Design and Performance Analysis of Frequency-Shift Keyed Transmitter using Rapidly Tunable Lasers

Abstract

Optical Frequency Shift Keying (FSK) is a modulation scheme that encodes data in the wavelength of a carrier signal. Due to the large amount of optical bandwidth available in the erbium, 1.55-𝜇m telecom band, FSK can potentially utilize a wide spectrum to achieve multi-Gb/s channel bandwidths. For free-space laser communication (lasercom) applications, links are usually point-to-point, have narrow beamwidths, and do not need to share a transmitting medium with other signals. Therefore, many lasercom applications could exploit the benefits of FSK by trading off spectral efficiency with power efficiency. This thesis investigates an FSK transmitter implementation utilizing a single, fast tunable laser, allowing scalability to high values of M-ary FSK, where M represents the number of wavelengths in the symbol constellation. This work will propose and implement a design for an FSKmodulated transmitter using a modulated-grating, y-branch tunable laser, and assess its suitability for lasercom applications.