Transparent ceramics: Processing, materials and applications

The non-deterministic nature of photon sources is a key limitation for single-photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single-photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon-based correlated photon pair sources in the telecommunications band, demonstrating a 62.4% increase in the heralded single-photon output without an increase in unwanted multipair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two-photon interference, required at the core of optical quantum computing and quantum communication protocols.

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Integrated spatial multiplexing of heralded single-photon sources

The present invention provides an electro-optic ceramic material including lead, zinc and niobium having a propagation loss of less than about 3 dB/cm and a quadratic electro-optic coefficient of greater than about 1x10-16 m2/V2 at 20 °C at a wavelength of 1550 nm. The present invention also provides electro-optic devices including an electro-optic ceramic material including lead, zinc and niobium having a propagation loss of less than about 3 dB/cm and a quadratic electro-optic coefficient of greater than about 1x10-16 m2/V2 at 20 °C at a wavelength of 1550 nm. The materials and devices of the present invention are useful in optical communications applications such as intensity and phase modulation, switching, and polarization control.

Electro-optic ceramic material and device

The present invention provides a rare-earth ions doped, especially erbium and ytterbium doped transparent electro-optic gain ceramic material consisting lead, zirconium, titanium and lanthanum. The electro-optic gain ceramic material either has a linear electro-optic coefficient or a quadratic electro-optic coefficient, which is greater than about 0.3×10−16 m2/V2 for the latter, a propagation loss of less than about 0.3 dB/mm, and an optical gain of great than 1.5 dB/mm at a wavelength of about 1550 nm while optically pumped by a 1.4 watts diode laser at a wavelength of 970 nm at 20° C. The present invention also provides electro-optic devices including a rare-earth ions doped, especially erbium and ytterbium doped, transparent electro-optic gain ceramic material consisting lead, zirconium, titanium and lanthanum. The present invention also provides lossless optical devices and amplifiers with an operating wavelength in the range of 1450 nm to 1700 nm while optically pumped at a wavelength in the range of 880 nm to 1020 nm. The materials and devices of the present invention are useful in light intensity, phase and polarization control at a wavelength of about 1550 nm.

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Transparent electro-optic gain ceramics and devices

It is a fundamental challenge in quantum optics to deterministically generate indistinguishable single photons through non-deterministic nonlinear optical processes, due to the intrinsic coupling of single- and multi-photon-generation probabilities in these processes. Actively multiplexing photons generated in many temporal modes can decouple these probabilities, but key issues are to minimize resource requirements to allow scalability, and to ensure indistinguishability of the generated photons. Here we demonstrate the multiplexing of photons from four temporal modes solely using fibre-integrated optics and off-the-shelf electronic components. We show a 100% enhancement to the single-photon output probability without introducing additional multi-photon noise. Photon indistinguishability is confirmed by a fourfold Hong–Ou–Mandel quantum interference with a 91±16% visibility after subtracting multi-photon noise due to high pump power. Our demonstration paves the way for scalable multiplexing of many non-deterministic photon sources to a single near-deterministic source, which will be of benefit to future quantum photonic technologies. Deterministically generated single photons are useful for quantum communications, but the processes that create such light are often non-deterministic. Here, the authors enhance the single-photon output probability by multiplexing photons from four temporal modes using fibre-integrated optics.

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Active temporal multiplexing of indistinguishable heralded single photons

An optical modulator is provided to control the intensity of a transmitted or reflected light. In a transmission mode, a separator splits arbitrarily polarized light into two polarization rays and one is made to travel a separate path from the other. A recombiner causes the two rays to recombine at an output unless an electro-optic phase retarder changes the polarization of the two rays, in which case, both of them miss the output by an amount which is a function of the voltage on the retarder. A normally-off version with low polarization mode dispersion is obtained by changing the orientation of the recombiner. A normally-on version with low polarization mode dispersion is obtained with a passive polarization direction rotation. Similar results can be obtained in a reflection mode where the input and output are on the same side of the modulator. Versions using a GRIN lens are particularly suited to modulation of light out of and back into fiber-optic cables. The device can be operated as a variable optical attenuator, an optical switch, or a high speed modulator and is insensitive to polarization of the input light. A preferred material for the phase retarder is a hot-pressed ceramic lead lanthanum zirconate titanate composition.

High-speed electro-optic modulator

This paper reports optical studies on transparent electro-optic ceramics, 2%Er:PLZT and 0.5%Er-2.5%Yb:PLZT. Strong photoluminescence was observed in these polycrystalline ceramics in the 1550 nm region when pumped by diode lasers either at ∼970nm or ∼800nm. Efficient green upconversion luminescence was also observed. Co-doping Yb 3+ did enhance the Er 3+ emission in the 1550nm region when pumped with ∼970 nm diode laser. This work provides important information for developing microchip and high-power ceramic lasers using Er-doped PLZT ceramics.

Novel Electro-Optic Ceramic Materials for Microchip and High Power Lasers

This work presents a study of electro-optic and magneto-optic films made by a Metal-Organic Chemical Liquid Deposition (MOCLD) method. Electro-optic thin film, La-modified Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PLMNT) and magneto-optic thin film, rare earth doped yittrium iron garnet (YIG) have been grown at different conditions. Low temperature growth on buffered semiconductor substrates has been studied for semiconductor device integration. High quality PLMNT film with EO coefficient of 1x10 -16 (m/V) 2 was obtained with MOCLD. Doped and undoped YIG onto MgO and glass substrates and also onto buffered semiconductors were successfully deposited using MOCLD method. Several of these films had successful rotations that were of device quality. Based on these high quality functional films, two dimensional photonic bandgap waveguide structures were designed and simulated.

Hua Jiang

Papers

Transparent electro-optic gain ceramics and devices

High-speed electro-optic modulator

Novel Electro-Optic Ceramic Materials for Microchip and High Power Lasers

Electro-Optic and Magneto-Optic Photonic Bandgap Materials Kevin

Upconverting phosphor thermometry for high temperature sensing applications