The STARNET coherent WDM computer communication network: experimental transceiver employing a novel modulation format

Abstract

We have designed, constructed, and investigated an experimental transceiver employing a novel combined PSK and ASK modulation format for the STARNET coherent WDM computer communication network. Using this experimental transceiver, we show that it is possible to transmit and receive 2.488 Gb/s PSK circuit-switched data and 125 Mb/s ASK packetswitched data on the same lightwave. The experimental transceiver employs a custom integrated-optic LiNbOs modulator with both phase and amplitude sections, a 2.488 Gb/s tunable PSK heterodyne receiver, and a 125 Mb/s ASK heterodyne receiver. Both meivers function properly with error rates less than and a sensitivity of -32.1 dBm; the corresponding optimum ASK modulation depth is 0.57. The resulting network power budget is 26.6 dB.

Improve the performance of orthogonal ASK/DPSK optical label switching by DC-balanced line encoding

“…To obtain an optimum overall receiver sensitivity, the split ratio of the coupler in the receiver should be adjusted such that for the minimum received power both ASK and DPSK receivers operate at their sensitivity limits [6]. However, for simplicity, we assume that a 3-dB coupler is used at the receiver, yielding an optimum value of ER where the payload and label have the same receiver sensitivity; this dual operation requirement is coincident with previous research in [13] and [24]. The calculated receiver sensitivity curves versus payload ER are shown in Fig.…”

“…The orthogonal modulation technique encodes the label information on the optical carrier wave in a modulation format that is orthogonal to that of the payload, e.g., the label information is differential phase-shift keying (DPSK) modulated on the phase or frequency-shift keying (FSK) modulated on the optical frequency, while the payload is modulated on the amplitude of the carrier; such methods are termed amplitude shift keying (ASK)/DPSK [7]- [10] and ASK/FSK [11], [12] labeling. Alternatively, the orthogonal label modulation format can be ASK superimposed on a payload with DPSK or FSK modulation [13]- [17]. The feasibility of orthogonal modulation labeling has been successfully demonstrated for all-optical label swapping and packet transmission [7]- [17].…”

An optical FSK transmitter based on an integrated DFB laser-EA modulator and its application in optical labeling

“…In a direct detection system, the label information can be modulated in either differential phase-shift-keying (DPSK) or frequency-shift-keying (FSK) format. The feasibility of the optical DPSK labeling has been experimentally validated [3], [4]. However, this scheme imposes stringent requirements on the laser linewidth.…”

“…Several optical labeling methods have been proposed and demonstrated as possible solutions [1], in which the label is attached by time multiplexing or subcarrier multiplexing with the data payload. The optical label can also be realized by angle modulation that is orthogonal to the intensity-modulated (IM) payload [2], [3]. In a direct detection system, the label information can be modulated in either differential phase-shift-keying (DPSK) or frequency-shift-keying (FSK) format.…”

Performance of Manchester-coded payload in an optical FSK labeling scheme

“…Several optical labeling methods have been proposed [1], and optical frequency-shift keying (FSK) labeling is regarded as a feasible solution [2], [3].…”