Integration of stimulation modalities (e.g. electrical, optical, and chemical) on a large array of neural probes can enable an investigation of important underlying mechanisms of brain disorders that is not possible through neural recordings alone. Furthermore, it is important to achieve this integration of multiple functionalities in a compact structure to utilize a large number of the mouse models. Here we present a successful optical modulation of in vivo neural signals of a transgenic mouse through our compact 2D MEMS neural array (optrodes). Using a novel fabrication method that embeds a lower cladding layer in a silicon substrate, we achieved a thin silicon 2D optrode array that is capable of delivering light to multiple sites using SU-8 as a waveguide core. Without additional modification to the microelectrodes, the measured impedance of the multiple microelectrodes was below 1 MΩ at 1 kHz. In addition, with a low background noise level (± 25 μV), neural spikes from different individual neurons were recorded on each microelectrode. Lastly, we successfully used our optrodes to modulate the neural activity of a transgenic mouse through optical stimulation. These results demonstrate the functionality of the 2D optrode array and its potential as a next-generation tool for optogenetic applications.

/pdf/in-vivo-optical-modulation-of-neural-signals-using-2qpeez07um.pdf

In vivo optical modulation of neural signals using monolithically integrated two-dimensional neural probe arrays.

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.

/pdf/ultra-high-bandwidth-quantum-secured-data-transmission-5a5zs5har2.pdf

Ultra-high bandwidth quantum secured data transmission

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.

/pdf/ultra-high-bandwidth-quantum-secured-data-transmission-5333veosyk.pdf

The interconnection of all things is developing a new diagram of future information networks. However, it is difficult to realize future applications with only one single technique. Collaboration between multiple advanced techniques is leading the way for the development of future information networks. Optical communication is an enabling technique to achieve high speed, long reach, and low latency communication, which plays an important role on the transformation of information networks. To achieve these advantages that caters to the characteristics of future information networks, collaboration of multiple advanced techniques with optical, which is called “optical plus X, could realize the vision of “all things connected with networks. In this paper, we focus on the collaboration between optical networks with other techniques, mainly discuss four representative aspects, which are “optical plus IP, “optical plus radio, “optical plus computing, and “optical plus AI. We discuss the challenges, timely works, and developing trends. Finally, we give the future visions for optical network towards a collaborative, converged and co-automatic optical network.

Towards converged, collaborative and co-automatic (3C) optical networks

State-of-the-art, prospects, and challenges of next-generation optical access technology based on tunable lasers are discussed. These considerations can also be applied to various backhaul and mobile fronthaul applications since these have similar characteristics and requirements, and have to share at least part of the optical distribution networks. Potential advantages of tunable lasers over competing approaches (e.g., seeded reflective transmitters) include higher bit-rate × reach products and better tolerance to reflections in the fiber plant. Today, the main issue is still the lack of available low-cost tunables with sufficient tuning range and launch power. However, significant progress has been made in the last few years to bring such lasers closer to commercialization. In this paper, we will review low-cost tunable laser approaches and report on latest technical results. We will also give an overview on current standardization activities and give an outlook on next-generation optical access, backhaul and fronthaul networks which also support active-site consolidation.

Access Networks Based on Tunable Lasers

In this book, Optical Wavelength Division Multiplexing (WDM) is approached from a strictly practical and application-oriented point of view. Based on the characteristics and constraints of modern fiber-optic components, transport systems and fibers, the textprovides relevant rules of thumb and practical hints for technology selection, WDM system and link dimensioning, and also for network-related aspects such as wavelength assignment and resilience mechanisms. Actual 10/40 Gb/s WDM systems are considered, and apreview ofthe upcoming 100 Gb/s systems and technologies for even higher bit rates is given as well.Key features:Considers WDM from ULH backbone (big picture view)down to PON access (micro view). Includes allmajor telecom and datacom applications. Provides the relevant background for state-of-the-art and next-gen systems. Offerspractical guidelines for system / link engineering.

Wavelength Division Multiplexing: A Practical Engineering Guide

In this article the operation of a novel, prototypical WDM-PON system with bi-directional data rates of up to 10.3 Gb/s is experimentally demonstrated. In the optical line terminal (OLT) a novel photonic integrated circuit (PIC) is deployed integrating an array of tunable lasers with Mach-Zehnder modulators and a star coupler. Wavelength control is achieved by a pilot-tone based scheme with a shared wavelength-locker (etalon). In the optical network unit (ONU) a novel Aluminium-containing laser is used, which has been specially designed for operation between 70deg C to 90deg C without requiring a thermo-electric cooler (TEC). For reduced cost and complexity the tunable laser is not equipped with an etalon. Instead it employs a generic contol algorithm, which is augmented by a pilot tone based scheme is used for centralized wavelength locking of all channels at the OLT.

Novel WDM-PON System with Shared Wavelength Locking and Full C-Band Tunability

We present a study on wavelength stability requirements for next generation passive optical network (PON) access systems in the light of induced timing jitter. Based on these findings different realization options of wavelength control methods for use in wavelength tunable PON systems are investigated.

Investigation of wavelength control methods for next generation passive optical access networks

The invention relates to a method of operating an optical transmission system ( 100 a , 100 b , 100 c ), wherein at least one optical data signal is transmitted over an optical transmission link ( 120 ), which particularly comprises at least one optical fiber ( 120 a ). The inventive method is characterized by modulating ( 200 ) said data signal with a test signal (s) having a predetermined modulation frequency f mod to obtain a modulated data signal (Pin), by receiving ( 210 ) a reflected portion (Pback) of said modulated data signal (Pin), and by determining ( 220 ) a fiber quality measure (a) depending on said received reflected portion (Pback) of said modulated signal (Pin).

Method of operating an optical transmission system, optical transmitter, and optical receiver

Next-generation WDM-PON solutions for metro and access systems will take advantage of remotely controlled wavelength-tunable ONUs to keep system costs as low as possible. For such a purpose, each ONU signal can be labeled by a pilot tone modulated onto the optical data stream. We report on the standardization status of this low-cost system in the new ITU-T G.metro draft recommendation, in the context of autonomous tuning. We also discuss some low-effort implementations of the pilot-tone labels and investigate the impact of these labels on the transmission channels.

Michael Eiselt

Papers

Wavelength Division Multiplexing: A Practical Engineering Guide

Novel WDM-PON System with Shared Wavelength Locking and Full C-Band Tunability

Investigation of wavelength control methods for next generation passive optical access networks

Method of operating an optical transmission system, optical transmitter, and optical receiver

Wavelength-agnostic WDM-PON system