LISA phasemeter development: Advanced prototyping

Abstract

Abstract.We present the status of our investigations on the LISA Phasemeter. The new prototype is based on a custom-designed breadboard with four high-speed ADC and two DAC channels, extended readout capabilities and a large FPGA (field programmable gate array). The required main functionalities and performance of the prototype have been demonstrated in laboratory conditions.

Phasemeter core for intersatellite laser heterodyne interferometry: modelling, simulations and experiments

“…The measurement needs to be performed with a noise level of the order of µcycle/ √ Hz. The readout system, or phasemeter, for these interferometers is implemented by digitising the heterodyne signals and determining the phase using an IQ demodulation system [2,3] implemented in an FPGA. Due to the high initial phase noise measured by each interferometer and also the continuously varying Doppler shifts in the LISA constellation, this digital IQ demodulation is embedded in a closed-loop phase and frequency tracking system, a phase-locked loop (PLL) or more specifically an all digital phase-locked loop (ADPLL).…”

Heterodyne laser frequency stabilization for long baseline optical interferometry in space-based gravitational wave detectors

“…An issue that arises is the masking of reference channel phase noise induced frequency fluctuations in a differential measurement. Since both lasers receive their error signal from the demodulation of their cavity signal against the same reference NCO, phase noise ϕ R (t) as introduced in (16) will drive the frequency of both laser 1 and laser 2 according to (18). This will affect their absolute stability, but in a measurement of their differential frequency noise there is a strong common-mode rejection of this phase noise driven frequency modulation.…”

“…PM prototyping is based on Field-ProgrammableGate-Arrays (FPGAs) [18], programmable microchips normally used for custom interfacing and streamlining calculations in real-time systems. The beat notes are digitized by ADCs at a sampling rate in the 50 MHz to 80 MHz range, depending on the actual implementation, Simplified PM channel layout.…”

An electro-optical simulator of the space based gravitational wave detector Elisa

“…The signal of each DDS channel is split, amplified and mixed before going through a low-pass filter and being measured by the phasemeter developped at the Albert Einstein Institute in Hanover Germany (see [2]). DDS channel 1 represents the local arm (i.e.…”