Bruno Dion

Photon counting techniques with silicon avalanche photodiodes.

The properties of avalanche photodiodes and associated electronics required for photon counting in the Geiger and the sub-Geiger modes are reviewed. When the Geiger mode is used, there are significant improvements reported in overall photon detection efficiencies (approaching 70% at 633 nm), and a timing jitter (under 200 ps) is achieved with passive quenching at high overvoltages (20-30 V). The results obtained by using an active-mode fast quench circuit capable of switching overvoltages as high as 15 V (giving photon detection efficiencies in the 50% range) with a dead time of less than 50 ns are reported. Larger diodes (up to 1 mm in diameter) that are usable in the Geiger mode and that have quantum efficiencies over 80% in the 500-800-nm range are also reported.

Photon-counting techniques with silicon avalanche photodiodes

Silicon avalanche photodiodes (APD) have been used for photon counting for a number of years. This paper reviews their properties and the associated electronics required for photon counting in the Geiger mode. Significant improvements are reported in overall photon detection efficiencies (approaching 75% at 633 nm), and timing jitter (under 200 ps) achieved at high over-voltages (20 - 30 V). Results obtained using an active-mode fast quench circuit capable of switching over-voltages as high as 20 V (giving photon detection efficiencies in the 50% range), are reported with a dead-time of less than 50 ns. Larger diodes (up to 1 mm diameter), usable in the Geiger mode, which have quantum efficiencies over 80% in the 500 - 800 nm range also are reported.

Highly hermetic fiber pigtailed electro-optics components for high-reliability avionics applications

We have developed methods to build and test highly hermetic electro-optic fiber pigtailed components for avionics applications in rugged environments. Our methods are compatible with cost-controlled volume production.

Overview of photon counting detectors based on CMOS processed single photon avalanche diodes (SPAD), InGaAs APDs, and novel hybrid (tube + APD) detectors

An overview of photon counting detection using CMOS compatible Single Photon Avalanche Diodes (SPAD) will be presented. These SPADs have a planar structure, and are processed using CMOS technology. The most promising aspect of this technology is the potential for building large area arrays that can be operated in photon counting mode - without the read-out noise and bulkiness associated with low noise CCD cameras. Using the iAQC (integrated Active Quenching Circuit) produced by Micro-Photonics Devices, a low noise InGaAs/InAlAs APD will be characterized for photon counting. Finally, Characterization data from a photon counting module using Intevac’s IPD’s (Tube+APD hybrd) will be presented for photon counting at 1064nm.

A 39-photon/bit direct-detection receiver at 810 nm, BER = 1x10-6, 60-Mbit/s QPPM

1 x 10 exp -6, 60 Mb/s QPPMMacGregor, Andrew; Dion, Bruno; Noeldeke, Christoph; Duchmann, Olivier

High coupling efficiency, highly robust optical fibre passive alignment

In this presentation we will present a new passive alignment method used to obtain highly efficient optical fibre coupling from VCSELs (vertical-cavity surface-emitting lasers). This method is compatible with low-cost, high-yield volume production of compact transceivers for applications in rugged environments. Coupling efficiencies larger than 94% have been obtained using this visually-aided passive alignment method for the coupling between a rounded-tip, 50μm core graded-index fibre and an 850nm VCSEL having an emission area diameter of approximately 25&mgr;m. Our alignment procedure was used to make compact, high-speed (2Gbps) transceivers that can work from -50 to 105oC. They have shown to be able to resist to mechanical shocks of more than 200g. They have also shown to maintain a constant coupling efficiency while being submitted to 35Grms random vibration tests around 200Hz.

Improved performance ladar receiver

Optical LADARs require high sensitivity near 1 nanowatt while also having fast recovery to overloads as high as 100W. Fast recovery is required in order to detect a secondary target from behind a bright target. In the current work, we have created a new family of LADAR receivers having a higher gain bandwidth product than most commercially available receivers. While maintaining the receiver bandwidth, a 4.8 × increase in responsivity can now be achieved. With cooling of the APD, these new receivers are offering more than a twofold time reduction of the NEP, allowing longer range coverage of the LADAR system. In addition, a new feature is the improvement of the overload recovery to 93ns from an laser pulse of 56mW, allowing close secondary target detection.

An overview of optical receiver module performance for eye-safe range finding, and lidar applications based on novel InGaAs APDs

Interest in eye-safe range-finding and lidar applications at 1060nm and 1550nm has increased dramatically in the last couple of years. However, APD receiver module performance has remained constant. This paper will present results from the characterization of an eye-safe module based on novel ultra -low excess noise InGaAs APD’s. The design basics of the APD and circuit will be discussed, with key performance characteristics highlighted. The principle of APD excess noise will be reviewed, and the effect it has on receiver module performance will be illustrated. A comparison of module performance between different receiver modules will be summarized.

Military and aerospace qualified transceiver modules

Manufactures of commercially available transceivers have reduced the cost of these modules by outsourcing production to low cost regions, and by engaging in multiple source agreements (MSA). Using key components developed for commercial transceivers, modules meeting Mil/Aero qualification requirements can be developed with minimal additional effort. This paper will examine the applications that may require qualified modules, packaging considerations for qualifying the modules, and additional functionality that are attractive to the Mil/Aero market.

High-speed 128-element avalanche photodiode array for optical computing applications

A high speed 128-element linear avalanche photodiode array, suitable for use in optical computing applications, has been designed and fabricated. The use of a guard ring surrounding the array results in low dark current and noise in the individual elements. Operation at gain 100 has shown good APD performance, with element dark currents less than 3 nA, noise less than 0.1 pA/Hz1/2, and rise and fall times about 1 ns. The design of the device makes it suitable for operation at frequencies up to 200 MHz. The paper includes the description of a solder bump mounting technique and multilayer substrate design which minimize capacitance between the elements, thereby maintaining low crosstalk. For further reduction of crosstalk, an alternative chip design is described in which a guard ring runs between all the elements.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.