COTS Programme Plenary 5/03/15 A. J. Seeds Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, United Kingdom.

2 Highlights- Improvement in UTC Response New 7x15 Old 7x15 Optical power 50mW Devices were illuminated by two optical telecommunication wavelength lasers of different wavelength coupled to the device by a single lens ended fibre focused upon the facet, with bias applied via Coplanar probes The output was measured directly by an electrical spectrum analyser or as IF generated from a calibrated mixer module.. The previously fabricated devices exhibit a sharp fall-off (-10dB/10GHz approx.) in output at low frequencies due to parasitic capacitance The new devices exhibit a shallower fall-off (-3dB/10GHz approx.) resulting in a 40dB improvement in output above 90 GHz. With improved responsivity by prevention of electrode damage during via etching and optimisation facet cleaving it is expected that the response will be much improved. Output of UTCs up to 110 GHz

Highlights- Foundry OPLL PD MMI DBR MMI SOA MMI SOA Photonic Integrated Circuit OFCG input Heterodyne output Loop filter Offset frequency generator Phase detector InP-based widely tuneable and high purity THz source based on heterodyne principle PIC was fabricated within generic foundry The following elements are included on single Photonic Integrated Circuit (PIC): ⁻ Tuneable DBR lasers ⁻ optical waveguides and MMI couplers ⁻ PIN photodetectors ⁻ Semiconductor Optical Amplifiers ⁻ Electro-Optic Phase Modulator Fig. Schematic OPLL PIC. Fig. Fabricated OPLL PIC photograph. Dimensions 2 x 6 mm

Highlights- 100 Gb/s Wireless (c) (a) (b) (d) 8 Gbaud QPSK 10 Gbaud QPSK 4 Sc x 12.5 Gbaud QPSK 187 GHz 200 GHz 48Gbps 60Gbps 100Gbps

Highlights- QCL-Waveguide Integration Ribbon bonding test undertaken at RAL Central ridge of sample device has been bonded into waveguide block All images supplied by B. Ellison, RAL

THz Amplitude THz Phase Amplitude-phase clusters Aluminium Epidermis Upper dermis Lower dermis Sub-dermal fat Muscle tissue Sensitive to tissue properties Y. L. Lim et al. Biomedical Optics Express 5, (2014) Highlights- Biomedical Imaging

COTS Workplan Stage Gating

Item 4- Selected Programme Outcomes O1 Integrated synthesised heterodyne source – UCLEE 2PY M1.1: Demonstration of integrated OFCG to be used as a reference source to lock the integrated OPLL (UCLEE Lalitha Ponnampalam) (M44) M1.2: Demonstration of tuneable integrated optical phase lock loop to achieve signal linewidth <1kHz (UCLEE Lalitha Ponnampalam) (M48) 8

Item 4- Selected Programme Outcomes O2 Integrated THz heterodyne radiometers, with QCL Los, offering an IF bandwidth of 2GHz, and matching ESA’s stringent passive cooling requirements at 150K for space exploration – ULEEDS 3.4 PY; UCLEE 1PY M2.1: Demonstration of direct detection of THz QCL radiation with a Schottky diode in an integrated micro-machined waveguide. (ULEEDS) (M48) M2.2: Month 54: Demonstration of heterodyne detection using a THz QCL LO and Schottky diode exploiting micro-machined waveguides. (ULEEDS) (M54) M2.3: Locked heterodyne source with frequency spacing >3THz for locking of QCLs (UCLEE Lalitha Ponnampalam) (M57) M2.4: Demonstration of an integrated THz heterodyne radiometer with a specification (frequency, operating temperature, stability and tuneability) informed by the requirements for a future earth-observation mission. (ULEEDS) (M60) 9

Item 4- Selected Programme Outcomes O3: Integrated 270 GHz wireless system including transmitter and receiver for I/Q modulated signal generation and detection with 100 Gb/s capability– UCLEE 4PY M3.1: Design of antenna integrated UTCs exhibiting total emitted power greater than 0.5 mW at 270 GHz, 100 GHz 3 dB bandwidth and directivity up to 20 dBi (UCLEE Michele Natrella) (M41) M3.2: 270GHz wireless system design with I/Q modulated signal generation at 100Gbps including link budget calculation (UCLEE Haymen Shams) (M44) M3.3: Fabrication and evaluation of UTC-with integrated antenna for transmission up to 300 GHz at 0.5 mW with 3dB bandwidth in excess of 100GHz (UCLEE Chris Graham) (M47) M3.4: 270GHz wireless system demonstration for I/Q modulated signal with 100Gbps using an advanced modulation format (UCLEE Haymen Shams) (M58) 10

Item 4- Selected Programme Outcomes O4: Demonstration of near-field microscopy and gas sensing instrumentation– ULEEDS 1.7 PY; UCLEE 1PY; UCAM 1.6PY M4.1: Evaluation of near-field modulation of THz QCL self-mixing signals. (ULEEDS) (M42) M4.2: Demonstration of traditional gas cell sensing system exploiting the wide frequency tuning from the external grating THz QCL source. (UCAM) (M45) M4.3: Integration of near-field probes with a femtosecond-locked THz QCL. (UCLEE Michele Natrella) (M48) M4.4: Demonstration of a near-field microscope based on self-mixing. (ULEEDS) (M60) M4.5: Demonstration of a novel gas sensing system utilising the THz waveguide as the gas cell whilst exploiting the wide frequency tuning from the external grating THz QCL source. (UCAM) (M60) 11

Item 4- Selected Programme Outcomes O5: Portfolio demonstrating the use of THz spectroscopy for measurement and manipulation of quantum states LCN 4 PY; ULEEDS 3.4PY; UCAM 1.6PY M5.1: Evaluation of 1550 nm CW locking of THz QCLs based on (a) side-band generation, and (b) injection locking with a photoconductive mixer. (ULEEDS) (M42) M5.2: QCL-based spectroscopy of 2.34 THz crystal field level in LiYF4:Ho1% (LCN Rodolfo Hermans) (M45) M5.3: Evaluation of THz interactions with gated nanostructures. (ULEEDS) (M48) M5.4: Integration of a THz waveguide into a 1.2K cryostat to facilitate quantum control experiments with a tuneable QCL source (UCAM) (M48). M5.5: CW injection locking with a 2 THz UTC. (ULEEDS) (M48) 12

Item 4- Selected Programme Outcomes O5: Portfolio demonstrating the use of THz spectroscopy for measurement and manipulation of quantum states LCN 4 PY; ULEEDS 3.4PY; UCAM 1.6PY M5.6: Optimized CW locked THz QCL systems. (ULEEDS) (M54) M5.7: Demonstration of continuous electronic tuning of THz QCLs over > 200 GHz (ULEEDS) (M54) M5.8: Demonstration of quantum oscillations in LiYF4:Ho1% using THz pulse trains (LCN Rodolfo Hermans (M54) M5.9: Demonstration of applications for THz QCL based systems for the manipulation of quantum states. (ULEEDS) (M60) 13

Summary Major technical advances over the last 6 months Most anticipated milestones achieved Target outcomes defined Required milestones defined Resource requirements determined and sub-contract amendments in progress 14