Femtosecond Optical Frequency Comb: Principle, Operation and Applications

Femtosecond Optical Frequency Comb: Principle, Operation and Applications
Author: Jun Ye
Publisher: Springer Science & Business Media
Total Pages: 373
Release: 2006-06-15
Genre: Science
ISBN: 0387237917
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Over the last few years, there has been a convergence between the fields of ultrafast science, nonlinear optics, optical frequency metrology, and precision laser spectroscopy. These fields have been developing largely independently since the birth of the laser, reaching remarkable levels of performance. On the ultrafast frontier, pulses of only a few cycles long have been produced, while in optical spectroscopy, the precision and resolution have reached one part in Although these two achievements appear to be completely disconnected, advances in nonlinear optics provided the essential link between them. The resulting convergence has enabled unprecedented advances in the control of the electric field of the pulses produced by femtosecond mode-locked lasers. The corresponding spectrum consists of a comb of sharp spectral lines with well-defined frequencies. These new techniques and capabilities are generally known as “femtosecond comb technology. ” They have had dramatic impact on the diverse fields of precision measurement and extreme nonlinear optical physics. The historical background for these developments is provided in the Foreword by two of the pioneers of laser spectroscopy, John Hall and Theodor Hänsch. Indeed the developments described in this book were foreshadowed by Hänsch’s early work in the 1970s when he used picosecond pulses to demonstrate the connection between the time and frequency domains in laser spectroscopy. This work complemented the advances in precision laser stabilization developed by Hall.

Temporal Characterisation of Optical Frequency Combs

Temporal Characterisation of Optical Frequency Combs
Author: Chaitanya Suhas Joshi
Publisher:
Total Pages: 53
Release: 2013
Genre:
ISBN:
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The emerging field of silicon photonics allows us to develop more efficient networks that go beyond the capabilities and limitations of current electronic networks. Integrated photonic solutions in the present and in the future will allow us to keep pace with Moore's Law. Expertise in Silicon fabrication is at a very advanced level due to its use in semiconductor electronics. This expertise can be applied directly to fabricating optical devices using silicon as a medium of propagation for light. Silicon shows a high non linear optical response with high intensities. The high intensities required to see non linearity can be achieved by using waveguides etched into the silicon which confine light to a small mode area thus increasing intensity. One application for silicon waveguide devices is the development of frequency combs. A frequency comb can act as an accurate frequency standard over a very large bandwidth that can range from the visible all the way through to the Mid IR. Applications for frequency combs can be found in high precision spectroscopy, optical metrology, highly precise optical atomic clocks and so on. By the very nature of its frequency spectrum, we expect to see short pulses in the temporal domain from a frequency comb. This thesis examines the building of an autocorrelation setup that can measure these pulses to high accuracy. We explore the choice of detection scheme, the choice of setup and go on to discuss some results from the setup that was built as part of the work leading up to this date.

Frequency Combs for Spectroscopy and Optical Metrology

Frequency Combs for Spectroscopy and Optical Metrology
Author: Md Imrul Kayes
Publisher:
Total Pages:
Release: 2019
Genre:
ISBN:
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"Since their inception, optical frequency combs have created novel avenues for numerous applications such as molecular spectroscopy, atomic clocks, coherent communications, and microwave photonics. The future of frequency combs lies in exploring different comb generation technique, customized for specific applications. This thesis explores the synthesis of novel optical frequency combs in the near infrared wavelength region and the applications of such combs in the field of high-resolution spectroscopy and precise distance measurement. First, the generation of an electro-optic frequency comb with adjustable central wavelength and frequency spacing is experimentally demonstrated. This frequency comb is sourced from a single mode Brillouin fiber laser having an ultra-narrow linewidth that improves the overall phase noise performance of the comb spectral lines. A combined effect of electro-optic modulation, dispersion compensation, and fiber nonlinearity convert the continuous wave laser into a wideband optical frequency comb encompassing the C-band. Next, this frequency comb is used for a high-resolution distance measurement system that operates from the repetition rate modulation of the comb signal. The repetition frequency of the electro-optic comb is adjustable with a high dynamic range. Such broad tunablity of the repetition rate facilitates the measurement of distances with μm level precision. Such a system is also capable of motion tracking thanks to the rapid scan rate of the repetition frequency. Next, the application of electro-optic combs in high-resolution Fourier transform spectroscopy is demonstrated by measuring absorption lines of a chemical sample at 1.55 μm. The pulse train from a frequency comb, subject to a repetition rate modulation, stores the spectral response of a sample when sent to a length imbalanced interferometer. Such a system is equivalent to a dual-comb spectrometer but without the need for a complex phase matching mechanism. Finally, a novel laser resonator is developed for high-resolution dual-comb spectroscopy at 1.9 μm. This resonator supports two counter-propagating laser oscillations sharing a common cavity which relaxes the phase matching requirement for dual-comb spectroscopy. A proof-of-concept experiment demonstrated the measurement of absorption lines of ambient water vapor with a 100 MHz resolution. This approach holds great promise for dual-comb spectroscopy in the mid-infrared region where many chemicals have strong fundamental transitions"--

