ABSTRACT
We present monolithically integrated multi-channel coherent L-band transmitter (Tx) and receiver (Rx) photonic integrated circuits (PICs) on InP substrates. The L-band PICs are able to provide post-forward error correction (FEC), error-free operation for dual-polarization (DP) 16-QAM coherent transmission at 33 Gbaud. These transceivers operate at 200 Gbps per channel and support 1.2 Tbps aggregate capacity per 6 channel PIC. We also demonstrate in this work a C + L band communication system with two C-band superchannels (2 x 6λ) and three L-band superchannels (3 x 6λ) over a 600 km link. The received signals all have Q > 7.7 dB, which is well above the error-free threshold of the FEC used in this work.
ABSTRACT
We report on the generation of continuous-wave widely tunable light between 2360 and 2530 nm using difference-frequency generation with a pump tuned between 938 and 952 nm and a signal tuned between 1490 and 1590 nm in a type-II phase-matched monolithic semiconductor waveguide. The device internal conversion efficiency is estimated to be 0.29% W(-1) cm(-2). This design which uses a single-sided Bragg reflection waveguide has the potential for on-chip spectroscopy, as well as environmental monitoring applications, where a tunable source of coherent radiation tuned between 2 and 3 µm wavelength is desired.
ABSTRACT
Creating miniature chip scale implementations of optical quantum information protocols is a dream for many in the quantum optics community. This is largely because of the promise of stability and scalability. Here we present a monolithically integratable chip architecture upon which is built a photonic device primitive called a Bragg reflection waveguide (BRW). Implemented in gallium arsenide, we show that, via the process of spontaneous parametric down conversion, the BRW is capable of directly producing polarization entangled photons without additional path difference compensation, spectral filtering or post-selection. After splitting the twin-photons immediately after they emerge from the chip, we perform a variety of correlation tests on the photon pairs and show non-classical behaviour in their polarization. Combined with the BRW's versatile architecture our results signify the BRW design as a serious contender on which to build large scale implementations of optical quantum processing devices.
ABSTRACT
The creation of monolithically integratable sources of single and entangled photons is a top research priority with formidable challenges: The production, manipulation, and measurement of the photons should all occur in the same material platform, thereby fostering stability and scalability. Here we demonstrate efficient photon pair production in a semiconductor platform, gallium arsenide. Our results show type-I spontaneous parametric down-conversion of laser light from a 2.2 mm long Bragg-reflection waveguide, and we estimate its internal pair production efficiency to be 2.0×10(-8) (pairs/pump photon). This is the first time that significant pair production has been demonstrated in a structure that can be electrically self-pumped and which can form the basis for passive optical circuitry, bringing us markedly closer to complete integration of quantum optical technologies.
ABSTRACT
We report the observation of type-0 phase-matching in bulk z-grown Al(x)Ga(1-x)As Bragg reflection waveguides where TM-polarized second-harmonic is generated using TM-polarized pump. For a pulsed pump with 1.8 ps temporal width and an average power of 3.3 mW, secondharmonic power of 16 microW was detected at 1567.8 nm. The normalized nonlinear conversion efficiency was obtained to be 2.84 x 10(3) %W(-1)cm(-2) in a 2.2 mm long waveguide. The highly versatile modal birefringence in Bragg reflection waveguides enabled the phase-matching of the three modalities; namely type-0 TM(omega)-->TM(2omega), type-I TE(omega)-->TM(2omega) and type-II TE(omega)+TMomega-->TE(2omega) interactions to simultaneously take place within a spectral bandwidth as small as 17 nm.
ABSTRACT
We demonstrate Type II difference-frequency generation (DFG) around 1550 nm in AlGaAs Bragg reflection waveguides using a pump around 778 nm and a signal within the C-band range. Difference-frequency power of 0.95 nW was obtained using a pump power of 62.9 mW and a signal power of 2.9 mW. Nonlinear conversion efficiency was estimated to be 2.5 x 10(-2)%/W(-1) cm(-2) in a 1.5-mm-long sample. Using numerical simulations, the phase-matching bandwidth was predicted to be 100 nm, while the measured DFG showed no sign of bandwidth limitation across a wavelength span of 40 nm, which was limited by instrumentation.
ABSTRACT
Efficient sum-frequency generation in epitaxial GaAs/AlGaAs waveguides is reported. Phase matching is achieved for type II nonlinear interaction using Bragg reflection waveguides. Continuous-wave signal and pump in 1550 nm wavelength window were used for upconversion of photons to the 775 nm region. For a pump and signal with powers of 0.69 mW and 0.35 mW, sum-frequency power of 35 nW was measured. The normalized conversion efficiency was estimated to be 298 %W(-1)cm(-2) in a device with a length of 2.2 mm. The bandwidth of the process was found to exceed 60 nm.
ABSTRACT
Bragg reflection waveguides are considered as monolithic sources of frequency correlated photon pairs generated using spontaneous-parametric down-conversion in a AlxGa1-xAs material system. The source described here offers unprecedented control over the process bandwidth, enabling bandwidth tunability between 1 nm and 450 nm while using the same wafer structure. This tuning is achieved by exploiting the powerful control over the waveguide dispersion properties afforded by the phase-matching technique used. The offered technology provides a route for realizing electrically pumped, monolithic photon pair sources on a chip with versatile characteristics.
ABSTRACT
We report the observation of continuous-wave second harmonic generation for a pump at 1559.9 nm in type-I phase-matched Bragg reflection waveguide using the GaAs/Al(x)Ga(1)1-(x)As material system. For an internal pump power of 94 mW, phase-matched second harmonic power of 23 nW was measured in a waveguide with a length of 1.96 mm and ridge width of 4 mum. The internal conversion efficiency of the process was estimated as 6.8 x 10-(3) %W-(1)cm-(2). The full-width at half-maximum bandwidth of the nonlinear process was found to be 0.91 nm.
