"Introduction". In: Fiber-Optic Communication Systems
102 CHAPTER 3. OPTICAL TRANSMITTERS Figure 3.17: Longitudinal-mode selectivity in a coupled-cavity laser. Phase shift in the ext ...
3.4. CONTROL OF LONGITUDINAL MODES 103 phase with the optical field inside the laser cavity because of the phase shift occurring ...
104 CHAPTER 3. OPTICAL TRANSMITTERS Figure 3.18: Coupled-cavity laser structures: (a) external-cavity laser; (b) cleaved-coupled ...
3.4. CONTROL OF LONGITUDINAL MODES 105 over a wavelength range exceeding 100 nm. By controlling the current in the phase- contro ...
106 CHAPTER 3. OPTICAL TRANSMITTERS Figure 3.19: Schematic of a 1.55-μm VCSEL made by using the wafer-bonding technique. (After ...
3.5. LASER CHARACTERISTICS 107 3.5.1 CW Characteristics A rigorous derivation of the rate equations generally starts from Maxwel ...
108 CHAPTER 3. OPTICAL TRANSMITTERS Figure 3.20:P–Icurves at several temperatures for a 1.3-μm buried heterostructure laser. (Af ...
3.5. LASER CHARACTERISTICS 109 the power emitted from each facet for a FP laser with equal facet reflectivities. For FP lasers w ...
110 CHAPTER 3. OPTICAL TRANSMITTERS 3.5.2 Small-Signal Modulation The modulation response of semiconductor lasers is studied by ...
3.5. LASER CHARACTERISTICS 111 Figure 3.21: Measured (solid curves) and fitted (dashed curves) modulation response of a 1.55- μm ...
112 CHAPTER 3. OPTICAL TRANSMITTERS response of a 1.55-μm DFB laser at several bias levels [70]. The 3-dB modulation bandwidth,f ...
3.5. LASER CHARACTERISTICS 113 Figure 3.22: Simulated modulation response of a semiconductor laser to 500-ps rectangular current ...
114 CHAPTER 3. OPTICAL TRANSMITTERS integrated electroabsorption modulator or an external LiNbO 3 modulator (see Section 3.6). O ...
3.5. LASER CHARACTERISTICS 115 Figure 3.23: RIN spectra at several power levels for a typical 1.55-μm semiconductor laser. where ...
116 CHAPTER 3. OPTICAL TRANSMITTERS acts as a bandpass filter of bandwidthΩRto spontaneous-emission fluctuations. At a given fre ...
3.5. LASER CHARACTERISTICS 117 where the phase fluctuation∆φ(τ)=φ(t+τ)−φ(t)is taken to be a Gaussian random process. The phase v ...
118 CHAPTER 3. OPTICAL TRANSMITTERS Figure 3.24: Measured linewidth as a function of emitted power for several 1.55-μm DFB laser ...
3.6. TRANSMITTER DESIGN 119 Figure 3.25: Transmitters employing (a) butt-coupling and (b) lens-coupling designs. (After Ref. [97 ...
120 CHAPTER 3. OPTICAL TRANSMITTERS by using fibers that are tapered or have a lensed tip. An external lens also improves the co ...
3.6. TRANSMITTER DESIGN 121 Figure 3.26: Driving circuit for a laser transmitter with feedback control to keep the average optic ...
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