ALMA Memo #396
A Photonic MM-Wave Reference and Local Oscillator Source

P. G. Huggard & B. N. Ellison (Rutherford Appleton Laboratory, Chilton)
P. Shen, N. J. Gomes & P. A. Davies (University of Kent, Canterbury)
W. P. Shillue, A. Vaccari, W. Grammer & J. M Payne(NRAO, Tucson)


2001-11-21

We report further progress on the development of a photonic mm-wave waveguide source suitable for application as a phase reference and as a local oscillator. The mm-wave power was generated in a W-band waveguide mount by the beating of two 1.55 µm laser beams in a modified commercial photodiode. Maximum optical to mm-wave power conversion efficiency of 1.8% was measured at 75 GHz, where an input power of +10 dBm yielded a non-saturated output power of -7.5 dBm. Measured output powers fell approximately as frequency^(-4) above 100 GHz, decreasing from about -10 dBm at 100 GHz to -40 dBm at 625 GHz. We remark that the mount is non-optimised for frequencies above 110 GHz, and so these measurements are a lower limit on the available power.

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