Optimizing bandwidth density in free space optical interconnects under the use of error correcting codes

Bandwidth density optimization of misaligned optical interconnects

“…The optical crosstalk noise results from the divergence nature of the laser beam as illustrated in Figures 1(a) and 1(c), while the detector amplifier thermal noise which is also known as the noise equivalent power (NEP) characterizes the employed photodetectors. As stated in [22], the bandwidth density (BD) of FSOI channels depends on the ratio of the data rate (R) of a single optical interconnect and the channel spacing (Δ) as ( 1):…”

“…where R is chosen such that the transmitter (modulator) can achieve this rate and the receiver (detector) can demodulate the laser beam efficiently. The relationship between the BD and signal to noise ratio (SNR) as well as other parameters of FSOIs system can be explored from the definition of R, which is defined as (20) [22],…”

“…where 𝑃 𝑜 is the transmitted power per optical channel in watt, S is the useful received optical signal by intended receiver, N is the optical crosstalk noise, and NEP is the noise equivalent power in watt per square root of Hertz. The definition of R in the above equation is derived based on the definition of SNR given by ( 3) [22].…”

“…The effect mainly reduces the SNR level required to achieve a predetermined bit error rate (BER) of the system. The BER is defined as in (12) [21], [22], [26], [27]:…”

“…However, the authors overestimated the crosstalk noise power in their work which led to suboptimum findings. Al-Ababneh and Int J Elec & Comp Eng ISSN: 2088-8708  Tawalbeh [22] studied the effect of fill factor of the photodetector array and the code rate of the ECCs on the bandwidth density of FSOI channels. It presented analytical and simulation results that demonstrate the importance of optimizing the fill factor which is defined as the ratio of the used detector diameter over the interconnect spacing.…”