We present a design of balanced homodyne receivers suitable for ultra-low noise quantum applications such as continuous-variable key distribution and random number generation. For best bandwidth performance die-level low-parasitic photodiode together with low-noise high-speed transimpedance amplifier are explored planar lightwave circuit splitter chip serving photomixer. Bandwidths 750 MHz 2.6 ...

This report describes the results of a test of a new configuration of laser synthesizer for ALMA. The ALMA laser synthesizer is the source of the 1 LO photonic reference, in which a two-wavelength optical beatnote is transmitted by optical fiber from the ALMA AOS technical building to each of the array antennas. It is then used at the antenna as the reference for the first local oscillator, aft...

A new tunable cw far-infrared difference-frequency spectrometer has been developed by mixing two single-mode visible dye lasers separated by terahertz frequencies in an ultrahigh-speed photoconductor. The photomixer device is fabricated with submicrometer interdigital electrodes driving a broadband self-complementary spiral antenna on epitaxial low-temperature-grown (LTG) GaAs material. The LTG...

A terahertz photoconductive source structure with nano-grating electrodes is proposed. The resonance modes of the one-dimensional nano-grating and their affect the optical power absorption are studied. In addition, an approach for optimal design of the grating to maximize the photocurrent for different proposed DC biases, is presented. The dependence of the photocurrent on physical parameters o...

1.0 Introduction The use of "microwave holography" as the primary method of evaluating the ALMA antennas and setting their panels has been the project's baseline for several years. There is a long history of such measurements in radio astronomy (e.g., [3-5]). We are particularly drawing on experience at the NRAO in holographic measurements of the 12 M Telescope, 140 Ft Telescope, and VLA antenn...

In the last few years, remarkable progress has been made in ultrafast, and high-speed, high power photodetectors, as reviewed in [ 1,2]. In terms of applications, the high-speed photodetectors can be divided into four general different categories: (1) high-speed digital communication systems, (2) RF photonic systems, (3) ultrafast optoelectronic sampling, and (4) optoelectronic generation of mi...

The birefringence of LiInS2 (LIS) crystals in the THz frequency region is investigated by THz time-domain spectroscopy (THz-TDS). The experimental results indicate that LIS has large birefringence and low absorption in the THz frequency region. The optical properties of LIS are quantitatively determined. A sharp absorption caused by a TO-phonon resonance is observed at around 1.70 THz when the ...