Edited by two recognised experts, this book in two volumes provides a comprehensive overview of integrated optics, from modelling to fabrication, materials to integration platforms, and characterization techniques to applications. The technology is explored in detail, and set in a broad context that addresses a range of current and potential future research and development trends. Volume 1 begins with introductory chapters on the history of integrated optics technology, design tools, and modelling techniques. The next section of the book goes on to discuss the range of materials used for integrated optics, their deposition techniques, and their specific applications, including glasses, plasmonic nanostructures, SOI and SOS, and III-V and II-VI semiconductors. Volume 2 addresses characterization techniques, integrated optical waveguides and devices. A range of applications are also discussed, including devices for sensing, telecommunications, optical amplifiers and lasers, and quantum computing. The introductory chapters are intended to be of use to newcomers to the field, but its depth and breadth of coverage means that this book is also appropriate reading for early-career and senior researchers wishing to refresh their knowledge or keep up to date with recent developments in integrated optics.

A technique to estimate an incoming radio frequency (RF) signal angle of arrival (AOA) irrespective of the RF signal amplitude is presented. It is based on measuring the DC voltage at the output of two modules where each of them consists of an optical modulator, an optical filter and a photodetector. An RF signal amplitude-independent AOA can be obtained from the ratio of the two DC voltages. Experimental results are presented that demonstrate 0°–63° AOA measurement with <3° errors for an RF signal with three different power levels of 3.2, −0.3 and −3.6 dBm into the modulator.

The low energy germanium detector (LEGe) is in all aspects optimised for performance at low and moderate energies. It has specific advantages over conventional planar or coaxial detectors. LEGe is a kind of semiconductor detector commonly used in X-ray detection. It can display the spectrum of X-ray and record photon counts. Photon fluence is used to describe the radiation field by recording the number of incident photons. In order to take full advantage of the low energy response of this intrinsically thin window detector, LEGe cryostats are usually equipped with a beryllium window, thin front and side contact allowing spectroscopy from 3 keV and above. The rear contact is of less than full area which gives a lower detector capacitance compared to a planar device of similar size. It is widely used in low energy gamma spectroscopy, X-ray absorption spectroscopy, nuclear safeguards or X-ray fluorescence spectrometer and X-ray diffraction. Spectrum is an intuitional and accurate description of X-ray radiation. In this work, experiment was carried out to calibrate the detector and test the spectrum, and then to calculate the energy resolution. The experiment results about energy resolution (full width at half maximum) are 222 eV (@5.9 keV) and 519 eV (@122 keV).

The authors present an adaptive algorithm based on a non-linear regression model for mitigating time-varying etalon drifts in line-scanned optical absorption spectrometers. By dynamically varying the etalon spectral background using physically realistic degrees of freedom, the authors’ dynamic etalon fitting-routine (DEF-R) significantly increases the spectral baseline recalibration interval as compared to conventional fringe subtraction models. They provide an empirical demonstration of the efficacy of DEF-R using an on-chip 10 cm silicon waveguide for near-infrared methane absorption spectroscopy at 6057 cm⁻¹, which suffers significant etalon spectral noise due to reflections and multi-path interference from stochastic line-edge roughness imperfections. They demonstrate the corresponding improvement in both spectral clean-up and long-term stability via Allan-variance analysis. For the sensor presented here, application of DEF-R enables Gaussian-noise limited performance for more than 10² s and provides almost an order-of-magnitude improvement in stability time with respect to conventional baseline subtraction. Although DEF-R is applied here to an on-chip sensor embodiment, they envision their technique to be applicable to any absorption sensor limited by time-varying etalon drifts.

A detailed study of the performance analysis of a low-cost PIN/heterojunction bipolar transistor (HBT) opto-electronic integated circuit (OEIC) is described. Measured and of 54 and 57 GHz for 10 × 10 µm² HBTs were achieved for such a large emitter size. The base and collector regions of the transistor were utilised to form a PIN photodiode which has a dc responsivity and quantum efficiency of 0.5 A/W and 0.45, respectively, without antireflection coating at a wavelength of 1.55 µm. For both active devices, a model was realised taking all parasitic and physical-based impacts into account, for example, equivalent circuit of the pads surrounding the devices and transit delay time across the collector depletion region. The simulation results of the discrete passive and active elements showed good agreement with experimental measurements. The OEIC module was implemented in Keysight-advanced design system software with a three-stage preamplifier which has a transimpedance gain of 40 dB Ω and a −3 dB bandwidth of 18 GHz. This corresponds to a transimpedance-gain product of 1.8 THz. A series peaking inductor technique was used in the design, contributing to an enhancement in the opto-electrical bandwidth of >60%. The optical/electrical response offers a bandwidth of ∼15 GHz, adequate for up to 20 Gb/s data rate operation.

The waveguide gate-type mechanism on micro-channel plate substrate was .rstly put forward for the complex photo detection in Free space optical communication (FSO). Based on the losses of energy coupling between both Micro-channel plates (MCP), we further proposed waveguide gate-type complex detecting mechanism, which was veri.ed in electron optic system by vacuum testing. With the application of the complex detecting mechanism, the device performance has greatly improved, including higher space optical transfer and wider dynamic detecting range.

We present an ultra-compact graphene-on-plasmonic slot waveguide photodetector with active size of 90 nm × 100 nm × 6 μm, which shows a responsivity of 300 mA/W, a 1.5-dB bandwidth exceeding 70 GHz and 72 GBd high-data rate reception for communication band of 1550 nm.

Carrier-less coherent detection based on phase retrieval (PR) is demonstrated for optical higher-order modulation formats. The PR receiver based on a two-dimensional photodetector array and a discreteness-aware PR algorithm successfully demodulated 10-Gbaud optical 16QAM and OFDM signals without using any local lights or optical hybrids.

Quantum dot infrared photodetectors (QDIPs) are receiving attention as next generation infrared photodetectors that offer high-sensitivity and high-temperature operation. The realisation of QDIPs on silicon (Si) substrates offer further great advantages in terms of cost reduction and higher-resolution focal plane arrays. Indium arsenide/gallium arsenide QDIPs grown directly on on-axis Si (100) substrates are demonstrated. These are expected to further reduce fabrication costs by utilising both the monolithic integration of QDIPs with Si readout integrated circuits and also the bare substrate cost (compared with offcut Si substrates). In the device, the peak detectivity at a temperature of 32 K is measured to be 5.8 × 10⁷ cm Hz^1/2/W of 6.2 μm at a bias 0.6 V, with a corresponding responsivity of 27 mA/W. This result indicates that QD structures directly grown on on-axis Si substrates are very promising for the realisation of high-performance QDIPs with low fabrication cost.

This study theoretically analyses the performance of multiple quantum well infrared photodetector mainly with the variation of active layer doping. However, the effect of temperature and applied bias has also been studied. Results show that the effect of doping on the responsivity is significant whereas on the dark current is less significant. Effect of temperature on the dark current is more significant compared with that of doping concentration. Moreover, concerning the detectivity of the device, choice of doping plays a significant role on the detector.