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A perfect storm of factors is driving data center operators and transceiver manufacturers to search for novel solutions that can address fiber-to-SiPh chip coupling challenges, to enable high-volume automated assembly and to drive down costs.

Using a proprietary high-speed laser writing technique, Optoscribe has produced a monolithic glass chip – OptoCplrLT™ – for low-loss coupling to SiPh grating couplers. Optoscribe’s solution uses low-loss light turning curved mirrors formed in the glass, instead of bent fiber arrays, to direct the light to or from the SiPh grating couplers. The curved mirrors simultaneously redirect and focus the light for optimal coupling to and from the Photonic Integrated Circuit (PIC) grating couplers. This prevents the need for bend-tolerant fiber solutions, which are often expensive, challenging and have some significant limitations in size and profile.

OptoCplrLT™ has a low-profile interface by design, less than 1.5mm height, which allows compact interface layouts that alleviate packaging constraints. Optoscribe’s solution is also compatible with industry standard materials and processes. For example, the glass chip has a coefficient of thermal expansion matched to the silicon chip, thereby maximising performance.

OptoCplrLT™ Specifications

Parameter Value Notes
Fiber type

 G657.A1 / G652

Operating wavelength 1280nm – 1625nm  
Insertion loss assembled <0.5dB   
Number of channels 2, 4, 8  Other channel count configurations are available on request 
Channel pitch 250μm Other channel pitch configurations are available on request 
Optical output angle 8 degrees to normal  Other angle options are available on request 
Working distance of focal plane 0-30μm (SiPh) Other working distances are available on request 
OptoCplrLT™ height <1.5mm  
Glass substrate material BF33  CTE 3.25 ppm/K


OptoCplrLT™ Schematic


Dimension Distance
D1 1.4
D2 2.6
D3 0.5
D4 0.515
D5 1
Dg 0.024
Hf 0.485



Key Advantages

• Simple single-stage passive fiber assembly

• Uses low-loss light turning curved mirrors which are formed in the glass

• Low profile interface; less than 1.5 mm in height, allowing compact interface layouts that alleviate packaging constraints

• Replaces difficult to assemble and expensive bent fiber arrays