Variable rate, multi-format receiver design for 10 to 40 Gb/s DPSK and OOK formats.

We demonstrate a continuously-variable bit-rate receiver from 10 to 40 Gbit/s for DPSK demodulation. Unlike previous DPSK demodulators, this receiver is also capable of passing intensity modulated waveforms without distortion. Degradations imposed by receiver imperfections are presented and compared with a traditional DPSK delay-line interferometer.

A 10-Gbit/s EML link using detuned narrowband optical filtering.

In this paper, the effects of asymmetric narrowband optical filtering are investigated in a 10-Gbit/s optical communication link using integrated electro-absorption modulated lasers (EML). We investigate the effect of EML chirp on link performance as well as the optimal filter bandwidth and wavelength detuning. We show that both the phase response and the spectral narrowing of the filter will enable a longer distance transmission by interacting with the EML transient chirp and compensating for the fiber chromatic dispersion. Experimentally, an 8.75-GHz filter is shown to improve the link distance by 40 km from 65 to 105 km, when transmitting over standard single mode fiber.

Reach extension in 10-Gb/s directly modulated transmission systems using asymmetric and narrowband optical filtering.

Optical filtering has been used to extend the reach of directly modulated laser in 10Gb/s WDM systems via two separate mechanisms: narrowing the broadened spectrum, and converting frequency modulation into useful amplitude modulation. We investigate in detail, the impact of asymmetric and narrowband optical filtering at the transmitter or receiver. Experimental demonstrations for both shorter distance and long-haul like transmission using optical filtering are performed. The transmission reach is nearly doubled from <25-km to >45-km without dispersion compensation. 1400-km error-free transmission (Q > 15.6-dB) is further achieved over dispersion-managed link for a directly modulated DFB laser within an 8x10-Gb/s WDM system.

Optical signal-to-noise ratio monitoring of an 80 Gbits/s polarization-multiplexed return-to-zero differential phase-shift keying channel.

We propose and experimentally demonstrate an optical signal-to-noise ratio (OSNR) monitoring technique for an 80 Gbits/s polarization-multiplexed return-to-zero differential phase-shift keying channel utilizing a narrowband optical filter and a low-speed detector. A maximum power increment of 19.7 dB is measured at a radio frequency (rf) of 250 MHz for monitoring of OSNR up to 27 dB, insensitive to chromatic dispersion of 0-300 ps/nm and polarization-mode dispersion (PMD) of 0-50 ps.