2017 Session M3: Monolithic Circuits; Location: Senaatszaal

Novel Sampled Grating Design for High Precision, Multiple Wavelength DFB Laser Arrays

Song TANG, Lianping HOU, Iain EDDIE, Xiangfei CHEN, John H. MARSH1 University of Glasgow, School of Engineering, Glasgow, G12 8QQ, U.K.
CST Global Ltd., 4 Stanley Blvd, Blantyre, Glasgow, G72 0BN U.K.
Nanjing University, College of Engineering and Applied Sciences, Nanjing, 210093, China

Distributed feedback (DFB) semiconductor laser arrays are important components for wavelength division multiplexing networks. Recently, the reconstruction-equivalentchirp (REC) technique, based on sampled Bragg gratings (SBGs), has been applied to DFB laser arrays to give precise wavelength control [1]. Rather than operating at the 0th-order reflection of the Bragg grating, the lasers make use of either the +1st- or −1storder reflections. However, the effective coupling coefficient, κ, of a sampled grating is reduced substantially from that of a uniform grating, because of the reduced duty cycle of the grating and because the effective index modulation seen by ±1st-order reflections is only 1/π times that of the 0th-order reflection. To overcome this, designs of SBGs with phase shifted grating sections have been proposed and demonstrated in fibre lasers. In these structures, the (not required) 0th-order mode is suppressed while the index modulation experienced by reflection orders is enhanced [2]. Here we have designed gratings using the REC technique with π-phase shifted gratings for DFB diode lasers.


Tunable Deeply Etched V-notch Reflectors

Mohamad Dernaika, Ludovic Caro, Niall P. Kelly, Maryam Shayesteh
and Frank H. Peters
Tyndall National Institute, Lee Maltings, Cork, Ireland
Departement of Electrical and Electronic Engineering, University College Cork, College Road, Cork, Ireland
Physics Department, University College Cork, College Road, Cork, Ireland Mohamad.dernaika@tyndall.ie

Monolithically integrated and tunable semiconductor lasers are of great interest for dense wavelength division multiplexing (DWDM) and conventional (WDM) networks. Distributed Bragg reflector and Distributed feedback lasers have demonstrated excellent performance in terms of supplying a single mode output with high stability. However, Bragg based lasers require high resolution lithography and multiple epitaxial growth steps, which adds to the fabrication complexity, time and cost.


Latest Developments in Low-Cost Integrated WDM Transceivers for Telecom Applications

Effect Photonics, Torenallee 20, Eindhoven, 5617 BC, The Netherlands

The need to support the ever-increasing data traffic demands has accelerated the development of the underlying network technology. Pluggable transceivers have now become a norm and industry has acknowledged that Photonic Integration, regardless of the material platform, is vital to the continuous scaling of optical networks. Indium phosphide (InP) based photonic integrated circuit (PIC) technology offers high performance and cost advantages when applied in Dense Wavelength Division Multiplexing (DWDM) long haul communication systems [1] – both in highly parallel systems as well as in single wavelength, high bit-rate systems. However, for short and medium reach applications, the cost and integration challenges become increasingly stringent. In this paper, we review technology aspects and trade-offs for the application of InP-based PICs in mid-range (10-100 km) pluggable transceivers. Latest results on integrated high-speed modulators will be presented, together with the innovations that are required to cost-effectively apply PIC technology into commercial products.


Optical Frequency Domain Reflectometry for Characterization of Distributed Bragg Reflectors

Dan Zhao, Dzmitry Pustakhod, Luc Augustin, Jeroen Bolk, Kevin Williams and Xaveer Leijtens
Eindhoven University of Technology, Den Dolech 2, 5612 AZ, Eindhoven, the Netherlands
Smart Photonics, Horsten 1, 5612 AX, Eindhoven, the Netherlands

Introduction: The Distributed Bragg Reflector (DBR) is an important waveguide component for achieving wavelength selective filter functions. To enable the DBR as a standard building block in the COBRA platform [1], a main challenge is the development of a high precision lithography technology on indium-phosphide (InP) wafers. Recently, we have successfully used the 193 nm DUV scanner to fabricate DBRs on InP wafers, for the first time [2]. Another challenge is to characterize the reflection spectra of fabricated buried DBRs. With a direct measurement of reflections from anti-reflection coated chips, the coupling loss between the fibre and sample is hard to be estimated. With cleaved chips, which enable self-referenced analysis, the coupling loss can be estimated. However, the contribution of the Fabry–Pérot cavity introduced by the facets need to be de-embedded to separate the pure grating reflection. In the optical frequency domain reflectometry (OFDR) method, we can separate the facet reflections from the grating response in the spatial domain.


Fully Integrated Optical Frequency Domain Reflectometry

Luis A. BRU, Gloria MICÓ, Daniel PASTOR, B. GARGALLO, David DOMENECH, Ana M. SÁNCHEZ3, Josep M. CIRERA, Javier SANCHEZ, Carlos DOMÍNGUEZ3 and Pascual MUÑOZ
Photonic-IC group @ Photonic Research Labs, Universitat Politècnica de Valencia, Spain
VLC Photonics S.L., Ed9B-UPV, c/ Camino de Vera s/n, Valencia, Spain
IMB-CNM-CSIC, Campus Belaterra UAB, Barcelona, Spain dpastor@dcom.upv.es

Optical Frequency Domain Reflectometry (OFDR) [1-5] provides valuable complex information (modulus and phase) in the time and optical frequency domains for characterization of new technologies and integrated devices. The standard approach employing fiber based Mach-Zehnder Interferometers (MZI) [1-5] requires dedicated bulky set-ups, subject to demanding stabilization conditions, in order to preserve the light polarization states and the optical phase variations due to temperature changes over long fiber MZIs (>4-5 meters in some cases due to the required fiber pigtails couple light to/from the photonic chip). Here we propose for the first time to our knowledge a fully Integrated OFDR (IOFDR) approach, where all the required MZI structures are cointegrated with the Device Under Test (DUT). The device was fabricated on a 100mm Si wafer, composed of a SiO2 buffer (2.5μm thick, n=1.464) grown by thermal, following a LPCVD Si3N4 layer with thickness 300nm (n= 2.01) and a 2.0μm thick SiO2 (n=1.45) deposited by PECVD.