We report a wavelength division multiplexed time-bin entangled photon pair source in telecom wavelength using a 10 μm radius Si ring resonator. This compact resonator has two add ports and two drop ports. By pumping one add port by a continuous laser, we demonstrate an efficient generation of two-wavelength division multiplexed time-bin entangled photon pairs in the telecom C-band, which come out of one drop port, and are then split into the signal and idler photons via a wavelength filter. The resonator structure enhances four-wave mixing for pair generation. Moreover, we demonstrate the double-port pumping where two counter propagating pump lights are injected to generate entanglement from the two drop ports simultaneously. We successfully observe the highly entangled outputs from both two drop ports. Surprisingly, the count rate at each drop port is even increased by twice that of the single-port pumping. Possible mechanisms of this observation are discussed. Our technique allows for the efficient use of the Si ring resonator and widens its functionality for variety of applications.
We report a wavelength division multiplexed time-bin entangled photon pair source in telecom wavelength using a 10 μm radius Si ring resonator. This compact resonator has two add ports and two drop ports. By pumping one add port by a continuous laser, we demonstrate an efficient generation of two-wavelength division multiplexed time-bin entangled photon pairs in the telecom C-band, which come out of one drop port, and are then split into the signal and idler photons via a wavelength filter. The resonator structure enhances four-wave mixing for pair generation. Moreover, we demonstrate the double-port pumping where two counter propagating pump lights are injected to generate entanglement from the two drop ports simultaneously. We successfully observe the highly entangled outputs from both two drop ports. Surprisingly, the count rate at each drop port is even increased by twice that of the single-port pumping. Possible mechanisms of this observation are discussed. Our technique allows for the efficient use of the Si ring resonator and widens its functionality for variety of applications.
We demonstrate time-bin entanglement generation in telecom wavelength using a 7 μm radius Si micro-ring resonator pumped by a continuous wave laser. The resonator structure can enhance spontaneous four wave mixing, leading to a photon pair generation rate of about 90-100 Hz with a laser pump power of as low as -3.92 dBm (0.41 mW). We succeed in observing time-bin entanglement with the visibility over 92%. Moreover, wavelength-tunability of the entangled photon pair is demonstrated by changing the operation temperature.
We report an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator. Thanks to suitable optimization, the source shows a large spectral brightness of 400\,pairs of entangled photons /s/MHz for 500μW pump power. Additionally, the resonator has been engineered so as to generate a frequency comb structure compatible with standard telecom dense wavelength division multiplexers. We demonstrate high-purity energy-time entanglement, i.e., free of photonic noise, with near perfect raw visibilities (>~98\%) between various channel pairs in the telecom C-band. Such a compact source stands as a path towards more complex quantum photonic circuits dedicated to quantum communication systems.
In this paper, we propose and demonstrate a scheme to generate discrete frequency entangled photon pairs based on a silicon micro-ring resonator. The resonator is placed in a Sagnac fiber loop. Stimulated by two pump lights at two different resonance wavelengths of the resonator, photon pairs at another two resonance wavelengths are generated along two opposite directions in the fiber loop, by the nondegenerate spontaneous four wave mixing in the resonator. Their states are superposed and interfered at the output ports of the fiber loop to generate frequency entangled photon pairs. On the other hand, since the pump lights come from two continuous wave lasers, energy-time entanglement is an intrinsic property of the generated photon pairs. The entanglements on frequency and energy-time are demonstrated experimentally by the experiments of spatial quantum beating and Franson-type interference, respectively, showing that the silicon micro-ring resonators are ideal candidates to realize complex photonic quantum state generation.
We report an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator. Thanks to suitable optimization, the source shows a large spectral brightness of 400 pairs of entangled photons /s/MHz for 500 μW pump power, compatible with standard telecom dense wavelength division multiplexers. We demonstrate high-purity energy-time entanglement, i.e., free of photonic noise, with near perfect raw visibilities (> 98%) between various channel pairs in the telecom C-band. Such a compact source stands as a path towards more complex quantum photonic circuits dedicated to quantum communication systems.
We report an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator. Thanks to suitable optimization, the source shows a large spectral brightness of 400 pairs of entangled photons /s/MHz for 500 μW pump power, compatible with standard telecom dense wavelength division multiplexers. We demonstrate high-purity energy-time entanglement, i.e., free of photonic noise, with near perfect raw visibilities (> 98%) between various channel pairs in the telecom C-band. Such a compact source stands as a path towards more complex quantum photonic circuits dedicated to quantum communication systems.
Integrated sources of single and entangled photons are currently one of the main topics in the field of integrated quantum optics [1]. Sources at telecom wavelength and compatible with the electronic \nintegrate circuit technology (CMOS) are particularly interesting for their compatibility with the existing fiber network and industrial fabrication processes [2]. As for classical communication, wavelength-division multiplexing (WDM,i.e. the possibility of simultaneously transmitting on the same channel different signals each encoded in a different frequency) could in principle be exploited also for quantum communication for increasing the transmission bit-rate. However, to date only few approaches have been proposed for generating wavelength multiplexing photon pairs in integrated platforms [3,4]. Moreover, until now no integrated photon source managed to achieve at the same time practical requirements such as narrow linewidths (required for quantum memories), compatibility with CMOS technology, multichannel emission, and stable long-term operation [5]. This is due to the fact that narrow linewidths are typically achieved with structures fundamentally incompatible with large-scale integration, while CMOS-compatible devices fail to achieve the high Q-factor required for exhibiting narrow linewidths. Here we report an integrated photon pair source based on a CMOS -compatible micro-ring resonator generating multiple, simultaneous, and independent photon pairs at different wavelengths distributed in a frequency comb, compatible with standard wavelength division multiplexing channels (DWDM, 200 GHz separation) and quantum memories (140 MHz linewidth), covering the full telecommunication band (L+C). We exploit a self-locked pumping scheme allowing an intrinsically stable operation even at the very low pump power levels typically used for photon pair generation. By enclosing the microring in an active external cavity[see Fig. 1(a)], the pump laser includes the microring itself, thus resulting in a passive self-locked pumping mechanism leading to several days of stable operation (compared to only few tens of minutes for standard schemes without active stabilization) [5]. The signal/idler photons are then separated according to their wavelength using a standard commercial DWDM filter, and then characterized by coincidence detection. Clear coincidence peaks [see Fig. 1(b)], with Coincidence to Accidental Ratios higher than 10, are obtained when selecting conjugate frequencies (while no coincidences are observed for non-conjugate signal/idler pair). Finally, Fig. 3(c) reports the measured heralded autocorrelation function, g (2)h, featured by a dip as low as 0.14<0.5, indicating the suitability of our device as heralded single photon source.\n