Ultra-Low Noise Quad Photoreceiver for Space Based Laser Interferometric Gravity Wave Detection

We propose to design and develop 2x2 quad p-i-n InGaAs Photoreceivers having the following characteristics: (a) Active area diameter 0.75 mm; (b) Wavelength coverage 850 to 1700 nm, with responsivity of 0.7 A/W at 1064 nm; (c) Bandwidth up to 20 MHz for the individual quadrant; (d) Group Delay < 6 degrees/MHz; (e) Photodiode capacitance for individual quadrant of <1.5 pF at a reverse bias of 5V; (f) Cross talk between the neighboring quadrants of -45 to -50 dB; (g) Equivalent excess noise per quadrant <2 pA/sq. rt. Hz in the pass band; and (h) Noise Equivalent Power (NEP) due to excess noise <2.9 pW/sq. rt. Hz in the pass band. Six prototype quad photoreceivers will be delivered during the Phase II contract. These devices will be an enabling technology for the success of the Laser Interferometry Space Antenna (LISA) which proposes to detect gravity waves by using a space based interferometric sensor having a baseline of 5 million kilometers. Detection of gravity waves is crucial to our fundamental understanding of nature, including the origin of the universe and experimental verification of the theory of relativity.