Programmable Spectral Filter in C-Band Based on Digital Micromirror Device

Abstract

Optical filters have been adopted in many applications such as reconfigurable telecommunication switches, tunable lasers and spectral imaging. However, most of commercialized filters based on a micro-electrical-mechanical system (MEMS) only provide a minimum bandwidth of 25 GHz in telecom so far. In this work, the programmable filter based on a digital micromirror device (DMD) experimentally demonstrated a minimum bandwidth of 12.5 GHz in C-band that matched the grid width of the International Telecommunication Union (ITU) G.694.1 standard. It was capable of filtering multiple wavebands simultaneously and flexibly by remotely uploading binary holograms onto the DMD. The number of channels and the center wavelength could be adjusted independently, as well as the channel bandwidth and the output power. The center wavelength tuning resolution of this filter achieved 0.033 nm and the insertion loss was about 10 dB across the entire C-band. Since the DMD had a high power handling capability (25 KW/cm2) of around 200 times that of the liquid crystal on silicon (LCoS) chip, the DMD-based filters are expected to be applied in high power situations.

Programmable High-Resolution Spectral Processor in C-band Enabled by Low-Cost Compact Light Paths

“…LCoS device combing with gratings can be further developed as programmable PSP for processing optical spectrum resources [15]. Recently, demonstrations have been reported on generating a reconfigurable PSP [15][16][17][18]. In [15], Gao et al proposed and demonstrated a flexible PSP based on a 4K LCoS with a minimum pixel spacing of 3.74 µm.…”

Editorial for the Special Issue on Optical MEMS

“…This special issue contains twelve research papers covering MEMS mirrors [1,2,3,4,5,6,7,8,9,10], MEMS variable optical attenuators (VOAs) [11], and tunable spectral filters [12]. These MEMS devices are based on three of the commonly used actuation mechanisms: electrothermal [1], electrostatic [2,3,4,5,6,7,11], and electromagnetic actuation [8,9,10]. MEMS optical scanners involving single mirrors are demonstrated or used in [1,2,3,8,9,10], while all other optical microsystems employ MEMS mirror arrays that are all based on DMDs [4,5,6,7].…”

“…These MEMS devices are based on three of the commonly used actuation mechanisms: electrothermal [1], electrostatic [2,3,4,5,6,7,11], and electromagnetic actuation [8,9,10]. MEMS optical scanners involving single mirrors are demonstrated or used in [1,2,3,8,9,10], while all other optical microsystems employ MEMS mirror arrays that are all based on DMDs [4,5,6,7]. This special issue also includes one review paper on metalens-based miniaturized optical systems [13].…”

“…Among the papers on single MEMS mirrors, two are focused on MEMS device fabrication [1,10], one on optimization of the driving signals [3], one on applying MEMS mirrors for confocal microscopy [2], and two on using MEMS mirrors to generate structural light patterns for 3D measurement [8,9]. Interestingly, there are several papers reporting various applications of DMDs, including spectral filtering [4], Hadamard spectroscopy [5], wavefront/aberration correction [6], and a tunable fiber laser [7].…”

“…Gao et al showed that a programmable filter based on a DMD can experimentally reach a minimum bandwidth as low as 12.5 GHz in C-band, where the number of channels and the center wavelength can be adjusted independently, as well as the channel bandwidth and the output power [4]. Lu et al employed a new Hadamard mask of variable-width stripes to improve the Signal-to-Noise Ratio (SNR) of a Hadamard transform near-infrared spectrometer by reducing the influence of stray light [5].…”