Numerical Modelling of Optical Frequency Comb Generation in Microresonators

Numerical Modelling of Optical Frequency Comb Generation in Microresonators
Author: Hamish Randle
Publisher:
Total Pages: 93
Release: 2012
Genre: Microresonators (Optoelectronics)
ISBN:
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Optical frequency combs are an exciting area of research with applications in Spectroscopy, optical sensing and telecommunications and in addition they have revolutionized the optical clock. Octave spanning frequency combs have been recently demonstrated using Microresonators. Made from a transparent material, these devices have spherical or toroidal shape and are typically between tens and hundreds of micrometers in size. The light is coupled in through a prism or fibre taper using evanescent wave coupling and circulates the cavity in highly confined whispering gallery modes. Due to the small modal cross section and long photon lifetimes there is a low threshold for nonlinear interaction. Researchers envisage these devices being used for low power microchip scale frequency comb sources in photonic devices. There has been much work on the experimental side of Microresonators, but little in the way of modelling, in particular the interesting nonlinear optical properties of these devices. This thesis describes a new method for modelling microresonator frequency combs, which reduces computational time compared to existing approaches. Two numerical simulation methods, the Newton-Raphson and split step Fourier, are chosen for their suitability to the study of steady state and dynamic regimes respectively. Simulations were performed using code written in MATLAB. We were able to simulate frequency combs with spans exceeding one octave of the spectral domain and containing over 1000 spectral modes, more than twice the number of modes than in any previously published study. The comb spectra were found to be in good agreement with experimental combs published by other researchers. Finally, some inroads were made to a numerical study of comb versatility.

Stable Optical Frequency Comb Generation and Applications in Arbitrary Waveform Generation, Signal Processing and Optical Data Mining

Stable Optical Frequency Comb Generation and Applications in Arbitrary Waveform Generation, Signal Processing and Optical Data Mining
Author: Sarper Ozharar
Publisher:
Total Pages: 130
Release: 2008
Genre: Data mining
ISBN:
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This thesis focuses on the generation and applications of stable optical frequency combs. Optical frequency combs are defined as equally spaced optical frequencies with a fixed phase relation among themselves. The conventional source of optical frequency combs is the optical spectrum of the modelocked lasers. In this work, we investigated alternative methods for optical comb generation, such as dual sine wave phase modulation, which is more practical and cost effective compared to modelocked lasers stabilized to a reference. Incorporating these comblines, we have generated tunable RF tones using the serrodyne technique. The tuning range was "1 MHz, limited by the electronic waveform generator, and the RF carrier frequency is limited by the bandwidth of the photodetector. Similarly, using parabolic phase modulation together with time division multiplexing, RF chirp extension has been realized. Another application of the optical frequency combs studied in this thesis is real time data mining in a bit stream. A novel optoelectronic logic gate has been developed for this application and used to detect an 8 bit long target pattern. Also another approach based on orthogonal Hadamard codes have been proposed and explained in detail. Also novel intracavity modulation schemes have been investigated and applied for various applications such as a) improving rational harmonic modelocking for repetition rate multiplication and pulse to pulse amplitude equalization, b) frequency skewed pulse generation for ranging and c) intracavity active phase modulation in amplitude modulated modelocked lasers for supermode noise spur suppression and integrated jitter reduction. The thesis concludes with comments on the future work and next steps to improve some of the results presented in this work.