frequency carrier, reaching 600Hz spectral linewidth without control loop nor thermal stabilization. As a proof of concept, the device proposed in this work produces a radio frequency at 6.1 GHz which has been evaluated as an electrical carrier in radio transmission experiments. Data rates of several Gbps using complex modulation formats such from BPSK to 64QAM have been successfully tested. The results are compliant with communications standards requirements, validating the use of such a source in Radio over Fibre (RoF) systems. This paper first presents the glass dual-mode laser design, followed by the characterization of the generated carrier to finally present the radio over fiber results.
In this work, we propose the realization of two single mode distributed feedback (DFB) lasers emitting at 1.5μm with ultra-narrow linewidths, co-integrated on a co-doped Erbium Ytterbium IOG11 glass substrate. The beating note of these two lasers on a fast photodiode is used to generate mm-wave signals. Each laser is composed of a waveguide fabricated by ion exchange with a Bragg grating etched on the top. In order to set a precise value of the mm-wave frequency, the emission wavelength of both DFB lasers must be accurately fixed. This is achieved by controlling the laser’s waveguide design. The beating produced between these lasers generates mm-wave signals from GHz to THz. The co-integration helps to enhance the beating quality by reducing fluctuations between the two lasers. Lasers are first studied independently: their optical power, linewidth and relative intensity noise are characterized. Finally, the beating signal quality is estimated through the characterization of the produced electrical spectrum.
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