Jiahao Huo

Polarization-Multiplexed DMT With IM-DD Using 2 × 2 MIMO Processing Based on SOP Estimation and MPBI Elimination

A simple polarization-multiplexed (PM) discrete multitone (DMT) system with intensity modulation and direct detection (IM-DD) is proposed for short-reach optical communications. Only four photodetectors (PDs) are required at the receiver, and no extra 90° hybrid and balanced detection is necessary. Novel digital signal processing (DSP) algorithms are proposed for state-of-polarization (SOP) estimation and subsequent mixed polarization beat interference (MPBI) elimination. These enable polarization demultiplexing and channel estimation to be implemented by a simple 2 × 2 multiple-input and multiple-output (MIMO) frequency-domain equalizer. The feasibility of the proposed PM-DMT-DD system and the effectiveness of the novel DSP algorithms are investigated via theoretical and simulation studies.

Single Channel 50 Gbit/s Transmission Over 40 km SSMF Without Optical Amplification and In-Line Dispersion Compensation Using a Single-End PD-Based PDM-SSB-DMT System

We experimentally demonstrate a single-end photodetector (PD) based polarization-division-multiplexing (PDM) system, in which the single-sideband orthogonal frequency-division multiplexing (SSB-OFDM) and discrete multitone (DMT) signals are modulated on two orthogonal polarizations respectively. Based on the frequency interleave design for dual-polarization, the spectral efficiency and chromatic dispersion tolerance can be optimized. We derive the theoretical model for the PDM-SSB-DMT system and detail the digital signal processing for demultiplexing at the receiver. We also successfully transmit a 50 Gb/s PDM-SSB-DMT signal with 14 GHz bandwidth over 40 km of uncompensated and unamplified standard single mode fiber (SSMF) with only 1.1 dB power penalty for a bit error rate of 3.8 × 10–3 relative to back-to-back transmissions.

Double-side EML for high speed optical short reach and metro applications

In this paper, the applications of recent developed double side electro-absorption modulated DFB laser (DS-EML) for high speed optical short reach and metro networking will be discussed.

Liquid-core photonic crystal fiber based plasmonic sensor with selective analyte channels

We present and numerically characterize a single liquid-core photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor. The two gold coated liquid analyte channels as big as core are placed near the core for easy excitation of free electrons to produce surface plasmon waves (SPWs). A sufficiently strong SPR is achieved by adjusting the size of the air holes between the core and the liquid analyte channels. The maximum positive refractive index (RI) sensitivity of3800nm/RIU is achieved in the sensing range of 1.45–1.46. The sensor shows a negative RI sensitivity once the RI of the analyte is greater than 1.5.

PDM-SSB-OFDM transmission over 80km SSMF based on a single photodetector at C-band

We experimentally demonstrated an 80-Gb/s PDM-SSB-OFDM transmission over 80km SSMF at C-band using a single photodetector. The two SSB-OFDM signals are placed with the different center frequency to share the guard band. The required OSNRs at 7% overhead HD-FEC threshold are 28.5dB and 29dB for BTB and 80km transmission respectively.

Techniques for performance evaluation of optical transmission system and module

In this paper, we discuss techniques for performance evaluation of optical transmission system and module, including short reach IM/DD and coherent transmission systems.

112-Gbit/s PDM-PAM4 transmission over 80-km SMF using digital coherent detection without optical amplifier

In this work, we experimentally demonstrated a 112 Gbit/s polarization-division-multiplexed (PDM) four-level pulse amplitude modulation (PAM4) transmission over 80-km single mode fiber (SMF) using digital coherent detection without optical amplifier and CD compensation for the short reach applications. Here, a signal-phase aided least-mean-square (SP-LMS) equalization algorithm is proposed to avoid the effects of carrier frequency offset and phase noise. Without additional carrier recovery algorithms, the PDM-PAM4 system shows good transmission performance. The received optical power (ROP) penalty is only about 0.2 dB after 80 km transmission comparing to back-to-back (BTB) transmission. A receiver sensitivity of -20dBm (at 7% FEC limit) can be reached after 80-km transmission.

112 Gb/s transmission over 80 km SSMF using PDM-PAM4 and coherent detection without optical amplifier.

Polarization-division-multiplexed (PDM) four-level pulse amplitude modulation (PAM4) with coherent detection is a promising low cost solution for 80 km inter-datacenter transmissions at 100 Gb/s and beyond. In this paper, three modified adaptive equalization algorithms for the PDM-PAM4 optical coherent systems, i.e. signal-phase aid least-mean-square (SP-LMS) algorithm, training multi-modulus algorithm (TMMA) and cascaded four-modulus algorithm (CMMA-4), are proposed and compared. Based on the proposed algorithms, 112 Gb/s PDM-PAM4 transmission over 80 km standard single mode fiber (SSMF) in C-band for a bit error rate (BER) below 3.8e-3 is successfully demonstrated without optical amplifier, chromatic dispersion (CD) pre-compensation and extra carrier recovery operations.

PDM PAM-4 with IM-DD using a simple MIMO DSP-based receiver for short reach communications

A simple MIMO DSP-based receiver is proposed for polarization multiplexing IM-DD system in short reach communication systems. The performance of the proposed receiver is demonstrated in a 224Gbit/s PDM-PAM4 10km IM-DD transmission system.