An Optical Parametric Amplified Fiber Switch for Optical Signal Processing and Regeneration

An optical parametric amplified (OPA) fiber switch is described in this paper. This device switches input signals without shifting the wavelength by changing the polarization state of the signal using optical parametric amplification. The OPA fiber switch features ultra-broadband, highly efficient switching with a high contrast ratio. We experimentally test the prototype of the OPA fiber switch, which uses a highly nonlinear fiber. Optical demultiplexing of 160 Gb/s differential phase-shift keying (DPSK) signals is demonstrated in the whole C-band and shows that it provides almost penalty-free optical detection. The application of amplitude noise suppression with the OPA fiber switch by using parametric gain saturation is then proposed and demonstrated for a 160 Gb/s DPSK signal. When it is set to an amplitude-limiting condition, the OPA fiber switch successfully increases the optical signal-to-noise ratio by 4 dB and effectively suppresses the phase deterioration in 160 Gb/s DPSK transmission by increasing the system margin by more than 5 dB.

I. Introduction

All-Optical signal processing is a key technology for developing flexible photonic networks [1]. In advanced photonic networks, various kinds of signal processing will be necessary to create efficient, compact, low-power optical switching nodes. The functions required in optical signal processing include optical regeneration, wavelength conversion, optical amplification, optical routing, and signal monitoring [1]–[14]. An optical switch with fully transparent features in both the time and wavelength domains is a key device for providing these functions. A practical optical switch should have a broad bandwidth over the entire transmission band and should be capable of ultrahigh-speed operation at a data rate of 100 Gb/s or higher. Several types of optical switches have been demonstrated. However, though these optical switches have good temporal resolution, they often show an insufficient switching efficiency and wavelength restrictions. An ultrahigh-speed optical switch with high switching efficiency must therefore be developed before optical signal processing can be put into practice.