Abstract

Multiwavelength sources are very important for dense wavelength-division-multiplexing (DWDM) high-capacity optical communications. Currently tunable laser diodes with single wavelength output are being vigorously investigated and commercialized to relieve inventory problem and improve dynamic add-drop functionality.^1,2 However simultaneous multiwave-length outputs have many advantages including no requirement of multiplexer, low cost, and simple configuration for DWDM test systems. There are three major categories to get simultaneous multiwavelength outputs such as multiwave-length Er-doped fiber lasers,^3–5 multiwavelength outputs from spectrum-sliced supercontinuum^6,7 and multiwavelength Raman fiber lasers.⁸ The multiwavelength output from spectrum-sliced supercontinuum is not a CW mode since the su-percontinuum sources are obtained by passing the short pulses from mode-locked lasers through spectrum-expansion optical components. It’s temporal pulse duration and repetition rate should be carefully designed to match the spectrum-expansion optical components. The multiwavelength Er-doped fiber lasers are useful, but outputs are not stable at room temperature due to homogeneous broadening of the lasing modes. These two types have usually polarized outputs. However, multiwavelength Raman fiber lasers can generate stable CW outputs. Such a Raman fiber laser with 19 channels was reported in 2001.⁸ In this paper we report simultaneous CW depolarized multiwavelength Raman fiber ring laser with 58 channels within 3 dB bandwidth and 50 GHz channel spacing at room temperature using fiber Fabry-Perot tunable filter (FFP-TF), 16 km dispersion-compensating fiber (DCF) and Raman pump laser diodes at 1428.2, 1445.8 and 1463.4 nm wavelengths. The degree of polarization (DOP) was measured as about 2.2% using HP8509B polarization analyzer. After de-multiplexing the multiwavelength outputs using 1 × 40 WDM demultiplexer, each channel’s DOP was also measured as about 2.2%. The spectral extinction ratio was more than 50 dB for entire channels. 1. Introduction Multiwavelength sources are very important for dense wavelength-division-multiplexing (DWDM) high-capacity optical communications. Currently tunable laser diodes with single wavelength output are being vigorously investigated and commercialized to relieve inventory problem and improve dynamic add-drop functionality.^1,2 However simultaneous multiwave-length outputs have many advantages including no requirement of multiplexer, low cost, and simple configuration for DWDM test systems. There are three major categories to get simultaneous multiwavelength outputs such as multiwave-length Er-doped fiber lasers,^3–5 multiwavelength outputs from spectrum-sliced supercontinuum^6,7 and multiwavelength Raman fiber lasers.⁸ The multiwavelength output from spectrum-sliced supercontinuum is not a CW mode since the su-percontinuum sources are obtained by passing the short pulses from mode-locked lasers through spectrum-expansion optical components. It’s temporal pulse duration and repetition rate should be carefully designed to match the spectrum-expansion optical components. The multiwavelength Er-doped fiber lasers are useful, but outputs are not stable at room temperature due to homogeneous broadening of the lasing modes. These two types have usually polarized outputs. However, multiwavelength Raman fiber lasers can generate stable CW outputs. Such a Raman fiber laser with 19 channels was reported in 2001.⁸ In this paper we report simultaneous CW depolarized multiwavelength Raman fiber ring laser with 58 channels within 3 dB bandwidth and 50 GHz channel spacing at room temperature using fiber Fabry-Perot tunable filter (FFP-TF), 16 km dispersion-compensating fiber (DCF) and Raman pump laser diodes at 1428.2, 1445.8 and 1463.4 nm wavelengths. The degree of polarization (DOP) was measured as about 2.2% using HP8509B polarization analyzer. After de-multiplexing the multiwavelength outputs using 1 × 40 WDM demultiplexer, each channel’s DOP was also measured as about 2.2%. The spectral extinction ratio was more than 50 dB for entire channels. This is the first report of a depolarized multiwavelength Raman fiber laser to our knowledge.

© 2002 Optical Society of America