Multi-cavity lasers

n this thesis we discuss the static and dynamic characteristics of a multi-cavity laser (MCL) consisting of an anti-reflection (AR) coated semiconductor laser in an external cavity with optical feedback from narrow fiber Bragg gratings (FBGs). The residual facet reflectivity of the AR coated facet plays a crucial role in determining characteristics of the MCL due to coupled cavity effects. This effect is exploited using a two section laser with optical feedback from two FBGs to demonstrate wavelength coding with a mode suppression ratio (MSR) of greater than ;The reflection spectrum of the FBG also plays a crucial role in determining the lasing characteristics of the device. The device has multiple lasing solutions at the same bias current even with a perfect AR coating if the bandwidth of the FBG is comparable to the mode spacing of the external cavity modes. Multiple lasing states is also possible due to coupled cavity effects.;The MCL is used to build an electro-optic flip-flop by switching between the multiple lasing states at the same bias current using electrical pulses to set and reset the device. The speed of operation of the electro-optic SR flip-flop is limited to about 100 MHz by the turn-on delay as well as timing jitter when switching between states by applying electrical pulses. Switching to a wavelength state of the flip-flop by coherently injecting photons into the device at that wavelength reduces the turn-on delay and timing jitter. The coherent optical pulse cannot be used to switch the flip-flop to a lasing state with higher carrier density.;A radio frequency (RF) signal tuned to the photon cavity round-trip time of a FBG defined cavity of the MCL, selects the wavelength defined by that BG as the lasing wavelength with a MSR of greater than...