New APD-based receivers providing tolerance to alignment jitter for binary optical communications

Receiver signal processing which leads to signal element waveforms satisfying Nyquist´s first and second criteria (with respect to the depressed optimum decision threshold encountered with high performance avalanche photodiode receivers) is considered. This results in an eye pattern for binary optical communications, which is well disposed around the depressed threshold. These new signal design targets are thus well suited to untimed transmission whilst also offering improved tolerance to alignment jitter when used in conventional fully retimed optical receivers. The practical realisation is considered to consist of signal shaping networks with responses closely approximating these new designs, and receiver performance is evaluated