N141-013 TITLE: Ruggedized Wideband High Power Balanced Photodiode Receiver

TECHNOLOGY AREAS: Air Platform, Sensors, Electronics

ACQUISITION PROGRAM: JSF-MS

RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.

OBJECTIVE: Develop and package high-power balanced photodiodes for wideband Radio Frequency (RF) photonics receiver applications.

DESCRIPTION: The need for compact ruggedized microwave photonic links arises in avionic platforms as photonics continues to provide unique solutions in a wide variety of military applications. The requirements for high dynamic range links have previously been demonstrated but a lack of packaged components able to withstand harsh environments persists. Photodiodes presently limit many multi-octave applications presenting a need for ruggedized high-power wideband photodiode receivers. Balanced photodiodes provide a number of advantages in high power link applications. Shot-noise limited performance at high optical power with advantages in link gain, spurious-free dynamic range and noise figure can be achieved through balanced detection. To achieve high-fidelity multi-octave performance, one proven technique uses balanced photodiodes to suppress photodiode even-order distortions.

The multi-octave dynamic range of a photonic link is typically quantified in terms of second-order and third-order output intercept points, OIP2 and OIP3, respectively. Balanced photodiodes offer the ability to suppress second-order distortion so that the link is third-order limited by modulator nonlinearities. High-power balanced photodiodes and packaging of these devices, providing balanced photodetector receivers for wideband RF photonic air platform applications is desired. Balanced photodiodes that operate at 1.3 micron and 1.55 micron require, per balanced pair, a 20 GHz bandwidth at 100 mA (50 mA per photodiode) and 40 GHz bandwidth at 50 mA (25 mA photodiode). The targeted OIP3 is 40 dBm at 20 GHz for 50 mA per photodiode with a minimum OIP3 of 30 dBm. The minimum required rejection for both common-mode noise and even-order distortion is 20 dB. An OIP2 of approximately 70 dBm is required to maintain a conventional Mach-Zehnder modulator link to be third-order limited for 1 MHz instantaneous bandwidth, which requires 50 dBm OIP2 per photodiode. Linearity specifications should be met across 20GHz bandwidth. The output power at 1-dB compression for the total packaged balanced photodetector receiver is required to be 14 dBm, such that the receiver does not degrade an intrinsic Mach-Zehnder compression at 100 mA. Low back reflection, single-mode fiber coupled surface-illuminated or edge-illuminated photodiode designs are encouraged. The efficiency should be high enough to keep power consumption low, with a target of 0.7 A/W effective DC responsivity referenced to the fiber inputs. The balanced photodiodes are required to be packaged providing balanced photodetector receivers with fiber pigtails and standard RF connector outputs such as 2.92 mm coaxial connectors. The packaged devices should maintain the RF bandwidth and linearity specifications discussed above. A balanced photodetector receiver package is required that has a package height less than or equal to 5 mm, a package volume of approximately 2.5 cubic centimeters. The packaged balanced photodetector receiver must operate over a temperature range of -40 to 100 degrees Celsius, and maintain hermeticity and optical alignment upon exposure to air platform vibration, thermal shock, mechanical shock, and temperature cycling environments.

PHASE I: Design and analyze a new approach for balanced photodiodes. Demonstrate feasibility of balanced photodiode response with a supporting proof of principle bench top experiment showing path to meeting Phase II goals. Design and analyze a balanced photodetector receiver package prototype.

PHASE II: Optimize the balanced photodiode and packaged photodetector receiver designs from Phase I. Build and test the balanced photodetector receiver to meet design specifications. The prototype should be able to be tested in an RF photonic link with the minimum performance levels reached. Characterize the packaged balanced photodetector receiver over the full -40 to 100 degree Celsius ambient temperature range and air platform thermal shock, vibration and mechanical shock spectrum. If necessary perform root cause analysis and remediate balanced photodiode and balanced photodetector receiver package failures. Deliver balanced photodetector receiver package prototypes on evaluation boards.

PHASE III: Perform extensive balanced photodiode and balanced photodetector receiver package reliability and durability testing. Transition the balanced photodetector receiver technology to radar systems, electronic warfare systems, and communication systems on appropriate platforms.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The technology would find application in commercial systems such as fiber optic networks and telecommunications.

REFERENCES:
1. Pappert, S. (2011). RF Photonics: Status, Challenges and Opportunities. IEEE Avionics, Fiber-Optics and Photonics Conference.

2. Urick, V., et al., (2012). Wideband Analog Photonic Links: Some Performance Limits and Considerations for Multi-Octave Implementations. Proc. SPIE RF and Millimeter-Wave Photonics II, vol. 8259.

3. Abbas, G., et al., (Oct. 1985). A Dual-Detector Optical Heterodyne Receiver for Local Oscillator Noise Suppression. J. of Lightw. Technol., vol. LT-3, no. 5, pp. 1110-1122.

4. Hastings, A., et al., (Aug. 1, 2008). Suppression of Even-Order Photodiode Nonlinearities in Multi-octave Photonic Links. J. of Lightw. Technol., vol. 26, no. 15, pp. 2557-2562.

5. Li, Z. et al., (Dec. 12, 2011). High-power high-linearity flip-chip bonded modified uni-traveling carrier photodiode. Optics Express, vol. 19, no. 26, pp. B385-B390.

6. Q. Zhou, Q., et al., (May 15, 2013). High-Power V-Band InGaAs/InP Photodiodes. IEEE Photon. Technol. Lett., vol. 25, no. 10, pp. 907-909.

KEYWORDS: Balanced Photodiode, Receiver, RF Photonics, Ultra-Wideband, High-Power, Packaging

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