Photonics

Abstract

A newly designed optical aluminosilicate glass that supports femotsecond laser written ultra-low loss optical waveguides is presented in this paper. Propagation losses as low as −0.020 ± 0.003 and −0.037 ± 0.003 dB cm−1 at 1310 and 1550 nm, respectively, are enabled by engineering the glass composition. Raman, Brillouin and electron microscopies are used to understand the origins of femtosecond laser-induced refractive index changes.

Abstract

This paper presents design and analysis of an optical memory and counter based on ultra-compact temporal integrators (INTs) using a graphene hybrid plasmonic add-drop ring resonator (GHP-ADRR) and pulley-type ring resonator (GHP-PRR) for optical signal processing. Due to the valuable features of graphene hybrid plasmonic technology, the footprint of these INTs is equal to 4 × 3.5 µm2 for GHP-ADRR and 5.4 × 3.6 µm2 for GHP-PRR. Also, the performance of the INTs has been analyzed by the three-dimensional finite-difference time-domain method in the frequency and time domains, and the accuracy of the results has been compared with those of the math counterparts and also key specifications of the first-order temporal INTs including phase jump, insertion loss, 3 dB bandwidth, rise time, integration time window, and energy efficiency have been investigated. Based on the results, both circuits have better performance than the photonic counterparts. Furthermore, the performance of these INTs has been evaluated in detail as a high-speed optical memory and counter. It has been illustrated that due to the greater quality factor of the GHP-PRR, this circuit has more accuracy for realizing the first-order integration, optical memory, and counter than the GHP-ADRR-based INT.

Abstract

We present ErAs:In(Al)GaAs-based terahertz transceiver modules, comprising transmitter and receiver components integrated on a single chip. The transceiver module is employed in a two-port single-path (TxRx-Rx) or 1.5-port pulsed free space photonic vector network analyzer setup, wherein the second receiver is an individual ErAs:InGaAs photoconductor. This configuration allows for simultaneous extraction of transmission and reflection coefficients or scattering parameters S21 and S11. The system achieves a peak dynamic range of ~59 dB for S21 and ~43 dB for S11 at a bandwidth reaching ~3.5 THz for the transmission and ~2.5 THz for the reflection path. These values are obtained by averaging over 500 traces at a scan rate of 4 Hz. The system exhibits superior frequency coverage compared to commercially available electronic vector network analyzers, thus offering a compact, cost-effective, broadband characterization solution for the benchmarking of terahertz devices and components.

Abstract

Efficient single-photon generation remains a big challenge in quantum photonics. A promising approach to overcome this challenge is to employ active multiplexing—repeating a nondeterministic photon pair generation process across orthogonal degrees of freedom and exploiting heralding to actively route the heralded photon to the desired single output mode via feedforward. The main barriers of multiplexing schemes, however, are minimizing resource requirements to allow scalability and the lack of availability of high-speed, low-loss switches. Here, we present an on-chip temporal multiplexing scheme utilizing thin-film lithium niobate (TFLN) photonics to effectively address these challenges. Our time-multiplexed source, operating at a rate of 62.2 MHz, enhances single-photon probability by a factor of 3.37 ± 0.05 without introducing additional multi-photon noise. This demonstration highlights the feasibility and potential of TFLN photonics for large-scale complex quantum information technologies.

Novel metamaterial-based architectures offer a promising platform for building mass-producible, reprogrammable schemes that perform computing tasks with light.

Really good overview of the components that go into a photonic integrated circuit.