EPS1000W
The entangled photon source (EPS) is an easytouse source of fibercoupled polarization entangled photons in the 1550 nm band. The EPS1000W generates polarization entangled signalidler pairs as well as a sequence of polarized alignment signals to aid in aligning subsequent measurement equipment (software selects if entangled photons or alignment photons are generated). The alignment signals allow measurement bases of polarization analyzers to be aligned despite unknown polarization transfer functions of the output fibers. The system is pulsed at a frequencylockable and tunable repetition rate, allowing multiple EPS’s to be synchronized for quantum interference experiments. Signal/idler photons are each generated over a 16 nm bandwidth, and ITUgrid filters are included to capture N photon pairs on 2⋅N fibers (N=3 is standard, but higher values available). The filtering system can be bypassed to allow customers to use their own filters. Many customizations are possible, including timebin entangled versions and tunable pump pulsewidth / wavelength, so please enquire about your particular needs.
Alignment Signal Operation  more information
Basic Features

Product Specifications
Attribute  Value  Units  Comments 

Pulse Rate  50  1,250  MHz  Extended rates available; electrical input and output signal for frequencylocking 
Filterisolated Photon Pairs  2  4  #  2⋅N: Number of ITU grid photon pairs isolated by filtering system; LC connectors standard 
Filter Bandwidth  0.3  nm  ITU grid 
Signal (or Idler) Spectral Bandwidth  16  nm  Central Wavelengths symmetric with respect to pump wavelength 
Pump Wavelength  1550.4  nm  Typical value; others available as an option 
Pump PulseWidth  100  ps  Typical value; other values available by request 
Pair Emission Probability (p)  5·10^{3}to 10^{4}  Probability each photon pair is emitted out of the filters (100 MHz rate); Entanglement quality depends on p**;  
CAR  10 to >100  Coincidence to accidental count ratio (CAR); depends on p  
Form Factor  3  U  3U 19" rackmountable box; 19x5.4x24 inches 
* Specifications are estimates subject to change without notice
**p is defined as the probability a pulse will emit a photon pair out of the filtering system (probability of a coincidence count using detectors of 100% quantum efficiency). Measured coincidence count rate through aligned polarization analyzers is CCmeas ≈ R⋅ 0.5⋅ p⋅ η2, where R is the pulse repetition rate and η is the net detection efficiency of a photon of optimal polarization from the EPS output (including single photon detection efficiency). Assuming R = 100 MHz, p=103, and η = 40%, the coincidence count rate is expected to be 8,000 per second for each photon pair. 
Typical Applications

Product Photo & Diagrams
Example TwoPhoton Interference measurement: 50 MHz gated singphoton avalanche diode (SPAD) detector, 1 second/point (peak is ~2 coincidence counts per million gates). 
Example Quantum State Tomography: 50 MHz gated SPAD, measured coincidence count maximum ~6 per million gates. 
EPS1000W Face Plate 