Please use this identifier to cite or link to this item:
https://scholarbank.nus.edu.sg/handle/10635/172295
Title: | OPTICAL POWER SPECTRA, FILTERING AND THE IMPLEMENTATION OF AN FSK COHERENT HETERODYNE SYSTEM | Authors: | CHEW YONG HUAT | Issue Date: | 1997 | Citation: | CHEW YONG HUAT (1997). OPTICAL POWER SPECTRA, FILTERING AND THE IMPLEMENTATION OF AN FSK COHERENT HETERODYNE SYSTEM. ScholarBank@NUS Repository. | Abstract: | This work originated form a university research project and the initial proposal was to construct an FSK heterodyne coherent system. Chapter 1 gives an overview on the basic technology. It contains introductory materials for the subsequent chapters, particularly for Chapter 5, where a description on the system design is given. Chapter 2 gives a general study on the optical spectra and band occupancy of optical CPFSK signal. An exact expression for the PSD of optical CPFSK signal modulated by a random binary signal, taking the effect of intensity modulation which always accompanies the frequency modulation into consideration, is derived. The effects of linewidth, frequency modulation depth on the band occupancy of the CPFSK signal are studied and approximate expressions to compute these bandwidth are derived. In Chapter 3, the principle in achieving an active optical filter whose finesse can be tuned over a wide range with its insertion loss maintained nearly constant is given. The feasibility to use the two kinds of 3x3 couplers to form double-ring and single-ring resonators is studied in Chapter 4. One of the key study in this chapter is to investigate whether the free-spectral-range of the double ring resonator, formed by using 3x3 directional couplers, will be extended. In Chapter 5, the exact expression to compute the optical line spectrum of the laser field under sinusoidal modulation is derived. The accuracy of the measurement based on the approximate expression is revised. Experiment to measure the FM characteristics curves of the laser diodes is described. Finally, the practical implementation of a simple coherent FSK heterodyne system using single filter demodulation scheme is described and bit-error-rate performance is measured. Chapter 6 summarizes the main conclusions along with suggestions for future research direction. | URI: | https://scholarbank.nus.edu.sg/handle/10635/172295 |
Appears in Collections: | Ph.D Theses (Restricted) |
Show full item record
Files in This Item:
File | Description | Size | Format | Access Settings | Version | |
---|---|---|---|---|---|---|
b20214467.pdf | 7.06 MB | Adobe PDF | RESTRICTED | None | Log In |
Google ScholarTM
Check
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.