Link to Relevant documents
- As of April 2019
Review in March 2018 Material by Yokogawa et al.,
- Main focus on the selection of the optical fibers
Review in August 2017 Material by Kambara et al.,
- Main focus on the readiness for the implementation.
Past Considerations (mostly back in 2012)
Optical Table Layout
Oscillator phase noise requirement for PLL local oscillator
Overview of Green Lock Scheme
Description of the blocks
When you combine two beams with power P, we get the beat note with amplitude of 2 alpha P Sin phi, where alpha is the contrast (0~1) and phi is the relative phase between the fields. Thus, the phase sensitivity is 2 alpha P [W/rad]. e.g. Two 1mW beams geneartes 4mWpp beat if the contrast is 1. The slope is 0.002 alpha W/rad.
For the broadband PD, InGaAs is not relevant because of the high junction capacitance. If we use Si PD (like FFD-100 phi=2.5mm), the responsivity is eta = 0.08 [A/W].
- BBPD Transimepedance and the shotnoise intercept current are assumed to be 1e3 [V/A] and 0.3 [mA], from the experience of LIGO BBPD.
Total gain is 1 [V/rad] if we assume alpha and P to be 0.5 and 12.5mW respectively.
- Shot noise
Shot noise of the modulated beam is described by <in^2> = 2 e [I0+1/2 dI Sin(phi)], according to N. Mio and K. Tsubono, Physics LettersA 164 (1992) 255-258. Does nonstationary part cancel because of the orthogonality of the RF and LO signals???
- Consider only the stationary part, in = sqrt(2 e I0). Thus in/eta/(2 alpha P) = sqrt(e / eta / alpha / P) [rad/rtHz]. This corresponds to 2.5e-8 rad/rtHz.
Frequency noise of NPRO
- 1e4/f [Hz/rtHz] according to R. Adhikari's PhD thesis.