Performance Improvement of 10Gb/s Direct Modulation OFDM by Optical Injection using Monolithically Integrated Discrete Mode Lasers

Investigation of the effects of laser non-linearity and RIN in direct modulation hybrid wired/wireless PON systems employing an integrated two section laser

“…Such integration allows for all photonic coupling to occur within a common substrate, where all functions are confined to one operating device [8]. This provides a cost effective device with a small footprint and eliminates issues such as polarization dependencies and lower power budgets (which is usually attributed to coupling losses).…”

“…More details on the device operation can be found in [15]. The additional etched features created on each section's ridge restrict the optical gain to that of a single operational mode, suppressing all others, enforcing single mode operation in that particular section [8].…”

“…1(b). The effects of nonlinearity and RIN are greatest at the relaxation oscillation, or resonant peak, frequency [8,11]. The resonant peak stems from the nonlinear interaction between photons and carriers in the laser cavity [16] and is a clear indication of frequencies at which laser nonlinearities occur.…”

“…In such directly modulated hybrid wired/wireless PONs, OFDM can be used both for wired and wireless services. A limiting factor associated with such systems is the induced nonlinearities from moderate bandwidth lasers, which can severely degrade the performance of multicarrier signals such as OFDM [8]. The nonlinear distortion of OFDM signals causes the loss of orthogonality between subcarriers which reside in the vicinity of the nonlinear region; this in turn results in inter-carrier interference [9].…”

“…It is advantageous to use integrated devices when employing optical injection, as this will lead to a compact and simple transmitter module. We have recently investigated the optical injection of a directly modulated laser (slave) with another laser diode (master), where both are monolithically integrated [8]. In this work we study the performance of this integrated device, in a hybrid wired/ wireless OFDM-PON distribution network.…”