Abstract:
Application of photomixer technologies to radio astronomy has been
developed under the collaboration between NAOJ and NTT Laboratories1-7. We
have evaluated high efficiency photomixers for W-band (75 - 110 GHz) and
D-band (110-170GHz) using UTC-PD8 photodiodes developed by NTT Photonics
Laboratories and fabricated by NTT Electronics Co. (NEL)9-10. Responsivity
of the photodiode is approximately 0.4 A/W. The photomixer output power is
measured for photocurrents ranging from 1mA to 10mA. The output power with
an optical input power of 0.7mW (0.28mA photocurrent) is estimated to be 1
W. This result indicates that the photomixers meet the requirement for the
ALMA photonic reference system without using the optical amplifier at each
antenna. We also measured output powers for 75GHz - 350GHz and noise
performances for 130GHz - 165GHz.
View a pdf version of ALMA Memo #516.
Last modified: 2005-03-03
alma-memos@nrao.edu